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Wei X, Yang L, Chen Z, Xia W, Chen Y, Cao M, He N. Molecular weight control of poly-γ-glutamic acid reveals novel insights into extracellular polymeric substance synthesis in Bacillus licheniformis. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:60. [PMID: 38711141 DOI: 10.1186/s13068-024-02501-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 04/04/2024] [Indexed: 05/08/2024]
Abstract
BACKGROUND The structural diversity of extracellular polymeric substances produced by microorganisms is attracting particular attention. Poly-gamma-glutamic acid (γ-PGA) is a widely studied extracellular polymeric substance from Bacillus species. The function of γ-PGA varies with its molecular weight (Mw). RESULTS Herein, different endogenous promoters in Bacillus licheniformis were selected to regulate the expression levels of pgdS, resulting in the formation of γ-PGA with Mw values ranging from 1.61 × 103 to 2.03 × 104 kDa. The yields of γ-PGA and exopolysaccharides (EPS) both increased in the pgdS engineered strain with the lowest Mw and viscosity, in which the EPS content was almost tenfold higher than that of the wild-type strain. Subsequently, the compositions of EPS from the pgdS engineered strain also changed. Metabolomics and RT-qPCR further revealed that improving the transportation efficiency of EPS and the regulation of carbon flow of monosaccharide synthesis could affect the EPS yield. CONCLUSIONS Here, we present a novel insight that increased pgdS expression led to the degradation of γ-PGA Mw and changes in EPS composition, thereby stimulating EPS and γ-PGA production. The results indicated a close relationship between γ-PGA and EPS in B. licheniformis and provided an effective strategy for the controlled synthesis of extracellular polymeric substances.
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Affiliation(s)
- Xiaoyu Wei
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, Fujian, China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, People's Republic of China
| | - Lijie Yang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, Fujian, China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, People's Republic of China
| | - Zhen Chen
- College of Life Science, Xinyang Normal University, Xinyang, 464000, China.
| | - Wenhao Xia
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, Fujian, China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, People's Republic of China
| | - Yongbin Chen
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, Fujian, China
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, People's Republic of China
| | - Mingfeng Cao
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, Fujian, China.
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, People's Republic of China.
| | - Ning He
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, Fujian, China.
- The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen, People's Republic of China.
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Zhu J, Wang X, Zhao J, Ji F, Zeng J, Wei Y, Xu L, Dong G, Ma X, Wang C. Genomic characterization and related functional genes of γ- poly glutamic acid producing Bacillus subtilis. BMC Microbiol 2024; 24:125. [PMID: 38622505 PMCID: PMC11017564 DOI: 10.1186/s12866-024-03262-z] [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: 11/04/2023] [Accepted: 03/15/2024] [Indexed: 04/17/2024] Open
Abstract
γ- poly glutamic acid (γ-PGA), a high molecular weight polymer, is synthesized by microorganisms and secreted into the extracellular space. Due to its excellent performance, γ-PGA has been widely used in various fields, including food, biomedical and environmental fields. In this study, we screened natto samples for two strains of Bacillus subtilis N3378-2at and N3378-3At that produce γ-PGA. We then identified the γ-PGA synthetase gene cluster (PgsB, PgsC, PgsA, YwtC and PgdS), glutamate racemase RacE, phage-derived γ-PGA hydrolase (PghB and PghC) and exo-γ-glutamyl peptidase (GGT) from the genome of these strains. Based on these γ-PGA-related protein sequences from isolated Bacillus subtilis and 181 B. subtilis obtained from GenBank, we carried out genotyping analysis and classified them into types 1-5. Since we found B. amyloliquefaciens LL3 can produce γ-PGA, we obtained the B. velezensis and B. amyloliquefaciens strains from GenBank and classified them into types 6 and 7 based on LL3. Finally, we constructed evolutionary trees for these protein sequences. This study analyzed the distribution of γ-PGA-related protein sequences in the genomes of B. subtilis, B. velezensis and B. amyloliquefaciens strains, then the evolutionary diversity of these protein sequences was analyzed, which provided novel information for the development and utilization of γ-PGA-producing strains.
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Affiliation(s)
- Jiayue Zhu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Xue Wang
- Guangdong key Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou, 510260, China
| | - Jianan Zhao
- Guangdong key Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou, 510260, China
| | - Fang Ji
- Guangdong key Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou, 510260, China
| | - Jun Zeng
- Guangdong key Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou, 510260, China
| | - Yanwen Wei
- Guangdong key Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou, 510260, China
| | - LiLi Xu
- Union Biology (Shanghai) Co., Ltd, Shanghai, 201100, China
| | - Guoying Dong
- College of Global Change and Earth System Science, Faculty of Geographical Science, Beijing Normal University, Beijing, 100875, China
| | - Xingyuan Ma
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China.
| | - Chengmin Wang
- Guangdong key Laboratory of Wild Animal Conservation and Utilization, Institute of Zoology, Guangdong Academy of Science, Guangzhou, 510260, China.
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Qiu Y, Xu D, Lei P, Li S, Xu H. Engineering functional homopolymeric amino acids: from biosynthesis to design. Trends Biotechnol 2024; 42:310-325. [PMID: 37775417 DOI: 10.1016/j.tibtech.2023.08.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/08/2023] [Accepted: 08/31/2023] [Indexed: 10/01/2023]
Abstract
Homopolymeric amino acids (HPAs) are a class of microbial polymers that can be classified into two categories: anionic and cationic HPAs. Notable examples include γ-poly-glutamic acid (γ-PGA) and ε-poly-L-lysine (ε-PL) that have wide-ranging applications in medicine, food, and agriculture. The primary method of manufacture is through microbial synthesis. In recent decades significant efforts have been made to enhance the production of HPAs, specifically focusing on γ-PGA and ε-PL. We comprehensively review current advances in understanding the synthetic mechanisms as well as metabolic engineering and fermentation process techniques to improve the production of HPAs. In addition, we discuss the major challenges and solutions associated with desired structure regulation of HPAs and the development of novel structures.
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Affiliation(s)
- Yibin Qiu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, PR China
| | - Delei Xu
- College of Biological and Food Engineering, Changshu Institute of Technology, 99 South Third Ring Road, Changshu 215500, PR China
| | - Peng Lei
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, PR China
| | - Sha Li
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, PR China.
| | - Hong Xu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, PR China; Nanjing Shineking Biotech Co. Ltd., Nanjing 210061, PR China.
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4
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Qiao M, Zhang T, Miao M. Minced Beef Meat Paste Characteristics: Gel Properties, Water Distribution, and Microstructures Regulated by Medium Molecular Mass of γ-Poly-Glutamic Acid. Foods 2024; 13:510. [PMID: 38397487 PMCID: PMC10887638 DOI: 10.3390/foods13040510] [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: 01/09/2024] [Revised: 02/01/2024] [Accepted: 02/04/2024] [Indexed: 02/25/2024] Open
Abstract
The influences of various m-γ-PGA (0.08-0.20%, w/w) concentrations on the properties of minced beef meat paste in terms of rheological properties, texture, moisture distribution, and microstructures were evaluated. The results indicated that m-γ-PGA enhanced the water-holding capacity, gel strength, texture, and whiteness of the minced beef meat paste. Based on the microstructural results, m-γ-PGA helped form a more organized and compact gel, thereby limiting the migration of water through the gel matrix. In contrast to the control group, the water-holding property, gel strength, and whiteness of minced meat paste gels with m-γ-PGA content of 0.12% increased from 75.89%, 584.51 g·cm, and 61.83 to 79.91%, 780.87 g·cm, and 62.54, respectively (p < 0.05), exhibiting the highest water-holding property and gel strength. Thus, m-γ-PGA exhibits great potential for minced meat paste products as a healthy gel water retainer and enhancer in low-fat meat products.
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Affiliation(s)
- Mengmeng Qiao
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; (M.Q.); (M.M.)
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Tao Zhang
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; (M.Q.); (M.M.)
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Ming Miao
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; (M.Q.); (M.M.)
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
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5
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Wang F, Chen Y, Zheng J, Yang C, Li L, Li R, Shi M, Li Z. Preparation of potential organic fertilizer rich in γ-polyglutamic acid via microbial fermentation using brewer's spent grain as basic substrate. BIORESOURCE TECHNOLOGY 2024; 394:130216. [PMID: 38122994 DOI: 10.1016/j.biortech.2023.130216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023]
Abstract
Brewer's spent grain (BSG) is a main byproduct of the beer industry. BSG is rich in a variety of nutrients, and the search for its effective, high-value utilization is ongoing. Environmental probiotic factor γ-PGA was produced by fermenting Bacillus subtilis with BSG substrate and the fermenting grain components were analyzed. The γ-PGA yield reached 31.58 ± 0.21 g/kg of BSG. Gas chromatography-mass spectrometry and non-targeted metabolomics analyses revealed 73 new volatile substances in the fermenting grains. Furthermore, 2,376 metabolites were upregulated after fermentation and several components were beneficial for plant growth and development (such as ectoine, acetyl eugenol, L-phenylalanine, niacin, isoprene, pantothenic acid, dopamine, glycine, proline, jasmonic acid, etc). These results show that it is possible to synthesize adequate amounts of γ-PGA for use as a functional fertilizer.
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Affiliation(s)
- Fengqing Wang
- College of Biotechnology, Sichuan University of Science and Engineering, Yibin 644000, China
| | - Yanmei Chen
- College of Biotechnology, Sichuan University of Science and Engineering, Yibin 644000, China
| | - Jia Zheng
- Wuliangye Yibin Co., Ltd., Yibin, Sichuan 644000, China
| | - Can Yang
- College of Biotechnology, Sichuan University of Science and Engineering, Yibin 644000, China
| | - Li Li
- College of Biotechnology, Sichuan University of Science and Engineering, Yibin 644000, China
| | - Rong Li
- College of Biotechnology, Sichuan University of Science and Engineering, Yibin 644000, China
| | - Meilin Shi
- College of Biotechnology, Sichuan University of Science and Engineering, Yibin 644000, China
| | - Zhongxuan Li
- College of Biotechnology, Sichuan University of Science and Engineering, Yibin 644000, China.
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6
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Xu G, Wang J, Shen J, Zhu Y, Liu W, Chen Y, Zha J, Zhang X, Zhang X, Shi J, Koffas MAG, Xu Z. Enhanced poly-γ-glutamic acid synthesis in Corynebacterium glutamicum by reconstituting PgsBCA complex and fermentation optimization. Metab Eng 2024; 81:238-248. [PMID: 38160746 DOI: 10.1016/j.ymben.2023.12.008] [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: 07/07/2023] [Revised: 12/14/2023] [Accepted: 12/18/2023] [Indexed: 01/03/2024]
Abstract
Previously, a novel Corynebacterium glutamicum strain for the de novo biosynthesis of tailored poly-γ-glutamic acid (γ-PGA) has been constructed by our group. The strain was based on the γ-PGA synthetase complex, PgsBCA, which is the only polyprotein complex responsible for γ-PGA synthesis in Bacillus spp. In the present study, PgsBCA was reconstituted and overexpressed in C. glutamicum to further enhance γ-PGA synthesis. First, we confirmed that all the components (PgsB, PgsC, and PgsA) of γ-PGA synthetase derived from B. licheniformis are necessary for γ-PGA synthesis, and γ-PGA was detected only when PgsB, PgsC, and PgsA were expressed in combination in C. glutamicum. Next, the expression level of each pgsB, pgsC, and pgsA was tuned in order to explore the effect of expression of each of the γ-PGA synthetase subunits on γ-PGA production. Results showed that increasing the transcription levels of pgsB or pgsC and maintaining a medium-level transcription level of pgsA led to 35.44% and 76.53% increase in γ-PGA yield (γ-PGA yield-to-biomass), respectively. Notably, the expression level of pgsC had the greatest influence (accounting for 68.24%) on γ-PGA synthesis, followed by pgsB. Next, genes encoding for PgsC from four different sources (Bacillus subtilis, Bacillus anthracis, Bacillus methylotrophicus, and Bacillus amyloliquefaciens) were tested in order to identify the influence of PgsC-encoding orthologues on γ-PGA production, but results showed that in all cases the synthesis of γ-PGA was significantly inhibited. Similarly, we also explored the influence of gene orthologues encoding for PgsB on γ-PGA production, and found that the titer increased to 17.14 ± 0.62 g/L from 8.24 ± 0.10 g/L when PgsB derived from B. methylotrophicus replaced PgsB alone in PgsBCA from B. licheniformis. The resulting strain was chosen for further optimization, and we achieved a γ-PGA titer of 38.26 g/L in a 5 L fermentor by optimizing dissolved oxygen level. Subsequently, by supplementing glucose, γ-PGA titer increased to 50.2 g/L at 48 h. To the best of our knowledge, this study achieved the highest titer for de novo production of γ-PGA from glucose, without addition of L-glutamic acid, resulting in a novel strategy for enhancing γ-PGA production.
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Affiliation(s)
- Guoqiang Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi, 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China; Yixing Institute of Food and Biotechnology, Yixing, 214200, China
| | - Jiyue Wang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi, 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China
| | - Jiancheng Shen
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi, 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China; Yixing Institute of Food and Biotechnology, Yixing, 214200, China
| | - Yaxin Zhu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi, 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China
| | - Wanjing Liu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi, 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China; Yixing Institute of Food and Biotechnology, Yixing, 214200, China
| | - Yuhang Chen
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi, 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China; Yixing Institute of Food and Biotechnology, Yixing, 214200, China
| | - Jian Zha
- School of Food and Biological Engineering, Shaanxi University of Science and Technology, Xi'an, Shaanxi, 710021, China
| | - Xiaomei Zhang
- Laboratory of Pharmaceutical Engineering, School of Life Science and Health Engineering, Jiangnan University, Wuxi, 214122, China; Yixing Institute of Food and Biotechnology, Yixing, 214200, China
| | - Xiaojuan Zhang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi, 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China
| | - Jinsong Shi
- Laboratory of Pharmaceutical Engineering, School of Life Science and Health Engineering, Jiangnan University, Wuxi, 214122, China; Yixing Institute of Food and Biotechnology, Yixing, 214200, China
| | - Mattheos A G Koffas
- Center for Biotechnology and Interdisciplinary Studies and Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY, 12180, USA.
| | - Zhenghong Xu
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, 214122, China; National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi, 214122, China; Jiangsu Provincial Engineering Research Center for Bioactive Product Processing Technology, Jiangnan University, Wuxi, 214122, China; Yixing Institute of Food and Biotechnology, Yixing, 214200, China.
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7
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Chen X, Peng Z, Ji X, Zhang J. Reducing Cellular Autolysis of Bacillus subtilis to Improve Keratinase Production. ACS Synth Biol 2023; 12:3106-3113. [PMID: 37677132 DOI: 10.1021/acssynbio.3c00458] [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] [Indexed: 09/09/2023]
Abstract
Bacillus subtilis has been shown to be an excellent expression host for keratinases due to its powerful secretion system. However, cellular autolysis limits its production capacity. Here, we selected seven genes with significantly upregulated transcript levels from 15 genes associated with cellular autolysis as knockout targets by qRT-PCR and constructed a total of 127 strains to reduce cellular autolysis. Among them, the biomass of B. subtilis BSΔXLPC-ker deficient in xpf, lytC, pcfA, and cwlC increased by 57%. This was confirmed by cell staining, green fluorescent protein imaging, and extracellular nucleic acid leakage assay. Keratinase activity was increased by 1.46-fold in the 5 L fermenter. In addition, the activities of nattokinase and subtilisin E were also increased by 1.50-fold and 1.43-fold, respectively, in the modified chassis cells, which further confirms the generalizability of the strategy. Thus, reducing cellular autolysis to increase the ability of B. subtilis to produce subtilisins is promising.
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Affiliation(s)
- Xiwen Chen
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
- Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
| | - Zheng Peng
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
- Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
| | - Xiaomei Ji
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
- Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
| | - Juan Zhang
- Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
- Science Center for Future Foods, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
- Engineering Research Center of Ministry of Education on Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
- Jiangsu Province Engineering Research Center of Food Synthetic Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China
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Wei X, Chen Z, Liu A, Yang L, Xu Y, Cao M, He N. Advanced strategies for metabolic engineering of Bacillus to produce extracellular polymeric substances. Biotechnol Adv 2023; 67:108199. [PMID: 37330153 DOI: 10.1016/j.biotechadv.2023.108199] [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: 03/05/2023] [Revised: 05/24/2023] [Accepted: 06/11/2023] [Indexed: 06/19/2023]
Abstract
Extracellular polymeric substances are mainly synthesized via a variety of biosynthetic pathways in bacteria. Bacilli-sourced extracellular polymeric substances, such as exopolysaccharides (EPS) and poly-γ-glutamic acid (γ-PGA), can serve as active ingredients and hydrogels, and have other important industrial applications. However, the functional diversity and widespread applications of these extracellular polymeric substances, are hampered by their low yields and high costs. Biosynthesis of extracellular polymeric substances is very complex in Bacillus, and there is no detailed elucidation of the reactions and regulations among various metabolic pathways. Therefore, a better understanding of the metabolic mechanisms is required to broaden the functions and increase the yield of extracellular polymeric substances. This review systematically summarizes the biosynthesis and metabolic mechanisms of extracellular polymeric substances in Bacillus, providing an in-depth understanding of the relationships between EPS and γ-PGA synthesis. This review provides a better clarification of Bacillus metabolic mechanisms during extracellular polymeric substance secretion and thus benefits their application and commercialization.
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Affiliation(s)
- Xiaoyu Wei
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Zhen Chen
- College of Life Science, Xinyang Normal University, Xinyang 464000, China.
| | - Ailing Liu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Lijie Yang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Yiyuan Xu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Mingfeng Cao
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China; Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province (IKKEM), Xiamen 361005, China.
| | - Ning He
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Lab for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China.
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9
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Chen S, Fu J, Yu B, Wang L. Development of a Conjugation-Based Genome Editing System in an Undomesticated Bacillus subtilis Strain for Poly-γ-glutamic Acid Production with Diverse Molecular Masses. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:7734-7743. [PMID: 37186794 DOI: 10.1021/acs.jafc.3c01505] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Poly-γ-glutamic acid (γ-PGA) is a biodegradable polymer produced by microorganisms. Biosynthesizing γ-PGA with diverse molecular masses (Mw) is an urgent industrial technical problem to be solved. Bacillus subtilis KH2, a high-Mw γ-PGA producer, is an ideal candidate for de novo production of γ-PGA with diverse Mw values. However, the inability to transfer DNA to this strain has limited its industrial use. In this study, a conjugation-based genetic operating system was developed in strain KH2. This system enabled us to modify the promoter of γ-PGA hydrolase PgdS in strain KH2 chromosome to de novo biosynthesize γ-PGA with diverse Mws. The conjugation efficiency was improved to 1.23 × 10-4 by establishing a plasmid replicon sharing strategy. A further increase to 3.15 × 10-3 was achieved after knocking out two restriction endonucleases. To demonstrate the potential of our newly established system, the pgdS promoter was replaced by different phase-dependent promoters. A series of strains producing γ-PGA with specific Mws of 411.73, 1356.80, 2233.30, and 2411.87 kDa, respectively, were obtained. The maximum yield of γ-PGA was 23.28 g/L. Therefore, we have successfully constructed ideal candidate strains for efficient γ-PGA production with a specific Mw value, which provides an important research basis for sustainable production of desirable γ-PGA.
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Affiliation(s)
- Shengbao Chen
- CAS Key Laboratory of Microbial Physiological & Metabolic Engineering, State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jiaming Fu
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Bo Yu
- CAS Key Laboratory of Microbial Physiological & Metabolic Engineering, State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Limin Wang
- CAS Key Laboratory of Microbial Physiological & Metabolic Engineering, State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
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10
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Yu Z, Wei Y, Fu C, Sablani SS, Huang Z, Han C, Li D, Sun Z, Qin H. Antimicrobial activity of gamma-poly (glutamic acid), a preservative coating for cherries. Colloids Surf B Biointerfaces 2023; 225:113272. [PMID: 36996631 DOI: 10.1016/j.colsurfb.2023.113272] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 03/13/2023] [Accepted: 03/16/2023] [Indexed: 03/30/2023]
Abstract
We investigated the minimum inhibitory concentration (MIC), antibacterial activity, and preservation ability of four molar masses of γ-polyglutamic acid (PGA) against Escherichia coli, Bacillus subtilis, and yeast. The antibacterial mechanism was determined based on the cell structure, membrane permeability, and microscopic morphology of the microorganisms. We then measured the weight loss, decay rate, total acid, catalase activity, peroxidase activity, and malondialdehyde content toward the possible use of PGA as a preservative coating for cherries. When the molar mass was greater than 700 kDa, the MIC for Escherichia coli and Bacillus subtilis was less than 2.5 mg/mL. The mechanism of action of the four molar masses of PGA was different with respect to the three microbial species, but a higher molar mass of PGA corresponded to stronger inhibition against the microbes. PGA of 2000 kDa molar mass damaged the microbial cellular structure, resulting in excretion of alkaline phosphatase, but PGA of 1.5 kDa molar mass affected the membrane permeability and the amount of soluble sugar. Scanning electron microscopy indicated the inhibitory effect of PGA. The antibacterial mechanism of PGA was related to the molar mass of PGA and the microbial membrane structure. Compared with the control, a PGA coating effectively inhibit the spoilage rate, delay the ripening, and prolong the shelf life of cherries.
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11
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Hoffmann K, Halmschlag B, Briel S, Sieben M, Putri S, Fukusaki E, Blank LM, Büchs J. Online measurement of the viscosity in shake flasks enables monitoring of γ-PGA production in depolymerase knockout mutants of Bacillus subtilis with the phosphate-starvation inducible promoter P pst. Biotechnol Prog 2023; 39:e3293. [PMID: 36081345 DOI: 10.1002/btpr.3293] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 07/26/2022] [Accepted: 08/11/2022] [Indexed: 11/10/2022]
Abstract
Poly-γ-glutamic acid (γ-PGA) is a biopolymer with a wide range of applications, mainly produced using Bacillus strains. The formation and concomitant secretion of γ-PGA increases the culture broth viscosity, while enzymatic depolymerisation and degradation of γ-PGA decreases the culture broth viscosity. In this study, the recently published ViMOS (Viscosity Monitoring Online System) is applied for optical online measurements of broth viscosity in eight parallel shake flasks. It is shown that the ViMOS is suitable to monitor γ-PGA production and degradation online in shake flasks. This online monitoring enables the detailed analysis of the Ppst promoter and γ-PGA depolymerase knockout mutants in genetically modified Bacillus subtilis 168. The Ppst promoter becomes active under phosphate starvation. The different single depolymerase knockout mutants are ∆ggt, ∆pgdS, ∆cwlO and a triple knockout mutant. An increase in γ-PGA yield in gγ-PGA /gglucose of 190% could be achieved with the triple knockout mutant compared to the Ppst reference strain. The single cwlO knockout also increased γ-PGA production, while the other single knockouts of ggt and pgdS showed no impact. Partial depolymerisation of γ-PGA occurred despite the triple knockout. The online measured data are confirmed with offline measurements. The online viscosity system directly reflects γ-PGA synthesis, γ-PGA depolymerisation, and changes in the molecular weight. Thus, the ViMOS has great potential to rapidly gain detailed and reliable information about new strains and cultivation conditions. The broadened knowledge will facilitate the further optimization of γ-PGA production.
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Affiliation(s)
- Kyra Hoffmann
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Birthe Halmschlag
- Institute of Applied Microbiology - iAMB, Aachen Biology and Biotechnology - ABBt, RWTH Aachen University, Aachen, Germany
| | - Simon Briel
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Michaela Sieben
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Sastia Putri
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan
| | - Eiichiro Fukusaki
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan
| | - Lars M Blank
- Institute of Applied Microbiology - iAMB, Aachen Biology and Biotechnology - ABBt, RWTH Aachen University, Aachen, Germany
| | - Jochen Büchs
- AVT - Biochemical Engineering, RWTH Aachen University, Aachen, Germany
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12
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Hu LX, Zhao M, Hu WS, Zhou MJ, Huang JB, Huang XL, Gao XL, Luo YN, Li C, Liu K, Xue ZL, Liu Y. Poly-γ-Glutamic Acid Production by Engineering a DegU Quorum-Sensing Circuit in Bacillus subtilis. ACS Synth Biol 2022; 11:4156-4170. [PMID: 36416371 DOI: 10.1021/acssynbio.2c00464] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
As a natural biological macromolecule, γ-polyglutamic acid (γ-PGA) plays a significant role in medicine, food, and cosmetic industries owing to its unique properties of biocompatibility, biodegradability, water solubility, and viscosity. Although many strategies have been adopted to increase the yield of γ-PGA in Bacillus subtilis, the effectiveness of these common approaches is not high because the strong viscosity affects cell growth. However, dynamic regulation based on quorum sensing (QS) has been extensively applied as a fundamental tool for fine-tuning gene expression in reaction to changes in cell density without adding expensive inducers. A modular PhrQ-RapQ-DegU QS system is developed based on promoter PD4, which is upregulated by phosphorylated DegU (DegU-P). In this study, first, we analyzed the DegU-based gene expression regulation system in B. subtilis 168. We constructed a promoter library of different abilities, selected suitable promoters from the library, and performed mutation screening on the selected promoters and degU region. Furthermore, we constructed a PhrQ-RapQ-DegU QS system to dynamically control the synthesis of γ-PGA in BS168. Cell growth and efficient synthesis of the target product can be dynamically balanced by the QS system. Our dynamic adjustment approach increased the yield of γ-PGA to 6.53-fold of that by static regulation in a 3 L bioreactor, which verified the effectiveness of this strategy. In summary, the PhrQ-RapQ-DegU QS system has been successfully integrated with biocatalytic functions to achieve dynamic metabolic pathway control in BS168, which can be stretched to a large number of microorganisms to fine-tune gene expression and enhance the production of metabolites.
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Affiliation(s)
- Liu-Xiu Hu
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu 241000, China.,Anhui Zhang Hengchun Pharmaceutical Co., Ltd., Wuhu 241000, China
| | - Ming Zhao
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu 241000, China.,Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, Wuhu 241000, China
| | - Wen-Song Hu
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu 241000, China
| | - Meng-Jie Zhou
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu 241000, China
| | - Jun-Bao Huang
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu 241000, China
| | - Xi-Lin Huang
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu 241000, China
| | - Xu-Li Gao
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu 241000, China
| | - Ya-Ni Luo
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu 241000, China
| | - Chuang Li
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu 241000, China.,Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, Wuhu 241000, China
| | - Kun Liu
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu 241000, China.,Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, Wuhu 241000, China
| | - Zheng-Lian Xue
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu 241000, China.,Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, Wuhu 241000, China
| | - Yan Liu
- College of Biological and Food Engineering, Anhui Polytechnic University, Wuhu 241000, China.,Anhui Engineering Laboratory for Industrial Microbiology Molecular Breeding, Wuhu 241000, China
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13
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Parati M, Khalil I, Tchuenbou-Magaia F, Adamus G, Mendrek B, Hill R, Radecka I. Building a circular economy around poly(D/L-γ-glutamic acid)- a smart microbial biopolymer. Biotechnol Adv 2022; 61:108049. [DOI: 10.1016/j.biotechadv.2022.108049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 10/03/2022] [Accepted: 10/06/2022] [Indexed: 11/26/2022]
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14
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Li Y, Yan Z, Liu J, Song C, Zhu F, Wang S. The evaluation of Bacillus-secreted polyglutamic acid as anti-scaling treatment for circulating cooling water. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:82762-82771. [PMID: 35752665 DOI: 10.1007/s11356-022-21299-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 06/01/2022] [Indexed: 06/15/2023]
Abstract
Polyaspartic acid is considered a green agent for the treatment of circulating cooling water. However, its chemosynthetic process is not green, as it requires significant amounts of energy and causes water pollution. In this work, we identified an analog of polyaspartic acid, namely polyglutamic acid (γ-PGA), which could be directly produced by Bacillus spp., and we explored its performance and scale inhibition mechanism as a scale inhibitor. We found that γ-PGA secreted by B. megaterium with a molecular weight of ~ 70 kDa showed poor scale inhibition, while the γ-PGA secreted by B. licheniformis with a molecular weight of ~ 15 kDa had a 26.87% higher efficiency compared to commercially available polyaspartic acid. The scale inhibition mechanism was explored using the γ-PGA material secreted by B. licheniformis. Fourier transform spectrometer, field emission scanning electron microscopy, and X-ray photoelectron spectroscopy analysis demonstrated that the scale inhibition performance of γ-PGA was due to the combination of its functional groups and Ca2+, which affected the growth process of CaCO3 and inhibited the formation of CaCO3. This study provided deeper insight into scale inhibition performance related to the scale inhibition mechanism.
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Affiliation(s)
- Yutong Li
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China
| | - Zhen Yan
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China
| | - Jun Liu
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China
| | - Chao Song
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China
| | - Fanping Zhu
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China
| | - Shuguang Wang
- Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China.
- Sino-French Research Institute for Ecology and Environment (ISFREE), School of Environmental Science and Engineering, Shandong University, Qingdao, 266237, China.
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15
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Zhang Z, He P, Cai D, Chen S. Genetic and metabolic engineering for poly-γ-glutamic acid production: current progress, challenges, and prospects. World J Microbiol Biotechnol 2022; 38:208. [DOI: 10.1007/s11274-022-03390-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 08/13/2022] [Indexed: 11/29/2022]
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16
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Li J, Chen S, Fu J, Xie J, Ju J, Yu B, Wang L. Efficient molasses utilization for low-molecular-weight poly-γ-glutamic acid production using a novel Bacillus subtilis stain. Microb Cell Fact 2022; 21:140. [PMID: 35842664 PMCID: PMC9287850 DOI: 10.1186/s12934-022-01867-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 07/05/2022] [Indexed: 11/26/2022] Open
Abstract
Background Poly-γ-glutamic acid (γ-PGA) is a biopolymer and has various applications based on its biocompatibility, non-toxicity, and edibility. Low-molecular-weight (Mw)-γ-PGA has promising applications in agriculture and pharmaceuticals. It is traditionally produced by enzymatic hydrolysis. Cost-effective bioproduction of low-Mw-γ-PGA is essential for commercial application of γ-PGA. Results Bacillus subtilis 242 is a newly isolated low-Mw-γ-PGA-producing strain. To develop cost-effective production of γ-PGA using this newly isolated strain, cane molasses and corn steep liquor were used to produce γ-PGA. The concentration of cane molasses was optimized and 100 g/L cane molasses resulted in high γ-PGA production. The effects of yeast extract and corn steep liquor on γ-PGA yield were investigated. High concentration of γ-PGA was obtained in the medium with corn steep liquor. A concentration of 32.14 g/L γ-PGA was achieved in fed-batch fermentation, with a productivity of 0.67 g/L/h and a percentage yield (gγ-PGA/gglutamate) of 106.39%. The Mw of γ-PGA was 27.99 kDa. Conclusion This study demonstrated the potential application of B. subtilis 242 for cost-effective production of low-Mw-γ-PGA from cane molasses.
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Affiliation(s)
- Jing Li
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology & Business University (BTBU), Beijing, 100048, People's Republic of China.,College of Life Science, Hebei Normal University, Shijiazhuang, 050024, People's Republic of China.,CAS Key Laboratory of Microbial Physiological & Metabolic Engineering, State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Shengbao Chen
- CAS Key Laboratory of Microbial Physiological & Metabolic Engineering, State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jiaming Fu
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037, People's Republic of China
| | - Jianchun Xie
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology & Business University (BTBU), Beijing, 100048, People's Republic of China
| | - Jiansong Ju
- College of Life Science, Hebei Normal University, Shijiazhuang, 050024, People's Republic of China
| | - Bo Yu
- CAS Key Laboratory of Microbial Physiological & Metabolic Engineering, State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Limin Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing Technology & Business University (BTBU), Beijing, 100048, People's Republic of China. .,CAS Key Laboratory of Microbial Physiological & Metabolic Engineering, State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
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17
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Efficient production of poly-γ-glutamic acid by Bacillus velezensis via solid-state fermentation and its application. FOOD BIOSCI 2022. [DOI: 10.1016/j.fbio.2022.101575] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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18
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Wang L, Chen S, Yu B. Poly-γ-glutamic acid: Recent achievements, diverse applications and future perspectives. Trends Food Sci Technol 2022. [DOI: 10.1016/j.tifs.2021.11.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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19
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Blanco FG, Hernández N, Rivero-Buceta V, Maestro B, Sanz JM, Mato A, Hernández-Arriaga AM, Prieto MA. From Residues to Added-Value Bacterial Biopolymers as Nanomaterials for Biomedical Applications. NANOMATERIALS 2021; 11:nano11061492. [PMID: 34200068 PMCID: PMC8228158 DOI: 10.3390/nano11061492] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 05/20/2021] [Accepted: 05/26/2021] [Indexed: 12/16/2022]
Abstract
Bacterial biopolymers are naturally occurring materials comprising a wide range of molecules with diverse chemical structures that can be produced from renewable sources following the principles of the circular economy. Over the last decades, they have gained substantial interest in the biomedical field as drug nanocarriers, implantable material coatings, and tissue-regeneration scaffolds or membranes due to their inherent biocompatibility, biodegradability into nonhazardous disintegration products, and their mechanical properties, which are similar to those of human tissues. The present review focuses upon three technologically advanced bacterial biopolymers, namely, bacterial cellulose (BC), polyhydroxyalkanoates (PHA), and γ-polyglutamic acid (PGA), as models of different carbon-backbone structures (polysaccharides, polyesters, and polyamides) produced by bacteria that are suitable for biomedical applications in nanoscale systems. This selection models evidence of the wide versatility of microorganisms to generate biopolymers by diverse metabolic strategies. We highlight the suitability for applied sustainable bioprocesses for the production of BC, PHA, and PGA based on renewable carbon sources and the singularity of each process driven by bacterial machinery. The inherent properties of each polymer can be fine-tuned by means of chemical and biotechnological approaches, such as metabolic engineering and peptide functionalization, to further expand their structural diversity and their applicability as nanomaterials in biomedicine.
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Affiliation(s)
- Francisco G. Blanco
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), 28040 Madrid, Spain; (F.G.B.); (N.H.); (V.R.-B.); (A.M.); (A.M.H.-A.)
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain
| | - Natalia Hernández
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), 28040 Madrid, Spain; (F.G.B.); (N.H.); (V.R.-B.); (A.M.); (A.M.H.-A.)
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain
| | - Virginia Rivero-Buceta
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), 28040 Madrid, Spain; (F.G.B.); (N.H.); (V.R.-B.); (A.M.); (A.M.H.-A.)
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain
| | - Beatriz Maestro
- Host-Parasite Interplay in Pneumococcal Infection Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain; (B.M.); (J.M.S.)
| | - Jesús M. Sanz
- Host-Parasite Interplay in Pneumococcal Infection Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain; (B.M.); (J.M.S.)
| | - Aránzazu Mato
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), 28040 Madrid, Spain; (F.G.B.); (N.H.); (V.R.-B.); (A.M.); (A.M.H.-A.)
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain
| | - Ana M. Hernández-Arriaga
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), 28040 Madrid, Spain; (F.G.B.); (N.H.); (V.R.-B.); (A.M.); (A.M.H.-A.)
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain
| | - M. Auxiliadora Prieto
- Interdisciplinary Platform for Sustainable Plastics towards a Circular Economy-Spanish National Research Council (SusPlast-CSIC), 28040 Madrid, Spain; (F.G.B.); (N.H.); (V.R.-B.); (A.M.); (A.M.H.-A.)
- Polymer Biotechnology Group, Microbial and Plant Biotechnology Department, Biological Research Centre Margarita Salas, CIB-CSIC, 28040 Madrid, Spain
- Correspondence:
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20
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Wang X, Han JN, Zhang X, Ma YY, Lin Y, Wang H, Li DJ, Zheng TR, Wu FQ, Ye JW, Chen GQ. Reversible thermal regulation for bifunctional dynamic control of gene expression in Escherichia coli. Nat Commun 2021; 12:1411. [PMID: 33658500 PMCID: PMC7930084 DOI: 10.1038/s41467-021-21654-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 02/03/2021] [Indexed: 11/08/2022] Open
Abstract
Genetically programmed circuits allowing bifunctional dynamic regulation of enzyme expression have far-reaching significances for various bio-manufactural purposes. However, building a bio-switch with a post log-phase response and reversibility during scale-up bioprocesses is still a challenge in metabolic engineering due to the lack of robustness. Here, we report a robust thermosensitive bio-switch that enables stringent bidirectional control of gene expression over time and levels in living cells. Based on the bio-switch, we obtain tree ring-like colonies with spatially distributed patterns and transformer cells shifting among spherical-, rod- and fiber-shapes of the engineered Escherichia coli. Moreover, fed-batch fermentations of recombinant E. coli are conducted to obtain ordered assembly of tailor-made biopolymers polyhydroxyalkanoates including diblock- and random-copolymer, composed of 3-hydroxybutyrate and 4-hydroxybutyrate with controllable monomer molar fraction. This study demonstrates the possibility of well-organized, chemosynthesis-like block polymerization on a molecular scale by reprogrammed microbes, exemplifying the versatility of thermo-response control for various practical uses.
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Affiliation(s)
- Xuan Wang
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Jia-Ning Han
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xu Zhang
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yue-Yuan Ma
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yina Lin
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Huan Wang
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Dian-Jie Li
- School of Physics, Peking University, Beijing, China
| | - Tao-Ran Zheng
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Fu-Qing Wu
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China
- MOE Key Lab of Industrial Biocatalysts, Department of Chemical Engineering, Tsinghua University, Beijing, China
| | - Jian-Wen Ye
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China.
- MOE Key Lab of Industrial Biocatalysts, Department of Chemical Engineering, Tsinghua University, Beijing, 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, China.
| | - Guo-Qiang Chen
- Center for Synthetic and Systems Biology, School of Life Sciences, Tsinghua University, Beijing, China.
- Tsinghua-Peking Center for Life Sciences, Beijing, China.
- MOE Key Lab of Industrial Biocatalysts, Department of Chemical Engineering, Tsinghua University, Beijing, China.
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21
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Connor AJ, Zha RH, Koffas M. Bioproduction of biomacromolecules for antiviral applications. Curr Opin Biotechnol 2021; 69:263-272. [PMID: 33667798 DOI: 10.1016/j.copbio.2021.01.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 01/14/2021] [Accepted: 01/25/2021] [Indexed: 02/07/2023]
Abstract
The societal damage brought on by viral epidemics indicates that next-generation antiviral treatments must be developed and deployed. Biomacromolecules are a diverse class of compounds that can potentially exhibit potent antiviral activity. Their efficacy and mechanisms of action are dependent upon multiple structural factors, including molecular weight, degree and position of sulfation, and backbone stereochemistry. Extracting biomacromolecules from animals and plants for healthcare applications is undesirable, as these methods are unable to yield products with well-defined chemical structures. Modern advances utilizing recombinant microbes and metabolic pathway engineering can be a key step towards large-scale bioproduction of tailored biomacromolecules for targeted antiviral applications.
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Affiliation(s)
- Alexander J Connor
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Runye H Zha
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Mattheos Koffas
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
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22
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Sun L, Xin F, Alper HS. Bio-synthesis of food additives and colorants-a growing trend in future food. Biotechnol Adv 2021; 47:107694. [PMID: 33388370 DOI: 10.1016/j.biotechadv.2020.107694] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 12/24/2020] [Accepted: 12/27/2020] [Indexed: 02/07/2023]
Abstract
Food additives and colorants are extensively used in the food industry to improve food quality and safety during processing, storage and packing. Sourcing of these molecules is predominately through three means: extraction from natural sources, chemical synthesis, and bio-production, with the first two being the most utilized. However, growing demands for sustainability, safety and "natural" products have renewed interest in using bio-based production methods. Likewise, the move to more cultured foods and meat alternatives requires the production of new additives and colorants. The production of bio-based food additives and colorants is an interdisciplinary research endeavor and represents a growing trend in future food. To highlight the potential of microbial hosts for food additive and colorant production, we focus on current advances for example molecules based on their utilization stage and bio-production yield as follows: (I) approved and industrially produced with high titers; (II) approved and produced with decent titers (in the g/L range), but requiring further engineering to reduce production costs; (III) approved and produced with very early stage titers (in the mg/L range); and (IV) new/potential candidates that have not been approved but can be sourced through microbes. Promising approaches, as well as current challenges and future directions will also be thoroughly discussed for the bioproduction of these food additives and colorants.
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Affiliation(s)
- Lichao Sun
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, People's Republic of China.
| | - Fengjiao Xin
- Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing 100193, People's Republic of China.
| | - Hal S Alper
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, 2500 Speedway Avenue, Austin, TX 78712, United States; McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton St. Stop C0400, Austin, TX 78712, United States.
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Li Y, Wang J, Liu N, Ke L, Zhao X, Qi G. Microbial synthesis of poly-γ-glutamic acid (γ-PGA) with fulvic acid powder, the waste from yeast molasses fermentation. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:180. [PMID: 33133238 PMCID: PMC7594462 DOI: 10.1186/s13068-020-01818-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 10/16/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Molasses is a wildly used feedstock for fermentation, but it also poses a severe wastewater-disposal problem worldwide. Recently, the wastewater from yeast molasses fermentation is being processed into fulvic acid (FA) powder as a fertilizer for crops, but it consequently induces a problem of soil acidification after being directly applied into soil. In this study, the low-cost FA powder was bioconverted into a value-added product of γ-PGA by a glutamate-independent producer of Bacillus velezensis GJ11. RESULTS FA power could partially substitute the high-cost substrates such as sodium glutamate and citrate sodium for producing γ-PGA. With FA powder in the fermentation medium, the amount of sodium glutamate and citrate sodium used for producing γ-PGA were both decreased around one-third. Moreover, FA powder could completely substitute Mg2+, Mn2+, Ca2+, and Fe3+ in the fermentation medium for producing γ-PGA. In the optimized medium with FA powder, the γ-PGA was produced at 42.55 g/L with a productivity of 1.15 g/(L·h), while only 2.87 g/L was produced in the medium without FA powder. Hydrolyzed γ-PGA could trigger induced systemic resistance (ISR), e.g., H2O2 accumulation and callose deposition, against the pathogen's infection in plants. Further investigations found that the ISR triggered by γ-PGA hydrolysates was dependent on the ethylene (ET) signaling and nonexpressor of pathogenesis-related proteins 1 (NPR1). CONCLUSIONS To our knowledge, this is the first report to use the industry waste, FA powder, as a sustainable substrate for microbial synthesis of γ-PGA. This bioprocess can not only develop a new way to use FA powder as a cheap feedstock for producing γ-PGA, but also help to reduce pollution from the wastewater of yeast molasses fermentation.
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Affiliation(s)
- Yazhou Li
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Jianghan Wang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Na Liu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Luxin Ke
- Department of Genetics and Genome Sciences, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 USA
| | - Xiuyun Zhao
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
| | - Gaofu Qi
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070 China
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24
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Motta Nascimento B, Nair NU. Characterization of a membrane enzymatic complex for heterologous production of poly-γ-glutamate in E. coli. Metab Eng Commun 2020; 11:e00144. [PMID: 32963960 PMCID: PMC7490850 DOI: 10.1016/j.mec.2020.e00144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/10/2020] [Accepted: 08/20/2020] [Indexed: 11/06/2022] Open
Abstract
Poly-γ-glutamic acid (PGA) produced by many Bacillus species is a polymer with many distinct and desirable characteristics. However, the multi-subunit enzymatic complex responsible for its synthesis, PGA Synthetase (PGS), has not been well characterized yet, in native nor in recombinant contexts. Elucidating structural and functional properties are crucial for future engineering efforts aimed at altering the catalytic properties of this enzyme. This study focuses on expressing the enzyme heterologously in the Escherichia coli membrane and characterizing localization, orientation, and activity of this heterooligomeric enzyme complex. In E. coli, we were able to produce high molecular weight PGA polymers with minimal degradation at titers of approximately 13 mg/L in deep-well microtiter batch cultures. Using fusion proteins, we observed, for the first time, the association and orientation of the different subunits with the inner cell membrane. These results provide fundamental structural information on this poorly studied enzyme complex and will aid future fundamental studies and engineering efforts. Successfully expressed active poly-γ-glutamate synthetase (PGS) in E. coli. Confirmed PGS localization at inner membrane of E. coli. Elucidated topology of PGS components in E. coli membrane. Culture and expression in microplates might allow future screening of a high number of samples. Faster production of poly-γ-glutamate in E. coli supernatant compared to B. subtilis.
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Affiliation(s)
- Bruno Motta Nascimento
- Department of Chemical and Biological Engineering, Tufts University, Medford, MA, 02155, USA
| | - Nikhil U Nair
- Department of Chemical and Biological Engineering, Tufts University, Medford, MA, 02155, USA
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25
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Sha Y, Qiu Y, Zhu Y, Sun T, Luo Z, Gao J, Feng X, Li S, Xu H. CRISPRi-Based Dynamic Regulation of Hydrolase for the Synthesis of Poly-γ-Glutamic Acid with Variable Molecular Weights. ACS Synth Biol 2020; 9:2450-2459. [PMID: 32794764 DOI: 10.1021/acssynbio.0c00207] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Poly-γ-glutamic acid (γ-PGA) is a decomposable polymer and has been useful in various industries. The biological functions of γ-PGA are closely linked with its molecular weight (MW). In this study, we established an efficient method to produce variable MWs of γ-PGA from renewable biomass (Jerusalem artichoke) by Bacillus amyloliquefaciens. First, a systematic engineering strategy was proposed in B. amyloliquefaciens to construct an optimal platform for γ-PGA overproduction, in which 24.95 g/L γ-PGA generation was attained. Second, 27.12 g/L γ-PGA with an MW of 20-30 kDa was obtained by introducing a γ-PGA hydrolase (pgdS) into the platform strain constructed above, which reveals a potential correlation between the expression level of pgdS and MW of γ-PGA. Then, a Clustered Regularly Interspaced Short Palindromic Repeats interference (CRISPRi) system was further designed to regulate pgdS expression levels, resulting in γ-PGA with variable MWs. Finally, a combinatorial approach based on three sgRNAs with different repression efficiencies was developed to achieve the dynamic regulation of pgdS and obtain tailor-made γ-PGA production in the MW range of 50-1400 kDa in one strain. This study illustrates a promising approach for the sustainable making of biopolymers with diverse molecular weights in one strain through the controllable expression of hydrolase using the CRISPRi system.
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Affiliation(s)
- Yuanyuan Sha
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, Jiangsu 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, Jiangsu 211816, P. R. China
| | - Yibin Qiu
- Department of Food Science and Technology, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing, Jiangsu 210037, P. R. China
| | - Yifan Zhu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, Jiangsu 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, Jiangsu 211816, P. R. China
| | - Tao Sun
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, Jiangsu 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, Jiangsu 211816, P. R. China
| | - Zhengshan Luo
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, Jiangsu 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, Jiangsu 211816, P. R. China
| | - Jian Gao
- School of Marine and Bioengineering, Yancheng Institute of Technology, Yancheng, Jiangsu 224051, P. R. China
| | - Xiaohai Feng
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, Jiangsu 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, Jiangsu 211816, P. R. China
| | - Sha Li
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, Jiangsu 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, Jiangsu 211816, P. R. China
| | - Hong Xu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, Jiangsu 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing, Jiangsu 211816, P. R. China
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26
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Poly-γ-glutamic acid production by Bacillus subtilis 168 using glucose as the sole carbon source: A metabolomic analysis. J Biosci Bioeng 2020; 130:272-282. [DOI: 10.1016/j.jbiosc.2020.04.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/22/2020] [Accepted: 04/26/2020] [Indexed: 11/18/2022]
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Wang D, Wang H, Zhan Y, Xu Y, Deng J, Chen J, Cai D, Wang Q, Sheng F, Chen S. Engineering Expression Cassette of pgdS for Efficient Production of Poly-γ-Glutamic Acids With Specific Molecular Weights in Bacillus licheniformis. Front Bioeng Biotechnol 2020; 8:728. [PMID: 32754581 PMCID: PMC7381323 DOI: 10.3389/fbioe.2020.00728] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 06/09/2020] [Indexed: 12/13/2022] Open
Abstract
Poly-γ-glutamic acid (γ-PGA) is an emerging biopolymer with various applications and γ-PGAs with different molecular weights exhibit distinctive properties. However, studies on the controllable molecular weights of biopolymers are limited. The purpose of this study is to achieve production of γ-PGAs with a wide range of molecular weights through manipulating the expression of γ-PGA depolymerase (PgdS) in Bacillus licheniformis WX-02. Firstly, the expression and secretion of PgdS were regulated through engineering its expression elements (four promoters and eight signal peptides), which generated γ-PGAs with molecular weights ranging from 6.82 × 104 to 1.78 × 106 Da. Subsequently, through combination of promoters with signal peptides, the production of γ-PGAs with a specific molecular weight could be efficiently obtained. Interestingly, the γ-PGA yield increased with the reduced molecular weight in flask cultures (Pearson correlation coefficient of −0.968, P < 0.01). Finally, in batch fermentation, the highest yield of γ-PGA with a weight-average molecular weight of 7.80 × 104 Da reached 39.13 g/L under glutamate-free medium. Collectively, we developed an efficient strategy for one-step production of γ-PGAs with specific molecular weights, which have potential application for industrial production of desirable γ-PGAs.
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Affiliation(s)
- Dong Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, China
| | - Huan Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, China
| | - Yangyang Zhan
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, China
| | - Yong Xu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, China
| | - Jie Deng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, China
| | | | - Dongbo Cai
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, China
| | - Qin Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, China
| | - Feng Sheng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, China
| | - Shouwen Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, College of Life Science, Hubei University, Wuhan, China
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28
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Sha Y, Huang Y, Zhu Y, Sun T, Luo Z, Qiu Y, Zhan Y, Lei P, Li S, Xu H. Efficient Biosynthesis of Low-Molecular-Weight Poly-γ-glutamic Acid Based on Stereochemistry Regulation in Bacillus amyloliquefaciens. ACS Synth Biol 2020; 9:1395-1405. [PMID: 32353226 DOI: 10.1021/acssynbio.0c00080] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Low-molecular-weight poly-γ-glutamic acid (LMW-γ-PGA) has attracted much attention because of its many potential applications in food, agriculture, medicine, and cosmetics. Enzymatic degradation is an efficient way for the synthesis of LMW-γ-PGA. However, the stereochemistry of γ-PGA limits the degradation of γ-PGA. This study identifies the role of γ-PGA synthase (pgsA) and glutamate racemase (racE) in the regulation of γ-PGA stereochemistry and demonstrates their combinational use for LMW-γ-PGA synthesis. First, the expression of pgsA and racE was enhanced, leading to improvements both in the molecular weight (Mw) and the d-glutamate proportion of γ-PGA. Then, an optimal combination of pgsA, racE, and γ-PGA hydrolase pgdS was constructed by exchanging the gene origins for the synthesis of LMW-γ-PGA. Finally, the Mw of γ-PGA was decreased to 6-8 kDa, which was much lower compared with the case without stereochemistry switching (20-30 kDa). This study provides a novel strategy to control the Mw of γ-PGA based on stereochemistry regulation and lays a solid foundation for synthesis of LMW-γ-PGA.
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Affiliation(s)
- Yuanyuan Sha
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, P. R. China
| | - Yueyuan Huang
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, P. R. China
| | - Yifan Zhu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, P. R. China
| | - Tao Sun
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, P. R. China
| | - Zhengshan Luo
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, P. R. China
| | - Yibin Qiu
- Department of Food Science and Technology, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, P. R. China
| | - Yijing Zhan
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, P. R. China
- Nanjing Shineking Biotech Co., Ltd, Nanjing 210061, P. R. China
| | - Peng Lei
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, P. R. China
| | - Sha Li
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, P. R. China
| | - Hong Xu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, P. R. China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, P. R. China
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29
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Halmschlag B, Putri SP, Fukusaki E, Blank LM. Identification of Key Metabolites in Poly-γ-Glutamic Acid Production by Tuning γ-PGA Synthetase Expression. Front Bioeng Biotechnol 2020; 8:38. [PMID: 32083073 PMCID: PMC7002566 DOI: 10.3389/fbioe.2020.00038] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Accepted: 01/16/2020] [Indexed: 11/13/2022] Open
Abstract
Poly-γ-glutamic acid (γ-PGA) production is commonly achieved using glycerol, citrate, and L-glutamic acid as substrates. The constitutive expression of the γ-PGA synthetase enabled γ-PGA production with Bacillus subtilis from glucose only. The precursors for γ-PGA synthesis, D- and L-glutamate, are ubiquitous metabolites. Hence, the metabolic flux toward γ-PGA directly depends on the concentration and activity of the synthetase and thereby on its expression. To identify pathway bottlenecks and important metabolites that are highly correlated with γ-PGA production from glucose, we engineered B. subtilis strains with varying γ-PGA synthesis rates. To alter the rate of γ-PGA synthesis, the expression level was controlled by two approaches: (1) Using promoter variants from the constitutive promoter P veg and (2) Varying induction strength of the xylose inducible promoter P xyl . The variation in the metabolism caused by γ-PGA production was investigated using metabolome analysis. The xylose-induction strategy revealed that the γ-PGA production rate increased the total fluxes through metabolism indicating a driven by demand adaption of the metabolism. Metabolic bottlenecks during γ-PGA from glucose were identified by generation of a model that correlates γ-PGA production rate with intracellular metabolite levels. The generated model indicates the correlation of certain metabolites such as phosphoenolpyruvate with γ-PGA production. The identified metabolites are targets for strain improvement to achieve high level γ-PGA production from glucose.
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Affiliation(s)
- Birthe Halmschlag
- Institute of Applied Microbiology-iAMB, Aachen Biology and Biotechnology-ABBt, RWTH Aachen University, Aachen, Germany
| | - Sastia P. Putri
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Osaka, Japan
| | - Eiichiro Fukusaki
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Osaka, Japan
| | - Lars M. Blank
- Institute of Applied Microbiology-iAMB, Aachen Biology and Biotechnology-ABBt, RWTH Aachen University, Aachen, Germany
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30
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Halmschlag B, Hoffmann K, Hanke R, Putri SP, Fukusaki E, Büchs J, Blank LM. Comparison of Isomerase and Weimberg Pathway for γ-PGA Production From Xylose by Engineered Bacillus subtilis. Front Bioeng Biotechnol 2020; 7:476. [PMID: 32039180 PMCID: PMC6985040 DOI: 10.3389/fbioe.2019.00476] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 12/23/2019] [Indexed: 11/13/2022] Open
Abstract
The production of poly-γ-glutamic acid (γ-PGA), a biopolymer consisting of D- and L-glutamic acid monomers, currently relies on L-glutamate, or citrate as carbon substrates. Here we aimed at using plant biomass-derived substrates such as xylose. γ-PGA producing microorganisms including Bacillus subtilis natively metabolize xylose via the isomerase pathway. The Weimberg pathway, a xylose utilization pathway first described for Caulobacter crescentus, offers a carbon-efficient alternative converting xylose to 2-oxoglutarate without carbon loss. We engineered a recombinant B. subtilis strain that was able to grow on xylose with a growth rate of 0.43 h-1 using a recombinant Weimberg pathway. Although ion-pair reversed-phase LC/MS/MS metabolome analysis revealed lower concentrations of γ-PGA precursors such as 2-oxoglutarate, the γ-PGA titer was increased 6-fold compared to the native xylose isomerase strain. Further metabolome analysis indicates a metabolic bottleneck in the phosphoenolpyruvate-pyruvate-oxaloacetate node causing bi-phasic (diauxic) growth of the recombinant Weimberg strain. Flux balance analysis (FBA) of the γ-PGA producing B. subtilis indicated that a maximal theoretical γ-PGA yield is achieved on D-xylose/ D-glucose mixtures. The results of the B. subtilis strain harboring the Weimberg pathway on such D-xylose/ D-glucose mixtures demonstrate indeed resource efficient, high yield γ-PGA production from biomass-derived substrates.
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Affiliation(s)
- Birthe Halmschlag
- Institute of Applied Microbiology, Aachen Biology and Biotechnology, RWTH Aachen University, Aachen, Germany
| | - Kyra Hoffmann
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - René Hanke
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Sastia P Putri
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Osaka, Japan
| | - Eiichiro Fukusaki
- Department of Biotechnology, Graduate School of Engineering, Osaka University, Osaka, Japan
| | - Jochen Büchs
- AVT-Biochemical Engineering, RWTH Aachen University, Aachen, Germany
| | - Lars M Blank
- Institute of Applied Microbiology, Aachen Biology and Biotechnology, RWTH Aachen University, Aachen, Germany
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