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Mathivanan K, Ameen F, Zhang R, Rakesh E. Application of Response Surface Methodology (RSM) in the statistical evaluation of biodiesel production from the neutral lipids of the Coelastrella-Nannochloropsis consortium. ENVIRONMENTAL RESEARCH 2024; 243:117829. [PMID: 38052355 DOI: 10.1016/j.envres.2023.117829] [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: 09/26/2023] [Revised: 11/24/2023] [Accepted: 11/29/2023] [Indexed: 12/07/2023]
Abstract
The paramount challenge in economically workable microalgal biodiesel production is the selection of a competent catalyst to improve the fatty acid methyl ester yield with desirable fatty acid composition. Though countless researchers have explored different homogeneous and heterogeneous catalysts to improve the transesterification efficacy, achieving greater biodiesel production from the neutral lipids of the microalgal consortium using a statistical tool, response surface methodology is scarce. Thus, the present study applied Response surface methodology to statistically analyze the biodiesel production from the neutral lipids of the indigenous Coelastrella-Nannochloropsis consortium (CNC) on the way to commercial feasibility. Onset of the study, the neutral lipids and acid value of the CNC were determined to be 18.74% and 2.73%, respectively. The transesterification of the neutral lipids of CNC was optimized through the coded factors in the RSM for various reaction parameters as combined influence viz., (i) Catalyst dose: methanol volume, (ii) Catalyst dose: reaction time; (iii) Catalyst dose: reaction temperature, (iv) Time: temperature, (v) time: methanol volume, (vi) temperature: methanol volume. Based on the ANOVA, coefficient determination, 2% KOH, 2 h time, 70 °C temperature, and 9 mL methanol volume were ascertained to be optimal values to accomplish 92% biodiesel production. Further, the biodiesel has desirable palmitic, palmitoleic, stearic, oleic, linoleic, and linolenic acids, with palmitic acid as the prevalent fatty acid contributing 16-18%. In addition, the tested fuel properties of CNC biodiesel satisfy international biodiesel standards.
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Affiliation(s)
- Krishnamurthy Mathivanan
- Key Laboratory of Marine Environmental Corrosion and Biofouling, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, China.
| | - Fuad Ameen
- Department of Botany & Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Ruiyong Zhang
- Key Laboratory of Marine Environmental Corrosion and Biofouling, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao, 266071, China.
| | - Eerla Rakesh
- Department of Microbiology, Kakatiya University, Hanumakonda, 506009, Telangana, India
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2
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Pugazhendhi A, Sharma A, Shan Ahamed T, Ramasamy KP, Sabour AAA, A Alshiekheid M, Thuy T, Mathimani T. Sugar cane bagasse hydrolysate (SBH) as a lucrative carbon supplement to upgrade the lipid and fatty acid production in Chlorococcum sp. for biodiesel through an optimized binary solvent system. ENVIRONMENTAL RESEARCH 2024; 241:117626. [PMID: 37956754 DOI: 10.1016/j.envres.2023.117626] [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: 09/15/2023] [Revised: 11/03/2023] [Accepted: 11/07/2023] [Indexed: 11/15/2023]
Abstract
Cost is the crucial impediment in commercializing microalgal biodiesel. Therefore, cultivating microalgae in cost-effective nutrients reduces the upstream process cost remarkably. Thus, in this study, sugar cane bagasse hydrolysate (SBH) as a lucrative carbon supplement for Chlorococcum sp. and subsequent lipid extraction via an optimized solvent system for biodiesel production was investigated. Characterization of SBH revealed the presence of various monosaccharides and other sugar derivatives such as glucose, fructose, xylose, arabinose, etc. The maximum dry cell weight of 1.7 g/L was estimated in cultures grown in 10 mL SBH. Different solvents such as diethyl ether (DEE), chloroform (CHL), ethyl acetate (ETA), hexane (HEX), methanol (MET), ethanol (ETOH), acetone (ACE) and also combination of solvents (2:1 ratio) such as DEE: MET, CHL: MET, HEX: MET, HEX: ETOH was tested for lipid extraction efficacy. Among solvents used, 12.3% and 18.4% of lipids were extracted using CHL and CHL: MET, respectively, from 10 mL SBH amended cultures. However, the biodiesel yield was found to be similar at about 70.16 % in both SBH and no SBH-added cultures. The fatty acid profile of the biodiesel shows palmitic, oleic, linoleic, linolenic, and arachidonic acid as principal fatty acids. Further, the levels of SFAs, MUFAs, and PUFAs in 10 mL SBH-added cells were 24.67, 12.89, and 34.24%, respectively. Eventually, the fuel properties of Chlorococcum sp. biodiesel, satisfying international biodiesel standards, make the biodiesel a viable diesel substitute in the future.
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Affiliation(s)
- Arivalagan Pugazhendhi
- Tecnologico de Monterrey, Centre of Bioengineering, NatProLab, Plant Innovation Lab, School of Engineering and Sciences, Queretaro, 76130, Mexico
| | - Ashutosh Sharma
- Tecnologico de Monterrey, Centre of Bioengineering, NatProLab, Plant Innovation Lab, School of Engineering and Sciences, Queretaro, 76130, Mexico
| | - Tharifkhan Shan Ahamed
- Department of Biotechnology, Microbiology and Bioinformatics, National College, Trichy, 620001, India
| | | | - Amal Abdullah A Sabour
- Department of Botany and Microbiology, College of Science, King Saud University, PO Box -2455, Riyadh, 11451, Saudi Arabia
| | - Maha A Alshiekheid
- Department of Botany and Microbiology, College of Science, King Saud University, PO Box -2455, Riyadh, 11451, Saudi Arabia
| | - Tgl Thuy
- Institute of Research and Development, Duy Tan University, Da Nang, Viet Nam; School of Engineering and Technology, Duy Tan University, Da Nang, Viet Nam
| | - Thangavel Mathimani
- Institute of Research and Development, Duy Tan University, Da Nang, Viet Nam; School of Engineering and Technology, Duy Tan University, Da Nang, Viet Nam.
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Rawat J, Pande V. Abiotic factors improving fatty acid profiling of freshwater indigenous microalgae isolated from Kumaun region of Uttarakhand, India. Braz J Microbiol 2023; 54:2961-2977. [PMID: 37943485 PMCID: PMC10689662 DOI: 10.1007/s42770-023-01146-4] [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: 03/11/2023] [Accepted: 10/04/2023] [Indexed: 11/10/2023] Open
Abstract
Microalgae have grabbed huge attention as a potential feedstock for biofuel production in response to the rise in energy consumption and the energy crisis. In the present study, indigenous microalgal strains were isolated from four freshwater lakes in the Kumaun region, Uttarakhand, India. Based on growth and lipid profiles, the four best-performing isolates were selected for further experiments. Initial identification of isolates was done by morphological observations, which were further validated by molecular identification using ITS sequencing. The screened cultures were subjected to abiotic stress conditions (varying concentrations of nitrogen and different temperatures) to monitor the biomass, lipid accumulation, and biochemical compositions (chlorophyll and carotenoids). The quantification of fatty acids was checked via gas chromatographic analysis. The strains were identified as KU_MA3 Chlamydopodium starrii, KU_MA4 Tetradesmus nygaardii, KU_MA5 Desmodesmus intermedius, and KU_MA6 Tetradesmus nygaardii. KU_MA3 Chlamydopodium starrii showed the best results in terms of growth and lipid production at 21 °C and 0.37 g/L NaNO2 concentration. The percentage of fatty acid methyl esters (FAMEs) attained >80% and met the standard for biodiesel properties. The strain has the potential to attain higher biomass and accumulate higher lipid content, and after some more studies, it can be used for upscaling processes and large-scale biodiesel production.
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Affiliation(s)
- Jyoti Rawat
- Department of Biotechnology, Kumaun University, Sir J. C. Bose Technical Campus Bhimtal (Nainital), Nainital, India
| | - Veena Pande
- Department of Biotechnology, Kumaun University, Sir J. C. Bose Technical Campus Bhimtal (Nainital), Nainital, India.
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4
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Dong G, Xu S, Shi S. De Novo Biosynthesis of Free Vaccenic Acid with a Low Content of Oleic Acid in Saccharomyces cerevisiae. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2023; 71:16204-16211. [PMID: 37856078 DOI: 10.1021/acs.jafc.3c04793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2023]
Abstract
Omega-7 (ω-7) fatty acids have potential application in the fields of nutraceutical, agricultural, and food industry. The natural ω-7 fatty acids are currently from plants or vegetable oils, which are unsustainable and limited by the availability of plant sources. Here, we developed an innovative biosynthetic route to produce vaccenic acid (C18:1 ω-7) while minimizing oleic acid (C18:1 ω-9) content in Saccharomyces cerevisiae. We have engineered S. cerevisiaeto produce C18:1 ω-7 by expressing a fatty acid elongase from Rattus norvegicus. To reduce the content of C18:1 ω-9, the endogenous desaturase Ole1 was replaced by the desaturase, which has specific activity on palmitoyl-coenzyme A (C16:0-CoA). Finally, the production of free C18:1 ω-7 was improved by optimizing the source of cytochrome b5 and overexpressing endoplasmic reticulum chaperones. After combining these strategies, the yield of C18:1 ω-7 was increased from 0 to 9.3 mg/g DCW and C18:1 ω-9 was decreased from 25.2 mg/g DCW to 1.6 mg/g DCW. This work shows a de novo synthetic pathway to produce the highest amount of free C18:1 ω-7 with a low content of C18:1 ω-9 in S. cerevisiae.
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Affiliation(s)
- Genlai Dong
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, North Third Ring Road 15, Chaoyang District, Beijing 100029, China
| | - Shijie Xu
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, North Third Ring Road 15, Chaoyang District, Beijing 100029, China
| | - Shuobo Shi
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, North Third Ring Road 15, Chaoyang District, Beijing 100029, China
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Strategies to Enhance the Biosynthesis of Monounsaturated Fatty Acids in Escherichia coli. BIOTECHNOL BIOPROC E 2023. [DOI: 10.1007/s12257-022-0295-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
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Pu Y, Cao Y, Xian M. Modification of Fatty Acid Composition of Escherichia coli by Co-Expression of Fatty Acid Desaturase and Thioesterase from Arabidopsis thaliana. BIOENGINEERING (BASEL, SWITZERLAND) 2022; 9:bioengineering9120771. [PMID: 36550977 PMCID: PMC9774610 DOI: 10.3390/bioengineering9120771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/22/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022]
Abstract
Fatty acid composition has an important influence on the fluidity of biological membranes, which is a key factor for the survival of Escherichia coli. With the aim to modify fatty acid composition in this experimentally friendly microorganism, the AtFab2 gene, encoding the Arabidopsis thaliana fatty acid desaturase, was expressed separately and jointly with AtFatA, a fatty acid thioesterase of the same plant origin. The expression of ATFab2 desaturase resulted in an enhancement of cis-vaccenic acid (18:1Δ11) contents, while amounts of palmitioleic acid (16:1Δ9) accumulated by E. coli were increased by 130% for the expression of the AtFatA thioesterase. In the final engineered strain co-expressing AtFab2 and AtFatA, the percentage of palmitic acid (16:0), the most abundant saturated fatty acid found in E. coli, was reduced to 29.9% and the ratio of unsaturated fatty acid to saturated fatty acid reached 2:1. Free fatty acids accounted for about 40% of total fatty acid profiles in the recombinant strain expressing both two genes, and the unsaturated fatty acid contents reached nearly 75% in the free fatty acid profiles. The increase of unsaturated fatty acid level might provide some implication for the construction of cold tolerant strains.
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Affiliation(s)
- Yihan Pu
- The High School Affiliated to Renmin University of China, Beijing 100086, China
| | - Yujin Cao
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Correspondence: (Y.C.); (M.X.)
| | - Mo Xian
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Correspondence: (Y.C.); (M.X.)
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Chen B, Wang F, Xie X, Liu H, Liu D, Ma L, Xiao G, Wang Q. Functional analysis of the dehydratase domains of the PUFA synthase from Emiliania huxleyi in Escherichia coli and Arabidopsis thaliana. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:123. [PMID: 36380342 PMCID: PMC9667614 DOI: 10.1186/s13068-022-02223-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Accepted: 11/04/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Polyunsaturated fatty acid (PUFA) synthase is a multi-domain mega-enzyme that effectively synthesizes a series of PUFAs in marine microorganisms. The dehydratase (DH) domain of a PUFA synthase plays a crucial role in double bond positioning in fatty acids. Sequencing results of the coccolithophore Emiliania huxleyi (E. huxleyi, Eh) indicated that this species contains a PUFA synthase with multiple DH domains. Therefore, the current study, sought to define the functions of these DH domains (EhDHs), by cloning and overexpressing the genes encoding FabA-like EhDHs in Escherichia coli (E. coli) and Arabidopsis thaliana (A. thaliana). RESULTS A complementation test showed that the two FabA-like DH domains could restore DH function in a temperature-sensitive (Ts) mutant. Meanwhile, overexpression of FabA-like EhDH1 and EhDH2 domains increased the production of unsaturated fatty acids (UFAs) in recombinant E. coli by 43.5-32.9%, respectively. Site-directed mutagenesis analysis confirmed the authenticity of active-site residues in these domains. Moreover, the expression of tandem EhDH1-DH2 in A. thaliana altered the fatty acids content, seed weight, and germination rate. CONCLUSIONS The two FabA-like DH domains in the E. huxleyi PUFA synthase function as 3-hydroxyacyl-acyl carrier protein dehydratase in E. coli. The expression of these domains in E. coli and A. thaliana can alter the fatty acid profile in E. coli and increase the seed lipid content and germination rate in A. thaliana. Hence, introduction of DH domains controlling the dehydration process of fatty acid biosynthesis in plants might offer a new strategy to increase oil production in oilseed plants.
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Affiliation(s)
- Bihan Chen
- Guangdong Provincial Key Laboratory of Lingnan Specialty Food Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China
- College of Light Industry and Food, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Feng Wang
- Guangdong Provincial Key Laboratory of Lingnan Specialty Food Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China
- College of Light Industry and Food, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Xi Xie
- Guangdong Provincial Key Laboratory of Lingnan Specialty Food Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China.
- College of Light Industry and Food, Zhongkai University of Agriculture and Engineering, Guangzhou, China.
| | - Huifan Liu
- Guangdong Provincial Key Laboratory of Lingnan Specialty Food Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China
- College of Light Industry and Food, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Dongjie Liu
- Guangdong Provincial Key Laboratory of Lingnan Specialty Food Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China
- College of Light Industry and Food, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Lukai Ma
- Guangdong Provincial Key Laboratory of Lingnan Specialty Food Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China
- College of Light Industry and Food, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Gengsheng Xiao
- Guangdong Provincial Key Laboratory of Lingnan Specialty Food Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China
- College of Light Industry and Food, Zhongkai University of Agriculture and Engineering, Guangzhou, China
| | - Qin Wang
- Guangdong Provincial Key Laboratory of Lingnan Specialty Food Science and Technology, Zhongkai University of Agriculture and Engineering, Guangzhou, China
- College of Light Industry and Food, Zhongkai University of Agriculture and Engineering, Guangzhou, China
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8
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Bai W, Anthony WE, Hartline CJ, Wang S, Wang B, Ning J, Hsu FF, Dantas G, Zhang F. Engineering diverse fatty acid compositions of phospholipids in Escherichia coli. Metab Eng 2022; 74:11-23. [PMID: 36058465 DOI: 10.1016/j.ymben.2022.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/15/2022] [Accepted: 08/26/2022] [Indexed: 11/28/2022]
Abstract
Bacterial fatty acids (FAs) are an essential component of the cellular membrane and are an important source of renewable chemicals as they can be converted to fatty alcohols, esters, ketones, and alkanes, and used as biofuels, detergents, lubricants, and commodity chemicals. Most prior FA bioconversions have been performed on the carboxylic acid group. Modification of the FA hydrocarbon chain could substantially expand the structural and functional diversity of FA-derived products. Additionally, the effects of such modified FAs on the growth and metabolic state of their producing cells are not well understood. Here we engineer novel Escherichia coli phospholipid biosynthetic pathways, creating strains with distinct FA profiles enriched in ω7-unsaturated FAs (ω7-UFAs, 75%), Δ5-unsaturated FAs (Δ5-UFAs, 60%), cyclopropane FAs (CFAs, 55%), internally-branched FAs (IBFAs, 40%), and Δ5,ω7-double unsaturated FAs (DUFAs, 46%). Although bearing drastically different FA profiles in phospholipids, UFA, CFA, and IBFA enriched strains display wild-type-like phenotypic profiling and growth. Transcriptomic analysis reveals DUFA production drives increased differential expression and the induction of the fur iron starvation transcriptional cascade, but higher TCA cycle activation compared to the UFA producing strain. This likely reflects a slight cost imparted for DUFA production, which resulted in lower maximum growth in some, but not all, environmental conditions. The IBFA-enriched strain was further engineered to produce free IBFAs, releasing 96 mg/L free IBFAs from 154 mg/L of the total cellular IBFA pool. This work has resulted in significantly altered FA profiles of membrane lipids in E. coli, greatly increasing our understanding of the effects of FA structure diversity on the transcriptome, growth, and ability to react to stress.
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Affiliation(s)
- Wenqin Bai
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, MO, 63130, USA
| | - Winston E Anthony
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine in St. Louis, Saint Louis, MO, 63110, USA
| | - Christopher J Hartline
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, MO, 63130, USA
| | - Shaojie Wang
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, MO, 63130, USA
| | - Bin Wang
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine in St. Louis, Saint Louis, MO, 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, Saint Louis, MO, 63110, USA
| | - Jie Ning
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine in St. Louis, Saint Louis, MO, 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, Saint Louis, MO, 63110, USA
| | - Fong-Fu Hsu
- Mass Spectrometry Resource, Division of Endocrinology, Metabolism, and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Gautam Dantas
- The Edison Family Center for Genome Sciences and Systems Biology, Washington University School of Medicine in St. Louis, Saint Louis, MO, 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, Saint Louis, MO, 63110, USA; Department of Molecular Microbiology, Washington University School of Medicine in St. Louis, Saint Louis, MO, 63110, USA; Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, MO, 63130, USA.
| | - Fuzhong Zhang
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, Saint Louis, MO, 63130, USA; Institute of Materials Science & Engineering, Washington University in St. Louis, Saint Louis, MO, 63130, USA.
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Mechanistic Insight into Phenolic Compounds Toxicity and State-of-the-art Strategies for Enhancing the Tolerance of Escherichia coli to Phenolic Compounds. BIOTECHNOL BIOPROC E 2022. [DOI: 10.1007/s12257-022-0019-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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10
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Bartholow TG, Sztain T, Young MA, Lee DJ, Davis TD, Abagyan R, Burkart MD. Control of Unsaturation in De Novo Fatty Acid Biosynthesis by FabA. Biochemistry 2022; 61:608-615. [PMID: 35255690 PMCID: PMC9769579 DOI: 10.1021/acs.biochem.2c00094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Carrier protein-dependent biosynthesis provides a thiotemplated format for the production of natural products. Within these pathways, many reactions display exquisite substrate selectivity, a regulatory framework proposed to be controlled by protein-protein interactions (PPIs). In Escherichia coli, unsaturated fatty acids are generated within the de novo fatty acid synthase by a chain length-specific interaction between the acyl carrier protein AcpP and the isomerizing dehydratase FabA. To evaluate PPI-based control of reactivity, interactions of FabA with AcpP bearing multiple sequestered substrates were analyzed through NMR titration and guided high-resolution docking. Through a combination of quantitative binding constants, residue-specific perturbation analysis, and high-resolution docking, a model for substrate control via PPIs has been developed. The in silico results illuminate the mechanism of FabA substrate selectivity and provide a structural rationale with atomic detail. Helix III positioning in AcpP communicates sequestered chain length identity recognized by FabA, demonstrating a powerful strategy to regulate activity by allosteric control. These studies broadly illuminate carrier protein-dependent pathways and offer an important consideration for future inhibitor design and pathway engineering.
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Affiliation(s)
- Thomas G Bartholow
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Terra Sztain
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Megan A Young
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - D John Lee
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Tony D Davis
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
| | - Ruben Abagyan
- School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California 92093, United States
| | - Michael D Burkart
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, United States
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11
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Vimali E, Gunaseelan S, Chitra Devi V, Mothil S, Arumugam M, Ashokkumar B, Ganesh Moorthy IM, Pugazhendhi A, Varalakshmi P. Comparative study of different catalysts mediated FAME conversion from macroalga Padina tetrastromatica biomass and hydrothermal liquefaction facilitated bio-oil production. CHEMOSPHERE 2022; 292:133485. [PMID: 34979211 DOI: 10.1016/j.chemosphere.2021.133485] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/15/2021] [Accepted: 12/29/2021] [Indexed: 06/14/2023]
Abstract
Marine macroalgae offer an endurable source of renewable biomass, which do not require cultivable area, fertilizers for cultivation for bioproducts production. In this study, marine brown macroalga Padina tetrastromatica as an alternate sustainable feedstock for the production of liquid fuels. Padina tetrastromatica biomass was collected from Mandapam; the coastal region of Rameswaram, Tamil Nadu, India. and the algal oil was extracted using sequential extractions using various solvents. Petroleum ether (PE) and dichloromethane (DCM) solvent fractions were found to have high lipids and further utilized for biodiesel production, wherein four different heterogeneous nanocatalysts (TiO2, Bio-Fe, GO, and MgO) and commercial homogeneous catalysts (HCl and NaOH) were employed for the transesterification. High fatty acid methyl ester (FAME) recovery (92.3%) was achieved from TiO2 mediated transesterification than the other conventional catalysts. Further, the conversion of algal biomass into bio-oil and by-products was carried out using hydrothermal liquefaction (HTL). Subsequently, the compounds were characterized by FT-IR and GC-MS analysis. The quality parameters of liquid biofuels were examined and they are in accordance with the international fuel standards. Thus, brown macroalga Padina tetrastromatica may be considered as an alternate feedstock for biofuel and other bioproducts production and TiO2 would be a suitable catalyst for the conversion of FAME.
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Affiliation(s)
- Elamathi Vimali
- Department of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, Madurai, 625021, Tamil Nadu, India.
| | - Sathaiah Gunaseelan
- Department of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, Madurai, 625021, Tamil Nadu, India.
| | - Venkatachalam Chitra Devi
- Department of Food Technology, Kongu Engineering College, Perundurai, Erode, 638060, Tamil Nadu, India
| | - Sengottian Mothil
- Department of Chemical Engineering, Kongu Engineering College, Perundurai, Erode, 638060, Tamil Nadu, India
| | - Muthu Arumugam
- Microbial Processes and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (NIIST), Thiruvananthapuram, 695019, Kerala, India
| | - Balasubramaniem Ashokkumar
- Department of Genetic Engineering, School of Biotechnology, Madurai Kamaraj University, Madurai, 625021, Tamil Nadu, India
| | - Innasi Muthu Ganesh Moorthy
- Department of Biotechnology, Kamaraj College of Engineering and Technology, Vellakulam, 625701, Tamil Nadu, India
| | - Arivalagan Pugazhendhi
- School of Renewable Energy, Maejo University, Chiang Mai, 50290, Thailand; College of Medical and Health Science, Asia University, Taichung, Taiwan.
| | - Perumal Varalakshmi
- Department of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, Madurai, 625021, Tamil Nadu, India.
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12
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Mains K, Peoples J, Fox JM. Kinetically guided, ratiometric tuning of fatty acid biosynthesis. Metab Eng 2021; 69:209-220. [PMID: 34826644 DOI: 10.1016/j.ymben.2021.11.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 10/29/2021] [Accepted: 11/21/2021] [Indexed: 11/29/2022]
Abstract
Cellular metabolism is a nonlinear reaction network in which dynamic shifts in enzyme concentration help regulate the flux of carbon to different products. Despite the apparent simplicity of these biochemical adjustments, their influence on metabolite biosynthesis tends to be context-dependent, difficult to predict, and challenging to exploit in metabolic engineering. This study combines a detailed kinetic model with a systematic set of in vitro and in vivo analyses to explore the use of enzyme concentration as a control parameter in fatty acid synthesis, an essential metabolic process with important applications in oleochemical production. Compositional analyses of a modeled and experimentally reconstituted fatty acid synthase (FAS) from Escherichia coli indicate that the concentration ratio of two native enzymes-a promiscuous thioesterase and a ketoacyl synthase-can tune the average length of fatty acids, an important design objective of engineered pathways. The influence of this ratio is sensitive to the concentrations of other FAS components, which can narrow or expand the range of accessible chain lengths. Inside the cell, simple changes in enzyme concentration can enhance product-specific titers by as much as 125-fold and elicit shifts in overall product profiles that rival those of thioesterase mutants. This work develops a kinetically guided approach for using ratiometric adjustments in enzyme concentration to control the product profiles of FAS systems and, broadly, provides a detailed framework for understanding how coordinated shifts in enzyme concentration can afford tight control over the outputs of nonlinear metabolic pathways.
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Affiliation(s)
- Kathryn Mains
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, 3415 Colorado Avenue, Boulder, CO, 80303, USA
| | - Jackson Peoples
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, 3415 Colorado Avenue, Boulder, CO, 80303, USA
| | - Jerome M Fox
- Department of Chemical and Biological Engineering, University of Colorado, Boulder, 3415 Colorado Avenue, Boulder, CO, 80303, USA.
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13
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A kinetic rationale for functional redundancy in fatty acid biosynthesis. Proc Natl Acad Sci U S A 2020; 117:23557-23564. [PMID: 32883882 DOI: 10.1073/pnas.2013924117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cells build fatty acids with biocatalytic assembly lines in which a subset of enzymes often exhibit overlapping activities (e.g., two enzymes catalyze one or more identical reactions). Although the discrete enzymes that make up fatty acid pathways are well characterized, the importance of catalytic overlap between them is poorly understood. We developed a detailed kinetic model of the fatty acid synthase (FAS) of Escherichia coli and paired that model with a fully reconstituted in vitro system to examine the capabilities afforded by functional redundancy in fatty acid synthesis. The model captures-and helps explain-the effects of experimental perturbations to FAS systems and provides a powerful tool for guiding experimental investigations of fatty acid assembly. Compositional analyses carried out in silico and in vitro indicate that FASs with multiple partially redundant enzymes enable tighter (i.e., more independent and/or broader range) control of distinct biochemical objectives-the total production, unsaturated fraction, and average length of fatty acids-than FASs with only a single multifunctional version of each enzyme (i.e., one enzyme with the catalytic capabilities of two partially redundant enzymes). Maximal production of unsaturated fatty acids, for example, requires a second dehydratase that is not essential for their synthesis. This work provides a kinetic, control-theoretic rationale for the inclusion of partially redundant enzymes in fatty acid pathways and supplies a valuable framework for carrying out detailed studies of FAS kinetics.
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14
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Sun S, Ding Y, Liu M, Xian M, Zhao G. Comparison of Glucose, Acetate and Ethanol as Carbon Resource for Production of Poly(3-Hydroxybutyrate) and Other Acetyl-CoA Derivatives. Front Bioeng Biotechnol 2020; 8:833. [PMID: 32850713 PMCID: PMC7396591 DOI: 10.3389/fbioe.2020.00833] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 06/29/2020] [Indexed: 01/11/2023] Open
Abstract
Poly(3-hydroxybutyrate) (PHB) is a biodegradable and biocompatible thermoplastic, and synthesized from the central metabolite acetyl-CoA. The acetyl-CoA synthesis from glucose presents low atomic economy due to the release of CO2 in pyruvate decarboxylation. As ethanol and acetate can be converted into acetyl-CoA directly, they were used as carbon source for PHB production in this study. The reductase mutant AdhE A267T/E568K was introduced into Escherichia coli to enable growth on ethanol, and acetate utilization was improved by overexpression of acetyl-CoA synthetase ACS. Comparison of the PHB production using glucose, ethanol or acetate as sole carbon source showed that the production and yield from ethanol was much higher than those from glucose and acetate, and metabolome analysis revealed the differences in metabolism of glucose, ethanol and acetate. Furthermore, other acetyl-CoA derived chemicals including 3-hydroxypropionate and phloroglucinol were produced from those three feedstocks, and similar results were achieved, suggesting that ethanol could be a suitable carbon source for the production of acetyl-CoA derivatives.
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Affiliation(s)
- Shenmei Sun
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yamei Ding
- Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
| | - Min Liu
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Mo Xian
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Guang Zhao
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China.,State Key Lab of Microbial Technology, Shandong University, Qingdao, China
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15
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An acid-tolerance response system protecting exponentially growing Escherichia coli. Nat Commun 2020; 11:1496. [PMID: 32198415 PMCID: PMC7083825 DOI: 10.1038/s41467-020-15350-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 03/05/2020] [Indexed: 01/05/2023] Open
Abstract
The ability to grow at moderate acidic conditions (pH 4.0–5.0) is important to Escherichia coli colonization of the host’s intestine. Several regulatory systems are known to control acid resistance in E. coli, enabling the bacteria to survive under acidic conditions without growth. Here, we characterize an acid-tolerance response (ATR) system and its regulatory circuit, required for E. coli exponential growth at pH 4.2. A two-component system CpxRA directly senses acidification through protonation of CpxA periplasmic histidine residues, and upregulates the fabA and fabB genes, leading to increased production of unsaturated fatty acids. Changes in lipid composition decrease membrane fluidity, F0F1-ATPase activity, and improve intracellular pH homeostasis. The ATR system is important for E. coli survival in the mouse intestine and for production of higher level of 3-hydroxypropionate during fermentation. Furthermore, this ATR system appears to be conserved in other Gram-negative bacteria. The ability to grow at acidic pH is crucial for E. coli colonization of the host’s intestine. Here, the authors identify an acid-tolerance response system that is important for E. coli exponential growth at pH 4.2, survival in the mouse intestine, and production of 3-hydroxypropionate during fermentation.
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16
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Kassab E, Fuchs M, Haack M, Mehlmer N, Brueck TB. Engineering Escherichia coli FAB system using synthetic plant genes for the production of long chain fatty acids. Microb Cell Fact 2019; 18:163. [PMID: 31581944 PMCID: PMC6777021 DOI: 10.1186/s12934-019-1217-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 09/24/2019] [Indexed: 12/14/2022] Open
Abstract
Background Sustainable production of microbial fatty acids derivatives has the potential to replace petroleum based equivalents in the chemical, cosmetic and pharmaceutical industry. Most fatty acid sources for production oleochemicals are currently plant derived. However, utilization of these crops are associated with land use change and food competition. Microbial oils could be an alternative source of fatty acids, which circumvents the issue with agricultural competition. Results In this study, we generated a chimeric microbial production system that features aspects of both prokaryotic and eukaryotic fatty acid biosynthetic pathways targeted towards the generation of long chain fatty acids. We redirected the type-II fatty acid biosynthetic pathway of Escherichia coli BL21 (DE3) strain by incorporating two homologues of the beta-ketoacyl-[acyl carrier protein] synthase I and II from the chloroplastic fatty acid biosynthetic pathway of Arabidopsis thaliana. The microbial clones harboring the heterologous pathway yielded 292 mg/g and 220 mg/g DCW for KAS I and KAS II harboring plasmids respectively. Surprisingly, beta-ketoacyl synthases KASI/II isolated from A. thaliana showed compatibility with the FAB pathway in E. coli. Conclusion The efficiency of the heterologous plant enzymes supersedes the overexpression of the native enzyme in the E. coli production system, which leads to cell death in fabF overexpression and fabB deletion mutants. The utilization of our plasmid based system would allow generation of plant like fatty acids in E. coli and their subsequent chemical or enzymatic conversion to high end oleochemical products.
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Affiliation(s)
- Elias Kassab
- Werner Siemens-Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich, 85748, Garching, Germany
| | - Monika Fuchs
- Werner Siemens-Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich, 85748, Garching, Germany
| | - Martina Haack
- Werner Siemens-Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich, 85748, Garching, Germany
| | - Norbert Mehlmer
- Werner Siemens-Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich, 85748, Garching, Germany
| | - Thomas B Brueck
- Werner Siemens-Chair of Synthetic Biotechnology, Department of Chemistry, Technical University of Munich, 85748, Garching, Germany.
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17
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Zhang J, Hao Y, Yin K, Mao Q, Xu R, Zhang Y, Ma Y, Wang Q. VqsA controls exotoxin production by directly binding to the promoter of asp in the pathogen Vibrio alginolyticus. FEMS Microbiol Lett 2019; 366:5379279. [PMID: 30865774 DOI: 10.1093/femsle/fnz056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 03/12/2019] [Indexed: 12/25/2022] Open
Abstract
Quorum sensing (QS) system is an important bacterial cell-to-cell signaling system controlling expression of various genes in response to cell densities. In vibrios, LuxR/AphA are two established master QS regulators (MQSRs), and VqsA is recently identified to be the third putative MQSR. As a novel LysR-type regulator, the regulon and the underlying regulation mechanisms of VqsA remains to be elucidated. Here our investigation indicated that the yields of alkaline serine protease (Asp), the exotoxin in Vibrio alginolyticus was dependent on both LuxR and VqsA in growth phase dependent manner. Various in vivo and in vitro analyses including electrophoretic mobility shift assays (EMSA) along with DNase I footprinting investigations demonstrated that VqsA positively controls asp expression through directly binding to the partially palindromic 29 bp binding motif in the promoter region of asp. Moreover, RNA-seq analysis validated the regulatory roles of VqsA in various processes in the organism. Collectively, our data showed that VqsA positively regulates the expression of exotoxin and other virulence-associated genes and is essential for the QS regulation in V. alginolyticus.
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Affiliation(s)
- Jun Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Yuan Hao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Kaiyu Yin
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Qiaoqiao Mao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China
| | - Rongjing Xu
- Yantai Development Zone TianYuan Aquatic Products Co., Ltd., Yantai 264006, Shandong Province, China
| | - Yuanxing Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.,Shanghai Engineering Research Center of Maricultured Animal Vaccines, 130 Meilong Road, Shanghai 200237, China
| | - Yue Ma
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.,Shanghai Engineering Research Center of Maricultured Animal Vaccines, 130 Meilong Road, Shanghai 200237, China
| | - Qiyao Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.,Shanghai Engineering Research Center of Maricultured Animal Vaccines, 130 Meilong Road, Shanghai 200237, China
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18
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Microbial Production of Fatty Acid via Metabolic Engineering and Synthetic Biology. BIOTECHNOL BIOPROC E 2019. [DOI: 10.1007/s12257-018-0374-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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19
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Cloning of the pks3 gene of Aurantiochytrium limacinum and functional study of the 3-ketoacyl-ACP reductase and dehydratase enzyme domains. PLoS One 2018; 13:e0208853. [PMID: 30533058 PMCID: PMC6289434 DOI: 10.1371/journal.pone.0208853] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 11/24/2018] [Indexed: 12/19/2022] Open
Abstract
Aurantiochytrium limacinum has received attention because of its abundance of polyunsaturated fatty acids (PUFAs), particularly docosahexaenoic acid (DHA). DHA is synthesized through the polyketide synthase (PKS) pathway in A. limacinum. The related enzymes of the PKS pathway are mainly expressed by three gene clusters, called pks1, pks2 and pks3. In this study, the full-length pks3 gene was obtained by polymerase chain reaction amplification and Genome Walking technology. Based on a domain analysis of the deduced amino acid sequence of the pks3 gene, 3-ketoacyl-ACP reductase (KR) and dehydratase (DH) enzyme domains were identified. Herein, A. limacinum OUC168 was engineered by gene knock-in of KR and DH using the 18S rDNA sequence as the homologous recombination site. Total fatty acid contents and the degree of unsaturation of total fatty acids increased after the kr or dh gene was knocked in. The cloning and functional study of the pks3 gene of A. limacinum establishes a foundation for revealing the DHA synthetic pathway. Gene knock-in of the enzyme domain associated with PKS synthesis has the potential to provide effective recombinant strains with higher DHA content for industrial applications.
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20
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Afrin S, Khan MRI, Zhang W, Wang Y, Zhang W, He L, Ma G. Membrane-Located Expression of Thioesterase From Acinetobacter baylyi Enhances Free Fatty Acid Production With Decreased Toxicity in Synechocystis sp. PCC6803. Front Microbiol 2018; 9:2842. [PMID: 30538684 PMCID: PMC6277518 DOI: 10.3389/fmicb.2018.02842] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 11/05/2018] [Indexed: 12/18/2022] Open
Abstract
It has been previously reported that photosynthetic production of extracellular free fatty acids (FFAs) in cyanobacteria was realized by thioesterases (TesA) mediated hydrolysis of fatty acyl-ACP in cytosol and excretion of the FFA outside of the cell. However, two major issues related to the genetically modified strains need to be addressed before the scale-up commercial application becomes possible: namely, the toxicity of FFAs, and the diversity of carbon lengths of fatty acids that could mimic the fossil fuel. To address those issues, we hypothesized that generating FFAs near membrane could facilitate rapid excretion of the FFA outside of the cell and thus decrease toxicity caused by intracellular FFAs in the cytosolic expression of thioesterase. To realize this, we localized a leaderless thioesterase (AcTesA) from Acinetobacter baylyi on the cytosolic side of the inner membrane of Synechocystis sp. PCC6803 using a membrane scaffolding system. The engineered strain with AcTesA on its membrane (mAcT) produced extracellular FFAs up to 171.9 ± 13.22 mg⋅L-1 compared with 40.24 ± 10.94 and 1.904 ± 0.158 mg⋅L-1 in the cytosol-expressed AcTesA (AcT) and wild-type (WT) strains, respectively. Moreover, the mAcT strain generated around 1.5 and 1.9 times less reactive oxygen species than AcT and WT, respectively. Approximately 78% of total FFAs were secreted with an average rate of 1 mg⋅L-1⋅h-1, which was higher than 0.44 mg⋅L-1⋅h-1 reported previously. In the case of mAcT strain, 60% of total secreted FFAs was monounsaturated (C18:1) which is the preferable biodiesel component. Therefore, the engineered mAcT strain shows enhanced FFAs production with less toxicity which is highly desirable for biodiesel production.
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Affiliation(s)
- Shajia Afrin
- Bio-X-Renji Hospital Research Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Md Rezaul Islam Khan
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Weiyi Zhang
- Shanghai Animal Disease Control Center, Shanghai, China
| | - Yushu Wang
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Weiwen Zhang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
| | - Lin He
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
| | - Gang Ma
- Bio-X-Renji Hospital Research Center, Renji Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.,Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders (Ministry of Education), Shanghai Jiao Tong University, Shanghai, China
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21
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Gao X, Wang X, Mao Q, Xu R, Zhou X, Ma Y, Liu Q, Zhang Y, Wang Q. VqsA, a Novel LysR-Type Transcriptional Regulator, Coordinates Quorum Sensing (QS) and Is Controlled by QS To Regulate Virulence in the Pathogen Vibrio alginolyticus. Appl Environ Microbiol 2018; 84:e00444-18. [PMID: 29625990 PMCID: PMC5981076 DOI: 10.1128/aem.00444-18] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 03/30/2018] [Indexed: 12/12/2022] Open
Abstract
The quorum sensing (QS) system controls bacterial group behaviors in response to cell density. In vibrios, LuxR and AphA are two master QS regulators (MQSRs) controlling gene expression in response to high or low cell density. Other regulators involved in the regulation of these two MQSRs and QS pathways remain to be determined. Here, we performed bacterial one-hybrid (B1H)-assay-based screens of transcriptional factors (TFs) to identify TFs that can directly regulate the expression of luxR and aphA from a library of 285 TFs encoded by the fish pathogen Vibrio alginolyticus A total of 7 TFs were identified to bind to the promoters of both luxR and aphA Among these TFs, the novel LysR-type transcriptional regulator (LTTR) VqsA could activate LuxR and repress AphA transcription. Meanwhile, LuxR and AphA exerted feedback inhibition and activation of vqsA expression, respectively, indicating that VqsA coordinates QS and is also regulated by QS. In addition, VqsA inhibited its own expression by directly binding to its own promoter region. The VqsA-binding sites in the promoter regions of luxR and aphA as well as the binding sites of LuxR, AphA, and VqsA in the vqsA gene were uncovered by electrophoretic mobility shift assays (EMSAs) and DNase I footprinting analysis. Finally, VqsA was verified to play essential roles in QS-regulated phenotypes, i.e., type VI secretion system 2 (T6SS2)-dependent interbacterial competition, biofilm formation, exotoxin production, and in vivo virulence of V. alginolyticus Collectively, our data showed that VqsA is an important QS regulator in V. alginolyticusIMPORTANCE Investigation of the mechanism of regulation of quorum sensing (QS) systems will facilitate an understanding of bacterial pathogenesis and the identification of effective QS interference (QSI) targets. Here, we systematically screened transcriptional factors (TFs) that modulate the expression of the master QS regulators (MQSRs) LuxR and AphA, and a novel LysR-type transcriptional regulator, VqsA, was identified. Our data illuminated the mechanisms mediating the interaction among LuxR, AphA, and VqsA as well as the effects of these regulators on the expression and output of QS. The impaired expression of virulence genes as a result of vqsA disruption demonstrated that VqsA is an important player in QS regulation and pathogenesis and may be the third MQSR involved in sensing environmental signals by vibrios to coordinate QS responses. This study will facilitate the development of strategies to interfere with QS and effectively control this pathogen that plagues the aquaculture industry.
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Affiliation(s)
- Xiating Gao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Xuetong Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Qiaoqiao Mao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Rongjing Xu
- Yantai Tianyuan Aquatic Co. Ltd., Shandong, Yantai, China
| | - Xiaohui Zhou
- Department of Pathobiology and Veterinary Science, University of Connecticut, Storrs, Connecticut, USA
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Yue Ma
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China
| | - Qin Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China
| | - Yuanxing Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China
| | - Qiyao Wang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
- Shanghai Engineering Research Center of Maricultured Animal Vaccines, Shanghai, China
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22
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Kim J, Yoo HW, Kim M, Kim EJ, Sung C, Lee PG, Park BG, Kim BG. Rewiring FadR regulon for the selective production of ω-hydroxy palmitic acid from glucose in Escherichia coli. Metab Eng 2018; 47:414-422. [PMID: 29719215 DOI: 10.1016/j.ymben.2018.04.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/19/2018] [Accepted: 04/28/2018] [Indexed: 12/28/2022]
Abstract
ω-Hydroxy palmitic acid (ω-HPA) is a valuable compound for an ingredient of artificially synthesized ceramides and an additive for lubricants and adhesives. Production of such a fatty acid derivative is limited by chemical catalysis, but plausible by biocatalysis. However, its low productivity issue, including formations of unsaturated fatty acid (UFA) byproducts in host cells, remains as a hurdle toward industrial biological processes. In this study, to achieve selective and high-level production of ω-HPA from glucose in Escherichia coli, FadR, a native transcriptional regulator of fatty acid metabolism, and its regulon were engineered. First, FadR was co-expressed with a thioesterase with a specificity toward palmitic acid production to enhance palmitic acid production yield, but a considerable quantity of UFAs was also produced. In order to avoid the UFA production caused by fadR overexpression, FadR regulon was rewired by i) mutating FadR consensus binding sites of fabA or fabB, ii) integrating fabZ into fabI operon, and iii) enhancing the strength of fabI promoter. This approach led to dramatic increases in both proportion (48.3-83.0%) and titer (377.8 mg/L to 675.8 mg/L) of palmitic acid, mainly due to the decrease in UFA synthesis. Introducing a fatty acid ω-hydroxylase, CYP153A35, into the engineered strain resulted in a highly selective production of ω-HPA (83.5 mg/L) accounting for 87.5% of total ω-hydroxy fatty acids. Furthermore, strategies, such as i) enhancement in CYP153A35 activity, ii) expression of a fatty acid transporter, iii) supplementation of triton X-100, and iv) separation of the ω-HPA synthetic pathway into two strains for a co-culture system, were applied and resulted in 401.0 mg/L of ω-HPA production. For such selective productions of palmitic acid and ω-HPA, the rewiring of FadR regulation in E. coli is a promising strategy to develop an industrial process with economical downstream processing.
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Affiliation(s)
- Joonwon Kim
- School of Chemical and Biological Engineering, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea; Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826, Republic of Korea
| | - Hee-Wang Yoo
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826, Republic of Korea; Interdisciplinary Program of Bioengineering, Seoul National University, Seoul 08826, Republic of Korea
| | - Minsuk Kim
- Institute of Engineering Research, Seoul National University, Seoul 08826, Republic of Korea
| | - Eun-Jung Kim
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826, Republic of Korea; Bio-MAX Institute, Seoul National University, Seoul 08826, Republic of Korea
| | - Changmin Sung
- Doping Control Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Pyung-Gang Lee
- School of Chemical and Biological Engineering, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea; Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826, Republic of Korea
| | - Beom Gi Park
- School of Chemical and Biological Engineering, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea; Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826, Republic of Korea
| | - Byung-Gee Kim
- School of Chemical and Biological Engineering, Seoul National University, 1, Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea; Institute of Molecular Biology and Genetics, Seoul National University, Seoul 08826, Republic of Korea; Interdisciplinary Program of Bioengineering, Seoul National University, Seoul 08826, Republic of Korea; Institute of Engineering Research, Seoul National University, Seoul 08826, Republic of Korea.
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23
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Production of cis-Vaccenic Acid-oriented Unsaturated Fatty Acid in Escherichia coli. BIOTECHNOL BIOPROC E 2018. [DOI: 10.1007/s12257-017-0473-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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24
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Toyoshima M, Sato N. Optimization of triacylglycerol and starch production in Chlamydomonas debaryana NIES-2212 with regard to light intensity and CO2 concentration. MICROBIOLOGY-SGM 2018; 164:359-368. [PMID: 29458672 DOI: 10.1099/mic.0.000603] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Triacylglycerol (TAG) and starch produced by micro-algae are potential sources of biofuel. Our previous studies showed that the unicellular green alga, Chlamydomonas debaryana NIES-2212, which is a rare species of Chlamydomonas that possesses phosphatidylcholine (PC), is a seed organism for the development of biofuel producers. This alga accumulates large amounts of TAG and starch under completely photo-autotrophic conditions during stationary phase without nutrient deprivation. The present study was performed to optimize the growth conditions of this alga with regard to light intensity and CO2 concentration to improve the efficiency of TAG and starch production. The growth rate of C. debaryana was greater at higher light intensity, although there was no significant difference in the final cell density of the culture. The highest contents of TAG and starch, approximately 200 fmol cell-1 and 600 pg cell-1, respectively, were achieved with a light intensity of 200 µmol m-2 s-1 bubbled with air containing 5.0 % CO2. These results suggest that optimization of light intensity and CO2 concentration can enhance the productivity of TAG and starch by C. debaryana NIES-2212.
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Affiliation(s)
- Masakazu Toyoshima
- Department of Life Sciences, Graduate School of Arts and Science, The University of Tokyo, Tokyo 153-8902, Japan.,Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo 102-0076, Japan.,Present address: Department of Bioinformatic Engineering, Graduate School of Information Science and Technology, Osaka University, 1-5 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Naoki Sato
- Department of Life Sciences, Graduate School of Arts and Science, The University of Tokyo, Tokyo 153-8902, Japan.,Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo 102-0076, Japan
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Cai S, Cheng H, Pang H, Jian J, Wu Z. AcfA is an essential regulator for pathogenesis of fish pathogen Vibrio alginolyticus. Vet Microbiol 2017; 213:35-41. [PMID: 29292001 DOI: 10.1016/j.vetmic.2017.11.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Revised: 09/25/2017] [Accepted: 11/17/2017] [Indexed: 12/22/2022]
Abstract
V. alginolyticus is an important opportunistic pathogen which causes vibriosis in aquatic animals. AcfA, as an accessory colonization factor, is hypothesized to be involved in the pathogenesis of infection. In this study, a mutant strain with an in-frame deletion removed nucleotides 86 to 561 of the acfA gene was constructed to reveal the role of AcfA in the physiology and virulence from V. alginolyticus. An acfA mutant showed a similar growth level, an obvious decrease in swarming motility and the activity of ECPase, a higher LD50 value by intraperitoneal injection of grouper fish compared to that of the wild-type. Furthermore, the deletion of acfA could enhance the level of biofilm formation and suppress the polar flagellum forming. The comparative proteomic analysis demonstrated the deletion mutation of acfA could up-regulate the expression of 4 proteins of p4alcd, deoD, phb and DctP, and down-regulate the expression of 8 proteins of Clp, hpV36980, ABCtp, pepD, arA, aggp, fla and ompA compared to that of the wild-type. The analysis of RT-qPCR showed the mRNA levels of DctP and deoD were significantly induced, and the mRNA levels of pepD, arA, fla and ompA were significantly reduced in acfA mutant compared with the wild-type. The results suggest that acfA may contribute to the overall success in the pathogenesis of V. alginolyticus by regulating the expression of some relevant genes.
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Affiliation(s)
- Shuanghu Cai
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Fisheries College of Guangdong Ocean University, Zhanjiang, China.
| | - Haiyan Cheng
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Fisheries College of Guangdong Ocean University, Zhanjiang, China
| | - Huanying Pang
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Fisheries College of Guangdong Ocean University, Zhanjiang, China
| | - Jichang Jian
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Fisheries College of Guangdong Ocean University, Zhanjiang, China
| | - Zaohe Wu
- Guangdong Provincial Key Laboratory of Pathogenic Biology and Epidemiology for Aquatic Economic Animals & Key Laboratory of Control for Diseases of Aquatic Economic Animals of Guangdong Higher Education Institutes, Fisheries College of Guangdong Ocean University, Zhanjiang, China
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Ketoacylsynthase Domains of a Polyunsaturated Fatty Acid Synthase in Thraustochytrium sp. Strain ATCC 26185 Can Effectively Function as Stand-Alone Enzymes in Escherichia coli. Appl Environ Microbiol 2017; 83:AEM.03133-16. [PMID: 28213537 DOI: 10.1128/aem.03133-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 02/03/2017] [Indexed: 11/20/2022] Open
Abstract
Thraustochytrium sp. strain ATCC 26185 accumulates a high level of docosahexaenoic acid (DHA), a nutritionally important ω-3 very-long-chain polyunsaturated fatty acid (VLCPUFA) synthesized primarily by polyunsaturated fatty acid (PUFA) synthase, a type I polyketide synthase-like megaenzyme. The PUFA synthase in this species comprises three large subunits, each with multiple catalytic domains. It was hypothesized that among these domains, ketoacylsynthase (KS) domains might be critical for catalyzing the condensation of specific unsaturated acyl-acyl carrier proteins (ACPs) with malonyl-ACP, thereby retaining double bonds in an extended acyl chain. To investigate the functions of these putative KS domains, two segment sequences from subunit A (KS-A) and subunit B (KS-B) of the PUFA synthase were dissected and then expressed as stand-alone enzymes in Escherichia coli The results showed that both KS-A and KS-B domains could complement the defective phenotypes of both E. colifabB and fabF mutants. Overexpression of these domains in wild-type E. coli led to increases in total fatty acid production. KS-B produced a higher ratio of unsaturated fatty acids (UFAs) to saturated fatty acids (SFAs), while KS-A could improve the overall production of fatty acids more effectively, particularly for the production of SFAs, implying that KS-A is more comparable to FabF, while KS-B is more similar to FabB in catalytic functions. Successful complementation and functional expression of the embedded KS domains in E. coli are the first step forward in studying the molecular mechanism of the PUFA synthase for the biosynthesis of VLCPUFAs in ThraustochytriumIMPORTANCE Very-long-chain polyunsaturated fatty acids (VLCPUFAs) are important for human health. They can be biosynthesized in either an aerobic pathway or an anaerobic pathway in nature. However, abundant VLCPUFAs in marine microorganisms are primarily synthesized by polyunsaturated fatty acid (PUFA) synthase, a megaenzyme with multiple subunits, each with multiple catalytic domains. Furthermore, the fundamental mechanism for this enzyme to synthesize these fatty acids still remains unknown. This report started with dissecting the embedded KS domains of the PUFA synthase from marine protist Thraustochytrium sp. strain ATCC 26185 and then expressing them in wild-type E. coli and mutants defective in condensation of acyl-ACP with malonyl-ACP. Successful complementation of the mutants and improved fatty acid production in the overexpression experiments indicate that these KS domains can effectively function as stand-alone enzymes in E. coli This result has paved the way for further studying of molecular mechanisms of the PUFA synthase for the biosynthesis of VLCPUFAs.
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Yoshida K, Hashimoto M, Hori R, Adachi T, Okuyama H, Orikasa Y, Nagamine T, Shimizu S, Ueno A, Morita N. Bacterial Long-Chain Polyunsaturated Fatty Acids: Their Biosynthetic Genes, Functions, and Practical Use. Mar Drugs 2016; 14:E94. [PMID: 27187420 PMCID: PMC4882568 DOI: 10.3390/md14050094] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 04/23/2016] [Accepted: 04/29/2016] [Indexed: 02/06/2023] Open
Abstract
The nutritional and pharmaceutical values of long-chain polyunsaturated fatty acids (LC-PUFAs) such as arachidonic, eicosapentaenoic and docosahexaenoic acids have been well recognized. These LC-PUFAs are physiologically important compounds in bacteria and eukaryotes. Although little is known about the biosynthetic mechanisms and functions of LC-PUFAs in bacteria compared to those in higher organisms, a combination of genetic, bioinformatic, and molecular biological approaches to LC-PUFA-producing bacteria and some eukaryotes have revealed the notably diverse organization of the pfa genes encoding a polyunsaturated fatty acid synthase complex (PUFA synthase), the LC-PUFA biosynthetic processes, and tertiary structures of the domains of this enzyme. In bacteria, LC-PUFAs appear to take part in specific functions facilitating individual membrane proteins rather than in the adjustment of the physical fluidity of the whole cell membrane. Very long chain polyunsaturated hydrocarbons (LC-HCs) such as hentriacontanonaene are considered to be closely related to LC-PUFAs in their biosynthesis and function. The possible role of LC-HCs in strictly anaerobic bacteria under aerobic and anaerobic environments and the evolutionary relationships of anaerobic and aerobic bacteria carrying pfa-like genes are also discussed.
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Affiliation(s)
- Kiyohito Yoshida
- Laboratory of Ecological Genetics, Section of Environmental Biology, Faculty of Environmental Earth Science, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
| | - Mikako Hashimoto
- Course in Ecological Genetics, Division of Biosphere Science, Graduate School of Environmental Science, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
| | - Ryuji Hori
- Technical Solution Center First Group, J-OIL MILLS, Inc., Chuo-ku, Tokyo 104-0044, Japan.
| | - Takumi Adachi
- Laboratory of Environmental Microbiology, Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
- Bioproduction Research Institute, Department of Life Science and Biotechnology, National Institute of Advanced Industrial Science and Technology (AIST), Toyohira-ku, Sapporo, Hokkaido 062-8517, Japan.
| | - Hidetoshi Okuyama
- Laboratory of Environmental Molecular Biology, Section of Environmental Biology, Faculty of Environmental Earth Science, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-0810, Japan.
| | - Yoshitake Orikasa
- Department Food Science, Obihiro University Agriculture Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
| | - Tadashi Nagamine
- ROM Co. Ltd., Togashi Bld., Chuo-ku, Sapporo, Hokkaido 060-0062, Japan.
| | - Satoru Shimizu
- Horonobe Research Institute for the Subsurface Environment, Northern Advancement Centre for Science and Technology, 5-3, Sakae-machi, Horonobe, Teshio-gun, Hokkaido 098-3221, Japan.
| | - Akio Ueno
- Horonobe Research Institute for the Subsurface Environment, Northern Advancement Centre for Science and Technology, 5-3, Sakae-machi, Horonobe, Teshio-gun, Hokkaido 098-3221, Japan.
| | - Naoki Morita
- Laboratory of Environmental Microbiology, Division of Applied Bioscience, Graduate School of Agriculture, Hokkaido University, Kita-ku, Sapporo, Hokkaido 060-8589, Japan.
- Bioproduction Research Institute, Department of Life Science and Biotechnology, National Institute of Advanced Industrial Science and Technology (AIST), Toyohira-ku, Sapporo, Hokkaido 062-8517, Japan.
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Toyoshima M, Sato N. High-Level Accumulation of Triacylglycerol and Starch in Photoautotrophically Grown Chlamydomonas debaryana NIES-2212. PLANT & CELL PHYSIOLOGY 2015; 56:2447-2456. [PMID: 26542110 DOI: 10.1093/pcp/pcv163] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/23/2015] [Indexed: 06/05/2023]
Abstract
Microalgae have the potential to produce triacylglycerol (TAG) and starch, which provide alternative sources of biofuel. A problem in using Chlamydomonas reinhardtii as a model for TAG production has been that this alga lacks phosphatidylcholine (PC), which is thought to be important for TAG synthesis in plants. We found that C. debaryana is one of the rare species of Chlamydomonas having PC. Here we show that this strain, grown under complete photoautotrophic conditions, accumulated TAG and starch up to 20 and 250 pg per cell, respectively, during the stationary phase without nutrient deprivation. Addition of nutrients in this state did not cause loss of TAG, which was found in dilution with fresh medium. The photosynthetically produced TAG contained a high level of monounsaturated fatty acids, which is a preferred property as a material for biodiesel. The oil bodies were present in the cytoplasm, either between the cytoplasmic membrane and the chloroplast or between the chloroplast and the nucleus, whereas the starch granules were present within the chloroplast. Oil bodies were also deposited as a broad layer in the peripheral space of the cytoplasm outside the chloroplast, and might be easily released from the cells by genetic, chemical or mechanical manipulation. These results suggest that C. debaryana is a promising seed organism for developing a good biofuel producer.
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Affiliation(s)
- Masakazu Toyoshima
- Department of Life Sciences, Graduate School of Arts and Science, The University of Tokyo, and Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo, Japan
| | - Naoki Sato
- Department of Life Sciences, Graduate School of Arts and Science, The University of Tokyo, and Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo, Japan
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29
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Wang D, Thakker C, Liu P, Bennett GN, San KY. Efficient production of free fatty acids from soybean meal carbohydrates. Biotechnol Bioeng 2015; 112:2324-33. [PMID: 25943383 DOI: 10.1002/bit.25633] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 04/05/2015] [Accepted: 04/29/2015] [Indexed: 11/09/2022]
Abstract
Conversion of biomass feedstock to chemicals and fuels has attracted increasing attention recently. Soybean meal, containing significant quantities of carbohydrates, is an inexpensive renewable feedstock. Glucose, galactose, and fructose can be obtained by enzymatic hydrolysis of soluble carbohydrates of soybean meal. Free fatty acids (FFAs) are valuable molecules that can be used as precursors for the production of fuels and other value-added chemicals. In this study, free fatty acids were produced by mutant Escherichia coli strains with plasmid pXZ18Z (carrying acyl-ACP thioesterase (TE) and (3R)-hydroxyacyl-ACP dehydratase) using individual sugars, sugar mixtures, and enzymatic hydrolyzed soybean meal extract. For individual sugar fermentations, strain ML211 (MG1655 fadD(-) fabR(-) )/pXZ18Z showed the best performance, which produced 4.22, 3.79, 3.49 g/L free fatty acids on glucose, fructose, and galactose, respectively. While the strain ML211/pXZ18Z performed the best with individual sugars, however, for sugar mixture fermentation, the triple mutant strain XZK211 (MG1655 fadD(-) fabR(-) ptsG(-) )/pXZ18Z with an additional deletion of ptsG encoding the glucose-specific transporter, functioned the best due to relieved catabolite repression. This strain produced approximately 3.18 g/L of fatty acids with a yield of 0.22 g fatty acids/g total sugar. Maximum free fatty acids production of 2.78 g/L with a high yield of 0.21 g/g was achieved using soybean meal extract hydrolysate. The results suggested that soybean meal carbohydrates after enzymatic treatment could serve as an inexpensive feedstock for the efficient production of free fatty acids.
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Affiliation(s)
- Dan Wang
- Department of Bioengineering, Rice University, 6100 Main Street, MS-362, Houston, Texas, 77005-1892
- College of Chemistry and Chemical Engineering, Chongqing University, Chongqing, P. R. China
| | | | - Ping Liu
- Department of Bioengineering, Rice University, 6100 Main Street, MS-362, Houston, Texas, 77005-1892
| | | | - Ka-Yiu San
- Department of Bioengineering, Rice University, 6100 Main Street, MS-362, Houston, Texas, 77005-1892.
- Department of Chemical and Biomolecular Engineering, Rice University, Houston, Texas.
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Improved n-butanol tolerance in Escherichia coli by controlling membrane related functions. J Biotechnol 2015; 204:33-44. [PMID: 25858152 DOI: 10.1016/j.jbiotec.2015.03.025] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 03/19/2015] [Accepted: 03/22/2015] [Indexed: 12/14/2022]
Abstract
As the increasing demand from both chemical and fuel markets, the interest in producing n-butanol using biological route has been rejuvenated to engineer an economical fermentation process, competing with the currently-dominant chemical synthesis. n-Butanol has been traditionally produced from the ABE fermentation of Clostridium acetobutylicum. This system, however, is not economically feasible due to its limited efficiency and the lack of genetic modification tools for further improvements. Alternatively, n-butanol synthesis pathway was successfully transferred into Escherichia coli and rapidly improved to reach a level of production comparable to the native producer. Nevertheless, the toxicity of n-butanol has become a common issue that either approach has to deal with. Previously, we reported our success in improving n-butanol tolerance in E. coli by engineering an Artificial Transcription Factor (ATF) that can modify the expression level of multiple targets simultaneously and improved the n-butanol tolerance of MG1655 strain to 1.5% (vol/vol) n-butanol. However, it was observed that some possible n-butanol tolerance mechanisms did not occurred upon the ATF expression, especially the membrane-related functions such as the homeoviscous adaptation, iron uptaking system, and efflux pump system. In this work, we attempted to enhance the n-butanol tolerance associated with the ATF by combining it with the membrane-related functions in E. coli, including the overexpression of fatty acid synthesis genes, iron-uptaking protein FeoA, and introducing a SrpABC efflux pump from Pseudomonas putida into E. coli. The synergistic effect of this combinatorial approach led to 4, 5, and 9-fold improved growths in the cultures containing 1, 1.5, and 2% (vol/vol) n-butanol, respectively, of an MG1655 knockout strain engineered for n-butanol production, and expanded the tolerance limit to 2% (vol/vol) n-butanol.
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31
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Finzel K, Lee DJ, Burkart MD. Using modern tools to probe the structure-function relationship of fatty acid synthases. Chembiochem 2015; 16:528-547. [PMID: 25676190 PMCID: PMC4545599 DOI: 10.1002/cbic.201402578] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Indexed: 12/25/2022]
Abstract
Fatty acid biosynthesis is essential to life and represents one of the most conserved pathways in nature, preserving the same handful of chemical reactions across all species. Recent interest in the molecular details of the de novo fatty acid synthase (FAS) has been heightened by demand for renewable fuels and the emergence of multidrug-resistant bacterial strains. Central to FAS is the acyl carrier protein (ACP), a protein chaperone that shuttles the growing acyl chain between catalytic enzymes within the FAS. Human efforts to alter fatty acid biosynthesis for oil production, chemical feedstock, or antimicrobial purposes has been met with limited success, due in part to a lack of detailed molecular information behind the ACP-partner protein interactions inherent to the pathway. This review will focus on recently developed tools for the modification of ACP and analysis of protein-protein interactions, such as mechanism-based crosslinking, and the studies exploiting them. Discussion specific to each enzymatic domain will focus first on mechanism and known inhibitors, followed by available structures and known interactions with ACP. Although significant unknowns remain, new understandings of the intricacies of FAS point to future advances in manipulating this complex molecular factory.
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Affiliation(s)
- Kara Finzel
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358 (USA)
| | - D. John Lee
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358 (USA)
| | - Michael D. Burkart
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093-0358 (USA)
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Beld J, Lee DJ, Burkart MD. Fatty acid biosynthesis revisited: structure elucidation and metabolic engineering. MOLECULAR BIOSYSTEMS 2015; 11:38-59. [PMID: 25360565 PMCID: PMC4276719 DOI: 10.1039/c4mb00443d] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Fatty acids are primary metabolites synthesized by complex, elegant, and essential biosynthetic machinery. Fatty acid synthases resemble an iterative assembly line, with an acyl carrier protein conveying the growing fatty acid to necessary enzymatic domains for modification. Each catalytic domain is a unique enzyme spanning a wide range of folds and structures. Although they harbor the same enzymatic activities, two different types of fatty acid synthase architectures are observed in nature. During recent years, strained petroleum supplies have driven interest in engineering organisms to either produce more fatty acids or specific high value products. Such efforts require a fundamental understanding of the enzymatic activities and regulation of fatty acid synthases. Despite more than one hundred years of research, we continue to learn new lessons about fatty acid synthases' many intricate structural and regulatory elements. In this review, we summarize each enzymatic domain and discuss efforts to engineer fatty acid synthases, providing some clues to important challenges and opportunities in the field.
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Affiliation(s)
- Joris Beld
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0358, USA.
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Enhanced free fatty acid production by codon-optimized Lactococcus lactis acyl-ACP thioesterase gene expression in Escherichia coli using crude glycerol. Enzyme Microb Technol 2014; 67:8-16. [DOI: 10.1016/j.enzmictec.2014.08.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Revised: 08/14/2014] [Accepted: 08/16/2014] [Indexed: 01/29/2023]
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Haushalter RW, Kim W, Chavkin TA, The L, Garber ME, Nhan M, Adams PD, Petzold CJ, Katz L, Keasling JD. Production of anteiso-branched fatty acids in Escherichia coli; next generation biofuels with improved cold-flow properties. Metab Eng 2014; 26:111-118. [PMID: 25250846 DOI: 10.1016/j.ymben.2014.09.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 08/09/2014] [Accepted: 09/08/2014] [Indexed: 01/28/2023]
Abstract
Microbial fermentation is emerging as an increasingly important resource for the production of fatty acids to serve as precursors for renewable diesel as well as detergents, lubricants and other industrial chemicals, as an alternative to traditional sources of reduced carbon such as petroleum. A major disadvantage of fuels derived from biological sources is their undesirable physical properties such as high cloud and pour points, and high viscosity. Here we report the development of an Escherichia coli strain that efficiently produces anteiso-branched fatty acids, which can be converted into downstream products with lower cloud and pour points than the mixtures of compounds produced via the native metabolism of the cell. This work addresses a serious limitation that must be overcome in order to produce renewable biodiesel and oleochemicals that perform as well as their petroleum-based counterparts.
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Affiliation(s)
- Robert W Haushalter
- Joint BioEnergy Institute, 5885 Hollis Street, 4th Floor, Emeryville, CA 94608, United States; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
| | - Woncheol Kim
- Joint BioEnergy Institute, 5885 Hollis Street, 4th Floor, Emeryville, CA 94608, United States; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
| | - Ted A Chavkin
- QB3 Institute, University of California-Berkeley, 5885 Hollis Street, 4th Floor, Emeryville, CA 94608, United States
| | - Lionadi The
- QB3 Institute, University of California-Berkeley, 5885 Hollis Street, 4th Floor, Emeryville, CA 94608, United States
| | - Megan E Garber
- QB3 Institute, University of California-Berkeley, 5885 Hollis Street, 4th Floor, Emeryville, CA 94608, United States
| | - Melissa Nhan
- Joint BioEnergy Institute, 5885 Hollis Street, 4th Floor, Emeryville, CA 94608, United States; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
| | - Paul D Adams
- Joint BioEnergy Institute, 5885 Hollis Street, 4th Floor, Emeryville, CA 94608, United States; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States; Department of Chemical & Biomolecular Engineering, Department of Bioengineering, University of California, Berkeley, CA 94720, United States
| | - Christopher J Petzold
- Joint BioEnergy Institute, 5885 Hollis Street, 4th Floor, Emeryville, CA 94608, United States; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
| | - Leonard Katz
- QB3 Institute, University of California-Berkeley, 5885 Hollis Street, 4th Floor, Emeryville, CA 94608, United States; Synthetic Biology Engineering Research Center, University of California, Berkeley, CA 94720, United States
| | - Jay D Keasling
- Joint BioEnergy Institute, 5885 Hollis Street, 4th Floor, Emeryville, CA 94608, United States; Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States; QB3 Institute, University of California-Berkeley, 5885 Hollis Street, 4th Floor, Emeryville, CA 94608, United States; Synthetic Biology Engineering Research Center, University of California, Berkeley, CA 94720, United States; Department of Chemical & Biomolecular Engineering, Department of Bioengineering, University of California, Berkeley, CA 94720, United States.
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He L, Xiao Y, Gebreselassie N, Zhang F, Antoniewiez MR, Tang YJ, Peng L. Central metabolic responses to the overproduction of fatty acids in Escherichia coli based on 13C-metabolic flux analysis. Biotechnol Bioeng 2014; 111:575-85. [PMID: 24122357 DOI: 10.1002/bit.25124] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Revised: 09/25/2013] [Accepted: 09/25/2013] [Indexed: 01/12/2023]
Abstract
We engineered a fatty acid overproducing Escherichia coli strain through overexpressing tesA (“pull”) and fadR (“push”) and knocking out fadE (“block”). This “pull-push-block” strategy yielded 0.17 g of fatty acids (C12–C18) per gram of glucose (equivalent to 48% of the maximum theoretical yield) in batch cultures during the exponential growth phase under aerobic conditions. Metabolic fluxes were determined for the engineered E. coli and its control strain using tracer ([1,2-13C]glucose) experiments and 13C-metabolic flux analysis. Cofactor (NADPH) and energy (ATP) balances were also investigated for both strains based on estimated fluxes. Compared to the control strain, fatty acid overproduction led to significant metabolic responses in the central metabolism: (1) Acetic acid secretion flux decreased 10-fold; (2) Pentose phosphate pathway and Entner–Doudoroff pathway fluxes increased 1.5- and 2.0-fold, respectively; (3) Biomass synthesis flux was reduced 1.9-fold; (4) Anaplerotic phosphoenolpyruvate carboxylation flux decreased 1.7-fold; (5) Transhydrogenation flux converting NADH to NADPH increased by 1.7-fold. Real-time quantitative RT-PCR analysis revealed the engineered strain increased the transcription levels of pntA (encoding the membrane-bound transhydrogenase) by 2.1-fold and udhA (encoding the soluble transhydrogenase) by 1.4-fold, which is in agreement with the increased transhydrogenation flux. Cofactor and energy balances analyses showed that the fatty acid overproducing E. coli consumed significantly higher cellular maintenance energy than the control strain. We discussed the strategies to future strain development and process improvements for fatty acid production in E. coli.
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36
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Metabolic engineering of Escherichia coli for efficient free fatty acid production from glycerol. Metab Eng 2014; 25:82-91. [PMID: 25014174 DOI: 10.1016/j.ymben.2014.06.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Revised: 06/23/2014] [Accepted: 06/26/2014] [Indexed: 01/15/2023]
Abstract
Crude glycerol, generated as waste by-product in biodiesel production process, has been considered as an important carbon source for converting to value-added bioproducts recently. Free fatty acids (FFAs) can be used as precursors for the production of biofuels or biochemicals. Microbial biosynthesis of FFAs can be achieved by introducing an acyl-acyl carrier protein thioesterase into Escherichia coli. In this study, the effect of metabolic manipulation of FFAs synthesis cycle, host genetic background and cofactor engineering on FFAs production using glycerol as feed stocks was investigated. The highest concentration of FFAs produced by the engineered stain reached 4.82g/L with the yield of 29.55% (g FFAs/g glycerol), about 83% of the maximum theoretical pathway value by the type II fatty acid synthesis pathway. In addition, crude glycerol from biodiesel plant was also used as feedstock in this study. The FFA production was 3.53g/L with a yield of 24.13%. The yield dropped slightly when crude glycerol was used as a carbon source instead of pure glycerol, while it still can reach about 68% of the maximum theoretical pathway yield.
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Cloning, characterization, and expression analysis of acyl–acyl carrier protein (ACP)-thioesterase B from seeds of Chinese Spicehush (Lindera communis). Gene 2014; 542:16-22. [DOI: 10.1016/j.gene.2014.03.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 03/09/2014] [Accepted: 03/12/2014] [Indexed: 01/19/2023]
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Ariöz C, Götzke H, Lindholm L, Eriksson J, Edwards K, Daley DO, Barth A, Wieslander A. Heterologous overexpression of a monotopic glucosyltransferase (MGS) induces fatty acid remodeling in Escherichia coli membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:1862-70. [PMID: 24726609 DOI: 10.1016/j.bbamem.2014.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/27/2014] [Accepted: 04/02/2014] [Indexed: 01/14/2023]
Abstract
The membrane protein monoglucosyldiacylglycerol synthase (MGS) from Acholeplasma laidlawii is responsible for the creation of intracellular membranes when overexpressed in Escherichia coli (E. coli). The present study investigates time dependent changes in composition and properties of E. coli membranes during 22h of MGS induction. The lipid/protein ratio increased by 38% in MGS-expressing cells compared to control cells. Time-dependent screening of lipids during this period indicated differences in fatty acid modeling. (1) Unsaturation levels remained constant for MGS cells (~62%) but significantly decreased in control cells (from 61% to 36%). (2) Cyclopropanated fatty acid content was lower in MGS producing cells while control cells had an increased cyclopropanation activity. Among all lipids, phosphatidylethanolamine (PE) was detected to be the most affected species in terms of cyclopropanation. Higher levels of unsaturation, lowered cyclopropanation levels and decreased transcription of the gene for cyclopropane fatty acid synthase (CFA) all indicate the tendency of the MGS protein to force E. coli membranes to alter its usual fatty acid composition.
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Affiliation(s)
- Candan Ariöz
- The Arrhenius Laboratories for Natural Sciences, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
| | - Hansjörg Götzke
- The Arrhenius Laboratories for Natural Sciences, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ljubica Lindholm
- The Arrhenius Laboratories for Natural Sciences, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Jonny Eriksson
- BMC, Department of Chemistry, Uppsala University, SE-751 23 Uppsala, Sweden
| | - Katarina Edwards
- BMC, Department of Chemistry, Uppsala University, SE-751 23 Uppsala, Sweden
| | - Daniel O Daley
- The Arrhenius Laboratories for Natural Sciences, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Andreas Barth
- The Arrhenius Laboratories for Natural Sciences, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ake Wieslander
- The Arrhenius Laboratories for Natural Sciences, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
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Janßen HJ, Steinbüchel A. Fatty acid synthesis in Escherichia coli and its applications towards the production of fatty acid based biofuels. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:7. [PMID: 24405789 PMCID: PMC3896788 DOI: 10.1186/1754-6834-7-7] [Citation(s) in RCA: 180] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 12/24/2013] [Indexed: 05/04/2023]
Abstract
The idea of renewable and regenerative resources has inspired research for more than a hundred years. Ideally, the only spent energy will replenish itself, like plant material, sunlight, thermal energy or wind. Biodiesel or ethanol are examples, since their production relies mainly on plant material. However, it has become apparent that crop derived biofuels will not be sufficient to satisfy future energy demands. Thus, especially in the last decade a lot of research has focused on the production of next generation biofuels. A major subject of these investigations has been the microbial fatty acid biosynthesis with the aim to produce fatty acids or derivatives for substitution of diesel. As an industrially important organism and with the best studied microbial fatty acid biosynthesis, Escherichia coli has been chosen as producer in many of these studies and several reviews have been published in the fields of E. coli fatty acid biosynthesis or biofuels. However, most reviews discuss only one of these topics in detail, despite the fact, that a profound understanding of the involved enzymes and their regulation is necessary for efficient genetic engineering of the entire pathway. The first part of this review aims at summarizing the knowledge about fatty acid biosynthesis of E. coli and its regulation, and it provides the connection towards the production of fatty acids and related biofuels. The second part gives an overview about the achievements by genetic engineering of the fatty acid biosynthesis towards the production of next generation biofuels. Finally, the actual importance and potential of fatty acid-based biofuels will be discussed.
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Affiliation(s)
- Helge Jans Janßen
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 3, D-48149, Münster, Germany
| | - Alexander Steinbüchel
- Institut für Molekulare Mikrobiologie und Biotechnologie, Westfälische Wilhelms-Universität Münster, Corrensstrasse 3, D-48149, Münster, Germany
- Environmental Sciences Department, King Abdulaziz University, Jeddah, Saudi Arabia
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Cao Y, Liu W, Xu X, Zhang H, Wang J, Xian M. Production of free monounsaturated fatty acids by metabolically engineered Escherichia coli. BIOTECHNOLOGY FOR BIOFUELS 2014; 7:59. [PMID: 24716602 PMCID: PMC4021618 DOI: 10.1186/1754-6834-7-59] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2013] [Accepted: 03/17/2014] [Indexed: 05/22/2023]
Abstract
BACKGROUND Monounsaturated fatty acids (MUFAs) are the best components for biodiesel when considering the low temperature fluidity and oxidative stability. However, biodiesel derived from vegetable oils or microbial lipids always consists of significant amounts of polyunsaturated and saturated fatty acids (SFAs) alkyl esters, which hampers its practical applications. Therefore, the fatty acid composition should be modified to increase MUFA contents as well as enhancing oil and lipid production. RESULTS The model microorganism Escherichia coli was engineered to produce free MUFAs. The fatty acyl-ACP thioesterase (AtFatA) and fatty acid desaturase (SSI2) from Arabidopsis thaliana were heterologously expressed in E. coli BL21 star(DE3) to specifically release free unsaturated fatty acids (UFAs) and convert SFAs to UFAs. In addition, the endogenous fadD gene (encoding acyl-CoA synthetase) was disrupted to block fatty acid catabolism while the native acetyl-CoA carboxylase (ACCase) was overexpressed to increase the malonyl coenzyme A (malonyl-CoA) pool and boost fatty acid biosynthesis. The finally engineered strain BL21ΔfadD/pE-AtFatAssi2&pA-acc produced 82.6 mg/L free fatty acids (FFAs) under shake-flask conditions and FFAs yield on glucose reached about 3.3% of the theoretical yield. Two types of MUFAs, palmitoleate (16:1Δ9) and cis-vaccenate (18:1Δ11) made up more than 75% of the FFA profiles. Fed-batch fermentation of this strain further enhanced FFAs production to a titer of 1.27 g/L without affecting fatty acid compositions. CONCLUSIONS This study demonstrated the possibility to regulate fatty acid composition by using metabolic engineering approaches. FFAs produced by the recombinant E. coli strain consisted of high-level MUFAs and biodiesel manufactured from these fatty acids would be more suitable for current diesel engines.
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Affiliation(s)
- Yujin Cao
- CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Wei Liu
- CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Xin Xu
- CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Haibo Zhang
- CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Jiming Wang
- CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
| | - Mo Xian
- CAS Key Laboratory of Bio-based Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, China
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41
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Scaglia B, Cassani E, Pilu R, Adani F. Expression of Arabidopsis thalianaS-ACP-DES3 in Escherichia colifor high-performance biodiesel production. RSC Adv 2014. [DOI: 10.1039/c4ra13001d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
pET15b expression vector (a) used to cloneArabidopsisDES3 gene (b) inE. coli.
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Affiliation(s)
- Barbara Scaglia
- Di.S.A.A. – Gruppo Ricicla – Biomass and Bioenergy Laboratory – University of Milan
- Milan, Italy
| | - Elena Cassani
- Di.S.A.A. – Genetic Laboratory – University of Milan
- Milan, Italy
| | - Roberto Pilu
- Di.S.A.A. – Gruppo Ricicla – Biomass and Bioenergy Laboratory – University of Milan
- Milan, Italy
| | - Fabrizio Adani
- Di.S.A.A. – Gruppo Ricicla – Biomass and Bioenergy Laboratory – University of Milan
- Milan, Italy
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42
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Expression of dehydratase domains from a polyunsaturated fatty acid synthase increases the production of fatty acids in Escherichia coli. Enzyme Microb Technol 2013; 55:133-9. [PMID: 24411456 DOI: 10.1016/j.enzmictec.2013.10.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 10/24/2013] [Accepted: 10/25/2013] [Indexed: 12/26/2022]
Abstract
Increasing the production of fatty acids by microbial fermentation remains an important step toward the generation of biodiesel and other portable liquid fuels. In this work, we report an Escherichia coli strain engineered to overexpress a fragment consisting of four dehydratase domains from the polyunsaturated fatty acid (PUFA) synthase enzyme complex from the deep-sea bacterium, Photobacterium profundum. The DH1-DH2-UMA enzyme fragment was excised from its natural context within a multi-enzyme PKS and expressed as a stand-alone protein. Fatty acids were extracted from the cell pellet, esterified with methanol and quantified by GC-MS analysis. Results show that the E. coli strain expressing the DH tetradomain fragment was capable of producing up to a 5-fold increase (80.31 mg total FA/L culture) in total fatty acids over the negative control strain lacking the recombinant enzyme. The enhancement in production was observed across the board for all the fatty acids that are typically made by E. coli. The overexpression of the DH tetradomain did not affect E. coli cell growth, thus showing that the observed enhancement in fatty acid production was not a result of effects associated with cell density. The observed enhancement was more pronounced at lower temperatures (3.8-fold at 16 °C, 3.5-fold at 22 °C and 1.5-fold at 30 °C) and supplementation of the media with 0.4% glycerol did not result in an increase in fatty acid production. All these results taken together suggest that either the dehydration of fatty acid intermediates are a limiting step in the E. coli fatty acid biosynthesis machinery, or that the recombinant dehydratase domains used in this study are also capable of catalyzing thioester hydrolysis of the final products. The enzyme in this report is a new tool which could be incorporated into other existing strategies aimed at improving fatty acid production in bacterial fermentations toward accessible biodiesel precursors.
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Lin F, Chen Y, Levine R, Lee K, Yuan Y, Lin XN. Improving fatty acid availability for bio-hydrocarbon production in Escherichia coli by metabolic engineering. PLoS One 2013; 8:e78595. [PMID: 24147139 PMCID: PMC3798384 DOI: 10.1371/journal.pone.0078595] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 09/22/2013] [Indexed: 02/03/2023] Open
Abstract
Previous studies have demonstrated the feasibility of producing fatty-acid-derived hydrocarbons in Escherichia coli. However, product titers and yields remain low. In this work, we demonstrate new methods for improving fatty acid production by modifying central carbon metabolism and storing fatty acids in triacylglycerol. Based on suggestions from a computational model, we deleted seven genes involved in aerobic respiration, mixed-acid fermentation, and glyoxylate bypass (in the order of cyoA, nuoA, ndh, adhE, dld, pta, and iclR) to modify the central carbon metabolic/regulatory networks. These gene deletions led to increased total fatty acids, which were the highest in the mutants containing five or six gene knockouts. Additionally, when two key enzymes in the fatty acid biosynthesis pathway were over-expressed, we observed further increase in strain △cyoA△adhE△nuoA△ndh△pta△dld, leading to 202 mg/g dry cell weight of total fatty acids, ~250% of that in the wild-type strain. Meanwhile, we successfully introduced a triacylglycerol biosynthesis pathway into E. coli through heterologous expression of wax ester synthase/acyl-coenzyme:diacylglycerol acyltransferase (WS/DGAT) enzymes. The added pathway improved both the amount and fuel quality of the fatty acids. These new metabolic engineering strategies are providing promising directions for future investigation.
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Affiliation(s)
- Fengming Lin
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
| | - Yu Chen
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Robert Levine
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Kilho Lee
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Yingjin Yuan
- School of Chemical Engineering and Technology, Tianjin University, Tianjin, P.R. China
| | - Xiaoxia Nina Lin
- Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, United States of America
- Center for Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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44
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Johnson CN. Fitness factors in vibrios: a mini-review. MICROBIAL ECOLOGY 2013; 65:826-851. [PMID: 23306394 DOI: 10.1007/s00248-012-0168-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 12/13/2012] [Indexed: 06/01/2023]
Abstract
Vibrios are Gram-negative curved bacilli that occur naturally in marine, estuarine, and freshwater systems. Some species include human and animal pathogens, and some vibrios are necessary for natural systems, including the carbon cycle and osmoregulation. Countless in vivo and in vitro studies have examined the interactions between vibrios and their environment, including molecules, cells, whole animals, and abiotic substrates. Many studies have characterized virulence factors, attachment factors, regulatory factors, and antimicrobial resistance factors, and most of these factors impact the organism's fitness regardless of its external environment. This review aims to identify common attributes among factors that increase fitness in various environments, regardless of whether the environment is an oyster, a rabbit, a flask of immortalized mammalian cells, or a planktonic chitin particle. This review aims to summarize findings published thus far to encapsulate some of the basic similarities among the many vibrio fitness factors and how they frame our understanding of vibrio ecology. Factors representing these similarities include hemolysins, capsular polysaccharides, flagella, proteases, attachment factors, type III secretion systems, chitin binding proteins, iron acquisition systems, and colonization factors.
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Affiliation(s)
- Crystal N Johnson
- Department of Environmental Sciences, Louisiana State University, Baton Rouge, LA, USA.
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45
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Production of long-chain hydroxy fatty acids by microbial conversion. Appl Microbiol Biotechnol 2013; 97:3323-31. [PMID: 23494626 DOI: 10.1007/s00253-013-4815-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Revised: 02/24/2013] [Accepted: 02/26/2013] [Indexed: 10/27/2022]
Abstract
Hydroxy fatty acids (HFAs) are very important chemicals for versatile applications in biodegradable polymer materials and cosmetic and pharmaceutical industries. They are difficult to be synthesized via chemical routes due to the inertness of the fatty acyl chain. In contrast, these fatty acids make up a major class of natural products widespread among bacteria, yeasts, and fungi. A number of microorganisms capable of producing HFAs from fatty acids or vegetable oils have been reported. Therefore, HFAs could be produced by biotechnological strategies, especially by microbial conversion processes. Microorganisms could oxidize fatty acids either at the terminal carbon or inside the acyl chain to produce various HFAs, including α-HFAs, β-HFAs, mid-position HFAs, ω-HFAs, di-HFAs, and tri-HFAs. The enzymes and their encoded genes responsible for the hydroxylation of the carbon chain have been identified and characterized during the past few years. The involved microbes and catalytic mechanisms for the production of different types of HFAs are systematically demonstrated in this review. It provides a better view of HFA biosynthesis and lays the foundation for further industrial production.
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Correlations Between FAS Elongation Cycle Genes Expression and Fatty Acid Production for Improvement of Long-Chain Fatty Acids in Escherichia coli. Appl Biochem Biotechnol 2013; 169:1606-19. [DOI: 10.1007/s12010-012-0088-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 12/28/2012] [Indexed: 02/04/2023]
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47
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Lee S, Park S, Lee J. Improvement of free fatty acid production in Escherichia coli using codon-optimized Streptococcus pyogenes acyl-ACP thioesterase. Bioprocess Biosyst Eng 2013; 36:1519-25. [PMID: 23297069 DOI: 10.1007/s00449-012-0882-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Accepted: 12/21/2012] [Indexed: 12/01/2022]
Abstract
Fatty acyl-acyl carrier protein (ACP) thioesterase (acyl-ACP TE) from Streptococcus pyogenes (strain MGAS10270) was codon-optimized and expressed in Escherichia coli K-12 W3110 and Escherichia coli K-12 MG1655. By employing codon-optimized S. pyogenes acyl-ACP TE to improve the total free fatty acids (FFAs) and to tailor the composition of FFAs, high-specificity production of saturated fatty acids (C12, C14) and unsaturated fatty acids (C18:1 C18:2) was achieved in recombinants. E. coli SGJS41 and SGJS46 (codon-optimized acyl-ACP TE of S. pyogenes) demonstrated the highest intracellular total FFA content (339 mg/l vs 342 mg/l); in particular, the content of C12 and C14 FFAs was about 3-5 fold, and the content of C18:1 and C18:2 FFAs was about 8-42 fold higher than that in the control E. coli and E. coli JES1017 (original acyl-ACP TE of S. pyogenes).
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Affiliation(s)
- Sunhee Lee
- Department of Chemical and Biomolecular Engineering, Sogang University, Seoul, 121-742, Republic of Korea
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48
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Khatri N, Khatri I, Subramanian S, Raychaudhuri S. Ethanolamine utilization in Vibrio alginolyticus. Biol Direct 2012; 7:45; discussion 45. [PMID: 23234435 PMCID: PMC3542024 DOI: 10.1186/1745-6150-7-45] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Accepted: 11/30/2012] [Indexed: 11/10/2022] Open
Abstract
UNLABELLED Ethanolamine is used as an energy source by phylogenetically diverse bacteria including pathogens, by the concerted action of proteins from the eut-operon. Previous studies have revealed the presence of eutBC genes encoding ethanolamine-ammonia lyase, a key enzyme that breaks ethanolamine into acetaldehyde and ammonia, in about 100 bacterial genomes including members of gamma-proteobacteria. However, ethanolamine utilization has not been reported for any member of the Vibrio genus. Our comparative genomics study reveals the presence of genes that are involved in ethanolamine utilization in several Vibrio species. Using Vibrio alginolyticus as a model system we demonstrate that ethanolamine is better utilized as a nitrogen source than as a carbon source. REVIEWERS This article was reviewed by Dr. Lakshminarayan Iyer and Dr. Vivek Anantharaman (nominated by Dr. L Aravind).
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Affiliation(s)
- Neelam Khatri
- CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh, India
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Kung Y, Runguphan W, Keasling JD. From fields to fuels: recent advances in the microbial production of biofuels. ACS Synth Biol 2012; 1:498-513. [PMID: 23656227 DOI: 10.1021/sb300074k] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Amid grave concerns over global climate change and with increasingly strained access to fossil fuels, the synthetic biology community has stepped up to the challenge of developing microbial platforms for the production of advanced biofuels. The adoption of gasoline, diesel, and jet fuel alternatives derived from microbial sources has the potential to significantly limit net greenhouse gas emissions. In this effort, great strides have been made in recent years toward the engineering of microorganisms to produce transportation fuels derived from alcohol, fatty acid, and isoprenoid biosynthesis. We provide an overview of the biosynthetic pathways devised in the strain development of biofuel-producing microorganisms. We also highlight many of the commonly used and newly devised engineering strategies that have been employed to identify and overcome pathway bottlenecks and problems of toxicity to maximize production titers.
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Affiliation(s)
- Yan Kung
- Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, California 94608, United States
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Weerawat Runguphan
- Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, California 94608, United States
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Jay D. Keasling
- Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, California 94608, United States
- Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Departments of Chemical and Biomolecular Engineering and Bioengineering, University of California, Berkeley, Berkeley, California 94720, United States
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50
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Zheng Y, Li L, Liu Q, Qin W, Yang J, Cao Y, Jiang X, Zhao G, Xian M. Boosting the free fatty acid synthesis of Escherichia coli by expression of a cytosolic Acinetobacter baylyi thioesterase. BIOTECHNOLOGY FOR BIOFUELS 2012; 5:76. [PMID: 23057831 PMCID: PMC3524773 DOI: 10.1186/1754-6834-5-76] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Accepted: 10/05/2012] [Indexed: 05/04/2023]
Abstract
BACKGROUND Thioesterases remove the fatty acyl moiety from the fatty acyl-acyl carrier proteins (ACPs), releasing them as free fatty acids (FFAs), which can be further used to produce a variety of fatty acid-based biofuels, such as biodiesel, fatty alcohols and alkanes. Thioesterases play a key role in the regulation of the fatty acid synthesis in Escherichia coli. Therefore, exploring more promising thioesterases will contribute to the development of industrial microbial lipids production. RESULTS We cloned and expressed a cytosolic Acinetobacter baylyi thioesterase ('AcTesA) in E. coli by deleting its leader sequence. Protein sequence alignment, structure modeling and site-directed mutagenesis demonstrated that Ser10, Gly48, Asn77, Asp158 and His161 residues composed the active centre of 'AcTesA. The engineered strain that overexpressed 'AcTesA achieved a FFAs titer of up to 501.2 mg/L in shake flask, in contrast to only 20.5 mg/L obtained in wild-type E. coli, demonstrating that the expression of 'AcTesA indeed boosted the synthesis of FFAs. The 'AcTesA exhibited a substrate preference towards the C8-C16 acyl groups, with C14:0, C16:1, C12:0 and C8:0 FFAs being the top four components. Optimization of expression level of 'AcTesA made the FFAs production increase to 551.3 mg/L. The FFAs production further increased to 716.1 mg/L by optimization of the culture medium. Fed-batch fermentation was also carried out to evaluate the FFAs production in a scaleable process. Finally, 3.6 g/L FFAs were accumulated within 48 h, and a maximal FFAs yield of 6.1% was achieved in 12-16 h post induction. CONCLUSIONS For the first time, an A. baylyi thioesterase was cloned and solubly expressed in the cytosol of E. coli. This leaderless thioesterase ('AcTesA) was found to be capable of enhancing the FFAs production of E. coli. Without detailed optimization of the strain and fermentation, the finally achieved 3.6 g/L FFAs is encouraging. In addition, 'AcTesA exhibited different substrate specificity from other thioesterases previously reported, and can be used to supply the fatty acid-based biofuels with high quality of FFAs. Altogether, this study provides a promising thioesterase for FFAs production, and is of great importance in enriching the library of useful thioesterases.
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Affiliation(s)
- Yanning Zheng
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lingling Li
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- College of Food Science, Sichuan Agricultural University, Yaan, 625014, China
| | - Qiang Liu
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- College of Food Science, Sichuan Agricultural University, Yaan, 625014, China
| | - Wen Qin
- College of Food Science, Sichuan Agricultural University, Yaan, 625014, China
| | - Jianming Yang
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yujin Cao
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Xinglin Jiang
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Guang Zhao
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
| | - Mo Xian
- Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, China
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