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Yaashikaa PR, Senthil Kumar P, Saravanan A, Karishma S, Rangasamy G. A biotechnological roadmap for decarbonization systems combined into bioenergy production: Prelude of environmental life-cycle assessment. CHEMOSPHERE 2023; 329:138670. [PMID: 37054843 DOI: 10.1016/j.chemosphere.2023.138670] [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: 11/10/2022] [Revised: 03/30/2023] [Accepted: 04/10/2023] [Indexed: 05/03/2023]
Abstract
Decarbonization has become a critical issue in recent years due to rising energy demands and diminishing oil resources. Decarbonization systems based on biotechnology have proven to be a cost-effective and environmentally benign technique of lowering carbon emissions. Bioenergy generation is an environmentally friendly technique for mitigating climate change in the energy industry, and it is predicted to play an important role in lowering global carbon emissions. This review essentially provides a new perspective on the unique biotechnological approaches and strategies based decarbonization pathways. Furthermore, the application of genetically engineered microbes in CO2 biomitigation and energy generation is particularly emphasized. The production of biohydrogen and biomethane via anaerobic digestion techniques has been highlighted in the perspective. In this review, role of microorganisms in bioconversion of CO2 into different types of bioproducts such as biochemical, biopolymers, biosolvents and biosurfactant was summarized. The current analysis, which includes an in-depth discussion of a biotechnology-based roadmap for the bioeconomy, provides a clear picture of sustainability, forthcoming challenges, and perspectives.
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Affiliation(s)
- P R Yaashikaa
- Department of Biotechnology, Saveetha School of Engineering, SIMATS, Chennai, 602105, India
| | - P Senthil Kumar
- Department of Chemical Engineering, Sri Sivasubramaniya Nadar College of Engineering, Kalavakkam, 603110, Tamil Nadu, India; Centre of Excellence in Water Research (CEWAR), Sri Sivasubramaniya Nadar College of Engineering, Kalavakkam, 603110, Tamil Nadu, India.
| | - A Saravanan
- Department of Biotechnology, Saveetha School of Engineering, SIMATS, Chennai, 602105, India
| | - S Karishma
- Department of Biotechnology, Saveetha School of Engineering, SIMATS, Chennai, 602105, India
| | - Gayathri Rangasamy
- School of Engineering, Lebanese American University, Byblos, Lebanon; University Centre for Research and Development & Department of Civil Engineering, Chandigarh University, Gharuan, Mohali, Punjab, 140413, India
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Madhavan A, Arun KB, Sindhu R, Nair BG, Pandey A, Awasthi MK, Szakacs G, Binod P. Design and genome engineering of microbial cell factories for efficient conversion of lignocellulose to fuel. BIORESOURCE TECHNOLOGY 2023; 370:128555. [PMID: 36586428 DOI: 10.1016/j.biortech.2022.128555] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 12/26/2022] [Accepted: 12/27/2022] [Indexed: 06/17/2023]
Abstract
The gradually increasing need for fossil fuels demands renewable biofuel substitutes. This has fascinated an increasing investigation to design innovative energy fuels that have comparable Physico-chemical and combustion characteristics with fossil-derived fuels. The efficient microbes for bioenergy synthesis desire the proficiency to consume a large quantity of carbon substrate, transfer various carbohydrates through efficient metabolic pathways, capability to withstand inhibitory components and other degradation compounds, and improve metabolic fluxes to synthesize target compounds. Metabolically engineered microbes could be an efficient methodology for synthesizing biofuel from cellulosic biomass by cautiously manipulating enzymes and metabolic pathways. This review offers a comprehensive perspective on the trends and advances in metabolic and genetic engineering technologies for advanced biofuel synthesis by applying various heterologous hosts. Probable technologies include enzyme engineering, heterologous expression of multiple genes, CRISPR-Cas technologies for genome editing, and cell surface display.
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Affiliation(s)
- Aravind Madhavan
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri, Kollam 690525 Kerala, India.
| | - K B Arun
- Department of Life Sciences, CHRIST (Deemed to be University), Bengaluru 560029, Karnataka, India
| | - Raveendran Sindhu
- Department of Food Technology, TKM Institute of Technology, Kollam 689 122, India
| | - Bipin G Nair
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri, Kollam 690525 Kerala, India
| | - Ashok Pandey
- Center for Innovation and Translational Research, CSIR-Indian Institute of Toxicology Research, Lucknow 226 001, India; Sustainability Cluster, School of Engineering, University of Petroleum and Energy Studies, Dehradun 248007, Uttarkhand, India; Centre for Energy and Environmental Sustainability, Lucknow 226 029, Uttar Pradesh, India
| | - Mukesh Kumar Awasthi
- College of Natural Resources and Environment, Northwest A & F University, Yangling, Shaanxi 712 100, China
| | - George Szakacs
- Budapest University of Technology and Economics, Department of Applied Biotechnology and Food Science, 1111 Budapest, Szent Gellert ter 4, Hungary
| | - Parameswaran Binod
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum 695 019, India
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Singhvi M, Kim BS. Green hydrogen production through consolidated bioprocessing of lignocellulosic biomass using nanobiotechnology approach. BIORESOURCE TECHNOLOGY 2022; 365:128108. [PMID: 36270388 DOI: 10.1016/j.biortech.2022.128108] [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: 08/25/2022] [Revised: 10/05/2022] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
The main objective of this study was to develop a sustainable process for hydrogen production by implementing nanotechnology in combination with consolidated bioprocessing (CBP) approach from lignocellulosic biomass (LCB). Peroxidase mimicking CeFe3O4 nanoparticles (NPs, 4.0 g/L) were applied for degradation of lignin from raw corn cob (CC) biomass for generation of cellulose-hemicellulose fractions amenable towards Clostridium cellulovorans during fermentation process. NP-treated biomass exhibited 43.26 % lignin removal from raw CC which was further employed for hydrogen fermentation by C. cellulovorans through CBP method. The strain yielded maximum 78.45 mL of cumulative hydrogen with hydrogen production rate of 1.55 mL/h using NP-treated CC. To the best of our knowledge, this is the first study on enhanced hydrogen production using NP-treated CC biomass in single pot fermentation which can prove to be a simpler, easier, and more economical process.
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Affiliation(s)
- Mamata Singhvi
- Department of Chemical Engineering, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea
| | - Beom Soo Kim
- Department of Chemical Engineering, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea.
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Xie W, Zhang Z, Bai S, Wu YR. Extracellular expression of agarolytic enzymes in Clostridium sp. strain and its application for butanol production from Gelidium amansii. BIORESOURCE TECHNOLOGY 2022; 363:127962. [PMID: 36115509 DOI: 10.1016/j.biortech.2022.127962] [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: 08/02/2022] [Revised: 09/07/2022] [Accepted: 09/08/2022] [Indexed: 06/15/2023]
Abstract
In this study, Clostridium sp. strain WK-AN1 carrying both genes of agarase (Aga0283) and neoagarobiose hydrolase (NH2780) were successfully constructed to convert agar polysaccharide directly into butanol, contributing to overcome the lack of algal hydrolases in solventogenic clostridia. Through the optimization by the Plackett-Burman design (PBD) and response surface methodology (RSM), a maximal butanol production of 6.42 g/L was achieved from 17.86 g/L agar. Further application of utilizing the butyric acid pretreated Gelidium amansii hydrolysate demonstrated the modified strain obtained the butanol production of 7.83 g/L by 1.63-fold improvement over the wild-type one. This work for the first time establishes a novel route to utilize red algal polysaccharides for butanol fermentation by constructing a solventogenic clostridia-specific secretory expression system for heterologous agarases, which will provide insights for future development of the sustainable third-generation biomass energy.
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Affiliation(s)
- Wei Xie
- Department of Biology, Shantou University, Shantou, Guangdong 515063, China
| | - Zhiqian Zhang
- Tidetron Bioworks Technology (Guangzhou) Co., Ltd., Guangzhou Qianxiang Bioworks Co., Ltd., Guangzhou, Guangdong 510000, China
| | - Shengkai Bai
- Department of Biology, Shantou University, Shantou, Guangdong 515063, China
| | - Yi-Rui Wu
- Tidetron Bioworks Technology (Guangzhou) Co., Ltd., Guangzhou Qianxiang Bioworks Co., Ltd., Guangzhou, Guangdong 510000, China.
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Lee JTE, Dutta N, Zhang L, Tsui TTH, Lim S, Tio ZK, Lim EY, Sun J, Zhang J, Wang CH, Ok YS, Ahring BK, Tong YW. Bioaugmentation of Methanosarcina thermophila grown on biochar particles during semi-continuous thermophilic food waste anaerobic digestion under two different bioaugmentation regimes. BIORESOURCE TECHNOLOGY 2022; 360:127590. [PMID: 35811056 DOI: 10.1016/j.biortech.2022.127590] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 06/30/2022] [Accepted: 07/02/2022] [Indexed: 06/15/2023]
Abstract
This study presents the effect of bioaugmentation of thermophilic anaerobic digestion of food waste with Methanosarcina thermophila grown on a wood-derived biochar. Two different supplementation regimes were tested, namely a single bioaugmentation (SBABC) in which 10% v/v of the microbes grown on biochar (1 g/L) is added at setup of the reactors, versus a routine bioaugmentation (RBABC) wherein the same amount of supplements were added over 10 feeding cycles. The optimally performing 'R' and 'S' reactors had increased methane yields by 37% and 32% over their respective controls while reactors SBABC 2 and 3 produced 21.89% and 56.09% higher average methane yield than RBABC 2 and 3, respectively. It appears that a single dose bioaugmentation is advantageous for improving AD as analysed in terms of average methane yield and VFA production. This study provides the basis for understanding how biochar and bioaugmentation can be used for engineering sustainable pilot-scale AD processes.
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Affiliation(s)
- Jonathan T E Lee
- Environmental Research Institute, National University of Singapore, Singapore; Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 Create Way, Singapore 138602, Singapore
| | - Nalok Dutta
- Bioproducts, Sciences and Engineering Laboratory, Washington State University Tricities. Biological Systems Engineering, Washington State University, USA
| | - Le Zhang
- Environmental Research Institute, National University of Singapore, Singapore; Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 Create Way, Singapore 138602, Singapore
| | - Thomas T H Tsui
- Environmental Research Institute, National University of Singapore, Singapore; Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 Create Way, Singapore 138602, Singapore
| | - Shuhan Lim
- Department of Chemical & Biomolecular Engineering, NUS, Singapore
| | - Zhi Kai Tio
- Department of Chemical & Biomolecular Engineering, NUS, Singapore
| | - Ee Yang Lim
- Department of Chemical & Biomolecular Engineering, NUS, Singapore
| | - Jiachen Sun
- Department of Chemical & Biomolecular Engineering, NUS, Singapore
| | - Jingxin Zhang
- China-UK Low Carbon College, Shanghai Jiao Tong University, Shanghai, China
| | - Chi-Hwa Wang
- Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 Create Way, Singapore 138602, Singapore; Department of Chemical & Biomolecular Engineering, NUS, Singapore
| | - Yong Sik Ok
- Korea Biochar Research Center, APRU Sustainable Waste Management & Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, South Korea
| | - Birgitte K Ahring
- Bioproducts, Sciences and Engineering Laboratory, Washington State University Tricities. Biological Systems Engineering, Washington State University, USA
| | - Yen Wah Tong
- Energy and Environmental Sustainability for Megacities (E2S2) Phase II, Campus for Research Excellence and Technological Enterprise (CREATE), 1 Create Way, Singapore 138602, Singapore; Department of Chemical & Biomolecular Engineering, NUS, Singapore.
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Ashokkumar V, Venkatkarthick R, Jayashree S, Chuetor S, Dharmaraj S, Kumar G, Chen WH, Ngamcharussrivichai C. Recent advances in lignocellulosic biomass for biofuels and value-added bioproducts - A critical review. BIORESOURCE TECHNOLOGY 2022; 344:126195. [PMID: 34710596 DOI: 10.1016/j.biortech.2021.126195] [Citation(s) in RCA: 108] [Impact Index Per Article: 54.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/16/2021] [Accepted: 10/19/2021] [Indexed: 06/13/2023]
Abstract
Lignocellulosic biomass is a highly renewable, economical, and carbon-neutral feedstock containing sugar-rich moieties that can be processed to produce second-generation biofuels and bio-sourced compounds. However, due to their heterogeneous multi-scale structure, the lignocellulosic materials have major limitations to valorization and exhibit recalcitrance to saccharification or hydrolysis by enzymes. In this context, this review focuses on the latest methods available and state-of-the-art technologies in the pretreatment of lignocellulosic biomass, which aids the disintegration of the complex materials into monomeric units. In addition, this review deals with the genetic engineering techniques to develop advanced strategies for fermentation processes or microbial cell factories to generate desired products in native or modified hosts. Further, it also intends to bridge the gap in developing various economically feasible lignocellulosic products and chemicals using biorefining technologies.
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Affiliation(s)
- Veeramuthu Ashokkumar
- Center of Excellence in Catalysis for Bioenergy and Renewable Chemicals (CBRC), Faculty of Science, Chulalongkorn University, Pathum Wan, Bangkok 10330, Thailand.
| | | | - Shanmugam Jayashree
- Department of Biotechnology, Stella Maris College (Autonomous), Chennai, Tamil Nadu 600086, India
| | - Santi Chuetor
- Department of Chemical Engineering, Faculty of Engineering, King Mongkut's University of Technology North Bangkok (KMUTNB), Bangkok, Thailand
| | - Selvakumar Dharmaraj
- Department of Marine Biotechnology, Academy of Maritime Education and Training [AMET] (Deemed to be University), Chennai 603112, Tamil Nadu, India
| | - Gopalakrishnan Kumar
- School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Republic of Korea; Institute of Chemistry, Bioscience and Environmental Engineering, Faculty of Science and Technology, University of Stavanger, Box 8600 Forus, 4036 Stavanger, Norway
| | - Wei-Hsin Chen
- Department of Aeronautics and Astronautics, National Cheng Kung University, Tainan 701, Taiwan; Research Center for Smart Sustainable Circular Economy, Tunghai University, Taichung 407, Taiwan; Department of Mechanical Engineering, National Chin-Yi University of Technology, Taichung 411, Taiwan
| | - Chawalit Ngamcharussrivichai
- Center of Excellence in Catalysis for Bioenergy and Renewable Chemicals (CBRC), Faculty of Science, Chulalongkorn University, Pathum Wan, Bangkok 10330, Thailand; Center of Excellence on Petrochemical and Materials Technology (PETROMAT), Chulalongkorn University, Pathumwan, Bangkok 10330, Thailand
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Lee J. Lessons from Clostridial Genetics: Toward Engineering Acetogenic Bacteria. BIOTECHNOL BIOPROC E 2021. [DOI: 10.1007/s12257-021-0062-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Aamer Mehmood M, Shahid A, Malik S, Wang N, Rizwan Javed M, Nabeel Haider M, Verma P, Umer Farooq Ashraf M, Habib N, Syafiuddin A, Boopathy R. Advances in developing metabolically engineered microbial platforms to produce fourth-generation biofuels and high-value biochemicals. BIORESOURCE TECHNOLOGY 2021; 337:125510. [PMID: 34320777 DOI: 10.1016/j.biortech.2021.125510] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 06/13/2023]
Abstract
Producing bio-based chemicals is imperative to establish an eco-friendly circular bioeconomy. However, the compromised titer of these biochemicals hampers their commercial implementation. Advances in genetic engineering tools have enabled researchers to develop robust strains producing desired titers of the next-generation biofuels and biochemicals. The native and non-native pathways have been extensively engineered in various host strains via pathway reconstruction and metabolic flux redirection of lipid metabolism and central carbon metabolism to produce myriad biomolecules including alcohols, isoprenoids, hydrocarbons, fatty-acids, and their derivatives. This review has briefly covered the research efforts made during the previous decade to produce advanced biofuels and biochemicals through engineered microbial platforms along with the engineering approaches employed. The efficiency of the various techniques along with their shortcomings is also covered to provide a comprehensive overview of the progress and future directions to achieve higher titer of fourth-generation biofuels and biochemicals while keeping environmental sustainability intact.
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Affiliation(s)
- Muhammad Aamer Mehmood
- School of Bioengineering, Sichuan University of Science and Engineering, Zigong, China; Bioenergy Research Centre, Department of Bioinformatics & Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Ayesha Shahid
- Bioenergy Research Centre, Department of Bioinformatics & Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Sana Malik
- Bioenergy Research Centre, Department of Bioinformatics & Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Ning Wang
- School of Bioengineering, Sichuan University of Science and Engineering, Zigong, China
| | - Muhammad Rizwan Javed
- Bioenergy Research Centre, Department of Bioinformatics & Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Muhammad Nabeel Haider
- Bioenergy Research Centre, Department of Bioinformatics & Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Pradeep Verma
- Department of Microbiology, Central University of Rajasthan, Bandarsindri, Kishangarh, Ajmer-305801, Rajasthan, India
| | - Muhammad Umer Farooq Ashraf
- Bioenergy Research Centre, Department of Bioinformatics & Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Nida Habib
- Bioenergy Research Centre, Department of Bioinformatics & Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Achmad Syafiuddin
- Department of Public Health, Universitas Nahdlatul Ulama Surabaya, 60237 Surabaya, East Java, Indonesia
| | - Raj Boopathy
- Department of Biological Sciences, Nicholls State University, Thibodaux, LA 70310, USA.
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Ning P, Yang G, Hu L, Sun J, Shi L, Zhou Y, Wang Z, Yang J. Recent advances in the valorization of plant biomass. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:102. [PMID: 33892780 PMCID: PMC8063360 DOI: 10.1186/s13068-021-01949-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 04/07/2021] [Indexed: 05/28/2023]
Abstract
Plant biomass is a highly abundant renewable resource that can be converted into several types of high-value-added products, including chemicals, biofuels and advanced materials. In the last few decades, an increasing number of biomass species and processing techniques have been developed to enhance the application of plant biomass followed by the industrial application of some of the products, during which varied technologies have been successfully developed. In this review, we summarize the different sources of plant biomass, the evolving technologies for treating it, and the various products derived from plant biomass. Moreover, the challenges inherent in the valorization of plant biomass used in high-value-added products are also discussed. Overall, with the increased use of plant biomass, the development of treatment technologies, and the solution of the challenges raised during plant biomass valorization, the value-added products derived from plant biomass will become greater in number and more valuable.
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Affiliation(s)
- Peng Ning
- Energy-rich Compounds Production by Photosynthetic Carbon Fixation Research Center, Shandong Key Lab of Applied Mycology, Qingdao Agricultural University, No. 700 Changcheng Road, Chengyang District, Qingdao, 266109, China
- College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Guofeng Yang
- College of Life Sciences, Qingdao Agricultural University, Qingdao, China
| | - Lihong Hu
- Institute of Chemical Industry of Forest Products, Key Laboratory of Biomass Energy and Material, CAF, Nanjing, China
| | - Jingxin Sun
- College of Food Science and Engineering, Qingdao Agricultural University, Qingdao, China
| | - Lina Shi
- Agricultural Integrated Service Center of Zhuyouguan, Longkou, Yantai, China
| | - Yonghong Zhou
- Institute of Chemical Industry of Forest Products, Key Laboratory of Biomass Energy and Material, CAF, Nanjing, China
| | - Zhaobao Wang
- Energy-rich Compounds Production by Photosynthetic Carbon Fixation Research Center, Shandong Key Lab of Applied Mycology, Qingdao Agricultural University, No. 700 Changcheng Road, Chengyang District, Qingdao, 266109, China.
- College of Life Sciences, Qingdao Agricultural University, Qingdao, China.
| | - Jianming Yang
- Energy-rich Compounds Production by Photosynthetic Carbon Fixation Research Center, Shandong Key Lab of Applied Mycology, Qingdao Agricultural University, No. 700 Changcheng Road, Chengyang District, Qingdao, 266109, China.
- College of Life Sciences, Qingdao Agricultural University, Qingdao, China.
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Cloning and characterization of a L-lactate dehydrogenase gene from Ruminococcaceae bacterium CPB6. World J Microbiol Biotechnol 2020; 36:182. [PMID: 33170386 DOI: 10.1007/s11274-020-02958-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 11/03/2020] [Indexed: 10/23/2022]
Abstract
Lactate are proved to be attractive electron donor for the production of n-caproic acid (CA) that is a high value-added fuel precursor and chemical feedstock, but little is known about molecular mechanism of lactate transformation. In the present study, the gene for L-lactate dehydrogenase (LDH, EC.1.1.1.27) from a Ruminococcaceae strain CPB6 was cloned and expressed in Escherichia coli BL21 (DE3) with plasmid pET28a. The recombinant LDH exhibited molecular weight of 36-38 kDa in SDS-PAGE. The purified LDH was found to have the maximal oxidation activity of 29.6 U/mg from lactate to pyruvate at pH 6.5, and the maximal reduction activity of 10.4 U/mg from pyruvate to lactate at pH 8.5, respectively. Strikingly, its oxidative activity predominates over reductive activity, leading to a 17-fold increase for the utilization of lactate in E. coli/pET28a-LDH than E. coli/pET28a. The CPB6 LDH gene encodes a 315 amino acid protein sharing 42.19% similarity with Clostridium beijerinckii LDH, and lower similarity with LDHs of other organisms. Significant difference were observed between the CPB6 LDH and C. beijerinckii and C. acetobutylicum LDH in the predicted tertiary structure and active center. Further, X-ray crystal structure analysis need to be performed to verify the specific active center of the CPB6 LDH and its role in the conversion of lactate into CA.
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Disruption of the lactate dehydrogenase and acetate kinase genes in Klebsiella pneumoniae HD79 to enhance 2,3-butanediol production, and related transcriptomics analysis. Biotechnol Lett 2020; 42:537-549. [PMID: 31974647 DOI: 10.1007/s10529-020-02802-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 01/13/2020] [Indexed: 12/18/2022]
Abstract
OBJECTIVES 2,3-Butanediol (2,3-BD) is widely used in several chemical syntheses as well as the manufacture of plastics, solvents, and antifreeze formulations, and can be manufactured by microbial glucose fermentation. Conventional (2,3-BD) fermentation typically has low productivity, yield, and purity, and is expensive for commercial applications. We aimed to delete the lactate dehydrogenase and acetate kinase (ldhA and ack) genes in Klebsiella pneumoniae HD79 by using λRed homologous recombination technology, to eliminate by-products and thereby improve (2,3-BD) production. We also analyzed the resulting gene changes by using transcriptomics. RESULTS The yield of (2,3-BD) from the mutant Klebsiella strain was 46.21 g/L, the conversion rate was 0.47 g/g, and the productivity was 0.64 g/L·h, which represented increases of 54.9%, 20.5%, and 106.5% respectively, compared to (WT) strains. Lactate and acetate decreased by 48.2% and 62.8%, respectively. Transcriptomics analysis showed that 4628 genes were differentially expressed (404 significantly up-regulated and 162 significantly down-regulated). Moreover, the (2,3-BD) operon genes were differentially expressed. CONCLUSION Our data showed that the biosynthesis of (2,3-BD) was regulated by inducers (lactate and acetate), a regulator (BudR), and carbon flux. Elimination of acidic by-products by ldhA and ack knockdown significantly improved (2,3-BD) production. Our results provide a deeper understanding of the mechanisms underlying (2,3-BD) production, and form a molecular basis for the improvement this process by genetic modification in the future.
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