1
|
Guan A, He Z, Wang X, Jia ZJ, Qin J. Engineering the next-generation synthetic cell factory driven by protein engineering. Biotechnol Adv 2024; 73:108366. [PMID: 38663492 DOI: 10.1016/j.biotechadv.2024.108366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 03/21/2024] [Accepted: 04/22/2024] [Indexed: 05/09/2024]
Abstract
Synthetic cell factory offers substantial advantages in economically efficient production of biofuels, chemicals, and pharmaceutical compounds. However, to create a high-performance synthetic cell factory, precise regulation of cellular material and energy flux is essential. In this context, protein components including enzymes, transcription factor-based biosensors and transporters play pivotal roles. Protein engineering aims to create novel protein variants with desired properties by modifying or designing protein sequences. This review focuses on summarizing the latest advancements of protein engineering in optimizing various aspects of synthetic cell factory, including: enhancing enzyme activity to eliminate production bottlenecks, altering enzyme selectivity to steer metabolic pathways towards desired products, modifying enzyme promiscuity to explore innovative routes, and improving the efficiency of transporters. Furthermore, the utilization of protein engineering to modify protein-based biosensors accelerates evolutionary process and optimizes the regulation of metabolic pathways. The remaining challenges and future opportunities in this field are also discussed.
Collapse
Affiliation(s)
- Ailin Guan
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, China
| | - Zixi He
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, China
| | - Xin Wang
- West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Zhi-Jun Jia
- West China School of Pharmacy, Sichuan University, Chengdu 610041, China
| | - Jiufu Qin
- College of Biomass Science and Engineering, Sichuan University, Chengdu 610065, China.
| |
Collapse
|
2
|
She M, Zhou H, Dong W, Xu Y, Gao L, Gao J, Yang Y, Yang Z, Cai D, Chen S. Modular metabolic engineering of Bacillus amyloliquefaciens for high-level production of green biosurfactant iturin A. Appl Microbiol Biotechnol 2024; 108:311. [PMID: 38676716 PMCID: PMC11055739 DOI: 10.1007/s00253-024-13083-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 02/19/2024] [Accepted: 02/21/2024] [Indexed: 04/29/2024]
Abstract
As a kind of biosurfactants, iturin A has attracted people's wide attentions due to their features of biodegradability, environmentally friendly, etc.; however, high production cost limited its extensive application, and the aim of this research wants to improve iturin A production in Bacillus amyloliquefaciens. Firstly, dual promoter was applied to strengthen iturin A synthetase expression, and its yield was increased to 1.25 g/L. Subsequently, original 5'-UTRs of downstream genes (ituA, ituB, and ituC) in iturin A synthetase cluster were optimized, which significantly increased mRNA secondary stability, and iturin A yield produced by resultant strain HZ-T3 reached 2.32 g/L. Secondly, synthetic pathway of α-glucosidase inhibitor 1-deoxynojirimycin was blocked to improve substrate corn starch utilization, and iturin A yield was increased by 34.91% to 3.13 g/L. Thirdly, efficient precursor (fatty acids, Ser, and Pro) supplies were proven as the critical role in iturin A synthesis, and 5.52 g/L iturin A was attained by resultant strain, through overexpressing yngH, serC, and introducing ocD. Meanwhile, genes responsible for poly-γ-glutamic acid, extracellular polysaccharide, and surfactin syntheses were deleted, which led to a 30.98% increase of iturin A yield. Finally, lipopeptide transporters were screened, and iturin A yield was increased by 17.98% in SwrC overexpression strain, reached 8.53 g/L, which is the highest yield of iturin A ever reported. This study laid a foundation for industrial production and application development of iturin A, and provided the guidance of metabolic engineering breeding for efficient production of other metabolites synthesized by non-ribosomal peptide synthetase. KEY POINTS: • Optimizing 5'-UTR is an effective tactics to regulate synthetase cluster expression. • Blocking 1-DNJ synthesis benefited corn starch utilization and iturin A production. • The iturin A yield attained in this work was the highest yield reported so far.
Collapse
Affiliation(s)
- Menglin She
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, 368 Youyi Avenue, Wuchang District, Wuhan, 430062, Hubei, People's Republic of China
| | - Huijuan Zhou
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, 368 Youyi Avenue, Wuchang District, Wuhan, 430062, Hubei, People's Republic of China
| | - Wanrong Dong
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, 368 Youyi Avenue, Wuchang District, Wuhan, 430062, Hubei, People's Republic of China
| | - Yuxiang Xu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, 368 Youyi Avenue, Wuchang District, Wuhan, 430062, Hubei, People's Republic of China
| | - Lin Gao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, 368 Youyi Avenue, Wuchang District, Wuhan, 430062, Hubei, People's Republic of China
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, People's Republic of China
| | - Jiaming Gao
- Hubei Corporation of China National Tobacco Corporation, Wuhan, 430000, People's Republic of China
| | - Yong Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, 368 Youyi Avenue, Wuchang District, Wuhan, 430062, Hubei, People's Republic of China
| | - Zhifan Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, 368 Youyi Avenue, Wuchang District, Wuhan, 430062, Hubei, People's Republic of China
| | - Dongbo Cai
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, 368 Youyi Avenue, Wuchang District, Wuhan, 430062, Hubei, People's Republic of China.
| | - Shouwen Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, 368 Youyi Avenue, Wuchang District, Wuhan, 430062, Hubei, People's Republic of China.
| |
Collapse
|
3
|
You J, Wang Y, Wang K, Du Y, Zhang X, Zhang X, Yang T, Pan X, Rao Z. Utilizing 5' UTR Engineering Enables Fine-Tuning of Multiple Genes within Operons to Balance Metabolic Flux in Bacillus subtilis. BIOLOGY 2024; 13:277. [PMID: 38666889 PMCID: PMC11047901 DOI: 10.3390/biology13040277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Revised: 04/10/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024]
Abstract
The application of synthetic biology tools to modulate gene expression to increase yield has been thoroughly demonstrated as an effective and convenient approach in industrial production. In this study, we employed a high-throughput screening strategy to identify a 5' UTR sequence from the genome of B. subtilis 168. This sequence resulted in a 5.8-fold increase in the expression level of EGFP. By utilizing the 5' UTR sequence to overexpress individual genes within the rib operon, it was determined that the genes ribD and ribAB serve as rate-limiting enzymes in the riboflavin synthesis pathway. Constructing a 5' UTR library to regulate EGFP expression resulted in a variation range in gene expression levels exceeding 100-fold. Employing the same 5' UTR library to regulate the expression of EGFP and mCherry within the operon led to a change in the expression ratio of these two genes by over 10,000-fold. So, employing a 5' UTR library to modulate the expression of the rib operon gene and construct a synthetic rib operon resulted in a 2.09-fold increase in riboflavin production. These results indicate that the 5' UTR sequence identified and characterized in this study can serve as a versatile synthetic biology toolkit for achieving complex metabolic network reconstruction. This toolkit can facilitate the fine-tuning of gene expression to produce target products.
Collapse
Affiliation(s)
- Jiajia You
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
- Yixing Institute of Food and Biotechnology Co., Ltd., Yixing 214200, China
| | - Yifan Wang
- Department of Food Science and Technology, Texas A & M University, College Station, TX 77843, USA;
| | - Kang Wang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Yuxuan Du
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Xiaoling Zhang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Xian Zhang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Taowei Yang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Xuewei Pan
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
| | - Zhiming Rao
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China; (J.Y.); (K.W.); (Y.D.); (X.Z.); (X.Z.); (T.Y.)
- Yixing Institute of Food and Biotechnology Co., Ltd., Yixing 214200, China
| |
Collapse
|
4
|
Kalia VC, Patel SKS, Karthikeyan KK, Jeya M, Kim IW, Lee JK. Manipulating Microbial Cell Morphology for the Sustainable Production of Biopolymers. Polymers (Basel) 2024; 16:410. [PMID: 38337299 DOI: 10.3390/polym16030410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 01/25/2024] [Accepted: 01/30/2024] [Indexed: 02/12/2024] Open
Abstract
The total rate of plastic production is anticipated to surpass 1.1 billion tons per year by 2050. Plastic waste is non-biodegradable and accumulates in natural ecosystems. In 2020, the total amount of plastic waste was estimated to be 367 million metric tons, leading to unmanageable waste disposal and environmental pollution issues. Plastics are produced from petroleum and natural gases. Given the limited fossil fuel reserves and the need to circumvent pollution problems, the focus has shifted to biodegradable biopolymers, such as polyhydroxyalkanoates (PHAs), polylactic acid, and polycaprolactone. PHAs are gaining importance because diverse bacteria can produce them as intracellular inclusion bodies using biowastes as feed. A critical component in PHA production is the downstream processing procedures of recovery and purification. In this review, different bioengineering approaches targeted at modifying the cell morphology and synchronizing cell lysis with the biosynthetic cycle are presented for product separation and extraction. Complementing genetic engineering strategies with conventional downstream processes, these approaches are expected to produce PHA sustainably.
Collapse
Affiliation(s)
- Vipin C Kalia
- Department of Chemical Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Sanjay K S Patel
- Department of Chemical Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Kugalur K Karthikeyan
- Department of Chemical Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Marimuthu Jeya
- Marine Biotechnology Division, National Institute of Ocean Technology, Chennai 600100, India
| | - In-Won Kim
- Department of Chemical Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| | - Jung-Kul Lee
- Department of Chemical Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 05029, Republic of Korea
| |
Collapse
|
5
|
Zhang X, Chen H, Ouyang P, Liu X. Next-generation industrial biotechnology for low-cost mass production of PHA. Trends Biotechnol 2024; 42:135-136. [PMID: 37833199 DOI: 10.1016/j.tibtech.2023.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Accepted: 09/25/2023] [Indexed: 10/15/2023]
Affiliation(s)
- Xiaohan Zhang
- PhaBuilder Biotech Co. Ltd, Shunyi District, Beijing, 101309, China
| | - Huanyu Chen
- PhaBuilder Biotech Co. Ltd, Shunyi District, Beijing, 101309, China
| | - Pengfei Ouyang
- PhaBuilder Biotech Co. Ltd, Shunyi District, Beijing, 101309, China
| | - Xu Liu
- PhaBuilder Biotech Co. Ltd, Shunyi District, Beijing, 101309, China.
| |
Collapse
|
6
|
Aghaali Z, Naghavi MR. Biotechnological Approaches for Enhancing Polyhydroxyalkanoates (PHAs) Production: Current and Future Perspectives. Curr Microbiol 2023; 80:345. [PMID: 37731015 DOI: 10.1007/s00284-023-03452-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 08/19/2023] [Indexed: 09/22/2023]
Abstract
The benefits of biotechnology are not limited to genetic engineering, but it also displays its great impact on industrial uses of crops (e.g., biodegradable plastics). Polyhydroxyalkanoates (PHAs) make a diverse class of bio-based and biodegradable polymers naturally synthesized by numerous microorganisms. However, several C3 and C4 plants have also been genetically engineered to produce PHAs. The highest production yield of PHAs was obtained with a well-known C3 plant, Arabidopsis thaliana, upto 40% of the dry weight of the leaf. This review summarizes all biotechnological mechanisms that have been adopted with the goal of increasing PHAs production in bacteria and plant species alike. Moreover, the possibility of using some methods that have not been applied in bioplastic science are discussed with special attention to plants. These include producing PHAs in transgenic hairy roots and cell suspension cultures, making transformed bacteria and plants via transposons, constructing an engineered metabolon, and overexpressing of phaP and the ABC operon concurrently. Taken together, that biotechnology will be highly beneficial for reducing plastic pollution through the implementation of biotechnological strategies is taken for granted.
Collapse
Affiliation(s)
- Zahra Aghaali
- Department of Genetic and Plant Breeding, Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran.
| | - Mohammad Reza Naghavi
- Division of Biotechnology, Department of Agronomy and Plant Breeding, College of Agricultural and Natural Resources, University of Tehran, Karaj, Iran.
| |
Collapse
|
7
|
Dong H, Yang X, Shi J, Xiao C, Zhang Y. Exploring the Feasibility of Cell-Free Synthesis as a Platform for Polyhydroxyalkanoate (PHA) Production: Opportunities and Challenges. Polymers (Basel) 2023; 15:polym15102333. [PMID: 37242908 DOI: 10.3390/polym15102333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/12/2023] [Accepted: 05/13/2023] [Indexed: 05/28/2023] Open
Abstract
The extensive utilization of traditional petroleum-based plastics has resulted in significant damage to the natural environment and ecological systems, highlighting the urgent need for sustainable alternatives. Polyhydroxyalkanoates (PHAs) have emerged as promising bioplastics that can compete with petroleum-based plastics. However, their production technology currently faces several challenges, primarily focused on high costs. Cell-free biotechnologies have shown significant potential for PHA production; however, despite recent progress, several challenges still need to be overcome. In this review, we focus on the status of cell-free PHA synthesis and compare it with microbial cell-based PHA synthesis in terms of advantages and drawbacks. Finally, we present prospects for the development of cell-free PHA synthesis.
Collapse
Affiliation(s)
- Huaming Dong
- School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan 430205, China
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
| | - Xue Yang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin 300308, China
| | - Jingjing Shi
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin 300308, China
| | - Chunqiao Xiao
- School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, Wuhan 430205, China
| | - Yanfei Zhang
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308, China
- National Center of Technology Innovation for Synthetic Biology, Tianjin 300308, China
| |
Collapse
|
8
|
Natural antimicrobial systems protected by complex polyhydroxyalkanoate matrices for food biopackaging applications - A review. Int J Biol Macromol 2023; 233:123418. [PMID: 36731700 DOI: 10.1016/j.ijbiomac.2023.123418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 01/15/2023] [Accepted: 01/21/2023] [Indexed: 02/01/2023]
Abstract
Interest is growing in entrapping natural antimicrobial compounds (NACs) within polyhydroxyalkanoates (PHAs) to produce active food-biopackaging systems. PHAs are versatile polymeric macromolecules that can protect NAC activity by entrapment. This work reviews 75 original papers and 18 patents published in the last 11 years concerning PHAs as matrices for NACs to summarize the physicochemical properties, release, and antimicrobial activities of systems fabricated from PHAs and NACs (PHA/NAC systems). PHA/NAC systems have recently been used as active food biopackaging systems to inactivate foodborne pathogens and prolong food shelf life. PHAs protect NACs by increasing the degradation temperature of some NACs and decreasing their loss of mass when heated. Some NACs also transform the PHA/NAC systems into more thermostable, flexible, and resistant when interacting with PHAs while also improving the barrier properties of the systems. NAC release and activity are also prolonged when NACs are trapped within PHAs. PHA/NAC systems, therefore, represent ecologically friendly materials with promising applications.
Collapse
|
9
|
Che L, Jin W, Zhou X, Han W, Chen Y, Chen C, Jiang G. Current status and future perspectives on the biological production of polyhydroxyalkanoates. ASIA-PAC J CHEM ENG 2023. [DOI: 10.1002/apj.2899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Affiliation(s)
- Lin Che
- School of Environment, Harbin Institute of Technology State Key Laboratory of Urban Water Resource and Environment, 150090 Harbin China
- Shenzhen Engineering Laboratory of Microalgae Bioenergy Harbin Institute of Technology (Shenzhen), 518055 Shenzhen China
| | - Wenbiao Jin
- School of Environment, Harbin Institute of Technology State Key Laboratory of Urban Water Resource and Environment, 150090 Harbin China
- Shenzhen Engineering Laboratory of Microalgae Bioenergy Harbin Institute of Technology (Shenzhen), 518055 Shenzhen China
| | - Xu Zhou
- School of Environment, Harbin Institute of Technology State Key Laboratory of Urban Water Resource and Environment, 150090 Harbin China
- Shenzhen Engineering Laboratory of Microalgae Bioenergy Harbin Institute of Technology (Shenzhen), 518055 Shenzhen China
| | - Wei Han
- School of Environment, Harbin Institute of Technology State Key Laboratory of Urban Water Resource and Environment, 150090 Harbin China
- Shenzhen Engineering Laboratory of Microalgae Bioenergy Harbin Institute of Technology (Shenzhen), 518055 Shenzhen China
| | - Yidi Chen
- School of Environment, Harbin Institute of Technology State Key Laboratory of Urban Water Resource and Environment, 150090 Harbin China
| | - Chuan Chen
- School of Environment, Harbin Institute of Technology State Key Laboratory of Urban Water Resource and Environment, 150090 Harbin China
| | - Guangming Jiang
- School of Civil, Mining and Environmental Engineering University of Wollongong Wollongong NSW 2522 Australia
| |
Collapse
|
10
|
Vicente D, Proença DN, Morais PV. The Role of Bacterial Polyhydroalkanoate (PHA) in a Sustainable Future: A Review on the Biological Diversity. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:2959. [PMID: 36833658 PMCID: PMC9957297 DOI: 10.3390/ijerph20042959] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 06/18/2023]
Abstract
Environmental challenges related to the mismanagement of plastic waste became even more evident during the COVID-19 pandemic. The need for new solutions regarding the use of plastics came to the forefront again. Polyhydroxyalkanoates (PHA) have demonstrated their ability to replace conventional plastics, especially in packaging. Its biodegradability and biocompatibility makes this material a sustainable solution. The cost of PHA production and some weak physical properties compared to synthetic polymers remain as the main barriers to its implementation in the industry. The scientific community has been trying to solve these disadvantages associated with PHA. This review seeks to frame the role of PHA and bioplastics as substitutes for conventional plastics for a more sustainable future. It is focused on the bacterial production of PHA, highlighting the current limitations of the production process and, consequently, its implementation in the industry, as well as reviewing the alternatives to turn the production of bioplastics into a sustainable and circular economy.
Collapse
Affiliation(s)
| | - Diogo Neves Proença
- Department of Life Sciences, Centre for Mechanical Engineering, Materials and Processes, University of Coimbra, 3000-456 Coimbra, Portugal
| | | |
Collapse
|
11
|
Liu Y, Zhao W, Wang S, Huo K, Chen Y, Guo H, Wang S, Liu R, Yang C. Unsterile production of a polyhydroxyalkanoate copolymer by Halomonas cupida J9. Int J Biol Macromol 2022; 223:240-251. [PMID: 36347367 DOI: 10.1016/j.ijbiomac.2022.10.275] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/26/2022] [Accepted: 10/31/2022] [Indexed: 11/08/2022]
Abstract
Microbial production of bioplastics polyhydroxyalkanoates (PHA) has opened new avenues to resolve "white pollution" caused by petroleum-based plastics. PHAs consisting of short- and medium-chain-length monomers, designated as SCL-co-MCL PHAs, exhibit much better thermal and mechanical properties than PHA homopolymers. In this study, a halophilic bacterium Halomonas cupida J9 was isolated from highly saline wastewater and proven to produce SCL-co-MCL PHA consisting of 3-hydroxybutyrate (3HB) and 3-hydroxydodecanoate (3HDD) from glucose and glycerol. Whole-genome sequencing and functional annotation suggest that H. cupida J9 may possess three putative PHA biosynthesis pathways and a class I PHA synthase (PhaCJ9). Interestingly, the purified His6-tagged PhaCJ9 from E. coli BL21 (DE3) showed polymerizing activity towards 3HDD-CoA and a phaCJ9-deficient mutant was unable to produce PHA, which indicated that a low-substrate-specificity PhaCJ9 was exclusively responsible for PHA polymerization in H. cupida J9. Docking simulation demonstrated higher binding affinity between 3HB-CoA and PhaCJ9 and identified the key residues involved in hydrogen bonds formation between 3-hydroxyacyl-CoA and PhaCJ9. Furthermore, His489 was identified by site-specific mutagenesis as the key residue for the interaction of 3HDD-CoA with PhaCJ9. Finally, PHA was produced by H. cupida J9 from glucose and glycerol in shake flasks and a 5-L fermentor under unsterile conditions. The open fermentation mode makes this strain a promising candidate for low-cost production of SCL-co-MCL PHAs. Especially, the low-specificity PhaCJ9 has great potential to be engineered for an enlarged substrate range to synthesize tailor-made novel SCL-co-MCL PHAs.
Collapse
Affiliation(s)
- Yujie Liu
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Wanwan Zhao
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Siqi Wang
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Kaiyue Huo
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Yaping Chen
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Hongfu Guo
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China
| | - Shufang Wang
- Key Laboratory of Bioactive Materials for Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Ruihua Liu
- Tianjin Key Laboratory of Protein Science, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Chao Yang
- Key Laboratory of Molecular Microbiology and Technology for Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China.
| |
Collapse
|
12
|
Pan X, Tang M, You J, Hao Y, Zhang X, Yang T, Rao Z. A Novel Method to Screen Strong Constitutive Promoters in Escherichia coli and Serratia marcescens for Industrial Applications. BIOLOGY 2022; 12:biology12010071. [PMID: 36671763 PMCID: PMC9855843 DOI: 10.3390/biology12010071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 12/18/2022] [Accepted: 12/28/2022] [Indexed: 01/04/2023]
Abstract
Promoters serve as the switch of gene transcription, playing an important role in regulating gene expression and metabolites production. However, the approach to screening strong constitutive promoters in microorganisms is still limited. In this study, a novel method was designed to identify strong constitutive promoters in E. coli and S. marcescens based on random genomic interruption and fluorescence-activated cell sorting (FACS) technology. First, genomes of E. coli, Bacillus subtilis, and Corynebacterium glutamicum were randomly interrupted and inserted into the upstream of reporter gene gfp to construct three promoter libraries, and a potential strong constitutive promoter (PBS) suitable for E. coli was screened via FACS technology. Second, the core promoter sequence (PBS76) of the screened promoter was identified by sequence truncation. Third, a promoter library of PBS76 was constructed by installing degenerate bases via chemical synthesis for further improving its strength, and the intensity of the produced promoter PBS76-100 was 59.56 times higher than that of the promoter PBBa_J23118. Subsequently, promoters PBBa_J23118, PBS76, PBS76-50, PBS76-75, PBS76-85, and PBS76-100 with different strengths were applied to enhance the metabolic flux of L-valine synthesis, and the L-valine yield was significantly improved. Finally, a strong constitutive promoter suitable for S. marcescens was screened by a similar method and applied to enhance prodigiosin production by 34.81%. Taken together, the construction of a promoter library based on random genomic interruption was effective to screen the strong constitutive promoters for fine-tuning gene expression and reprogramming metabolic flux in various microorganisms.
Collapse
Affiliation(s)
- Xuewei Pan
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Mi Tang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Jiajia You
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Yanan Hao
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Xian Zhang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| | - Taowei Yang
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
- Correspondence: ; Tel.: +86-510-85916881
| | - Zhiming Rao
- Key Laboratory of Industrial Biotechnology of the Ministry of Education, Laboratory of Applied Microorganisms and Metabolic Engineering, School of Biotechnology, Jiangnan University, Wuxi 214122, China
| |
Collapse
|
13
|
Zhang X, Zhao C, Shao M, Chen Y, Liu P, Chen G. The roadmap of bioeconomy in China. ENGINEERING BIOLOGY 2022; 6:71-81. [PMID: 36968339 PMCID: PMC9995158 DOI: 10.1049/enb2.12026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 11/23/2022] [Indexed: 12/05/2022] Open
Abstract
The bioeconomy drives the development of life science and biotechnology as a blueprint for the future development of human society, and offers a cross-cutting perspective on the societal transformation towards long-term sustainability and the transition away from the non-renewable economy. Moreover, the sustainable bioeconomy strategies are consistent with the United Nation's (UN) Sustainable Development Goals (SDG) and are becoming the centre of the achievement for SDG. The Chinese '14th Five-Year Plan for Bioeconomy Development' (2021-2025), including the development goals of China's bioeconomy containing biomedicine, agriculture, bio-manufacturing and bio-security as a strategic priority, is discussed. The plan offers three pathways to improve bioeconomy, including technological innovation, industrialisation and policy supports. Finally, it concludes China's first bioeconomy development plan as a success, suggesting the key role of industrial biotechnology in bioeconomy.
Collapse
Affiliation(s)
- Xu Zhang
- Key Laboratory of Industrial Biocatalysis, Ministry of Education Department of Chemical Engineering Center of Synthetic and Systems Biology Tsinghua‐Peking Center of Life Sciences Tsinghua University Beijing China
| | - Cuihuan Zhao
- Center of Synthetic and Systems Biology School of Life Sciences Tsinghua University Beijing China
| | - Ming‐Wei Shao
- Center of Synthetic and Systems Biology School of Life Sciences Tsinghua University Beijing China
| | - Yi‐Ling Chen
- Center of Synthetic and Systems Biology School of Life Sciences Tsinghua University Beijing China
| | - Puyuan Liu
- Faculty of Science University of Waterloo Waterloo Ontario Canada
| | - Guo‐Qiang Chen
- Key Laboratory of Industrial Biocatalysis, Ministry of Education Department of Chemical Engineering Center of Synthetic and Systems Biology Tsinghua‐Peking Center of Life Sciences Tsinghua University Beijing China
- Center of Synthetic and Systems Biology School of Life Sciences Tsinghua University Beijing China
| |
Collapse
|
14
|
Novel Production Methods of Polyhydroxyalkanoates and Their Innovative Uses in Biomedicine and Industry. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238351. [PMID: 36500442 PMCID: PMC9740486 DOI: 10.3390/molecules27238351] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/25/2022] [Accepted: 11/27/2022] [Indexed: 12/03/2022]
Abstract
Polyhydroxyalkanoate (PHA), a biodegradable polymer obtained from microorganisms and plants, have been widely used in biomedical applications and devices, such as sutures, cardiac valves, bone scaffold, and drug delivery of compounds with pharmaceutical interests, as well as in food packaging. This review focuses on the use of polyhydroxyalkanoates beyond the most common uses, aiming to inform about the potential uses of the biopolymer as a biosensor, cosmetics, drug delivery, flame retardancy, and electrospinning, among other interesting uses. The novel applications are based on the production and composition of the polymer, which can be modified by genetic engineering, a semi-synthetic approach, by changing feeding carbon sources and/or supplement addition, among others. The future of PHA is promising, and despite its production costs being higher than petroleum-based plastics, tools given by synthetic biology, bioinformatics, and machine learning, among others, have allowed for great production yields, monomer and polymer functionalization, stability, and versatility, a key feature to increase the uses of this interesting family of polymers.
Collapse
|
15
|
Halomonas spp., as chassis for low-cost production of chemicals. Appl Microbiol Biotechnol 2022; 106:6977-6992. [PMID: 36205763 DOI: 10.1007/s00253-022-12215-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/26/2022] [Accepted: 09/27/2022] [Indexed: 11/02/2022]
Abstract
Halomonas spp. are the well-studied platform organisms or chassis for next-generation industrial biotechnology (NGIB) due to their contamination-resistant nature combined with their fast growth property. Several Halomonas spp. have been studied regarding their genomic information and molecular engineering approaches. Halomonas spp., especially Halomonas bluephagenesis, have been engineered to produce various biopolyesters such as polyhydroxyalkanoates (PHA), proteins including surfactants and enzymes, small molecular compounds including amino acids and derivates, as well as organic acids. This paper reviews all the progress reported in the last 10 years regarding this robust microbial cell factory. KEY POINTS: • Halomonas spp. are robust chassis for low-cost production of chemicals • Genomic information of some Halomonas spp. has been revealed • Molecular tools and approaches for Halomonas spp. have been developed • Halomonas spp. are becoming more and more important for biotechnology.
Collapse
|
16
|
Luo J, Efimova E, Volke DC, Santala V, Santala S. Engineering cell morphology by CRISPR interference in Acinetobacter baylyi ADP1. Microb Biotechnol 2022; 15:2800-2818. [PMID: 36005297 DOI: 10.1111/1751-7915.14133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 07/29/2022] [Accepted: 08/08/2022] [Indexed: 11/26/2022] Open
Abstract
Microbial production of intracellular compounds can be engineered by redirecting the carbon flux towards products and increasing the cell size. Potential engineering strategies include exploiting clustered regularly interspaced short palindromic repeats interference (CRISPRi)-based tools for controlling gene expression. Here, we applied CRISPRi for engineering Acinetobacter baylyi ADP1, a model bacterium for synthesizing intracellular storage lipids, namely wax esters. We first established an inducible CRISPRi system for strain ADP1, which enables tightly controlled repression of target genes. We then targeted the glyoxylate shunt to redirect carbon flow towards wax esters. Second, we successfully employed CRISPRi for modifying cell morphology by repressing ftsZ, an essential gene required for cell division, in combination with targeted knock-outs to generate significantly enlarged filamentous or spherical cells respectively. The engineered cells sustained increased wax ester production metrics, demonstrating the potential of cell morphology engineering in the production of intracellular lipids.
Collapse
Affiliation(s)
- Jin Luo
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland
| | - Elena Efimova
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland
| | - Daniel Christoph Volke
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Ville Santala
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland
| | - Suvi Santala
- Faculty of Engineering and Natural Sciences, Tampere University, Tampere, Finland
| |
Collapse
|
17
|
Biopolymer production in microbiology by application of metabolic engineering. Polym Bull (Berl) 2022. [DOI: 10.1007/s00289-021-03820-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
18
|
Hou J, Zhang X, Wu Y, Jie J, Wang Z, Chen GQ, Sun J, Wu LP. Amphiphilic and fatigue-resistant organohydrogels for small-diameter vascular grafts. SCIENCE ADVANCES 2022; 8:eabn5360. [PMID: 35905180 PMCID: PMC9337766 DOI: 10.1126/sciadv.abn5360] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 06/15/2022] [Indexed: 05/27/2023]
Abstract
Hydrogels are used in vascular tissue engineering because of their good biocompatibility. However, most natural hydrogels exhibit high swelling ratio, poor mechanical stability, and low durability, which are key limitations for wider applications. Amphiphilic and fatigue-resistant organohydrogels were fabricated here via the click chemical reaction of unsaturated functional microbial polyhydroxyalkanoates and polyethylene glycol diacrylate and a combination of two-dimensional material graphdiyne. These organohydrogels were maintained stable in body fluids over time, and their tensile moduli remained unchanged after more than 2000 cycles of cyclic stretching. The tubular scaffolds presented good biocompatibility and perfusion in vitro. After transplantation in vivo, the vascular grafts exhibited obvious cell infiltration and tissue regeneration, having a higher patency rate than the control group in 3 months. This fabrication method provides a strategy of improving and promoting the application of organohydrogels as implant materials for small-diameter vascular graft.
Collapse
Affiliation(s)
- Jinfei Hou
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Xu Zhang
- Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Tsinghua University, Beijing 100084, China
- Center of Synthetic and Systems Biology, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Yuqiong Wu
- Center for Chemical Biology and Drug Discovery, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, People’s Republic of China
| | - Junjin Jie
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Zhenxing Wang
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Guo-Qiang Chen
- Department of Chemical Engineering, Tsinghua University, Beijing 100084, China
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Tsinghua University, Beijing 100084, China
- Center of Synthetic and Systems Biology, School of Life Sciences, Tsinghua-Peking Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiaming Sun
- Department of Plastic Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Lin-Ping Wu
- Center for Chemical Biology and Drug Discovery, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou 510530, People’s Republic of China
| |
Collapse
|
19
|
Cyanophycin Granule Polypeptide: a Neglected High Value-Added Biopolymer, Synthesized in Activated Sludge on a Large Scale. Appl Environ Microbiol 2022; 88:e0074222. [PMID: 35862662 PMCID: PMC9317870 DOI: 10.1128/aem.00742-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Recovery of microbial synthetic polymers with high economic value and market demand in activated sludge has attracted extensive attention. This work analyzed the synthesis of cyanophycin granule peptide (CGP) in activated sludge and its adsorption capacity for heavy metals and dyes. The distribution and expression of synthetic genes for eight biopolymers in two wastewater treatment plants (WWTPs) were analyzed by metagenomics and metatranscriptomics. The results indicate that the abundance and expression level of CGP synthase (cphA) are similar to those of polyhydroxyalkanoate polymerase, implying high synthesis of CGP in activated sludges. CGP in activated sludge is mainly polymerized from aspartic acid and arginine, and its secondary structure is mainly β-sheet. The crude yields of CGP are as high as 104 ± 26 and 76 ± 13 mg/g dry sludge in winter and in summer, respectively, comparable to those of polyhydroxyalkanoate and alginate. CGP has a stronger adsorption capacity for anionic pollutants (Cr (VI) and methyl orange) than for cationic pollutants because it is rich in guanidine groups. This study highlights prospects for recovery and application of CGP from WWTPs. IMPORTANCE The conversion of organic pollutants into bioresources by activated sludge can reduce the carbon dioxide emission of wastewater treatment plants. Identification of new high value-added biopolymers produced by activated sludge is beneficial to recover bioresources. Cyanophycin granule polypeptide (CGP), first discovered in cyanobacteria, has unique chemical and material properties suitable for industrial food, medicine, cosmetics, water treatment, and agriculture applications. Here, we revealed for the first time that activated sludge has a remarkable ability to produce CGP. These findings could further facilitate the conversion of wastewater treatment plants into resource recycling plants.
Collapse
|
20
|
Gao Q, Yang H, Wang C, Xie XY, Liu KX, Lin Y, Han SY, Zhu M, Neureiter M, Lin Y, Ye JW. Advances and trends in microbial production of polyhydroxyalkanoates and their building blocks. Front Bioeng Biotechnol 2022; 10:966598. [PMID: 35928942 PMCID: PMC9343942 DOI: 10.3389/fbioe.2022.966598] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Accepted: 07/01/2022] [Indexed: 11/13/2022] Open
Abstract
With the rapid development of synthetic biology, a variety of biopolymers can be obtained by recombinant microorganisms. Polyhydroxyalkanoates (PHA) is one of the most popular one with promising material properties, such as biodegradability and biocompatibility against the petrol-based plastics. This study reviews the recent studies focusing on the microbial synthesis of PHA, including chassis engineering, pathways engineering for various substrates utilization and PHA monomer synthesis, and PHA synthase modification. In particular, advances in metabolic engineering of dominant workhorses, for example Halomonas, Ralstonia eutropha, Escherichia coli and Pseudomonas, with outstanding PHA accumulation capability, were summarized and discussed, providing a full landscape of diverse PHA biosynthesis. Meanwhile, we also introduced the recent efforts focusing on structural analysis and mutagenesis of PHA synthase, which significantly determines the polymerization activity of varied monomer structures and PHA molecular weight. Besides, perspectives and solutions were thus proposed for achieving scale-up PHA of low cost with customized material property in the coming future.
Collapse
Affiliation(s)
- Qiang Gao
- Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, QH, China
| | - Hao Yang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Chi Wang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Xin-Ying Xie
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Kai-Xuan Liu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Ying Lin
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Shuang-Yan Han
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Mingjun Zhu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Markus Neureiter
- Institute for Environmental Biotechnology, Department of Agrobiotechnology, University of Natural Resources and Life Sciences, Tulln, Austria
- *Correspondence: Markus Neureiter, ; Yina Lin, ; Jian-Wen Ye,
| | - Yina Lin
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
- *Correspondence: Markus Neureiter, ; Yina Lin, ; Jian-Wen Ye,
| | - Jian-Wen Ye
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
- *Correspondence: Markus Neureiter, ; Yina Lin, ; Jian-Wen Ye,
| |
Collapse
|
21
|
Chen Z, Zhang J, Lyu Q, Wang H, Ji X, Yan Z, Chen F, Dahlgren RA, Zhang M. Modular configurations of living biomaterials incorporating nano-based artificial mediators and synthetic biology to improve bioelectrocatalytic performance: A review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 824:153857. [PMID: 35176368 DOI: 10.1016/j.scitotenv.2022.153857] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/24/2022] [Accepted: 02/09/2022] [Indexed: 06/14/2023]
Abstract
Currently, the industrial application of bioelectrochemical systems (BESs) that are incubated with natural electrochemically active microbes (EABs) is limited due to inefficient extracellular electron transfer (EET) by natural EABs. Notably, recent studies have identified several novel living biomaterials comprising highly efficient electron transfer systems allowing unparalleled proficiency of energy conversion. Introduction of these biomaterials into BESs could fundamentally increase their utilization for a wide range of applications. This review provides a comprehensive assessment of recent advancements in the design of living biomaterials that can be exploited to enhance bioelectrocatalytic performance. Further, modular configurations of abiotic and biotic components promise a powerful enhancement through integration of nano-based artificial mediators and synthetic biology. Herein, recent advancements in BESs are synthesized and assessed, including heterojunctions between conductive nanomaterials and EABs, in-situ hybrid self-assembly of EABs and nano-sized semiconductors, cytoprotection in biohybrids, synthetic biological modifications of EABs and electroactive biofilms. Since living biomaterials comprise a broad range of disciplines, such as molecular biology, electrochemistry and material sciences, full integration of technological advances applied in an interdisciplinary framework will greatly enhance/advance the utility and novelty of BESs. Overall, emerging fundamental knowledge concerning living biomaterials provides a powerful opportunity to markedly boost EET efficiency and facilitate the industrial application of BESs to meet global sustainability challenges/goals.
Collapse
Affiliation(s)
- Zheng Chen
- School of Public Health and Management, Wenzhou Medical University, Wenzhou 325035, People's Republic of China; School of Environmental Science & Engineering, Tan Kah Kee College, Xiamen University, Zhangzhou 363105, People's Republic of China; Fujian Provincial Key Lab of Coastal Basin Environment, Fujian Polytechnic Normal University, Fuqing 350300, People's Republic of China.
| | - Jing Zhang
- School of Environmental Science & Engineering, Tan Kah Kee College, Xiamen University, Zhangzhou 363105, People's Republic of China
| | - Qingyang Lyu
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People's Republic of China
| | - Honghui Wang
- School of Environmental Science & Engineering, Tan Kah Kee College, Xiamen University, Zhangzhou 363105, People's Republic of China
| | - Xiaoliang Ji
- School of Public Health and Management, Wenzhou Medical University, Wenzhou 325035, People's Republic of China
| | - Zhiying Yan
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, People's Republic of China
| | - Fang Chen
- Fujian Provincial Key Lab of Coastal Basin Environment, Fujian Polytechnic Normal University, Fuqing 350300, People's Republic of China
| | - Randy A Dahlgren
- School of Public Health and Management, Wenzhou Medical University, Wenzhou 325035, People's Republic of China; Department of Land, Air and Water Resources, University of California, Davis, CA 95616, USA
| | - Minghua Zhang
- School of Public Health and Management, Wenzhou Medical University, Wenzhou 325035, People's Republic of China; Department of Land, Air and Water Resources, University of California, Davis, CA 95616, USA
| |
Collapse
|
22
|
Adaptive Laboratory Evolution of Halomonas bluephagenesis Enhances Acetate Tolerance and Utilization to Produce Poly(3-hydroxybutyrate). Molecules 2022; 27:molecules27093022. [PMID: 35566371 PMCID: PMC9103988 DOI: 10.3390/molecules27093022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/02/2022] [Accepted: 05/06/2022] [Indexed: 11/17/2022] Open
Abstract
Acetate is a promising economical and sustainable carbon source for bioproduction, but it is also a known cell-growth inhibitor. In this study, adaptive laboratory evolution (ALE) with acetate as selective pressure was applied to Halomonas bluephagenesis TD1.0, a fast-growing and contamination-resistant halophilic bacterium that naturally accumulates poly(3-hydroxybutyrate) (PHB). After 71 transfers, the evolved strain, B71, was isolated, which not only showed better fitness (in terms of tolerance and utilization rate) to high concentrations of acetate but also produced a higher PHB titer compared with the parental strain TD1.0. Subsequently, overexpression of acetyl-CoA synthetase (ACS) in B71 resulted in a further increase in acetate utilization but a decrease in PHB production. Through whole-genome resequencing, it was speculated that genetic mutations (single-nucleotide variation (SNV) in phaB, mdh, and the upstream of OmpA, and insertion of TolA) in B71 might contribute to its improved acetate adaptability and PHB production. Finally, in a 5 L bioreactor with intermittent feeding of acetic acid, B71 was able to produce 49.79 g/L PHB and 70.01 g/L dry cell mass, which were 147.2% and 82.32% higher than those of TD1.0, respectively. These results highlight that ALE provides a reliable method to harness H. bluephagenesis to metabolize acetate for the production of PHB or other high-value chemicals more efficiently.
Collapse
|
23
|
Behera S, Priyadarshanee M, Das S. Polyhydroxyalkanoates, the bioplastics of microbial origin: Properties, biochemical synthesis, and their applications. CHEMOSPHERE 2022; 294:133723. [PMID: 35085614 DOI: 10.1016/j.chemosphere.2022.133723] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 01/13/2022] [Accepted: 01/20/2022] [Indexed: 06/14/2023]
Abstract
The rising plastic pollution deteriorates the environment significantly as these petroleum-based plastics are not biodegradable, and their production requires natural fuels (energy source) and other resources. Polyhydroxyalkanoates (PHAs) are bioplastic and a sustainable and eco-friendly alternative to synthetic plastics. PHAs can be entirely synthesized using various microorganisms such as bacteria, algae, and fungi. These value-added biopolymers show promising properties such as enhanced biodegradability, biocompatibility, and other chemo-mechanical properties. Further, it has been established that the properties of PHA polymers depend on the substrates and chemical composition (monomer unit) of these polymers. PHAs hold great potential as an alternative to petroleum-based polymers, and further research for economic production and utilization of these biopolymers is required. The review describes the synthesis mechanism and different properties of microbially synthesized PHAs for various applications. The classification of PHAs and the multiple techniques necessary for their detection and evaluation have been discussed. In addition, the synthesis mechanism involving the genetic regulation of these biopolymers in various microbial groups has been described. This review provides information on various commercially available PHAs and their application in multiple sectors. The industrial production of these microbially synthesized polymers and the different extraction methods have been reviewed in detail. Furthermore, the review provides an insight into the potential applications of this biopolymer in environmental, industrial, and biomedical applications.
Collapse
Affiliation(s)
- Shivananda Behera
- Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela, 769 008, Odisha, India
| | - Monika Priyadarshanee
- Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela, 769 008, Odisha, India
| | - Surajit Das
- Laboratory of Environmental Microbiology and Ecology (LEnME), Department of Life Science, National Institute of Technology, Rourkela, 769 008, Odisha, India.
| |
Collapse
|
24
|
Gurdo N, Volke DC, Nikel PI. Merging automation and fundamental discovery into the design–build–test–learn cycle of nontraditional microbes. Trends Biotechnol 2022; 40:1148-1159. [DOI: 10.1016/j.tibtech.2022.03.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 03/12/2022] [Accepted: 03/16/2022] [Indexed: 12/29/2022]
|
25
|
Metabolic engineering strategies to produce medium-chain oleochemicals via acyl-ACP:CoA transacylase activity. Nat Commun 2022; 13:1619. [PMID: 35338129 PMCID: PMC8956717 DOI: 10.1038/s41467-022-29218-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 03/04/2022] [Indexed: 11/12/2022] Open
Abstract
Microbial lipid metabolism is an attractive route for producing oleochemicals. The predominant strategy centers on heterologous thioesterases to synthesize desired chain-length fatty acids. To convert acids to oleochemicals (e.g., fatty alcohols, ketones), the narrowed fatty acid pool needs to be reactivated as coenzyme A thioesters at cost of one ATP per reactivation - an expense that could be saved if the acyl-chain was directly transferred from ACP- to CoA-thioester. Here, we demonstrate such an alternative acyl-transferase strategy by heterologous expression of PhaG, an enzyme first identified in Pseudomonads, that transfers 3-hydroxy acyl-chains between acyl-carrier protein and coenzyme A thioester forms for creating polyhydroxyalkanoate monomers. We use it to create a pool of acyl-CoA’s that can be redirected to oleochemical products. Through bioprospecting, mutagenesis, and metabolic engineering, we develop three strains of Escherichia coli capable of producing over 1 g/L of medium-chain free fatty acids, fatty alcohols, and methyl ketones. Microbial production of oleochemicals involves strategies of expressing thioesterase to narrow the substrate pool for the termination enzyme at the expense of one ATP. Here, the authors developed an alternative energy-efficient strategy to use of an acyl-ACP transacylase to produce medium chain oleochemicals in E. coli.
Collapse
|
26
|
Brar KK, Raheja Y, Chadha BS, Magdouli S, Brar SK, Yang YH, Bhatia SK, Koubaa A. A paradigm shift towards production of sustainable bioenergy and advanced products from Cannabis/hemp biomass in Canada. BIOMASS CONVERSION AND BIOREFINERY 2022; 14:1-22. [PMID: 35342682 PMCID: PMC8934023 DOI: 10.1007/s13399-022-02570-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 03/06/2022] [Accepted: 03/08/2022] [Indexed: 05/22/2023]
Abstract
The global cannabis (Cannabis sativa) market was 17.7 billion in 2019 and is expected to reach up to 40.6 billion by 2024. Canada is the 2nd nation to legalize cannabis with a massive sale of $246.9 million in the year 2021. Waste cannabis biomass is managed using disposal strategies (i.e., incineration, aerobic/anaerobic digestion, composting, and shredding) that are not good enough for long-term environmental sustainability. On the other hand, greenhouse gas emissions and the rising demand for petroleum-based fuels pose a severe threat to the environment and the circular economy. Cannabis biomass can be used as a feedstock to produce various biofuels and biochemicals. Various research groups have reported production of ethanol 9.2-20.2 g/L, hydrogen 13.5 mmol/L, lipids 53.3%, biogas 12%, and biochar 34.6% from cannabis biomass. This review summarizes its legal and market status (production and consumption), the recent advancements in the lignocellulosic biomass (LCB) pre-treatment (deep eutectic solvents (DES), and ionic liquids (ILs) known as "green solvents") followed by enzymatic hydrolysis using glycosyl hydrolases (GHs) for the efficient conversion efficiency of pre-treated biomass. Recent advances in the bioconversion of hemp into oleochemicals, their challenges, and future perspectives are outlined. A comprehensive insight is provided on the trends and developments of metabolic engineering strategies to improve product yield. The thermochemical processing of disposed-off hemp lignin into bio-oil, bio-char, synthesis gas, and phenol is also discussed. Despite some progress, barricades still need to be met to commercialize advanced biofuels and compete with traditional fuels.
Collapse
Affiliation(s)
- Kamalpreet Kaur Brar
- Department of Civil Engineering, Lassonde School of Engineering, York University, North York, Toronto, ON M3J 1P3 Canada
- Centre Technologique Des Residue Industriels (CTRI), 433 Boulevard du college, Rouyn-Noranda, J9X0E1 Canada
| | - Yashika Raheja
- Department of Microbiology, Guru Nanak Dev University, Amritsar, 143005 India
| | | | - Sara Magdouli
- Department of Civil Engineering, Lassonde School of Engineering, York University, North York, Toronto, ON M3J 1P3 Canada
- Centre Technologique Des Residue Industriels (CTRI), 433 Boulevard du college, Rouyn-Noranda, J9X0E1 Canada
| | - Satinder Kaur Brar
- Department of Civil Engineering, Lassonde School of Engineering, York University, North York, Toronto, ON M3J 1P3 Canada
| | - Yung-Hun Yang
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul, 05029 Republic of Korea
- Institute for Ubiquitous Information Technology and Applications, Seoul, 05029 Republic of Korea
| | - Shashi Kant Bhatia
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul, 05029 Republic of Korea
- Institute for Ubiquitous Information Technology and Applications, Seoul, 05029 Republic of Korea
| | - Ahmed Koubaa
- Institut de Recherche Sur Les Forêts, Université du Québec en Abitibi-Témiscamingue, Université, Rouyn-Noranda, 445 Boulevard de l’ Université, Rouyn-Noranda, QC J9X5E4 Canada
| |
Collapse
|
27
|
Immethun CM, Kathol M, Changa T, Saha R. Synthetic Biology Tool Development Advances Predictable Gene Expression in the Metabolically Versatile Soil Bacterium Rhodopseudomonas palustris. Front Bioeng Biotechnol 2022; 10:800734. [PMID: 35372317 PMCID: PMC8966681 DOI: 10.3389/fbioe.2022.800734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Accepted: 02/16/2022] [Indexed: 11/13/2022] Open
Abstract
Harnessing the unique biochemical capabilities of non-model microorganisms would expand the array of biomanufacturing substrates, process conditions, and products. There are non-model microorganisms that fix nitrogen and carbon dioxide, derive energy from light, catabolize methane and lignin-derived aromatics, are tolerant to physiochemical stresses and harsh environmental conditions, store lipids in large quantities, and produce hydrogen. Model microorganisms often only break down simple sugars and require low stress conditions, but they have been engineered for the sustainable manufacture of numerous products, such as fragrances, pharmaceuticals, cosmetics, surfactants, and specialty chemicals, often by using tools from synthetic biology. Transferring complex pathways has proven to be exceedingly difficult, as the cofactors, cellular conditions, and energy sources necessary for this pathway to function may not be present in the host organism. Utilization of unique biochemical capabilities could also be achieved by engineering the host; although, synthetic biology tools developed for model microbes often do not perform as designed in other microorganisms. The metabolically versatile Rhodopseudomonas palustris CGA009, a purple non-sulfur bacterium, catabolizes aromatic compounds derived from lignin in both aerobic and anaerobic conditions and can use light, inorganic, and organic compounds for its source of energy. R. palustris utilizes three nitrogenase isozymes to fulfill its nitrogen requirements while also generating hydrogen. Furthermore, the bacterium produces two forms of RuBisCo in response to carbon dioxide/bicarbonate availability. While this potential chassis harbors many beneficial traits, stable heterologous gene expression has been problematic due to its intrinsic resistance to many antibiotics and the lack of synthetic biology parts investigated in this microbe. To address these problems, we have characterized gene expression and plasmid maintenance for different selection markers, started a synthetic biology toolbox specifically for the photosynthetic R. palustris, including origins of replication, fluorescent reporters, terminators, and 5′ untranslated regions, and employed the microbe’s endogenous plasmid for exogenous protein production. This work provides essential synthetic biology tools for engineering R. palustris’ many unique biochemical processes and has helped define the principles for expressing heterologous genes in this promising microbe through a methodology that could be applied to other non-model microorganisms.
Collapse
|
28
|
Meng D, Miao C, Liu Y, Wang F, Chen L, Huang Z, Fan X, Gu P, Li Q. Metabolic engineering for biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from glucose and propionic acid in recombinant Escherichia coli. BIORESOURCE TECHNOLOGY 2022; 348:126786. [PMID: 35114368 DOI: 10.1016/j.biortech.2022.126786] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/22/2022] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
In this study, novel polyhydroxyalkanoate (PHA)-associated genes (phaCp and phaABp) cloned from Propylenella binzhouense L72T were expressed in Escherichiacoli cells for PHA production, and the recombinant strains were used to analyze PHA yields with various substrates. The highest poly (3-hydroxybutyrate-co-3-hydroxy-valerate) (PHBV) yield (1.06 g/L) and cell dry weight (3.31 g/L) in E. coli DH5α/ΔptsG-CpABp were achieved by using glucose and propionicacid as substrates. Structural verification of PHBV produced by E. coli DH5α/ΔptsG-CpABp was performed to evaluate the characteristics of the polymers using Fourier transform infrared spectroscopy and nuclear magnetic resonance analysis. In addition, the X-ray diffraction results showed improved crystallinity of PHBV, and thermogravimetric analysis showed good thermal stability of 298 °C. The above findings indicated that the expression of phaCp and phaABp genes resulted in improved PHBV synthesis activity, and the polymer had better performance at higher processing temperatures.
Collapse
Affiliation(s)
- Dong Meng
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Changfeng Miao
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Yuling Liu
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Fang Wang
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Lu Chen
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Zhaosong Huang
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Xiangyu Fan
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Pengfei Gu
- School of Biological Science and Technology, University of Jinan, Jinan, PR China
| | - Qiang Li
- School of Biological Science and Technology, University of Jinan, Jinan, PR China.
| |
Collapse
|
29
|
Goto S, Miyahara Y, Taguchi S, Tsuge T, Hiroe A. Enhanced Production of (R)-3-Hydroxybutyrate Oligomers by Coexpression of Molecular Chaperones in Recombinant Escherichia coli Harboring a Polyhydroxyalkanoate Synthase Derived from Bacillus cereus YB-4. Microorganisms 2022; 10:microorganisms10020458. [PMID: 35208913 PMCID: PMC8878867 DOI: 10.3390/microorganisms10020458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/14/2022] [Accepted: 02/14/2022] [Indexed: 12/10/2022] Open
Abstract
The biodegradable polyester poly-(R)-3-hydroxybutyrate [P(3HB)] is synthesized by a polymerizing enzyme called polyhydroxyalkanoate (PHA) synthase and accumulates in a wide variety of bacterial cells. Recently, we demonstrated the secretory production of a (R)-3HB oligomer (3HBO), a low-molecular-weight P(3HB), by using recombinant Escherichia coli expressing PHA synthases. The 3HBO has potential value as an antibacterial substance and as a building block for various polymers. In this study, to construct an efficient 3HBO production system, the coexpression of molecular chaperones and a PHA synthase derived from Bacillus cereus YB-4 (PhaRCYB4) was examined. First, genes encoding enzymes related to 3HBO biosynthesis (phaRCYB4, phaA and phaB derived from Ralstonia eutropha H16) and two types of molecular chaperones (groEL, groES, and tig) were introduced into the E. coli strains BW25113 and BW25113ΔadhE. As a result, coexpression of the chaperones promoted the enzyme activity of PHA synthase (approximately 2–3-fold) and 3HBO production (approximately 2-fold). The expression assay of each chaperone and PHA synthase subunit (PhaRYB4 and PhaCYB4) indicated that the combination of the two chaperone systems (GroEL-GroES and TF) supported the folding of PhaRYB4 and PhaCYB4. These results suggest that the utilization of chaperone proteins is a valuable approach to enhance the formation of active PHA synthase and the productivity of 3HBO.
Collapse
Affiliation(s)
- Saki Goto
- Department of Chemistry for Life Sciences and Agriculture, Faculty of Life Sciences, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan; (S.G.); (S.T.)
- MIRAI, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan; (Y.M.); (T.T.)
| | - Yuki Miyahara
- MIRAI, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan; (Y.M.); (T.T.)
- Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan
| | - Seiichi Taguchi
- Department of Chemistry for Life Sciences and Agriculture, Faculty of Life Sciences, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan; (S.G.); (S.T.)
| | - Takeharu Tsuge
- MIRAI, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan; (Y.M.); (T.T.)
- Department of Materials Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan
| | - Ayaka Hiroe
- Department of Chemistry for Life Sciences and Agriculture, Faculty of Life Sciences, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya, Tokyo 156-8502, Japan; (S.G.); (S.T.)
- MIRAI, Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan; (Y.M.); (T.T.)
- Correspondence:
| |
Collapse
|
30
|
Koller M, Mukherjee A. A New Wave of Industrialization of PHA Biopolyesters. Bioengineering (Basel) 2022; 9:bioengineering9020074. [PMID: 35200427 PMCID: PMC8869736 DOI: 10.3390/bioengineering9020074] [Citation(s) in RCA: 56] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 01/24/2022] [Accepted: 02/08/2022] [Indexed: 12/12/2022] Open
Abstract
The ever-increasing use of plastics, their fossil origin, and especially their persistence in nature have started a wave of new innovations in materials that are renewable, offer the functionalities of plastics, and are biodegradable. One such class of biopolymers, polyhydroxyalkanoates (PHAs), are biosynthesized by numerous microorganisms through the conversion of carbon-rich renewable resources. PHA homo- and heteropolyesters are intracellular products of secondary microbial metabolism. When isolated from microbial biomass, PHA biopolymers mimic the functionalities of many of the top-selling plastics of petrochemical origin, but biodegrade in soil, freshwater, and marine environments, and are both industrial- and home-compostable. Only a handful of PHA biopolymers have been studied in-depth, and five of these reliably match the desired material properties of established fossil plastics. Realizing the positive attributes of PHA biopolymers, several established chemical companies and numerous start-ups, brand owners, and converters have begun to produce and use PHA in a variety of industrial and consumer applications, in what can be described as the emergence of the “PHA industry”. While this positive industrial and commercial relevance of PHA can hardly be described as the first wave in its commercial development, it is nonetheless a very serious one with over 25 companies and start-ups and 30+ brand owners announcing partnerships in PHA production and use. The combined product portfolio of the producing companies is restricted to five types of PHA, namely poly(3-hydroxybutyrate), poly(4-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), and poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), even though PHAs as a class of polymers offer the potential to generate almost limitless combinations of polymers beneficial to humankind. To date, by varying the co-monomer type and content in these PHA biopolymers, their properties emulate those of the seven top-selling fossil plastics, representing 230 million t of annual plastics production. Capacity expansions of 1.5 million t over the next 5 years have been announced. Policymakers worldwide have taken notice and are encouraging industry to adopt biodegradable and compostable material solutions. This wave of commercialization of PHAs in single-use and in durable applications holds the potential to make the decisive quantum leap in reducing plastic pollution, the depletion of fossil resources, and the emission of greenhouse gases and thus fighting climate change. This review presents setbacks and success stories of the past 40 years and the current commercialization wave of PHA biopolymers, their properties, and their fields of application.
Collapse
Affiliation(s)
- Martin Koller
- Office of Research Management and Service, c/o Institute of Chemistry, University of Graz, NAWI Graz, Heinrichstrasse 28/IV, 8010 Graz, Austria
- ARENA—Association for Resource Efficient and Sustainable Technologies, Inffeldgasse 21b, 8010 Graz, Austria
- Correspondence: ; Tel.: +43-316-380-5463
| | - Anindya Mukherjee
- Global Organization for PHA (GO!PHA), Oudebrugsteeg 9, 1012 JN Amsterdam, The Netherlands;
- PHAXTEC, Inc., Wake Forest, NC 27587, USA
| |
Collapse
|
31
|
Eraslan K, Aversa C, Nofar M, Barletta M, Gisario A, Salehiyan R, Alkan Goksu Y. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH): synthesis, properties, and applications - A Review. Eur Polym J 2022. [DOI: 10.1016/j.eurpolymj.2022.111044] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
32
|
Li J, Zhang X, Udduttula A, Fan ZS, Chen JH, Sun AR, Zhang P. Microbial-Derived Polyhydroxyalkanoate-Based Scaffolds for Bone Tissue Engineering: Biosynthesis, Properties, and Perspectives. Front Bioeng Biotechnol 2022; 9:763031. [PMID: 34993185 PMCID: PMC8724543 DOI: 10.3389/fbioe.2021.763031] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 11/17/2021] [Indexed: 01/15/2023] Open
Abstract
Polyhydroxyalkanoates (PHAs) are a class of structurally diverse natural biopolyesters, synthesized by various microbes under unbalanced culture conditions. PHAs as biomedical materials have been fabricated in various forms to apply to tissue engineering for the past years due to their excellent biodegradability, inherent biocompatibility, modifiable mechanical properties, and thermo-processability. However, there remain some bottlenecks in terms of PHA production on a large scale, the purification process, mechanical properties, and biodegradability of PHA, which need to be further resolved. Therefore, scientists are making great efforts via synthetic biology and metabolic engineering tools to improve the properties and the product yields of PHA at a lower cost for the development of various PHA-based scaffold fabrication technologies to widen biomedical applications, especially in bone tissue engineering. This review aims to outline the biosynthesis, structures, properties, and the bone tissue engineering applications of PHA scaffolds with different manufacturing technologies. The latest advances will provide an insight into future outlooks in PHA-based scaffolds for bone tissue engineering.
Collapse
Affiliation(s)
- Jian Li
- Shenzhen Engineering Research Center for Medical Bioactive Materials, Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xu Zhang
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Tsinghua University, Beijing, China.,Department of Chemical Engineering, Tsinghua University, Beijing, China
| | - Anjaneyulu Udduttula
- Shenzhen Engineering Research Center for Medical Bioactive Materials, Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Zhi Shan Fan
- Shenzhen Engineering Research Center for Medical Bioactive Materials, Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Jian Hai Chen
- Shenzhen Engineering Research Center for Medical Bioactive Materials, Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Antonia RuJia Sun
- Shenzhen Engineering Research Center for Medical Bioactive Materials, Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Peng Zhang
- Shenzhen Engineering Research Center for Medical Bioactive Materials, Center for Translational Medicine Research and Development, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| |
Collapse
|
33
|
Zhang X, Liu XY, Yang H, Chen JN, Lin Y, Han SY, Cao Q, Zeng HS, Ye JW. A Polyhydroxyalkanoates-Based Carrier Platform of Bioactive Substances for Therapeutic Applications. Front Bioeng Biotechnol 2022; 9:798724. [PMID: 35071207 PMCID: PMC8767415 DOI: 10.3389/fbioe.2021.798724] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 12/02/2021] [Indexed: 12/13/2022] Open
Abstract
Bioactive substances (BAS), such as small molecule drugs, proteins, RNA, cells, etc., play a vital role in many therapeutic applications, especially in tissue repair and regeneration. However, the therapeutic effect is still a challenge due to the uncontrollable release and instable physico-chemical properties of bioactive components. To address this, many biodegradable carrier systems of micro-nano structures have been rapidly developed based on different biocompatible polymers including polyhydroxyalkanoates (PHA), the microbial synthesized polyesters, to provide load protection and controlled-release of BAS. We herein highlight the developments of PHA-based carrier systems in recent therapeutic studies, and give an overview of its prospective applications in various disease treatments. Specifically, the biosynthesis and material properties of diverse PHA polymers, designs and fabrication of micro- and nano-structure PHA particles, as well as therapeutic studies based on PHA particles, are summarized to give a comprehensive landscape of PHA-based BAS carriers and applications thereof. Moreover, recent efforts focusing on novel-type BAS nano-carriers, the functionalized self-assembled PHA granules in vivo, was discussed in this review, proposing the underlying innovations of designs and fabrications of PHA-based BAS carriers powered by synthetic biology. This review outlines a promising and applicable BAS carrier platform of novelty based on PHA particles for different medical uses.
Collapse
Affiliation(s)
- Xu Zhang
- Department of Chemical Engineering, Tsinghua University, Beijing, China
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Tsinghua University, Beijing, China
- Tsinghua-Peking Center of Life Sciences, Beijing, China
| | - Xin-Yi Liu
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Hao Yang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Jiang-Nan Chen
- Tsinghua-Peking Center of Life Sciences, Beijing, China
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Ying Lin
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Shuang-Yan Han
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Qian Cao
- China Manned Space Agency, Beijing, China
| | - Han-Shi Zeng
- Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Guangzhou, China
| | - Jian-Wen Ye
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| |
Collapse
|
34
|
Obruča S, Dvořák P, Sedláček P, Koller M, Sedlář K, Pernicová I, Šafránek D. Polyhydroxyalkanoates synthesis by halophiles and thermophiles: towards sustainable production of microbial bioplastics. Biotechnol Adv 2022; 58:107906. [DOI: 10.1016/j.biotechadv.2022.107906] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 12/15/2021] [Accepted: 01/07/2022] [Indexed: 01/10/2023]
|
35
|
Zhang Y, Liu H, Liu Y, Huo K, Wang S, Liu R, Yang C. A promoter engineering-based strategy enhances polyhydroxyalkanoate production in Pseudomonas putida KT2440. Int J Biol Macromol 2021; 191:608-617. [PMID: 34582907 DOI: 10.1016/j.ijbiomac.2021.09.142] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/18/2021] [Accepted: 09/20/2021] [Indexed: 11/24/2022]
Abstract
Polyhydroxyalkanoate (PHA), a class of biopolyester synthesized by various bacteria, is considered as an alternative to petroleum-based plastics because of its excellent physochemical and material properties. Pseudomonas putida KT2440 can produce medium-chain-length PHA (mcl-PHA) from glucose, fatty acid and glycerol, and its whole-genome sequences and cellular metabolic networks have been intensively researched. In this study, we aim to improve the PHA yield of P. putida KT2440 using a novel promoter engineering-based strategy. Unlike previous studies, endogenous strong promoters screening from P. putida KT2440 instead of synthetic or exogenous promoters was applied to the optimization of PHA biosynthesis pathway. Based on RNA-seq and promoter prediction, 30 putative strong promoters from P. putida KT2440 were identified. Subsequently, the strengths of these promoters were characterized by reporter gene assays. Furthermore, each of 10 strong promoters screened by transcriptional level and GFP fluorescence was independently inserted into upstream of PHA synthase gene (phaC1) on chromosome. As a result, the transcriptional levels of the phaC1 and phaC2 genes in almost all of the promoter-substituted strains were improved, and the relative PHA yields of the three promoter-substituted strains KTU-P1C1, KTU-P46C1 and KTU-P51C1 were improved obviously, reaching 30.62 wt%, 33.24 wt% and 33.29 wt% [the ratio of PHA weight to cell dry weight (CDW)], respectively. By further deletion of the glucose dehydrogenase gene in KTU-P1C1, KTU-P46C1 and KTU-P51C1, the relative PHA yield of the resulting mutant strain KTU-P46C1-∆gcd increased by 5.29% from 33.24% to 38.53%. Finally, by inserting P46 into upstream of pyruvate dehydrogenase gene in the genome of KTU-P46C1-∆gcd, the relative PHA yield and CDW of the resulting strain KTU-P46C1A-∆gcd reached nearly 42 wt% and 4.06 g/l, respectively, which increased by 90% and 40%, respectively, compared with the starting strain KTU. In particular, the absolute PHA yield of KTU-P46C1A-∆gcd reached 1.7 g/l, with a 165% improvement compared with the strain KTU. Herein, we report the highest PHA yield obtained by P. putida KT2440 in shake-flask fermentation to date. We demonstrate for the first time the effectiveness of endogenous strong promoters for improving the PHA yield and biomass of P. putida KT2440. More importantly, our findings highlight great potential of this strategy for enhanced production of secondary metabolites and heterologous proteins in P. putida KT2440.
Collapse
Affiliation(s)
- Yiting Zhang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China.
| | - Honglu Liu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China.
| | - Yujie Liu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China.
| | - Kaiyue Huo
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China.
| | - Shufang Wang
- Key Laboratory of Bioactive Materials, Ministry of Education, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Ruihua Liu
- Tianjin Key Laboratory of Protein Science, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Chao Yang
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, College of Life Sciences, Nankai University, Tianjin, China.
| |
Collapse
|
36
|
Dhakal N, Acharya B. Syngas Fermentation for the Production of Bio-Based Polymers: A Review. Polymers (Basel) 2021; 13:polym13223917. [PMID: 34833218 PMCID: PMC8618084 DOI: 10.3390/polym13223917] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 11/04/2021] [Accepted: 11/09/2021] [Indexed: 11/21/2022] Open
Abstract
Increasing environmental awareness among the general public and legislators has driven this modern era to seek alternatives to fossil-derived products such as fuel and plastics. Addressing environmental issues through bio-based products driven from microbial fermentation of synthetic gas (syngas) could be a future endeavor, as this could result in both fuel and plastic in the form of bioethanol and polyhydroxyalkanoates (PHA). Abundant availability in the form of cellulosic, lignocellulosic, and other organic and inorganic wastes presents syngas catalysis as an interesting topic for commercialization. Fascination with syngas fermentation is trending, as it addresses the limitations of conventional technologies like direct biochemical conversion and Fischer–Tropsch’s method for the utilization of lignocellulosic biomass. A plethora of microbial strains is available for syngas fermentation and PHA production, which could be exploited either in an axenic form or in a mixed culture. These microbes constitute diverse biochemical pathways supported by the activity of hydrogenase and carbon monoxide dehydrogenase (CODH), thus resulting in product diversity. There are always possibilities of enzymatic regulation and/or gene tailoring to enhance the process’s effectiveness. PHA productivity drags the techno-economical perspective of syngas fermentation, and this is further influenced by syngas impurities, gas–liquid mass transfer (GLMT), substrate or product inhibition, downstream processing, etc. Product variation and valorization could improve the economical perspective and positively impact commercial sustainability. Moreover, choices of single-stage or multi-stage fermentation processes upon product specification followed by microbial selection could be perceptively optimized.
Collapse
|
37
|
Lee SO, Xie Q, Fried SD. Optimized Loopable Translation as a Platform for the Synthesis of Repetitive Proteins. ACS CENTRAL SCIENCE 2021; 7:1736-1750. [PMID: 34729417 PMCID: PMC8554844 DOI: 10.1021/acscentsci.1c00574] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Indexed: 06/13/2023]
Abstract
The expression of long proteins with repetitive amino acid sequences often presents a challenge in recombinant systems. To overcome this obstacle, we report a genetic construct that circularizes mRNA in vivo by rearranging the topology of a group I self-splicing intron from T4 bacteriophage, thereby enabling "loopable" translation. Using a fluorescence-based assay to probe the translational efficiency of circularized mRNAs, we identify several conditions that optimize protein expression from this system. Our data suggested that translation of circularized mRNAs could be limited primarily by the rate of ribosomal initiation; therefore, using a modified error-prone PCR method, we generated a library that concentrated mutations into the initiation region of circularized mRNA and discovered mutants that generated markedly higher expression levels. Combining our rational improvements with those discovered through directed evolution, we report a loopable translator that achieves protein expression levels within 1.5-fold of the levels of standard vectorial translation. In summary, our work demonstrates loopable translation as a promising platform for the creation of large peptide chains, with potential utility in the development of novel protein materials.
Collapse
|
38
|
Rao Y, Li P, Xie X, Li J, Liao Y, Ma X, Cai D, Chen S. Construction and Characterization of a Gradient Strength Promoter Library for Fine-Tuned Gene Expression in Bacillus licheniformis. ACS Synth Biol 2021; 10:2331-2339. [PMID: 34449215 DOI: 10.1021/acssynbio.1c00242] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bacillus licheniformis DW2 is an important industrial strain for bacitracin production, and it is also used for biochemical production, however, the lack of effective toolkit for precise regulation of gene expression hindered its application seriously. Here, a gradient strength promoter library was constructed based on bacitracin synthetase gene cluster promoter PbacA. First, different PbacA promoter variants were constructed via coupling PbacA with various 5'-UTRs, and expression ranges of 32.6-741.8% were attained among these promoters. Then, three promoters, PUbay (strong), PbacA (middle), and PUndh (weakest), were applied for red fluorescent protein (RFP) and keratinase expression assays, and these promoters were proven to have good universality for different proteins. Second, the promoter of bacitracin synthetase gene cluster was replaced by these three promoters, and bacitraicn titer was enhanced by 14.62% when PUbay was applied, which was decreased by 98.05% under the mediation of PUndh compared with that of the original strain DW2. Third, promoters PUbay, PUyvgO, and PUndh were selected to regulate the expression levels of critical genes that are responsible for pucheriminic acid synthesis, and pucheriminic acid yield was increased by 194.1% via manipulating synthetic and competitive pathways. Finally, promoters PUbay, PbacA, and PUndh were applied for green fluorescent protein (GFP) and RFP expression in Escherichia coli, and consistent effects were attained based on our results. Taken together, a gradient strength promoter library was constructed in this research, which provided an effective toolkit for fine-tuning gene expression and reprogramming metabolite metabolic flux in B. licheniformis.
Collapse
Affiliation(s)
- Yi Rao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, People's Republic of China
| | - Peifen Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, People's Republic of China
| | - Xinxin Xie
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, People's Republic of China
| | - Jiemin Li
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, People's Republic of China
| | - Yongqing Liao
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, People's Republic of China
| | - Xin Ma
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, People's Republic of China
| | - Dongbo Cai
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, People's Republic of China
| | - Shouwen Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Sciences, Hubei University, Wuhan, 430062, People's Republic of China
- Fujian Provincial Key Laboratory of Eco-Industrial Green Technology, College of Ecological and Resource Engineering, Wuyi University, Wuyishan 354300, People's Republic of China
| |
Collapse
|
39
|
Kozaeva E, Volkova S, Matos MRA, Mezzina MP, Wulff T, Volke DC, Nielsen LK, Nikel PI. Model-guided dynamic control of essential metabolic nodes boosts acetyl-coenzyme A-dependent bioproduction in rewired Pseudomonas putida. Metab Eng 2021; 67:373-386. [PMID: 34343699 DOI: 10.1016/j.ymben.2021.07.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/23/2021] [Accepted: 07/29/2021] [Indexed: 01/16/2023]
Abstract
Pseudomonas putida is evolutionarily endowed with features relevant for bioproduction, especially under harsh operating conditions. The rich metabolic versatility of this species, however, comes at the price of limited formation of acetyl-coenzyme A (CoA) from sugar substrates. Since acetyl-CoA is a key metabolic precursor for a number of added-value products, in this work we deployed an in silico-guided rewiring program of central carbon metabolism for upgrading P. putida as a host for acetyl-CoA-dependent bioproduction. An updated kinetic model, integrating fluxomics and metabolomics datasets in addition to manually-curated information of enzyme mechanisms, identified targets that would lead to increased acetyl-CoA levels. Based on these predictions, a set of plasmids based on clustered regularly interspaced short palindromic repeats (CRISPR) and dead CRISPR-associated protein 9 (dCas9) was constructed to silence genes by CRISPR interference (CRISPRi). Dynamic reduction of gene expression of two key targets (gltA, encoding citrate synthase, and the essential accA gene, encoding subunit A of the acetyl-CoA carboxylase complex) mediated an 8-fold increase in the acetyl-CoA content of rewired P. putida. Poly(3-hydroxybutyrate) (PHB) was adopted as a proxy of acetyl-CoA availability, and two synthetic pathways were engineered for biopolymer accumulation. By including cell morphology as an extra target for the CRISPRi approach, fully rewired P. putida strains programmed for PHB accumulation had a 5-fold increase in PHB titers in bioreactor cultures using glucose. Thus, the strategy described herein allowed for rationally redirecting metabolic fluxes in P. putida from central metabolism towards product biosynthesis-especially relevant when deletion of essential pathways is not an option.
Collapse
Affiliation(s)
- Ekaterina Kozaeva
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Svetlana Volkova
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Marta R A Matos
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Mariela P Mezzina
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Tune Wulff
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Daniel C Volke
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark
| | - Lars K Nielsen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark; Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Pablo I Nikel
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800, Kongens Lyngby, Denmark.
| |
Collapse
|
40
|
Halomonas as a chassis. Essays Biochem 2021; 65:393-403. [PMID: 33885142 PMCID: PMC8314019 DOI: 10.1042/ebc20200159] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/24/2021] [Accepted: 03/26/2021] [Indexed: 01/04/2023]
Abstract
With the rapid development of systems and synthetic biology, the non-model bacteria, Halomonas spp., have been developed recently to become a cost-competitive platform for producing a variety of products including polyesters, chemicals and proteins owing to their contamination resistance and ability of high cell density growth at alkaline pH and high salt concentration. These salt-loving microbes can partially solve the challenges of current industrial biotechnology (CIB) which requires high energy-consuming sterilization to prevent contamination as CIB is based on traditional chassis, typically, Escherichia coli, Bacillus subtilis, Pseudomonas putida and Corynebacterium glutamicum. The advantages and current status of Halomonas spp. including their molecular biology and metabolic engineering approaches as well as their applications are reviewed here. Moreover, a systematic strain engineering streamline, including product-based host development, genetic parts mining, static and dynamic optimization of modularized pathways and bioprocess-inspired cell engineering are summarized. All of these developments result in the term called next-generation industrial biotechnology (NGIB). Increasing efforts are made to develop their versatile cell factories powered by synthetic biology to demonstrate a new biomanufacturing strategy under open and continuous processes with significant cost-reduction on process complexity, energy, substrates and fresh water consumption.
Collapse
|
41
|
Microbial cell factories for the production of polyhydroxyalkanoates. Essays Biochem 2021; 65:337-353. [PMID: 34132340 DOI: 10.1042/ebc20200142] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 05/14/2021] [Accepted: 05/26/2021] [Indexed: 12/20/2022]
Abstract
Pollution caused by persistent petro-plastics is the most pressing problem currently, with 8 million tons of plastic waste dumped annually in the oceans. Plastic waste management is not systematized in many countries, because it is laborious and expensive with secondary pollution hazards. Bioplastics, synthesized by microorganisms, are viable alternatives to petrochemical-based thermoplastics due to their biodegradable nature. Polyhydroxyalkanoates (PHAs) are a structurally and functionally diverse group of storage polymers synthesized by many microorganisms, including bacteria and Archaea. Some of the most important PHA accumulating bacteria include Cupriavidus necator, Burkholderia sacchari, Pseudomonas sp., Bacillus sp., recombinant Escherichia coli, and certain halophilic extremophiles. PHAs are synthesized by specialized PHA polymerases with assorted monomers derived from the cellular metabolite pool. In the natural cycle of cellular growth, PHAs are depolymerized by the native host for carbon and energy. The presence of these microbial PHA depolymerases in natural niches is responsible for the degradation of bioplastics. Polyhydroxybutyrate (PHB) is the most common PHA with desirable thermoplastic-like properties. PHAs have widespread applications in various industries including biomedicine, fine chemicals production, drug delivery, packaging, and agriculture. This review provides the updated knowledge on the metabolic pathways for PHAs synthesis in bacteria, and the major microbial hosts for PHAs production. Yeasts are presented as a potential candidate for industrial PHAs production, with their high amenability to genetic engineering and the availability of industrial-scale technology. The major bottlenecks in the commercialization of PHAs as an alternative for plastics and future perspectives are also critically discussed.
Collapse
|
42
|
Lhamo P, Behera SK, Mahanty B. Process optimization, metabolic engineering interventions and commercialization of microbial polyhydroxyalkanoates production - A state-of-the art review. Biotechnol J 2021; 16:e2100136. [PMID: 34132046 DOI: 10.1002/biot.202100136] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 05/29/2021] [Accepted: 06/03/2021] [Indexed: 12/31/2022]
Abstract
Microbial polyhydroxyalkanoates (PHAs) produced using renewable resources could be the best alternative for conventional plastics. Despite their incredible potential, commercial production of PHAs remains very low. Nevertheless, sincere attempts have been made by researchers to improve the yield and economic viability of PHA production by utilizing low-cost agricultural or industrial wastes. In this context, the use of efficient microbial culture or consortia, adoption of experimental design to trace ideal growth conditions, nutritional requirements, and intervention of metabolic engineering tools have gained significant attention. This review has been structured to highlight the important microbial sources for PHA production, use of conventional and non-conventional substrates, product optimization using experimental design, metabolic engineering strategies, and global players in the commercialization of PHA in the past two decades. The challenges about PHA recovery and analysis have also been discussed which possess indirect hurdle while expanding the horizon of PHA-based bioplastics. Selection of appropriate microorganism and substrate plays a vital role in improving the productivity and characteristics of PHAs. Experimental design-based bioprocess, use of metabolic engineering tools, and optimal product recovery techniques are invaluable in this dimension. Optimization strategies, which are being explored in isolation, need to be logically integrated for the successful commercialization of microbial PHAs.
Collapse
Affiliation(s)
- Pema Lhamo
- Department of Biotechnology, Karunya Institute of Technology and Sciences, Coimbatore, Tamil Nadu, India
| | - Shishir Kumar Behera
- Industrial Ecology Research Group, School of Chemical Engineering, Vellore Institute of Technology, Vellore, Tamil Nadu, India
| | - Biswanath Mahanty
- Department of Biotechnology, Karunya Institute of Technology and Sciences, Coimbatore, Tamil Nadu, India
| |
Collapse
|
43
|
Vu DH, Wainaina S, Taherzadeh MJ, Åkesson D, Ferreira JA. Production of polyhydroxyalkanoates (PHAs) by Bacillus megaterium using food waste acidogenic fermentation-derived volatile fatty acids. Bioengineered 2021; 12:2480-2498. [PMID: 34115556 PMCID: PMC8806590 DOI: 10.1080/21655979.2021.1935524] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
High production costs still hamper fast expansion of commercial production of polyhydroxyalkanoates (PHAs). This problem is greatly related to the cultivation medium which accounts for up to 50% of the whole process costs. The aim of this research work was to evaluate the potential of using volatile fatty acids (VFAs), derived from acidogenic fermentation of food waste, as inexpensive carbon sources for the production of PHAs through bacterial cultivation. Bacillus megaterium could assimilate glucose, acetic acid, butyric acid, and caproic acid as single carbon sources in synthetic medium with maximum PHAs production yields of 9-11%, on a cell dry weight basis. Single carbon sources were then replaced by a mixture of synthetic VFAs and by a VFAs-rich stream from the acidogenic fermentation of food waste. After 72 h of cultivation, the VFAs were almost fully consumed by the bacterium in both media and PHAs production yields of 9-10%, on cell dry weight basis, were obtained. The usage of VFAs mixture was found to be beneficial for the bacterial growth that tackled the inhibition of propionic acid, iso-butyric acid, and valeric acid when these volatile fatty acids were used as single carbon sources. The extracted PHAs were revealed to be polyhydroxybutyrate (PHB) by characterization methods of Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). The obtained results proved the possibility of using VFAs from acidogenic fermentation of food waste as a cheap substrate to reduce the cost of PHAs production.
Collapse
Affiliation(s)
- Danh H Vu
- Swedish Centre for Resource Recovery, University of Borås, Sweden
| | - Steven Wainaina
- Swedish Centre for Resource Recovery, University of Borås, Sweden
| | | | - Dan Åkesson
- Swedish Centre for Resource Recovery, University of Borås, Sweden
| | - Jorge A Ferreira
- Swedish Centre for Resource Recovery, University of Borås, Sweden
| |
Collapse
|
44
|
Zhao X, Zhang Y, Cheng Y, Sun H, Bai S, Li C. Identifying environmental hotspots and improvement strategies of vanillin production with life cycle assessment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 769:144771. [PMID: 33477040 DOI: 10.1016/j.scitotenv.2020.144771] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 12/24/2020] [Accepted: 12/25/2020] [Indexed: 06/12/2023]
Abstract
Vanillin, an important aroma chemical, can be synthesized through industrial oxidation processes and biotechnological processes. Studying the environmental impacts of synthetic vanillin production processes is fundamental to making these processes feasible and sustainable; however, few studies have focused on such analyses. This study involved performing a life cycle assessment (LCA) to evaluate multiple industrial synthesis and biosynthesis processes for producing synthetic vanillin. The results indicated that human toxicity potential (HTP) appeared to be the most affected indicator among all the impact categories considered. The dominant drivers of the HTP of the vanillin synthesis process were electricity consumption and ultrapure water consumption. Improvement strategies were then proposed to investigate the possibility of reducing the environmental burdens created by vanillin synthesis. Natural gas power generation was determined to be the best choice for replacing traditional coal-fired power generation, thus reducing the negative impacts of these processes on the environment. The best ways to reduce chemical consumption were to recover organic solvents and to replace ultrapure water with industrial or distilled water. All these improvement strategies were demonstrated to be able to effectively reduce the HTP. In addition, suggestions for evaluating scaled-up vanillin production, increasing the LCA coverage to include technological advancements in biosynthesis techniques, and introducing cost-benefit analysis into the LCA were discussed.
Collapse
Affiliation(s)
- Xinyue Zhao
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Yuting Zhang
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China
| | - Yi Cheng
- College of Science, China Agricultural University, Beijing 100083, China
| | - Hongliang Sun
- Changchun Municipal Engineering Design & Research Institute, 130033 Changchun, China
| | - Shunwen Bai
- School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
| | - Chunyan Li
- College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China.
| |
Collapse
|
45
|
Koch M, Forchhammer K. Polyhydroxybutyrate: A Useful Product of Chlorotic Cyanobacteria. Microb Physiol 2021; 31:67-77. [PMID: 33979794 DOI: 10.1159/000515617] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Accepted: 03/02/2021] [Indexed: 11/19/2022]
Abstract
Polyhydroxybutyrate (PHB) is a carbon polymer with diverse functions, varying greatly on the organism producing it. This microreview describes the current knowledge about PHB metabolism, structure, and different physiological roles with a special focus on cyanobacteria. Despite the physiological function of PHB in the cyanobacterial phylum still being unknown, these organisms provide the unique opportunity to directly convert atmospheric CO2 into bioplastic using a solar-based process. Recent research on PHB metabolism in the cyanobacterial model organism Synechocystis revealed a sophisticated control of PHB granule formation. Novel insights about the metabolic background of PHB synthesis resulted in the engineering of the first cyanobacterial superproducer strain.
Collapse
Affiliation(s)
- Moritz Koch
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Karl Forchhammer
- Interfaculty Institute of Microbiology and Infection Medicine Tübingen, Eberhard Karls University Tübingen, Tübingen, Germany
| |
Collapse
|
46
|
Sindhu R, Madhavan A, Arun KB, Pugazhendhi A, Reshmy R, Awasthi MK, Sirohi R, Tarafdar A, Pandey A, Binod P. Metabolic circuits and gene regulators in polyhydroxyalkanoate producing organisms: Intervention strategies for enhanced production. BIORESOURCE TECHNOLOGY 2021; 327:124791. [PMID: 33579565 DOI: 10.1016/j.biortech.2021.124791] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/19/2021] [Accepted: 01/23/2021] [Indexed: 06/12/2023]
Abstract
Worldwide worries upsurge concerning environmental pollutions triggered by the accumulation of plastic wastes. Biopolymers are promising candidates for resolving these difficulties by replacing non-biodegradable plastics. Among biopolymers, polyhydroxyalkanoates (PHAs), are natural polymers that are synthesized and accumulated in a range of microorganisms, are considered as promising biopolymers since they have biocompatibility, biodegradability, and other physico-chemical properties comparable to those of synthetic plastics. Consequently, considerable research have been attempted to advance a better understanding of mechanisms related to the metabolic synthesis and characteristics of PHAs and to develop native and recombinant microorganisms that can proficiently produce PHAs comprising desired monomers with high titer and productivity for industrial applications. Recent developments in metabolic engineering and synthetic biology applied to enhance PHA synthesis include, promoter engineering, ribosome-binding site (RBS) engineering, development of synthetic constructs etc. This review gives a brief overview of metabolic routes and regulators of PHA production and its intervention strategies.
Collapse
Affiliation(s)
- Raveendran Sindhu
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Trivandrum 695 019, Kerala, India
| | - Aravind Madhavan
- Rajiv Gandhi Centre for Biotechnology, Trivandrum 695 014, Kerala, India
| | - K B Arun
- Rajiv Gandhi Centre for Biotechnology, Trivandrum 695 014, Kerala, India
| | - Arivalagan Pugazhendhi
- Innovative Green Product Synthesis and Renewable Environment Development Research Group, Faculty of Environment and Labour Safety, Ton Duc Thang University, Ho Chi Minh City, Viet Nam
| | - R Reshmy
- Post Graduate and Research Department of Chemistry, Bishop Moore College, Mavelikara 690 110, Kerala, India
| | - Mukesh Kumar Awasthi
- College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi Province 712100, PR China
| | - Ranjna Sirohi
- Department of Post Harvest Process and Food Engineering, G.B. Pant University of Agriculture and Technology, Pantnagar, Uttarakhand 263 145, India
| | - Ayon Tarafdar
- Divison of Livestock Production and Management, ICAR-Indian Veterinary Research Institute, Izatnagar, Bareilly 243 122, Uttar Pradesh, India
| | - Ashok Pandey
- Centre for Innovation and Translational Research, CSIR- Indian Institute for Toxicology Research (CSIR-IITR), 31 MG Marg, Lucknow 226 001, India
| | - Parameswaran Binod
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST), Trivandrum 695 019, Kerala, India.
| |
Collapse
|
47
|
Lin Y, Guan Y, Dong X, Ma Y, Wang X, Leng Y, Wu F, Ye JW, Chen GQ. Engineering Halomonas bluephagenesis as a chassis for bioproduction from starch. Metab Eng 2021; 64:134-145. [PMID: 33577951 DOI: 10.1016/j.ymben.2021.01.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 12/22/2020] [Accepted: 01/30/2021] [Indexed: 10/22/2022]
Abstract
Halomonas bluephagenesis has been successfully engineered to produce multiple products under open unsterile conditions utilizing costly glucose as the carbon source. It would be highly interesting to investigate if H. bluephagenesis, a chassis for the Next Generation Industrial Biotechnology (NGIB), can be reconstructed to become an extracellular hydrolytic enzyme producer replacing traditional enzyme producer Bacillus spp. If successful, cost of bulk hydrolytic enzymes such as amylase and protease, can be significantly reduced due to the contamination resistant and robust growth of H. bluephagenesis. This also allows H. bluephagenesis to be able to grow on low cost substrates such as starch. The modularized secretion machinery was constructed and fine-tuned in H. bluephagenesis using codon-optimized gene encoding α-amylase from Bacillus lichenifomis. Screening of suitable signal peptides and linkers based on super-fold green fluorescence protein (sfGFP) for enhanced expression in H. bluephagenesis resulted in a 7-fold enhancement of sfGFP secretion in the recombinant H. bluephagenesis. When the gene encoding sfGFP was replaced by α-amylase encoding gene, recombinant H. bluephagenesis harboring this amylase secretory system was able to produce poly(3-hydroxybutyrate) (PHB), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (P34HB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), ectoine and L-threonine utilizing starch as the growth substrate, respectively. Recombinant H. bluephagenesis TN04 expressing genes encoding α-amylase and glucosidase on chromosome and plasmid-based systems, respectively, was able to grow on corn starch to approximately 10 g/L cell dry weight containing 51% PHB when grown in shake flasks. H. bluephagenesis was demonstrated to be a chassis for productions of extracellular enzymes and multiple products from low cost corn starch.
Collapse
Affiliation(s)
- Yina Lin
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, 100084, China
| | - Yuying Guan
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xu Dong
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yueyuan Ma
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xuan Wang
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, 100084, China
| | - Yuchen Leng
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Fuqing Wu
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, 100084, China; MOE Key Lab of Industrial Biocatalysis, Tsinghua University, Beijing, 100084, China
| | - Jian-Wen Ye
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, 100084, China; Center for Materials Synthetic Biology, CAS Key Laboratory of Quantitative Engineering Biology, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.
| | - Guo-Qiang Chen
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, 100084, China; Tsinghua-Peking Center for Life Sciences, 100084, China; MOE Key Lab of Industrial Biocatalysis, Tsinghua University, Beijing, 100084, China.
| |
Collapse
|
48
|
Direct RBS Engineering of the biosynthetic gene cluster for efficient productivity of violaceins in E. coli. Microb Cell Fact 2021; 20:38. [PMID: 33557849 PMCID: PMC7869524 DOI: 10.1186/s12934-021-01518-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 01/12/2021] [Indexed: 02/07/2023] Open
Abstract
Background Violaceins have attracted much attention as potential targets used in medicines, food additives, insecticides, cosmetics and textiles, but low productivity was the key factor to limit their large-scale applications. This work put forward a direct RBS engineering strategy to engineer the violacein biosynthetic gene cluster cloned from Chromobacterium violaceum ATCC 12,472 to efficiently improve the fermentation titers. Results Through four-rounds of engineering of the native RBSs within the violaceins biosynthetic operon vioABCDE, this work apparently broke through the rate-limiting steps of intermediates conversion, resulting in 2.41-fold improvement of violaceins production compared to the titers of the starting strain Escherichia coli BL21(DE3) (Vio12472). Furthermore, by optimizing the batch-fermentation parameters including temperature, concentration of IPTG inducer and fermentation time, the maximum yield of violaceins from (BCDE)m (tnaA−) reached 3269.7 µM at 2 mM tryptophan in the medium. Interestingly, rather than previous reported low temperature (20 ℃), we for the first time found the RBS engineered Escherichia coli strain (BCDE)m worked better at higher temperature (30 ℃ and 37 ℃), leading to a higher-level production of violaceins. Conclusions To our knowledge, this is the first time that a direct RBS engineering strategy is used for the biosynthesis of natural products, having the potential for a greater improvement of the product yields within tryptophan hyperproducers and simultaneously avoiding the costly low temperature cultivation for large-scale industrial production of violaciens. This direct RBS engineering strategy could also be easily and helpfully used in engineering the native RBSs of other larger and value-added natural product biosynthetic gene clusters by widely used site-specific mutagenesis methods represented by inverse PCR or CRISPR-Cas9 techniques to increase their fermentation titers in the future.![]()
Collapse
|
49
|
Nduko JM, Taguchi S. Microbial Production of Biodegradable Lactate-Based Polymers and Oligomeric Building Blocks From Renewable and Waste Resources. Front Bioeng Biotechnol 2021; 8:618077. [PMID: 33614605 PMCID: PMC7889595 DOI: 10.3389/fbioe.2020.618077] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/17/2020] [Indexed: 12/20/2022] Open
Abstract
Polyhydroxyalkanoates (PHAs) are naturally occurring biopolymers produced by microorganisms. PHAs have become attractive research biomaterials in the past few decades owing to their extensive potential industrial applications, especially as sustainable alternatives to the fossil fuel feedstock-derived products such as plastics. Among the biopolymers are the bioplastics and oligomers produced from the fermentation of renewable plant biomass. Bioplastics are intracellularly accumulated by microorganisms as carbon and energy reserves. The bioplastics, however, can also be produced through a biochemistry process that combines fermentative secretory production of monomers and/or oligomers and chemical synthesis to generate a repertoire of biopolymers. PHAs are particularly biodegradable and biocompatible, making them a part of today's commercial polymer industry. Their physicochemical properties that are similar to those of petrochemical-based plastics render them potential renewable plastic replacements. The design of efficient tractable processes using renewable biomass holds key to enhance their usage and adoption. In 2008, a lactate-polymerizing enzyme was developed to create new category of polyester, lactic acid (LA)-based polymer and related polymers. This review aims to introduce different strategies including metabolic and enzyme engineering to produce LA-based biopolymers and related oligomers that can act as precursors for catalytic synthesis of polylactic acid. As the cost of PHA production is prohibitive, the review emphasizes attempts to use the inexpensive plant biomass as substrates for LA-based polymer and oligomer production. Future prospects and challenges in LA-based polymer and oligomer production are also highlighted.
Collapse
Affiliation(s)
- John Masani Nduko
- Department of Dairy and Food Science and Technology, Faculty of Agriculture, Egerton University, Egerton, Kenya
| | - Seiichi Taguchi
- Department of Chemistry for Life Sciences and Agriculture, Faculty of Life Sciences and Agriculture, Tokyo University of Agriculture, Tokyo, Japan
| |
Collapse
|
50
|
Turco R, Santagata G, Corrado I, Pezzella C, Di Serio M. In vivo and Post-synthesis Strategies to Enhance the Properties of PHB-Based Materials: A Review. Front Bioeng Biotechnol 2021; 8:619266. [PMID: 33585417 PMCID: PMC7874203 DOI: 10.3389/fbioe.2020.619266] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 11/30/2020] [Indexed: 12/13/2022] Open
Abstract
The transition toward "green" alternatives to petroleum-based plastics is driven by the need for "drop-in" replacement materials able to combine characteristics of existing plastics with biodegradability and renewability features. Promising alternatives are the polyhydroxyalkanoates (PHAs), microbial biodegradable polyesters produced by a wide range of microorganisms as carbon, energy, and redox storage material, displaying properties very close to fossil-fuel-derived polyolefins. Among PHAs, polyhydroxybutyrate (PHB) is by far the most well-studied polymer. PHB is a thermoplastic polyester, with very narrow processability window, due to very low resistance to thermal degradation. Since the melting temperature of PHB is around 170-180°C, the processing temperature should be at least 180-190°C. The thermal degradation of PHB at these temperatures proceeds very quickly, causing a rapid decrease in its molecular weight. Moreover, due to its high crystallinity, PHB is stiff and brittle resulting in very poor mechanical properties with low extension at break, which limits its range of application. A further limit to the effective exploitation of these polymers is related to their production costs, which is mostly affected by the costs of the starting feedstocks. Since the first identification of PHB, researchers have faced these issues, and several strategies to improve the processability and reduce brittleness of this polymer have been developed. These approaches range from the in vivo synthesis of PHA copolymers, to the enhancement of post-synthesis PHB-based material performances, thus the addition of additives and plasticizers, acting on the crystallization process as well as on polymer glass transition temperature. In addition, reactive polymer blending with other bio-based polymers represents a versatile approach to modulate polymer properties while preserving its biodegradability. This review examines the state of the art of PHA processing, shedding light on the green and cost-effective tailored strategies aimed at modulating and optimizing polymer performances. Pioneering examples in this field will be examined, and prospects and challenges for their exploitation will be presented. Furthermore, since the establishment of a PHA-based industry passes through the designing of cost-competitive production processes, this review will inspect reported examples assessing this economic aspect, examining the most recent progresses toward process sustainability.
Collapse
Affiliation(s)
- Rosa Turco
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Naples, Italy
| | - Gabriella Santagata
- Institute for Polymers, Composites and Biomaterials, National Council of Research, Pozzuoli, Italy
| | - Iolanda Corrado
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Naples, Italy
| | - Cinzia Pezzella
- Department of Agricultural Sciences, University of Naples Federico II, Portici, Italy
| | - Martino Di Serio
- Department of Chemical Sciences, University of Naples Federico II, Complesso Universitario di Monte Sant'Angelo, Naples, Italy
| |
Collapse
|