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Cheng B, Zhang D, Lin Q, Xi S, Ma J, Zan F, Biswal BK, Wang Z, Guo G. Short-chain fatty acid production and phosphorous recovery from waste activated sludge via anaerobic fermentation: A comparison of in-situ and ex-situ thiosulfate-assisted Fe 2+/persulfate pretreatment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 871:162172. [PMID: 36775172 DOI: 10.1016/j.scitotenv.2023.162172] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 02/07/2023] [Accepted: 02/07/2023] [Indexed: 06/18/2023]
Abstract
Recently, increasing attention is given on the resource and energy recovery (e.g. short-chain fatty acids (SCFAs) and phosphorus (P)) from waste active sludge (WAS) under the "Dual carbon goals". This study compared four thiosulfate-assisted Fe2+/persulfate (TAFP) pretreatments of WAS, i.e. in-situ TAFP pretreatment (R1), ex-situ TAFP pretreatment (R2), in-situ TAFP pretreatment + pH adjustment (R3) and ex-situ TAFP pretreatment + pH adjustment (R4), followed by anaerobic fermentation over 20 days for SCFA production and P recovery. The results showed that the maximal SCFA yields in R1-4 were 730.2 ± 7.0, 1017.4 ± 13.9, 860.1 ± 40.8, and 1072.0 ± 33.2 mg COD/L, respectively, significantly higher than Control (365.2 ± 17.8 mg COD/L). The findings indicated that TAFP pretreatments (particularly ex-situ TAFP pretreatment) enhanced WAS disintegration and provided more soluble organics and subsequently promoted SCFA production. The P fractionation results showed the non-apatite inorganic P increased from 11.6 ± 0.2 mg P/g TSS in Control to 11.8 ± 0.5 (R1), 12.4 ± 0.3 (R2), 13.2 ± 0.7 (R3) and 12.7 ± 0.7 mg P/g TSS (R4), suggesting TAFP pretreatments improved P bioavailability due to formation of Fe-P mineral (Fe(H2PO4)2·2H2O), which could be recycled through magnetic separators. These findings were further strengthened by the analysis of microbial community and related marker genes that fermentative bacteria containing SCFA biosynthesis genes (e.g. pyk, pdhA, accA and accB) and iron-reducing bacteria containing iron-related proteins (e.g. feoA and feoB) were enriched in R1-4 (dominant in ex-situ pretreatment systems, R2 and R4). Economic evaluation further verified ex-situ TAFP pretreatment was cost-effective and a better strategy over other operations to treat WAS for SCFA production and P recovery.
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Affiliation(s)
- Boyi Cheng
- School of Environmental Science and Engineering, Huazhong University of Science and Technology (HUST), Key Laboratory of Water and Wastewater Treatment (HUST), MOHURD, Wuhan 430074, China
| | - Da Zhang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology (HUST), Key Laboratory of Water and Wastewater Treatment (HUST), MOHURD, Wuhan 430074, China
| | - Qingshan Lin
- School of Environmental Science and Engineering, Huazhong University of Science and Technology (HUST), Key Laboratory of Water and Wastewater Treatment (HUST), MOHURD, Wuhan 430074, China
| | - Shihao Xi
- School of Environmental Science and Engineering, Huazhong University of Science and Technology (HUST), Key Laboratory of Water and Wastewater Treatment (HUST), MOHURD, Wuhan 430074, China
| | - Jie Ma
- School of Environmental Science and Engineering, Huazhong University of Science and Technology (HUST), Key Laboratory of Water and Wastewater Treatment (HUST), MOHURD, Wuhan 430074, China
| | - Feixiang Zan
- School of Environmental Science and Engineering, Huazhong University of Science and Technology (HUST), Key Laboratory of Water and Wastewater Treatment (HUST), MOHURD, Wuhan 430074, China
| | - Basanta Kumar Biswal
- Department of Civil & Environmental Engineering, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Zongping Wang
- School of Environmental Science and Engineering, Huazhong University of Science and Technology (HUST), Key Laboratory of Water and Wastewater Treatment (HUST), MOHURD, Wuhan 430074, China
| | - Gang Guo
- School of Environmental Science and Engineering, Huazhong University of Science and Technology (HUST), Key Laboratory of Water and Wastewater Treatment (HUST), MOHURD, Wuhan 430074, China.
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Chen G, Harwood JL, Lemieux MJ, Stone SJ, Weselake RJ. Acyl-CoA:diacylglycerol acyltransferase: Properties, physiological roles, metabolic engineering and intentional control. Prog Lipid Res 2022; 88:101181. [PMID: 35820474 DOI: 10.1016/j.plipres.2022.101181] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/31/2022] [Accepted: 07/04/2022] [Indexed: 12/15/2022]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) catalyzes the last reaction in the acyl-CoA-dependent biosynthesis of triacylglycerol (TAG). DGAT activity resides mainly in membrane-bound DGAT1 and DGAT2 in eukaryotes and bifunctional wax ester synthase-diacylglycerol acyltransferase (WSD) in bacteria, which are all membrane-bound proteins but exhibit no sequence homology to each other. Recent studies also identified other DGAT enzymes such as the soluble DGAT3 and diacylglycerol acetyltransferase (EaDAcT), as well as enzymes with DGAT activities including defective in cuticular ridges (DCR) and steryl and phytyl ester synthases (PESs). This review comprehensively discusses research advances on DGATs in prokaryotes and eukaryotes with a focus on their biochemical properties, physiological roles, and biotechnological and therapeutic applications. The review begins with a discussion of DGAT assay methods, followed by a systematic discussion of TAG biosynthesis and the properties and physiological role of DGATs. Thereafter, the review discusses the three-dimensional structure and insights into mechanism of action of human DGAT1, and the modeled DGAT1 from Brassica napus. The review then examines metabolic engineering strategies involving manipulation of DGAT, followed by a discussion of its therapeutic applications. DGAT in relation to improvement of livestock traits is also discussed along with DGATs in various other eukaryotic organisms.
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Affiliation(s)
- Guanqun Chen
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Membrane Protein Disease Research Group, Edmonton T6G 2H7, Canada
| | - Scot J Stone
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
| | - Randall J Weselake
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada
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Wang L, Chen L, Yang S, Tan X. Photosynthetic Conversion of Carbon Dioxide to Oleochemicals by Cyanobacteria: Recent Advances and Future Perspectives. Front Microbiol 2020; 11:634. [PMID: 32362881 PMCID: PMC7181335 DOI: 10.3389/fmicb.2020.00634] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Accepted: 03/20/2020] [Indexed: 11/21/2022] Open
Abstract
Sustainable production of biofuels and biochemicals has been broadly accepted as a solution to lower carbon dioxide emissions. Besides being used as lubricants or detergents, oleochemicals are also attractive biofuels as they are compatible with existing transport infrastructures. Cyanobacteria are autotrophic prokaryotes possessing photosynthetic abilities with mature genetic manipulation systems. Through the introduction of exogenous or the modification of intrinsic metabolic pathways, cyanobacteria have been engineered to produce various bio-chemicals and biofuels over the past decade. In this review, we specifically summarize recent progress on photosynthetic production of fatty acids, fatty alcohols, fatty alk(a/e)nes, and fatty acid esters by genetically engineered cyanobacteria. We also summarize recent reports on fatty acid and lipid metabolisms of cyanobacteria and provide perspectives for economic cyanobacterial oleochemical production in the future.
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Affiliation(s)
- Li Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan, China
| | - Liyuan Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan, China
| | - Xiaoming Tan
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, School of Life Sciences, Hubei University, Wuhan, China
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Lin WR, Tan SI, Hsiang CC, Sung PK, Ng IS. Challenges and opportunity of recent genome editing and multi-omics in cyanobacteria and microalgae for biorefinery. BIORESOURCE TECHNOLOGY 2019; 291:121932. [PMID: 31387837 DOI: 10.1016/j.biortech.2019.121932] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 07/26/2019] [Accepted: 07/27/2019] [Indexed: 06/10/2023]
Abstract
Microalgae and cyanobacteria are easy to culture, with higher growth rates and photosynthetic efficiencies compared to terrestrial plants, and thus generating higher productivity. The concept of microalgal biorefinery is to assimilate carbon dioxide and convert it to chemical energy/value-added products, such as vitamins, carotenoids, fatty acids, proteins and nucleic acids, to be applied in bioenergy, health foods, aquaculture feed, pharmaceutical and medical fields. Therefore, microalgae are annotated as the third generation feedstock in bioenergy and biorefinery. In past decades, many studies thrived to improve the carbon sequestration efficiency as well as enhance value-added compounds from different algae, especially via genetic engineering, synthetic biology, metabolic design and regulation. From the traditional Agrobacterium-mediated transformation DNA to novel CRISPR (clustered regularly interspaced short palindromic repeats) technology applied in microalgae and cyanobacteria, this review has highlighted the genome editing technology for biorefinery that is a highly environmental friendly trend to sustainable and renewable development.
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Affiliation(s)
- Way-Rong Lin
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC
| | - Shih-I Tan
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC
| | - Chuan-Chieh Hsiang
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC
| | - Po-Kuei Sung
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan, ROC.
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Sankaranarayanan K, Antaris XX, Palanski BA, El Gamal A, Kao CM, Fitch WL, Fischer CR, Khosla C. Tunable Enzymatic Synthesis of the Immunomodulator Lipid IV A To Enable Structure-Activity Analysis. J Am Chem Soc 2019; 141:9474-9478. [PMID: 31184877 PMCID: PMC7206895 DOI: 10.1021/jacs.9b03066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Lipid A family of glycolipids, found in the outer membranes of all Gram-negative bacteria, exhibits considerable structural diversity in both lipid and glycan moieties. The lack of facile methods to prepare analogues of these natural products represents a major roadblock in understanding the relationship between their structure and immunomodulatory activities. Here we present a modular, cell-free multienzymatic platform to access these structure-activity relationships. By individually purifying 19 Escherichia coli proteins and reconstituting them in vitro in the presence of acetyl-CoA, UDP- N-acetylglucosamine, NADPH, and ATP, we have developed a system capable of synthesizing Lipid IVA, the first bioactive intermediate in the Lipid A pathway. Our reconstituted multienzyme system revealed considerable promiscuity for orthologs with distinct substrate specificity, as illustrated by swapping enzymes from distantly related cyanobacterial and Pseudomonas species. Analysis of the agonistic and antagonistic activities of the resulting products against the THP-1 human monocytic cell line revealed hitherto unrecognized trends, while opening the door to harnessing the potent biological activities of these complex glycolipid natural products.
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Affiliation(s)
| | - Xirui X. Antaris
- Department of Chemistry, Stanford, California 94305, United States
| | - Brad A. Palanski
- Department of Chemistry, Stanford, California 94305, United States
| | - Abrahim El Gamal
- Department of Chemistry, Stanford, California 94305, United States
| | - Camilla M. Kao
- Department of Biochemistry, and Stanford, California 94305, United States
| | - William L. Fitch
- Department of Medicine, and Stanford, California 94305, United States
| | - Curt R. Fischer
- Department of Stanford ChEM-H, Stanford University, Stanford, California 94305, United States
| | - Chaitan Khosla
- Department of Chemical Engineering, Stanford, California 94305, United States
- Department of Chemistry, Stanford, California 94305, United States
- Department of Biochemistry, and Stanford, California 94305, United States
- Department of Stanford ChEM-H, Stanford University, Stanford, California 94305, United States
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6
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Short Chain Fatty Acid Biosynthesis in Microalgae Synechococcus sp. PCC 7942. Mar Drugs 2019; 17:md17050255. [PMID: 31035409 PMCID: PMC6562792 DOI: 10.3390/md17050255] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Accepted: 04/25/2019] [Indexed: 01/05/2023] Open
Abstract
Short chain fatty acids (SCFAs) are valued as a functional material in cosmetics. Cyanobacteria can accumulate SCFAs under some conditions, the related mechanism is unclear. Two potential genes Synpcc7942_0537 (fabB/F) and Synpcc7942_1455 (fabH) in Synechococcus sp. PCC 7942 have homology with fabB/F and fabH encoding β-ketoacyl ACP synthases (I/II/III) in plants. Therefore, effects of culture time and cerulenin on SCFAs accumulation, expression levels and functions of these two potential genes were studied. The results showed Synechococcus sp. PCC 7942 accumulated high SCFAs (C12 + C14) in early growth stage (day 4) and at 7.5g/L cerulenin concentration, reaching to 2.44% and 2.84% of the total fatty acids respectively, where fabB/F expression was down-regulated. Fatty acid composition analysis showed C14 increased by 65.19% and 130% respectively, when fabB/F and fabH were antisense expressed. C14 increased by 10.79% (fab(B/F)-) and 6.47% (fabH-) under mutation conditions, while C8 increased by six times in fab(B/F)- mutant strain. These results suggested fabB/F is involved in fatty acid elongation (C <18) and the elongation of cis-16:1 to cis-18:1 fatty acid in Synechococcus sp. PCC 7942, while fabH was involved in elongation of fatty acid synthesis, which were further confirmed in complementary experiments of E. coli. The research could provide the scientific basis for the breeding of SCFA-rich microalgae species.
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Yan Q, Pfleger BF. Revisiting metabolic engineering strategies for microbial synthesis of oleochemicals. Metab Eng 2019; 58:35-46. [PMID: 31022535 DOI: 10.1016/j.ymben.2019.04.009] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 04/20/2019] [Accepted: 04/21/2019] [Indexed: 02/06/2023]
Abstract
Microbial production of oleochemicals from renewable feedstocks remains an attractive route to produce high-energy density, liquid transportation fuels and high-value chemical products. Metabolic engineering strategies have been applied to demonstrate production of a wide range of oleochemicals, including free fatty acids, fatty alcohols, esters, olefins, alkanes, ketones, and polyesters in both bacteria and yeast. The majority of these demonstrations synthesized products containing long-chain fatty acids. These successes motivated additional effort to produce analogous molecules comprised of medium-chain fatty acids, molecules that are less common in natural oils and therefore of higher commercial value. Substantial progress has been made towards producing a subset of these chemicals, but significant work remains for most. The other primary challenge to producing oleochemicals in microbes is improving the performance, in terms of yield, rate, and titer, of biocatalysts such that economic large-scale processes are feasible. Common metabolic engineering strategies include blocking pathways that compete with synthesis of oleochemical building blocks and/or consume products, pulling flux through pathways by removing regulatory signals, pushing flux into biosynthesis by overexpressing rate-limiting enzymes, and engineering cells to tolerate the presence of oleochemical products. In this review, we describe the basic fundamentals of oleochemical synthesis and summarize advances since 2013 towards improving performance of heterotrophic microbial cell factories.
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Affiliation(s)
- Qiang Yan
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, United States; DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Wisconsin-Madison, Madison, WI 53706, United States
| | - Brian F Pfleger
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI 53706, United States; DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Wisconsin-Madison, Madison, WI 53706, United States; Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI 53706, United States.
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8
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Sun T, Li S, Song X, Pei G, Diao J, Cui J, Shi M, Chen L, Zhang W. Re-direction of carbon flux to key precursor malonyl-CoA via artificial small RNAs in photosynthetic Synechocystis sp. PCC 6803. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:26. [PMID: 29441124 PMCID: PMC5798194 DOI: 10.1186/s13068-018-1032-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 01/23/2018] [Indexed: 05/24/2023]
Abstract
BACKGROUND Photosynthetic cyanobacteria have attracted a significant attention as promising chassis to produce renewable fuels and chemicals due to their capability to utilizing solar energy and CO2. Notably, the enhancing supply of key precursors like malonyl-CoA would benefit the production of many bio-compounds. Nevertheless, the lacking of genetic tools in cyanobacteria, especially the knockdown strategies for essential pathways, has seriously restricted the attempts to re-direct carbon flux from the central carbohydrate metabolism to the synthesis of bioproducts. RESULTS Aiming at developing new genetic tools, two small RNA regulatory tools are reported for the model cyanobacterium Synechocystis sp. PCC6803, based on paired termini RNAs as well as the exogenous Hfq chaperone and MicC scaffold (Hfq-MicC) previously developed in Escherichia coli. Both regulatory tools functioned well in regulating exogenous reporter gene lacZ and endogenous glgC gene in Synechocystis sp. PCC6803, achieving a downregulation of gene expression up to 90% compared with wildtype. In addition, the Hfq-MicC tool was developed to simultaneously regulate multiple genes related to essential fatty acids biosynthesis, which led to decreased fatty acids content by 11%. Furthermore, aiming to re-direct the carbon flux, the Hfq-MicC tool was utilized to interfere the competing pathway of malonyl-CoA, achieving an increased intracellular malonyl-CoA abundance up to 41% (~ 698.3 pg/mL/OD730 nm) compared to the wildtype. Finally, the Hfq-MicC system was further modified into an inducible system based on the theophylline-inducible riboswitch. CONCLUSIONS In this study, two small RNA regulatory tools for manipulating essential metabolic pathways and re-directing carbon flux are reported for Synechocystis sp. PCC6803. The work introduces efficient and valuable metabolic regulatory strategies for photosynthetic cyanobacteria.
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Affiliation(s)
- Tao Sun
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072 People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072 People’s Republic of China
| | - Shubin Li
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072 People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072 People’s Republic of China
| | - Xinyu Song
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072 People’s Republic of China
| | - Guangsheng Pei
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072 People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072 People’s Republic of China
| | - Jinjin Diao
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072 People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072 People’s Republic of China
| | - Jinyu Cui
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072 People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072 People’s Republic of China
| | - Mengliang Shi
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072 People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072 People’s Republic of China
| | - Lei Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072 People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072 People’s Republic of China
| | - Weiwen Zhang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering & Technology, Tianjin University, Tianjin, 300072 People’s Republic of China
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, 300072 People’s Republic of China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, 300072 People’s Republic of China
- Center for Biosafety Research and Strategy, Tianjin University, Tianjin, People’s Republic of China
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Santos-Merino M, Garcillán-Barcia MP, de la Cruz F. Engineering the fatty acid synthesis pathway in Synechococcus elongatus PCC 7942 improves omega-3 fatty acid production. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:239. [PMID: 30202434 PMCID: PMC6123915 DOI: 10.1186/s13068-018-1243-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 08/27/2018] [Indexed: 05/09/2023]
Abstract
BACKGROUND The microbial production of fatty acids has received great attention in the last few years as feedstock for the production of renewable energy. The main advantage of using cyanobacteria over other organisms is their ability to capture energy from sunlight and to transform CO2 into products of interest by photosynthesis, such as fatty acids. Fatty acid synthesis is a ubiquitous and well-characterized pathway in most bacteria. However, the activity of the enzymes involved in this pathway in cyanobacteria remains poorly explored. RESULTS To characterize the function of some enzymes involved in the saturated fatty acid synthesis in cyanobacteria, we genetically engineered Synechococcus elongatus PCC 7942 by overexpressing or deleting genes encoding enzymes of the fatty acid synthase system and tested the lipid profile of the mutants. These modifications were in turn used to improve alpha-linolenic acid production in this cyanobacterium. The mutant resulting from fabF overexpression and fadD deletion, combined with the overexpression of desA and desB desaturase genes from Synechococcus sp. PCC 7002, produced the highest levels of this omega-3 fatty acid. CONCLUSIONS The fatty acid composition of S. elongatus PCC 7942 can be significantly modified by genetically engineering the expression of genes coding for the enzymes involved in the first reactions of fatty acid synthesis pathway. Variations in fatty acid composition of S. elongatus PCC 7942 mutants did not follow the pattern observed in Escherichia coli derivatives. Some of these modifications can be used to improve omega-3 fatty acid production. This work provides new insights into the saturated fatty acid synthesis pathway and new strategies that might be used to manipulate the fatty acid content of cyanobacteria.
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Affiliation(s)
- María Santos-Merino
- Instituto de Biomedicina y Biotecnología de Cantabria (Universidad de Cantabria—Consejo Superior de Investigaciones Científicas), Santander, Cantabria Spain
| | - M. Pilar Garcillán-Barcia
- Instituto de Biomedicina y Biotecnología de Cantabria (Universidad de Cantabria—Consejo Superior de Investigaciones Científicas), Santander, Cantabria Spain
| | - Fernando de la Cruz
- Instituto de Biomedicina y Biotecnología de Cantabria (Universidad de Cantabria—Consejo Superior de Investigaciones Científicas), Santander, Cantabria Spain
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10
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Zhang H, Liu Y, Yao C, Cao X, Tian J, Xue S. FabG can function as PhaB for poly-3-hydroxybutyrate biosynthesis in photosynthetic cyanobacteria Synechocystis sp. PCC 6803. Bioengineered 2017; 8:707-715. [PMID: 28494182 DOI: 10.1080/21655979.2017.1317574] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The production of poly-3-hydroxybutyrate (PHB) by photosynthetic cyanobacteria is a potentially sustainable production method for the biodegradable plastics industry. β-Ketoacyl-ACP reductase (FabG), from the photosynthetic cyanobacterium Synechocystis sp. PCC 6803 (SpFabG), is the first NADPH-dependent reductase in the fatty acid biosynthesis pathway. Its structure is similar to that of acetoacetyl-CoA reductase (SpPhaB), which is critical for PHB synthesis and can replace SpPhaB for acetoacetyl-CoA reduction in vitro. However, the specific function of SpFabG in fatty acid synthesis and whether SpFabG could participate in PHB synthesis in vivo were not yet clear. In this study, the role of SpFabG in fatty acid synthesis was first verified in vivo by knocking down and overexpressing of fabG. It was shown that SpFabG was essential yet not rate-limiting for fatty acid biosynthesis. The biochemical characterization of SpFabG using acetoacetyl-CoA as the substrate showed that the optimum temperature, optimum pH, Km and kcat were 30°C, 7, 2.30 mM, and 19.85 s-1, respectively, which exemplified the ability of SpFabG to reduce acetoacetyl-CoA with a relatively low affinity and weak catalytic efficiency. Functional analysis of SpFabG in vivo indicated that SpFabG was able to partially complement SpPhaB under nitrogen-deprived conditions, and overexpression of fabG led to the diversion of partial carbon flux from fatty acid toward PHB synthesis.
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Affiliation(s)
- Haowei Zhang
- a School of Engineering, Dalian Polytechnic University , Liaoning , Dalian , China
| | - Yinghui Liu
- b Marine Bioengineering Group, Dalian Institute of Chemical Physics , Chinese Academy of Sciences , Dalian , China
| | - Changhong Yao
- c Department of Pharmaceutical & Biological Engineering , School of Chemical Engineering, Sichuan University , Chengdu , Sichuan , China
| | - Xupeng Cao
- b Marine Bioengineering Group, Dalian Institute of Chemical Physics , Chinese Academy of Sciences , Dalian , China
| | - Jing Tian
- a School of Engineering, Dalian Polytechnic University , Liaoning , Dalian , China
| | - Song Xue
- b Marine Bioengineering Group, Dalian Institute of Chemical Physics , Chinese Academy of Sciences , Dalian , China
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Hill EA, Chrisler WB, Beliaev AS, Bernstein HC. A flexible microbial co-culture platform for simultaneous utilization of methane and carbon dioxide from gas feedstocks. BIORESOURCE TECHNOLOGY 2017; 228:250-256. [PMID: 28092828 DOI: 10.1016/j.biortech.2016.12.111] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/30/2016] [Accepted: 12/31/2016] [Indexed: 06/06/2023]
Abstract
A new co-cultivation technology is presented that converts greenhouse gasses, CH4 and CO2, into microbial biomass. The methanotrophic bacterium, Methylomicrobium alcaliphilum 20z, was coupled to a cyanobacterium, Synechococcus PCC 7002 via oxygenic photosynthesis. The system exhibited robust growth on diverse gas mixtures ranging from biogas to those representative of a natural gas feedstock. A continuous processes was developed on a synthetic natural gas feed that achieved steady-state by imposing coupled light and O2 limitations on the cyanobacterium and methanotroph, respectively. Continuous co-cultivation resulted in an O2 depleted reactor and does not require CH4/O2 mixtures to be fed into the system, thereby enhancing process safety considerations over traditional methanotroph mono-culture platforms. This co-culture technology is scalable with respect to its ability to utilize different gas streams and its biological components constructed from model bacteria that can be metabolically customized to produce a range of biofuels and bioproducts.
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Affiliation(s)
- Eric A Hill
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - William B Chrisler
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Alex S Beliaev
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Hans C Bernstein
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA; The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA.
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12
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Ye Z, Li X, Cheng Y, Liu Z, Tan G, Zhu F, Fu S, Deng Z, Liu T. Evaluation of 3-hydroxypropionate biosynthesis in vitro by partial introduction of the 3-hydroxypropionate/4-hydroxybutyrate cycle from Metallosphaera sedula. J Ind Microbiol Biotechnol 2016; 43:1313-21. [PMID: 27300329 PMCID: PMC4983293 DOI: 10.1007/s10295-016-1793-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Accepted: 05/31/2016] [Indexed: 01/03/2023]
Abstract
The chemical 3-hydroxypropionate (3HP) is an important starting reagent for the commercial synthesis of specialty chemicals. In this study, a part of the 3-hydroxypropionate/4-hydroxybutyrate cycle from Metallosphaera sedula was utilized for 3HP production. To study the basic biochemistry of this pathway, an in vitro-reconstituted system was established using acetyl-CoA as the substrate for the kinetic analysis of this system. The results indicated that 3HP formation was sensitive to acetyl-CoA carboxylase and malonyl-CoA reductase, but not malonate semialdehyde reductase. Also, the competition between 3HP formation and fatty acid production was analyzed both in vitro and in vivo. This study has highlighted how metabolic flux is controlled by different catalytic components. We believe that this reconstituted system would be valuable for understanding 3HP biosynthesis pathway and for future engineering studies to enhance 3HP production.
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Affiliation(s)
- Ziling Ye
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, People's Republic of China
| | - Xiaowei Li
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, People's Republic of China
| | - Yongbo Cheng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, People's Republic of China
| | - Zhijie Liu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, People's Republic of China
| | - Gaoyi Tan
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, People's Republic of China
| | - Fayin Zhu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, People's Republic of China
| | - Shuai Fu
- J1 Biotech, Co., Ltd, Wuhan, 430075, People's Republic of China
| | - Zixin Deng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, People's Republic of China.,Hubei Engineering Laboratory for Synthetic Microbiology, Wuhan Institute of Biotechnology, Wuhan, 430075, People's Republic of China.,The State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200030, People's Republic of China
| | - Tiangang Liu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, People's Republic of China. .,Hubei Engineering Laboratory for Synthetic Microbiology, Wuhan Institute of Biotechnology, Wuhan, 430075, People's Republic of China. .,Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Wuhan, 430068, People's Republic of China.
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13
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Beld J, Abbriano R, Finzel K, Hildebrand M, Burkart MD. Probing fatty acid metabolism in bacteria, cyanobacteria, green microalgae and diatoms with natural and unnatural fatty acids. MOLECULAR BIOSYSTEMS 2016; 12:1299-312. [PMID: 26886879 DOI: 10.1039/c5mb00804b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In both eukaryotes and prokaryotes, fatty acid synthases are responsible for the biosynthesis of fatty acids in an iterative process, extending the fatty acid by two carbon units every cycle. Thus, odd numbered fatty acids are rarely found in nature. We tested whether representatives of diverse microbial phyla have the ability to incorporate odd-chain fatty acids as substrates for their fatty acid synthases and their downstream enzymes. We fed various odd and short chain fatty acids to the bacterium Escherichia coli, cyanobacterium Synechocystis sp. PCC 6803, green microalga Chlamydomonas reinhardtii and diatom Thalassiosira pseudonana. Major differences were observed, specifically in the ability among species to incorporate and elongate short chain fatty acids. We demonstrate that E. coli, C. reinhardtii, and T. pseudonana can produce longer fatty acid products from short chain precursors (C3 and C5), while Synechocystis sp. PCC 6803 lacks this ability. However, Synechocystis can incorporate and elongate longer chain fatty acids due to acyl-acyl carrier protein synthetase (AasS) activity, and knockout of this protein eliminates the ability to incorporate these fatty acids. In addition, expression of a characterized AasS from Vibrio harveyii confers a similar capability to E. coli. The ability to desaturate exogenously added fatty acids was only observed in Synechocystis and C. reinhardtii. We further probed fatty acid metabolism of these organisms by feeding desaturase inhibitors to test the specificity of long-chain fatty acid desaturases. In particular, supplementation with thia fatty acids can alter fatty acid profiles based on the location of the sulfur in the chain. We show that coupling sensitive gas chromatography mass spectrometry to supplementation of unnatural fatty acids can reveal major differences between fatty acid metabolism in various organisms. Often unnatural fatty acids have antibacterial or even therapeutic properties. Feeding of short precursors now gives us easy access to these extended molecules.
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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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Gu H, Jinkerson RE, Davies FK, Sisson LA, Schneider PE, Posewitz MC. Modulation of Medium-Chain Fatty Acid Synthesis in Synechococcus sp. PCC 7002 by Replacing FabH with a Chaetoceros Ketoacyl-ACP Synthase. FRONTIERS IN PLANT SCIENCE 2016; 7:690. [PMID: 27303412 PMCID: PMC4880568 DOI: 10.3389/fpls.2016.00690] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 05/05/2016] [Indexed: 05/12/2023]
Abstract
The isolation or engineering of algal cells synthesizing high levels of medium-chain fatty acids (MCFAs) is attractive to mitigate the high clouding point of longer chain fatty acids in algal based biodiesel. To develop a more informed understanding of MCFA synthesis in photosynthetic microorganisms, we isolated several algae from Great Salt Lake and screened this collection for MCFA accumulation to identify strains naturally accumulating high levels of MCFA. A diatom, Chaetoceros sp. GSL56, accumulated particularly high levels of C14 (up to 40%), with the majority of C14 fatty acids allocated in triacylglycerols. Using whole cell transcriptome sequencing and de novo assembly, putative genes encoding fatty acid synthesis enzymes were identified. Enzymes from this Chaetoceros sp. were expressed in the cyanobacterium Synechococcus sp. PCC 7002 to validate gene function and to determine whether eukaryotic enzymes putatively lacking bacterial evolutionary control mechanisms could be used to improve MCFA production in this promising production strain. Replacement of the Synechococcus 7002 native FabH with a Chaetoceros ketoacyl-ACP synthase III increased MCFA synthesis up to fivefold. The level of increase is dependent on promoter strength and culturing conditions.
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Affiliation(s)
- Huiya Gu
- Department of Chemistry and Geochemistry, Colorado School of Mines, GoldenCO, USA
| | - Robert E. Jinkerson
- Department of Plant Biology, Carnegie Institution for Science, StanfordCA, USA
| | - Fiona K. Davies
- Department of Chemistry and Geochemistry, Colorado School of Mines, GoldenCO, USA
| | - Lyle A. Sisson
- Department of Chemistry and Geochemistry, Colorado School of Mines, GoldenCO, USA
| | - Philip E. Schneider
- Department of Chemistry and Geochemistry, Colorado School of Mines, GoldenCO, USA
| | - Matthew C. Posewitz
- Department of Chemistry and Geochemistry, Colorado School of Mines, GoldenCO, USA
- *Correspondence: Matthew C. Posewitz,
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15
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Lowry B, Walsh CT, Khosla C. In Vitro Reconstitution of Metabolic Pathways: Insights into Nature's Chemical Logic. Synlett 2015; 26:1008-1025. [PMID: 26207083 PMCID: PMC4507746 DOI: 10.1055/s-0034-1380264] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
In vitro analysis of metabolic pathways is becoming a powerful method to gain a deeper understanding of Nature's core biochemical transformations. With astounding advancements in biotechnology, purification of a metabolic pathway's constitutive enzymatic components is becoming a tractable problem, and such in vitro studies allow scientists to capture the finer details of enzymatic reaction mechanisms, kinetics, and the identity of organic product molecules. In this review, we present eleven metabolic pathways that have been the subject of in vitro reconstitution studies in the literature in recent years. In addition, we have selected and analyzed subset of four case studies within these eleven examples that exemplify remarkable organic chemistry occurring within biology. These examples serves as tangible reminders that Nature's biochemical routes obey the fundamental principles of organic chemistry, and the chemical mechanisms are reminiscent of those featured in traditional synthetic organic routes. The illustrations of biosynthetic chemistry depicted in this review may inspire the development of biomimetic chemistries via abiotic chemical techniques.
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Affiliation(s)
- Brian Lowry
- Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, CA 94305, USA;
| | - Christopher T Walsh
- Stanford University Chemistry, Engineering, and Medicine for Human Health (ChEM-H), Stanford University, 443 Via Ortega, Stanford, CA 94305
| | - Chaitan Khosla
- Department of Chemical Engineering, Stanford University, 443 Via Ortega, Stanford, CA 94305, USA; ; Stanford University Chemistry, Engineering, and Medicine for Human Health (ChEM-H), Stanford University, 443 Via Ortega, Stanford, CA 94305 ; Department of Chemistry, 333 Campus Drive Mudd Building, Stanford University, Stanford, CA 94305, USA;
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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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Luan G, Qi Y, Wang M, Li Z, Duan Y, Tan X, Lu X. Combinatory strategy for characterizing and understanding the ethanol synthesis pathway in cyanobacteria cell factories. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:184. [PMID: 26594240 PMCID: PMC4654843 DOI: 10.1186/s13068-015-0367-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 10/28/2015] [Indexed: 05/09/2023]
Abstract
BACKGROUND Photosynthetic production of chemicals and fuels by recycling CO2 in cyanobacteria is a promising solution facing energy shortage and resource declination. Ethanol is an attractive and demonstrative biofuel product, and ethanol synthesis in cyanobacteria has been achieved by assembling of a pathway consisting of pyruvate decarboxylase (PDCzm) and alcohol dehydrogenase II (slr1192). For enabling more powerful ethanol photosynthetic production, an optimized and balanced catalyzing route was required. In this work, we provided a paradigm for systematically characterizing and optimizing the PDCzm-slr1192 pathway from engineered cyanobacteria strains, combining in vitro reconstitution, genetic engineering and feeding-cultivation. RESULTS We reconstituted the PDCzm-slr1192 pathway in vitro and performed specific titration assays for enzymes, substrates, cofactors, and metal ions. In the in vitro system, K 50 of PDCzm was 0.326 μM, with a V max of 2.074 μM/s; while for slr1192, the values were 0.109 μM and 1.722 μM/s, respectively. Titration response discrepancy indicated that PDCzm rather than slr1192 was the rate-limiting factor for ethanol synthesis. In addition, a 4:6 concentration ratio of PDCzm-slr1192 would endow the reaction with a maximal specific catalytic activity. Titration assays for other components were also performed. K m values for NADPH, pyruvate, TPP, Mg(2+) and acetaldehyde were 0.136, 6.496, 0.011, 0.104, and 0.393 mM, respectively. We further constructed Synechocystis mutant strains with diverse PDCzm-slr1192 concentrations and ratios, and compared the growth and ethanol synthesis performances. The results revealed that activities of PDCzm indeed held control over the ethanol generation capacities. We performed pyruvate-feeding treatment with the newly developed Syn-YQ4 strain, and confirmed that improvement of pyruvate supply would direct more carbon flow to ethanol formation. CONCLUSIONS We systematically characterized and optimized the PDCzm-slr1192 pathway in engineered cyanobacteria for ethanol production. Information gained from in vitro monitoring and genetic engineering revealed that for further enhancing ethanol synthesis capacities, PDCzm activities needed enhancement, and the PDCzm-slr1192 ratio should be improved and held to about 1:1.5. Considering actual metabolites concentrations of cyanobacteria cells, enhancing pyruvate supply was also a promising strategy for further updating the current ethanol photosynthetic cell factories.
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Affiliation(s)
- Guodong Luan
- />Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
- />Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
| | - Yunjing Qi
- />Qingdao University of Science and Technology, Qingdao, 266061 China
| | - Min Wang
- />Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
- />Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
| | - Zhimin Li
- />Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
- />Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
- />College of Bioscience and Bioengineering, Jiangxi Agricultural University, Nanchang, 330045 Jiangxi China
| | - Yangkai Duan
- />Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
- />Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
- />University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Xiaoming Tan
- />Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
- />Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
| | - Xuefeng Lu
- />Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
- />Shandong Provincial Key Laboratory of Synthetic Biology, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No. 189 Songling Road, Qingdao, 266101 China
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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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19
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Liu Q, Wu K, Cheng Y, Lu L, Xiao E, Zhang Y, Deng Z, Liu T. Engineering an iterative polyketide pathway in Escherichia coli results in single-form alkene and alkane overproduction. Metab Eng 2014; 28:82-90. [PMID: 25536488 DOI: 10.1016/j.ymben.2014.12.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 12/07/2014] [Accepted: 12/12/2014] [Indexed: 11/28/2022]
Abstract
Alkanes and alkenes are ideal biofuels, due to their high energy content and ability to be safely transported. To date, fatty acid-derived pathways for alkane and alkene bioproduction have been thoroughly explored. In this study, we engineered the pathway of the iterative Type I polyketide synthase (PKS) SgcE with the cognate thioesterase (TE) SgcE10 in Escherichia coli, with the goal of overproducing pentadecaheptaene (PDH) followed by its hydrogenation to pentadecane (PD). Based on initial in vitro titration assays, we learned that PDH production is strongly dependent on the SgcE10:SgcE ratio. Thus, we engineered a high-yield E. coli strain by fine-tuning SgcE10 expression via synthetic promoters. We analyzed engineered E. coli strains using a modified multiple reactions monitoring mass spectrometry (MRM-MS)-based targeted proteomic approach, using a chimeric SgcE10 and SgcE fusion construct to gain insight into expression levels of the two proteins. Lastly, through fed-batch fermentation followed by flow chemical hydrogenation, we obtained a PD yield of nearly 140mg/L in single-alkane form. Thus, we not only employed a metabolic engineering approach to the iterative polyketide pathway, we highlighted the potential of PKS shunt products to play a role in the production of single-form and high-value chemicals.
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Affiliation(s)
- Qian Liu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China; Hubei Engineering Laboratory for Synthetic Microbiology, Wuhan Institute of Biotechnology, Wuhan 430075, China
| | - Kaiyue Wu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China; J1 Biotech, Co. Ltd., Wuhan 430075, China
| | - Yongbo Cheng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China; Hubei Engineering Laboratory for Synthetic Microbiology, Wuhan Institute of Biotechnology, Wuhan 430075, China
| | - Lei Lu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China; Hubei Engineering Laboratory for Synthetic Microbiology, Wuhan Institute of Biotechnology, Wuhan 430075, China
| | - Erting Xiao
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China; Hubei Engineering Laboratory for Synthetic Microbiology, Wuhan Institute of Biotechnology, Wuhan 430075, China
| | - Yuchen Zhang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China; Hubei Engineering Laboratory for Synthetic Microbiology, Wuhan Institute of Biotechnology, Wuhan 430075, China
| | - Zixin Deng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China; Hubei Engineering Laboratory for Synthetic Microbiology, Wuhan Institute of Biotechnology, Wuhan 430075, China
| | - Tiangang Liu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, and Wuhan University School of Pharmaceutical Sciences, Wuhan 430071, China; Hubei Engineering Laboratory for Synthetic Microbiology, Wuhan Institute of Biotechnology, Wuhan 430075, China.
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