1
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Ponsetto P, Sasal EM, Mazzoli R, Valetti F, Gilardi G. The potential of native and engineered Clostridia for biomass biorefining. Front Bioeng Biotechnol 2024; 12:1423935. [PMID: 39219620 PMCID: PMC11365079 DOI: 10.3389/fbioe.2024.1423935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2024] [Accepted: 08/06/2024] [Indexed: 09/04/2024] Open
Abstract
Since their first industrial application in the acetone-butanol-ethanol (ABE) fermentation in the early 1900s, Clostridia have found large application in biomass biorefining. Overall, their fermentation products include organic acids (e.g., acetate, butyrate, lactate), short chain alcohols (e.g., ethanol, n-butanol, isobutanol), diols (e.g., 1,2-propanediol, 1,3-propanediol) and H2 which have several applications such as fuels, building block chemicals, solvents, food and cosmetic additives. Advantageously, several clostridial strains are able to use cheap feedstocks such as lignocellulosic biomass, food waste, glycerol or C1-gases (CO2, CO) which confer them additional potential as key players for the development of processes less dependent from fossil fuels and with reduced greenhouse gas emissions. The present review aims to provide a survey of research progress aimed at developing Clostridium-mediated biomass fermentation processes, especially as regards strain improvement by metabolic engineering.
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Affiliation(s)
| | | | - Roberto Mazzoli
- Structural and Functional Biochemistry, Laboratory of Proteomics and Metabolic Engineering of Prokaryotes, Department of Life Sciences and Systems Biology, University of Torino, Torino, Italy
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2
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Shipmon JC, Rathinasabapathi P, Broich ML, Hemansi, Eiteman MA. Production of Esters in Escherichia coli Using Citrate Synthase Variants. Microorganisms 2024; 12:1338. [PMID: 39065106 PMCID: PMC11278746 DOI: 10.3390/microorganisms12071338] [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: 06/03/2024] [Revised: 06/24/2024] [Accepted: 06/27/2024] [Indexed: 07/28/2024] Open
Abstract
Acetate esters comprise a wide range of products including fragrances and industrial solvents. Biosynthesis of esters offers a promising alternative to chemical synthesis because such routes use renewable carbohydrate resources and minimize the generation of waste. One biochemical method for ester formation relies on the ATF1 gene from Saccharomyces cerevisiae, which encodes alcohol-O-acyltransferase (AAT) which converts acetyl-CoA and an exogenously supplied alcohol into the ester. In this study, the formation of several acetate esters via AAT was examined in Escherichia coli chromosomally expressing citrate synthase variants, which create a metabolic bottleneck at acetyl-CoA. In shake flask cultures, variant strains generated more acetate esters than the strains expressing the wild-type citrate synthase. In a controlled bioreactor, E. coli GltA[A267T] generated 3.9 g propyl acetate in 13 h, corresponding to a yield of 0.155 g propyl acetate/g glucose, which is 18% greater than that obtained by the wild-type GltA control. These results demonstrate the ability of citrate synthase variants to redistribute carbon from central metabolism into acetyl-CoA-derived biochemicals.
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Affiliation(s)
- Jacoby C. Shipmon
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, GA 30602, USA; (J.C.S.)
| | - Pasupathi Rathinasabapathi
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, GA 30602, USA; (J.C.S.)
- Department of Genetic Engineering, SRM Institute of Science and Technology, Chengalpattu District, Kattankulathur 603202, Tamil Nadu, India
| | - Michael L. Broich
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, GA 30602, USA; (J.C.S.)
| | - Hemansi
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, GA 30602, USA; (J.C.S.)
- Department of Microbiology, Central University of Haryana, Mahendergarh 123029, Haryana, India
| | - Mark A. Eiteman
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, GA 30602, USA; (J.C.S.)
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3
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Lu J, Jiang W, Dong W, Zhou J, Zhang W, Jiang Y, Xin F, Jiang M. Construction of a Microbial Consortium for the De Novo Synthesis of Butyl Butyrate from Renewable Resources. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:3350-3361. [PMID: 36734010 DOI: 10.1021/acs.jafc.2c07650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Butyl butyrate has shown wide applications in food, cosmetic, and biofuel sectors. Currently, biosynthesis of butyl butyrate still requires exogenous addition of precursors and lipase, which increases the production cost and limits further large-scale development. In this study, a microbial consortium was first designed to realize direct butyl butyrate production from lignocellulose. The highest butyl butyrate concentration of 34.42 g/L was detected in the solvent phase from 60 g/L glucose using a microbial coculture system composed of Clostridium acetobutylicum NJ4 and Clostridium tyrobutyricum LD with the elimination of butyric acid supplementation. Meanwhile, 13.52 g/L butyl butyrate was synthesized from 60 g/L glucose using a microbial consortium composed of three strains including strain NJ4, strain LD, and Escherichia coli BL21- pET-29a(+)-LE without the addition of any exogenous precursors and lipase. In addition, 2.94 g/L butyl butyrate could be directly produced from 60 g/L microcrystalline cellulose when Trichoderma asperellum was added to the above-mentioned three-strain microbial consortium. This four-strain microbial consortium represents the first study regarding the direct butyl butyrate production from lignocellulose without the supplementation of exogenous precursors and lipase, which may be extended to the biosynthesis of other short-chain esters, such as ethyl acetate and butyl lactate.
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Affiliation(s)
- Jiasheng Lu
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China
| | - Wankui Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China
| | - Weiliang Dong
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, P. R. China
| | - Jie Zhou
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, P. R. China
| | - Wenming Zhang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, P. R. China
| | - Yujia Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China
| | - Fengxue Xin
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, P. R. China
| | - Min Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, P. R. China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing Tech University, Nanjing 211816, P. R. China
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4
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Cui Y, Ma X, Lee SH, He J, Yang KL, Zhou K. Production of butyl butyrate from lignocellulosic biomass through Escherichia coli-Clostridium beijerinckii G117 co-culture. Process Biochem 2023. [DOI: 10.1016/j.procbio.2023.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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5
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Dykstra JC, van Oort J, Yazdi AT, Vossen E, Patinios C, van der Oost J, Sousa DZ, Kengen SWM. Metabolic engineering of Clostridium autoethanogenum for ethyl acetate production from CO. Microb Cell Fact 2022; 21:243. [DOI: 10.1186/s12934-022-01964-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 10/18/2022] [Indexed: 11/25/2022] Open
Abstract
Abstract
Background
Ethyl acetate is a bulk chemical traditionally produced via energy intensive chemical esterification. Microbial production of this compound offers promise as a more sustainable alternative process. So far, efforts have focused on using sugar-based feedstocks for microbial ester production, but extension to one-carbon substrates, such as CO and CO2/H2, is desirable. Acetogens present a promising microbial platform for the production of ethyl esters from these one-carbon substrates.
Results
We engineered the acetogen C. autoethanogenum to produce ethyl acetate from CO by heterologous expression of an alcohol acetyltransferase (AAT), which catalyzes the formation of ethyl acetate from acetyl-CoA and ethanol. Two AATs, Eat1 from Kluyveromyces marxianus and Atf1 from Saccharomyces cerevisiae, were expressed in C. autoethanogenum. Strains expressing Atf1 produced up to 0.2 mM ethyl acetate. Ethyl acetate production was barely detectable (< 0.01 mM) for strains expressing Eat1. Supplementation of ethanol was investigated as potential boost for ethyl acetate production but resulted only in a 1.5-fold increase (0.3 mM ethyl acetate). Besides ethyl acetate, C. autoethanogenum expressing Atf1 could produce 4.5 mM of butyl acetate when 20 mM butanol was supplemented to the growth medium.
Conclusions
This work offers for the first time a proof-of-principle that autotrophic short chain ester production from C1-carbon feedstocks is possible and offers leads on how this approach can be optimized in the future.
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6
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Controlling selectivity of modular microbial biosynthesis of butyryl-CoA-derived designer esters. Metab Eng 2021; 69:262-274. [PMID: 34883244 DOI: 10.1016/j.ymben.2021.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 11/21/2021] [Accepted: 12/01/2021] [Indexed: 02/02/2023]
Abstract
Short-chain esters have broad utility as flavors, fragrances, solvents, and biofuels. Controlling selectivity of ester microbial biosynthesis has been an outstanding metabolic engineering problem. In this study, we enabled the de novo fermentative microbial biosynthesis of butyryl-CoA-derived designer esters (e.g., butyl acetate, ethyl butyrate, butyl butyrate) in Escherichia coli with controllable selectivity. Using the modular design principles, we generated the butyryl-CoA-derived ester pathways as exchangeable production modules compatible with an engineered chassis cell for anaerobic production of designer esters. We designed these modules derived from an acyl-CoA submodule (e.g., acetyl-CoA, butyryl-CoA), an alcohol submodule (e.g., ethanol, butanol), a cofactor regeneration submodule (e.g., NADH), and an alcohol acetyltransferase (AAT) submodule (e.g., ATF1, SAAT) for rapid module construction and optimization by manipulating replication (e.g., plasmid copy number), transcription (e.g., promoters), translation (e.g., codon optimization), pathway enzymes, and pathway induction conditions. To further enhance production of designer esters with high selectivity, we systematically screened various strategies of protein solubilization using protein fusion tags and chaperones to improve the soluble expression of multiple pathway enzymes. Finally, our engineered ester-producing strains could achieve 19-fold increase in butyl acetate production (0.64 g/L, 96% selectivity), 6-fold increase in ethyl butyrate production (0.41 g/L, 86% selectivity), and 13-fold increase in butyl butyrate production (0.45 g/L, 54% selectivity) as compared to the initial strains. Overall, this study presented a generalizable framework to engineer modular microbial platforms for anaerobic production of butyryl-CoA-derived designer esters from renewable feedstocks.
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7
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Feng J, Zhang J, Ma Y, Feng Y, Wang S, Guo N, Wang H, Wang P, Jiménez-Bonilla P, Gu Y, Zhou J, Zhang ZT, Cao M, Jiang D, Wang S, Liu XW, Shao Z, Borovok I, Huang H, Wang Y. Renewable fatty acid ester production in Clostridium. Nat Commun 2021; 12:4368. [PMID: 34272383 PMCID: PMC8285483 DOI: 10.1038/s41467-021-24038-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 05/26/2021] [Indexed: 11/25/2022] Open
Abstract
Bioproduction of renewable chemicals is considered as an urgent solution for fossil energy crisis. However, despite tremendous efforts, it is still challenging to generate microbial strains that can produce target biochemical to high levels. Here, we report an example of biosynthesis of high-value and easy-recoverable derivatives built upon natural microbial pathways, leading to improvement in bioproduction efficiency. By leveraging pathways in solventogenic clostridia for co-producing acyl-CoAs, acids and alcohols as precursors, through rational screening for host strains and enzymes, systematic metabolic engineering-including elimination of putative prophages, we develop strains that can produce 20.3 g/L butyl acetate and 1.6 g/L butyl butyrate. Techno-economic analysis results suggest the economic competitiveness of our developed bioprocess. Our principles of selecting the most appropriate host for specific bioproduction and engineering microbial chassis to produce high-value and easy-separable end products may be applicable to other bioprocesses. Esters can be used as fuels and specialty chemicals for food flavoring, cosmetic and pharmaceutical industries. Here, the authors systematically engineer clostridia, including discovery and deletion of prophages to increase strain stability, for the production of butyl acetate and butyl butyrate from corn stover at low cost.
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Affiliation(s)
- Jun Feng
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA.,Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL, USA
| | - Jie Zhang
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA.,Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL, USA
| | - Yuechao Ma
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA.,Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL, USA
| | - Yiming Feng
- Department of Food Science and Technology, Virginia Tech, Blacksburg, VA, USA
| | - Shangjun Wang
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA.,Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL, USA
| | - Na Guo
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA.,Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL, USA
| | - Haijiao Wang
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA.,Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL, USA
| | - Pixiang Wang
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA.,Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL, USA
| | - Pablo Jiménez-Bonilla
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA.,Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL, USA.,School of Chemistry, National University (UNA), Heredia, Costa Rica
| | - Yanyan Gu
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA.,Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL, USA
| | - Junping Zhou
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA.,Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL, USA
| | - Zhong-Tian Zhang
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA.,Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL, USA
| | - Mingfeng Cao
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, USA.,NSF Engineering Research Center for Biorenewable Chemicals, Iowa State University, Ames, IA, USA
| | - Di Jiang
- Department of Applied Chemistry, University of Science and Technology of China, Hefei, China
| | - Shuning Wang
- State Key Laboratory of Microbial Technology, Microbial Technology Institute, Shandong University, Qingdao, China
| | - Xian-Wei Liu
- Department of Applied Chemistry, University of Science and Technology of China, Hefei, China
| | - Zengyi Shao
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, USA.,NSF Engineering Research Center for Biorenewable Chemicals, Iowa State University, Ames, IA, USA
| | - Ilya Borovok
- The Shmunis School of Biomedicine and Cancer Research, Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv, Israel
| | - Haibo Huang
- Department of Food Science and Technology, Virginia Tech, Blacksburg, VA, USA.
| | - Yi Wang
- Department of Biosystems Engineering, Auburn University, Auburn, AL, USA. .,Center for Bioenergy and Bioproducts, Auburn University, Auburn, AL, USA.
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8
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Sinumvayo JP, Li Y, Zhang Y. Microbial production of butyl butyrate: from single strain to cognate consortium. BIORESOUR BIOPROCESS 2021; 8:50. [PMID: 38650250 PMCID: PMC10992917 DOI: 10.1186/s40643-021-00403-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 06/07/2021] [Indexed: 11/10/2022] Open
Abstract
Butyl butyrate (BB) is an important chemical with versatile applications in beverage, food and cosmetics industries. Since chemical synthesis of BB may cause adverse impacts on the environment, biotechnology is an emerging alternative approach for microbial esters biosynthesis. BB can be synthesized by using a single Clostridium strain natively producing butanol or butyrate, with exogenously supplemented butyrate or butanol, in the presence of lipase. Recently, E. coli strains have been engineered to produce BB, but the titer and yield remained very low. This review highlighted a new trend of developing cognate microbial consortium for BB production and associated challenges, and end up with new prospects for further improvement for microbial BB biosynthesis.
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Affiliation(s)
- Jean Paul Sinumvayo
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yin Li
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Yanping Zhang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
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9
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Wang Q, Al Makishah NH, Li Q, Li Y, Liu W, Sun X, Wen Z, Yang S. Developing Clostridia as Cell Factories for Short- and Medium-Chain Ester Production. Front Bioeng Biotechnol 2021; 9:661694. [PMID: 34164382 PMCID: PMC8215697 DOI: 10.3389/fbioe.2021.661694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Accepted: 04/19/2021] [Indexed: 11/21/2022] Open
Abstract
Short- and medium-chain volatile esters with flavors and fruity fragrances, such as ethyl acetate, butyl acetate, and butyl butyrate, are usually value-added in brewing, food, and pharmacy. The esters can be naturally produced by some microorganisms. As ester-forming reactions are increasingly deeply understood, it is possible to produce esters in non-natural but more potential hosts. Clostridia are a group of important industrial microorganisms since they can produce a variety of volatile organic acids and alcohols with high titers, especially butanol and butyric acid through the CoA-dependent carbon chain elongation pathway. This implies sufficient supplies of acyl-CoA, organic acids, and alcohols in cells, which are precursors for ester production. Besides, some Clostridia could utilize lignocellulosic biomass, industrial off-gas, or crude glycerol to produce other branched or straight-chain alcohols and acids. Therefore, Clostridia offer great potential to be engineered to produce short- and medium-chain volatile esters. In the review, the efforts to produce esters from Clostridia via in vitro lipase-mediated catalysis and in vivo alcohol acyltransferase (AAT)-mediated reaction are comprehensively revisited. Besides, the advantageous characteristics of several Clostridia and clostridial consortia for bio-ester production and the driving force of synthetic biology to clostridial chassis development are also discussed. It is believed that synthetic biotechnology should enable the future development of more effective Clostridia for ester production.
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Affiliation(s)
- Qingzhuo Wang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Naief H Al Makishah
- Department of Environmental Sciences, Faculty of Meteorology, Environment and Arid Land Agriculture, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Qi Li
- College of Life Sciences, Sichuan Normal University, Chengdu, China
| | - Yanan Li
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Wenzheng Liu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Xiaoman Sun
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Zhiqiang Wen
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Sheng Yang
- Huzhou Center of Industrial Biotechnology, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,Key Laboratory of Synthetic Biology, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
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10
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Sinumvayo JP, Zhao C, Liu G, Li Y, Zhang Y. One-pot production of butyl butyrate from glucose using a cognate "diamond-shaped" E. coli consortium. BIORESOUR BIOPROCESS 2021; 8:18. [PMID: 38650238 PMCID: PMC10992435 DOI: 10.1186/s40643-021-00372-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/15/2021] [Indexed: 11/10/2022] Open
Abstract
Esters are widely used in plastics, textile fibers, and general petrochemicals. Usually, esters are produced via chemical synthesis or enzymatic processes from the corresponding alcohols and acids. However, the fermentative production of esters from alcohols and/or acids has recently also become feasible. Here we report a cognate microbial consortium capable of producing butyl butyrate. This microbial consortium consists of two engineered butyrate- and butanol-producing E. coli strains with nearly identical genetic background. The pathways for the synthesis of butyrate and butanol from butyryl-CoA in the respective E. coli strains, together with a lipase-catalyzed esterification reaction, created a "diamond-shaped" consortium. The concentration of butyrate and butanol in the fermentation vessel could be altered by adjusting the inoculation ratios of each E. coli strain in the consortium. After optimization, the consortium produced 7.2 g/L butyl butyrate with a yield of 0.12 g/g glucose without the exogenous addition of butanol or butyrate. To our best knowledge, this is the highest titer and yield of butyl butyrate produced by E. coli reported to date. This study thus provides a new way for the biotechnological production of esters.
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Affiliation(s)
- Jean Paul Sinumvayo
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chunhua Zhao
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guoxia Liu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Yin Li
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Yanping Zhang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
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11
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Fang D, Wen Z, Lu M, Li A, Ma Y, Tao Y, Jin M. Metabolic and Process Engineering of Clostridium beijerinckii for Butyl Acetate Production in One Step. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:9475-9487. [PMID: 32806108 DOI: 10.1021/acs.jafc.0c00050] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
n-Butyl acetate is an important food additive commonly produced via concentrated sulfuric acid catalysis or immobilized lipase catalysis of butanol and acetic acid. Compared with chemical methods, an enzymatic approach is more environmentally friendly; however, it incurs a higher cost due to lipase production. In vivo biosynthesis via metabolic engineering offers an alternative to produce n-butyl acetate. This alternative combines substrate production (butanol and acetyl-coenzyme A (acetyl-CoA)), alcohol acyltransferase expression, and esterification reaction in one reactor. The alcohol acyltransferase gene ATF1 from Saccharomyces cerevisiae was introduced into Clostridium beijerinckii NCIMB 8052, enabling it to directly produce n-butyl acetate from glucose without lipase addition. Extractants were compared and adapted to realize glucose fermentation with in situ n-butyl acetate extraction. Finally, 5.57 g/L of butyl acetate was produced from 38.2 g/L of glucose within 48 h, which is 665-fold higher than that reported previously. This demonstrated the potential of such a metabolic approach to produce n-butyl acetate from biomass.
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Affiliation(s)
- Dahui Fang
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, China
| | - Zhiqiang Wen
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, China
| | - Minrui Lu
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, China
| | - Ang Li
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, China
| | - Yuheng Ma
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, China
| | - Ye Tao
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, China
| | - Mingjie Jin
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, China
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12
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Bohnenkamp AC, Kruis AJ, Mars AE, Wijffels RH, van der Oost J, Kengen SWM, Weusthuis RA. Multilevel optimisation of anaerobic ethyl acetate production in engineered Escherichia coli. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:65. [PMID: 32280373 PMCID: PMC7137189 DOI: 10.1186/s13068-020-01703-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 03/25/2020] [Indexed: 05/05/2023]
Abstract
BACKGROUND Ethyl acetate is a widely used industrial solvent that is currently produced by chemical conversions from fossil resources. Several yeast species are able to convert sugars to ethyl acetate under aerobic conditions. However, performing ethyl acetate synthesis anaerobically may result in enhanced production efficiency, making the process economically more viable. RESULTS We engineered an E. coli strain that is able to convert glucose to ethyl acetate as the main fermentation product under anaerobic conditions. The key enzyme of the pathway is an alcohol acetyltransferase (AAT) that catalyses the formation of ethyl acetate from acetyl-CoA and ethanol. To select a suitable AAT, the ethyl acetate-forming capacities of Atf1 from Saccharomyces cerevisiae, Eat1 from Kluyveromyces marxianus and Eat1 from Wickerhamomyces anomalus were compared. Heterologous expression of the AAT-encoding genes under control of the inducible LacI/T7 and XylS/Pm promoters allowed optimisation of their expression levels. CONCLUSION Engineering efforts on protein and fermentation level resulted in an E. coli strain that anaerobically produced 42.8 mM (3.8 g/L) ethyl acetate from glucose with an unprecedented efficiency, i.e. 0.48 C-mol/C-mol or 72% of the maximum pathway yield.
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Affiliation(s)
- Anna C. Bohnenkamp
- Bioprocess Engineering, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Aleksander J. Kruis
- Bioprocess Engineering, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Astrid E. Mars
- Biobased Products, Wageningen University and Research, Bornse Weilanden 9, 6708 WG Wageningen, The Netherlands
| | - Rene H. Wijffels
- Bioprocess Engineering, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
- Faculty of Biosciences and Aquaculture, Nord University, 8049 Bodø, Norway
| | - John van der Oost
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Servé W. M. Kengen
- Laboratory of Microbiology, Wageningen University and Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Ruud A. Weusthuis
- Bioprocess Engineering, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
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Xin F, Zhang W, Jiang M. Bioprocessing Butanol into More Valuable Butyl Butyrate. Trends Biotechnol 2019; 37:923-926. [DOI: 10.1016/j.tibtech.2019.03.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 03/11/2019] [Accepted: 03/19/2019] [Indexed: 10/27/2022]
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Noh HJ, Lee SY, Jang YS. Microbial production of butyl butyrate, a flavor and fragrance compound. Appl Microbiol Biotechnol 2019; 103:2079-2086. [PMID: 30659333 DOI: 10.1007/s00253-018-09603-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 12/26/2018] [Accepted: 12/27/2018] [Indexed: 12/11/2022]
Abstract
Butyl butyrate (BB) has been widely used as a flavor and fragrance compound in the beverage, food, perfume, and cosmetic industries. Currently, BB is produced through two-step processes; butanol and butyrate are first produced and are used as precursors for the esterification reactions to yield BB in the next step. Recently, an alternative process to the current process has been developed by using microorganisms for the one-pot BB production. In the one-pot BB process, alcohol acyl transferases (AATs) and lipases play roles in the esterification of butanol together with their co-substrates butyryl-CoA and butyrate, respectively. In this paper, we review the characteristics of two enzymes including AAT and lipase in the esterification reaction. Also, we review the one-pot processes for BB production by employing the wild-type and engineered Clostridium species and the engineered Escherichia coli strains, with the combination of AATs and lipases.
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Affiliation(s)
- Hyeon Ji Noh
- Department of Agricultural Chemistry and Food Science Technology, Division of Applied Life Science (BK21 Plus Program), Institute of Agriculture & Life Science (IALS), Gyeongsang National University, Jinju, Republic of Korea
| | - Sang Yup Lee
- Department of Chemical and Biomolecular Engineering (BK21 Plus Program), BioProcess Engineering Research Center, Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
| | - Yu-Sin Jang
- Department of Agricultural Chemistry and Food Science Technology, Division of Applied Life Science (BK21 Plus Program), Institute of Agriculture & Life Science (IALS), Gyeongsang National University, Jinju, Republic of Korea.
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15
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Noh HJ, Woo JE, Lee SY, Jang YS. Metabolic engineering of Clostridium acetobutylicum for the production of butyl butyrate. Appl Microbiol Biotechnol 2018; 102:8319-8327. [PMID: 30076425 DOI: 10.1007/s00253-018-9267-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 05/31/2018] [Accepted: 07/19/2018] [Indexed: 10/28/2022]
Abstract
Butyl butyrate is widely used as a fragrance additive for foods and beverages. The first step in the currently used process is the production of precursors, including butanol and butyrate, from petroleum using chemical catalysts, followed by the conversion of precursors to butyl butyrate by immobilized lipase. In this work, we engineered Clostridium acetobutylicum for the selective, one-step production of butyl butyrate from glucose. C. acetobutylicum ATCC 824, possessing a strong carbon flux that yields butanol and butyryl-CoA, was selected as a host and was engineered by introducing alcohol acyltransferases (AATs) from Fragaria x ananassa (strawberry) or Malus sp. (apple). Batch culture of the engineered C. acetobutylicum strain CaSAAT expressing the strawberry SAAT gene produced 50.07 mg/L of butyl butyrate with a selectivity of 84.8% of total esters produced. Also, the engineered C. acetobutylicum strain CaAAAT expressing the apple AAAT gene produced 40.60 mg/L of butyl butyrate with a selectivity of 87.4%. This study demonstrated the feasibility of the one-step fermentation of butyl butyrate from glucose in the engineered C. acetobutylicum, as a proof of concept.
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Affiliation(s)
- Hyeon Ji Noh
- Institute of Agriculture & Life Science (IALS), Department of Agricultural Chemistry and Food Science Technology, Division of Applied Life Science (BK21 Plus Program), Gyeongsang National University, Jinju, Republic of Korea
| | - Ji Eun Woo
- Institute of Agriculture & Life Science (IALS), Department of Agricultural Chemistry and Food Science Technology, Division of Applied Life Science (BK21 Plus Program), Gyeongsang National University, Jinju, Republic of Korea
| | - Sang Yup Lee
- Department of Chemical and Biomolecular Engineering (BK21 Plus Program), BioProcess Engineering Research Center, Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
| | - Yu-Sin Jang
- Institute of Agriculture & Life Science (IALS), Department of Agricultural Chemistry and Food Science Technology, Division of Applied Life Science (BK21 Plus Program), Gyeongsang National University, Jinju, Republic of Korea.
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Xin F, Dong W, Jiang Y, Ma J, Zhang W, Wu H, Zhang M, Jiang M. Recent advances on conversion and co-production of acetone-butanol-ethanol into high value-added bioproducts. Crit Rev Biotechnol 2017; 38:529-540. [PMID: 28911245 DOI: 10.1080/07388551.2017.1376309] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Butanol is an important bulk chemical and has been regarded as an advanced biofuel. Large-scale production of butanol has been applied for more than 100 years, but its production through acetone-butanol-ethanol (ABE) fermentation process by solventogenic Clostridium species is still not economically viable due to the low butanol titer and yield caused by the toxicity of butanol and a by-product, such as acetone. Renewed interest in biobutanol as a biofuel has spurred technological advances to strain modification and fermentation process design. Especially, with the development of interdisciplinary processes, the sole product or even the mixture of ABE produced through ABE fermentation process can be further used as platform chemicals for high value added product production through enzymatic or chemical catalysis. This review aims to comprehensively summarize the most recent advances on the conversion of acetone, butanol and ABE mixture into various products, such as isopropanol, butyl-butyrate and higher-molecular mass alkanes. Additionally, co-production of other value added products with ABE was also discussed.
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Affiliation(s)
- Fengxue Xin
- a State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering , Nanjing Tech University , Nanjing , P.R. China.,b Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing Tech University , Nanjing , P.R. China
| | - Weiliang Dong
- a State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering , Nanjing Tech University , Nanjing , P.R. China.,b Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing Tech University , Nanjing , P.R. China
| | - Yujia Jiang
- a State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering , Nanjing Tech University , Nanjing , P.R. China
| | - Jiangfeng Ma
- a State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering , Nanjing Tech University , Nanjing , P.R. China.,b Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing Tech University , Nanjing , P.R. China
| | - Wenming Zhang
- a State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering , Nanjing Tech University , Nanjing , P.R. China.,b Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing Tech University , Nanjing , P.R. China
| | - Hao Wu
- a State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering , Nanjing Tech University , Nanjing , P.R. China.,b Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing Tech University , Nanjing , P.R. China
| | - Min Zhang
- a State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering , Nanjing Tech University , Nanjing , P.R. China.,b Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing Tech University , Nanjing , P.R. China
| | - Min Jiang
- a State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering , Nanjing Tech University , Nanjing , P.R. China.,b Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM) , Nanjing Tech University , Nanjing , P.R. China
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Zhang ZT, Taylor S, Wang Y. In situ esterification and extractive fermentation for butyl butyrate production with Clostridium tyrobutyricum. Biotechnol Bioeng 2017; 114:1428-1437. [PMID: 28295202 DOI: 10.1002/bit.26289] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/04/2017] [Accepted: 03/09/2017] [Indexed: 02/05/2023]
Abstract
Butyl butyrate (BB) is a valuable chemical that can be used as flavor, fragrance, extractant, and so on in various industries. Meanwhile, BB can also be used as a fuel source with excellent compatibility as gasoline, aviation kerosene, and diesel components. The conventional industrial production of BB is highly energy-consuming and generates various environmental pollutants. Recently, there have been tremendous interests in producing BB from renewable resources through biological routes. In this study, based on the fermentation using the hyper-butyrate producing strain Clostridium tyrobutyricum ATCC 25755, efficient BB production through in situ esterification was achieved by supplementation of lipase and butanol into the fermentation. Three commercially available lipases were assessed and the one from Candida sp. (recombinant, expressed in Aspergillus niger) was identified with highest catalytic activity for BB production. Various conditions that might affect BB production in the fermentation have been further evaluated, including the extractant type, enzyme loading, agitation, pH, and butanol supplementation strategy. Under the optimized conditions (5.0 g L-1 of enzyme loading, pH at 5.5, butanol kept at 10.0 g L-1 ), 34.7 g L-1 BB was obtained with complete consumption of 50 g L-1 glucose as the starting substrate. To our best knowledge, the BB production achieved in this study is the highest among the ever reported from the batch fermentation process. Our results demonstrated an excellent biological platform for renewable BB production from low-value carbon sources. Biotechnol. Bioeng. 2017;114: 1428-1437. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Zhong-Tian Zhang
- Department of Biosystems Engineering, Auburn University, 215 Tom E. Corley Building, Auburn, Alabama 36849
| | - Steven Taylor
- Department of Biosystems Engineering, Auburn University, 215 Tom E. Corley Building, Auburn, Alabama 36849.,Center for Bioenergy and Bioproducts, Auburn University, Auburn, Alabama
| | - Yi Wang
- Department of Biosystems Engineering, Auburn University, 215 Tom E. Corley Building, Auburn, Alabama 36849.,Center for Bioenergy and Bioproducts, Auburn University, Auburn, Alabama
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Lin JL, Zhu J, Wheeldon I. Rapid ester biosynthesis screening reveals a high activity alcohol-O-acyltransferase (AATase) from tomato fruit. Biotechnol J 2016; 11:700-7. [PMID: 26814045 DOI: 10.1002/biot.201500406] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 11/24/2015] [Accepted: 01/22/2016] [Indexed: 12/25/2022]
Abstract
Ethyl and acetate esters are naturally produced in various yeasts, plants, and bacteria. The biosynthetic pathways that produce these esters share a common reaction step, the condensation of acetyl/acyl-CoA with an alcohol by alcohol-O-acetyl/acyltransferase (AATase). Recent metabolic engineering efforts exploit AATase activity to produce fatty acid ethyl esters as potential diesel fuel replacements as well as short- and medium-chain volatile esters as fragrance and flavor compounds. These efforts have been limited by the lack of a rapid screen to quantify ester biosynthesis. Enzyme engineering efforts have also been limited by the lack of a high throughput screen for AATase activity. Here, we developed a high throughput assay for AATase activity and used this assay to discover a high activity AATase from tomato fruit, Solanum lycopersicum (Atf-S.l). Atf1-S.l exhibited broad specificity towards acyl-CoAs with chain length from C4 to C10 and was specific towards 1-pentanol. The AATase screen also revealed new acyl-CoA substrate specificities for Atf1, Atf2, Eht1, and Eeb1 from Saccharomyces cerevisiae, and Atf-C.m from melon fruit, Cucumis melo, thus increasing the pool of characterized AATases that can be used in ester biosynthesis of ester-based fragrance and flavor compounds as well as fatty acid ethyl ester biofuels.
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Affiliation(s)
- Jyun-Liang Lin
- Chemical and Environmental Engineering, University of California, Riverside, CA, USA
| | - Jie Zhu
- Biochemistry, University of California, Riverside, CA, USA
| | - Ian Wheeldon
- Chemical and Environmental Engineering, University of California, Riverside, CA, USA.
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Xin F, Basu A, Yang KL, He J. Strategies for production of butanol and butyl-butyrate through lipase-catalyzed esterification. BIORESOURCE TECHNOLOGY 2016; 202:214-9. [PMID: 26710347 DOI: 10.1016/j.biortech.2015.11.068] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 11/21/2015] [Accepted: 11/24/2015] [Indexed: 05/24/2023]
Abstract
In this study, a fermentation process for production of butanol and butyl-butyrate by using Clostridium sp. strain BOH3 is developed. This strain is able to produce butyric acid and butanol when it ferments 60 g/L xylose. Meanwhile, it also excreted indigenous lipases (induced by olive oil) which naturally convert butyric acid and butanol into 1.2 g/L of butyl-butyrate. When Bio-OSR was used as both an inducer for lipase and extractant for butyl-butyrate, the butyl-butyrate concentration can reach 6.3 g/L. To further increase the yield, additional lipases and butyric acid are added to the fermentation system. Moreover, kerosene was used as an extractant to remove butyl-butyrate in situ. When all strategies are combined, 22.4 g/L butyl-butyrate can be produced in a fed-batch reactor spiked with 70 g/L xylose and 7.9 g/L butyric acid, which is 4.5-fold of that in a similar system (5 g/L) with hexadecane as the extractant.
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Affiliation(s)
- Fengxue Xin
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576, Singapore
| | - Anindya Basu
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576, Singapore
| | - Kun-Lin Yang
- Department of Chemical and Bimolecular Engineering, National University of Singapore, Singapore 117576, Singapore
| | - Jianzhong He
- Department of Civil and Environmental Engineering, National University of Singapore, Singapore 117576, Singapore.
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Zhu J, Lin JL, Palomec L, Wheeldon I. Microbial host selection affects intracellular localization and activity of alcohol-O-acetyltransferase. Microb Cell Fact 2015; 14:35. [PMID: 25880435 PMCID: PMC4367896 DOI: 10.1186/s12934-015-0221-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 01/27/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A key pathway for ester biosynthesis in yeast is the condensation of an alcohol with acetyl-CoA by alcohol-O-acetyltransferase (AATase). This pathway is also prevalent in fruit, producing short and medium chain volatile esters during ripening. In this work, a series of six AATases from Saccharomyces and non-Saccharomyces yeasts as well as tomato fruit were evaluated with respect to their activity, intracellular localization, and expression in Saccharomyces cerevisiae and Escherichia coli cell hosts. The series of AATases includes Atf1 and Atf2 from S. cerevisiae, as well as AATases from S. pastorianus, Kluyveromyces lactis, Pichia anomala, and Solanum lycopersicum (tomato). RESULTS When expressed in S. cerevisiae, Atf1, Atf2, and an AATase from S. pastorianus localized to lipid droplets, while AATases from non-Saccharomyces yeasts and tomato fruit did not localize to intracellular membranes and were localized to the cytoplasm. All AATases studied here formed intracellular aggregates when expressed in E. coli, and western blot analysis revealed that expression levels in E. coli were upwards of 100-fold higher than in S. cerevisiae. Fermentation and whole cell lysate activity assays of the two most active AATases, Atf1 from S. cerevisiae and an AATase from tomato fruit, demonstrated that the aggregates were enzymatically active, but with highly reduced specific activity in comparison to activity in S. cerevisiae. Activity was partially recovered at lower expression levels, coinciding with smaller intracellular aggregates. In vivo and in vitro activity assays from heterologously expressed Atf1 from S. cerevisiae, which localizes to lipid droplets under homologous expression, demonstrates that its activity is not membrane dependent. CONCLUSIONS The results of these studies provide important information on the biochemistry of AATases under homologous and heterologous expression with two common microbial hosts for biochemical processes, S. cerevisiae and E. coli. All studied AATases formed aggregates with low enzymatic activity when expressed in E. coli and any membrane localization observed in S. cerevisiae was lost in E. coli. In addition, AATases that were found to localize to lipid droplet membranes in S. cerevisiae were found to not be membrane dependent with respect to activity.
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Affiliation(s)
- Jie Zhu
- Department of Biochemistry, University of California, Riverside, USA, 92521.
| | - Jyun-Liang Lin
- Department of Chemical and Environmental Engineering, University of California, Riverside, USA, 92521.
| | - Leidy Palomec
- Department of Chemical and Environmental Engineering, University of California, Riverside, USA, 92521.
| | - Ian Wheeldon
- Department of Chemical and Environmental Engineering, University of California, Riverside, USA, 92521.
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Lin JL, Wheeldon I. Dual N- and C-terminal helices are required for endoplasmic reticulum and lipid droplet association of alcohol acetyltransferases in Saccharomyces cerevisiae. PLoS One 2014; 9:e104141. [PMID: 25093817 PMCID: PMC4122449 DOI: 10.1371/journal.pone.0104141] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Accepted: 07/05/2014] [Indexed: 11/21/2022] Open
Abstract
In the yeast Saccharomyces cerevisiae two alcohol acetyltransferases (AATases), Atf1 and Atf2, condense short chain alcohols with acetyl-CoA to produce volatile acetate esters. Such esters are, in large part, responsible for the distinctive flavors and aromas of fermented beverages including beer, wine, and sake. Atf1 and Atf2 localize to the endoplasmic reticulum (ER) and Atf1 is known to localize to lipid droplets (LDs). The mechanism and function of these localizations are unknown. Here, we investigate potential mechanisms of Atf1 and Atf2 membrane association. Segments of the N- and C-terminal domains of Atf1 (residues 24–41 and 508–525, respectively) are predicted to be amphipathic helices. Truncations of these helices revealed that the terminal domains are essential for ER and LD association. Moreover, mutations of the basic or hydrophobic residues in the N-terminal helix and hydrophobic residues in the C-terminal helix disrupted ER association and subsequent sorting from the ER to LDs. Similar amphipathic helices are found at both ends of Atf2, enabling ER and LD association. As was the case with Atf1, mutations to the N- and C-terminal helices of Atf2 prevented membrane association. Sequence comparison of the AATases from Saccharomyces, non-Saccharomyces yeast (K. lactis and P. anomala) and fruits species (C. melo and S. lycopersicum) showed that only AATases from Saccharomyces evolved terminal amphipathic helices. Heterologous expression of these orthologs in S. cerevisiae revealed that the absence of terminal amphipathic helices eliminates LD association. Combined, the results of this study suggest a common mechanism of membrane association for AATases via dual N- and C-terminal amphipathic helices.
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Affiliation(s)
- Jyun-Liang Lin
- Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, California, United States of America
| | - Ian Wheeldon
- Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, California, United States of America
- * E-mail:
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van den Berg C, Heeres AS, van der Wielen LAM, Straathof AJJ. Simultaneous Clostridial fermentation, lipase-catalyzed esterification, and ester extraction to enrich diesel with butyl butyrate. Biotechnol Bioeng 2012; 110:137-42. [PMID: 22833369 DOI: 10.1002/bit.24618] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2012] [Revised: 07/09/2012] [Accepted: 07/16/2012] [Indexed: 11/09/2022]
Abstract
The recovery of 1-butanol from fermentation broth is energy-intensive since typical concentrations in fermentation broth are below 20 g L(-1). To prevent butanol inhibition and high downstream processing costs, we aimed at producing butyl esters instead of 1-butanol. It is shown that it is possible to perform simultaneously clostridial fermentation, esterification of the formed butanol to butyl butyrate, and extraction of this ester by hexadecane. The very high partition coefficient of butyl butyrate pulls the esterification towards the product side even at fermentation pH and relatively low butanol concentrations. The hexadecane extractant is a model diesel compound and is nontoxic to the cells. If butyl butyrate enriched diesel can directly be used as car fuel, no product recovery is required. A proof-of-principle experiment for the one-pot bio-ester production from glucose led to 5 g L(-1) butyl butyrate in the hexadecane phase. The principle may be extended to a wide range of esters, especially to longer chain ones.
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Affiliation(s)
- Corjan van den Berg
- Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands
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Seregina TA, Shakulov RS, Debabov VG, Mironov AS. Construction of a butyrate-producing E. coli strain without the use of heterologous genes. APPL BIOCHEM MICRO+ 2010. [DOI: 10.1134/s000368381008003x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Sumby KM, Grbin PR, Jiranek V. Microbial modulation of aromatic esters in wine: Current knowledge and future prospects. Food Chem 2010. [DOI: 10.1016/j.foodchem.2009.12.004] [Citation(s) in RCA: 304] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Park YC, Shaffer CEH, Bennett GN. Microbial formation of esters. Appl Microbiol Biotechnol 2009; 85:13-25. [PMID: 19714327 DOI: 10.1007/s00253-009-2170-x] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2009] [Revised: 07/27/2009] [Accepted: 07/28/2009] [Indexed: 12/22/2022]
Abstract
Small aliphatic esters are important natural flavor and fragrance compounds and have numerous uses as solvents and as chemical intermediates. Besides the chemical or lipase-catalyzed formation of esters from alcohols and organic acids, small volatile esters are made by several biochemical routes in microbes. This short review will cover the biosynthesis of esters from acyl-CoA and alcohol condensation, from oxidation of hemiacetals formed from aldehydes and alcohols, and from the insertion of oxygen adjacent to the carbonyl group in a straight chain or cyclic ketone by Baeyer-Villiger monooxygenases. The physiological role of the ester-forming reactions can allow degradation of ketones for use as a carbon source and may play a role in detoxification of aldehydes or recycling cofactors. The enzymes catalyzing each of these processes have been isolated and characterized, and a number of genes encoding the proteins from various microbes have been cloned and functionally expressed. The use of these ester-forming organisms or recombinant organisms expressing the appropriate genes as biocatalysts in biotechnology to make specific esters and chiral lactones has been studied in recent years.
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Affiliation(s)
- Yong Cheol Park
- Department of General Education, Kookmin University, Seoul, South Korea
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