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Chau THT, Nguyen AD, Lee EY. Boosting the acetol production in methanotrophic biocatalyst Methylomonas sp. DH-1 by the coupling activity of heteroexpressed novel protein PmoD with endogenous particulate methane monooxygenase. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:7. [PMID: 35418298 PMCID: PMC8764830 DOI: 10.1186/s13068-022-02105-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 01/04/2022] [Indexed: 11/10/2022]
Abstract
BACKGROUND Methylacidiphilum sp. IT6 has been validated its C3 substrate assimilation pathway via acetol as a key intermediate using the PmoCAB3, a homolog of the particulate methane monooxygenase (pMMO). From the transcriptomic data, the contribution of PmoD of strain IT6 in acetone oxidation was questioned. Methylomonas sp. DH-1, a type I methanotroph containing pmo operon without the existence of its pmoD, has been deployed as a biocatalyst for the gas-to-liquid bioconversion of methane and propane to methanol and acetone. Thus, Methylomonas sp. DH-1 is a suitable host for investigation. The PmoD-expressed Methylomonas sp. DH-1 can also be deployed for acetol production, a well-known intermediate for various industrial applications. Microbial production of acetol is a sustainable approach attracted attention so far. RESULTS In this study, bioinformatics analyses elucidated that novel protein PmoD is a C-terminal transmembrane-helix membrane with the proposed function as a transport protein. Furthermore, the whole-cell biocatalyst was constructed in Methylomonas sp. DH-1 by co-expression the PmoD of Methylacidiphilum sp. IT6 with the endogenous pMMO to enable acetone oxidation. Under optimal conditions, the maximum accumulation, and specific productivity of acetol were 18.291 mM (1.35 g/L) and 0.317 mmol/g cell/h, respectively. The results showed the first coupling activity of pMMO with a heterologous protein PmoD, validated the involvement of PmoD in acetone oxidation, and demonstrated an unprecedented production of acetol from acetone in type I methanotrophic biocatalyst. From the data achieved in batch cultivation conditions, an assimilation pathway of acetone via acetol as the key intermediate was also proposed. CONCLUSION Using bioinformatics tools, the protein PmoD has been elucidated as the membrane protein with the proposed function as a transport protein. Furthermore, results from the assays of PmoD-heteroexpressed Methylomonas sp. DH-1 as a whole-cell biocatalyst validated the coupling activity of PmoD with pMMO to convert acetone to acetol, which also unlocks the potential of this recombinant biocatalyst for acetol production. The proposed acetone-assimilated pathway in the recombinant Methylomonas sp. DH-1, once validated, can extend the metabolic flexibility of Methylomonas sp. DH-1.
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Affiliation(s)
- Tin Hoang Trung Chau
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, 17104, Yongin-si, Gyeonggi-do, South Korea
| | - Anh Duc Nguyen
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, 17104, Yongin-si, Gyeonggi-do, South Korea
| | - Eun Yeol Lee
- Department of Chemical Engineering (BK21 FOUR Integrated Engineering Program), Kyung Hee University, 17104, Yongin-si, Gyeonggi-do, South Korea.
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Systems Metabolic Engineering of Methanotrophic Bacteria for Biological Conversion of Methane to Value-Added Compounds. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2022; 180:91-126. [DOI: 10.1007/10_2021_184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Lee HM, Ren J, Yu MS, Kim H, Kim WY, Shen J, Yoo SM, Eyun SI, Na D. Construction of a tunable promoter library to optimize gene expression in Methylomonas sp. DH-1, a methanotroph, and its application to cadaverine production. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:228. [PMID: 34863247 PMCID: PMC8645107 DOI: 10.1186/s13068-021-02077-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 11/16/2021] [Indexed: 05/11/2023]
Abstract
BACKGROUND As methane is 84 times more potent than carbon dioxide in exacerbating the greenhouse effect, there is an increasing interest in the utilization of methanotrophic bacteria that can convert harmful methane into various value-added compounds. A recently isolated methanotroph, Methylomonas sp. DH-1, is a promising biofactory platform because of its relatively fast growth. However, the lack of genetic engineering tools hampers its wide use in the bioindustry. RESULTS Through three different approaches, we constructed a tunable promoter library comprising 33 promoters that can be used for the metabolic engineering of Methylomonas sp. DH-1. The library had an expression level of 0.24-410% when compared with the strength of the lac promoter. For practical application of the promoter library, we fine-tuned the expressions of cadA and cadB genes, required for cadaverine synthesis and export, respectively. The strain with PrpmB-cadA and PDnaA-cadB produced the highest cadaverine titre (18.12 ± 1.06 mg/L) in Methylomonas sp. DH-1, which was up to 2.8-fold higher than that obtained from a non-optimized strain. In addition, cell growth and lysine (a precursor of cadaverine) production assays suggested that gene expression optimization through transcription tuning can afford a balance between the growth and precursor supply. CONCLUSIONS The tunable promoter library provides standard and tunable components for gene expression, thereby facilitating the use of methanotrophs, specifically Methylomonas sp. DH-1, as a sustainable cell factory.
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Affiliation(s)
- Hyang-Mi Lee
- Department of Biomedical Engineering, Chung-Ang University, 84 Heukseok-ro Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Jun Ren
- Department of Biomedical Engineering, Chung-Ang University, 84 Heukseok-ro Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Myeong-Sang Yu
- Department of Biomedical Engineering, Chung-Ang University, 84 Heukseok-ro Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Hyunjoo Kim
- Department of Biomedical Engineering, Chung-Ang University, 84 Heukseok-ro Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Woo Young Kim
- Department of Biomedical Engineering, Chung-Ang University, 84 Heukseok-ro Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Junhao Shen
- Department of Biomedical Engineering, Chung-Ang University, 84 Heukseok-ro Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Seung Min Yoo
- Department of Biomedical Engineering, Chung-Ang University, 84 Heukseok-ro Dongjak-gu, Seoul, 06974, Republic of Korea
| | - Seong-Il Eyun
- Department of Life Science, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Dokyun Na
- Department of Biomedical Engineering, Chung-Ang University, 84 Heukseok-ro Dongjak-gu, Seoul, 06974, Republic of Korea.
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Genome-scale revealing the central metabolic network of the fast growing methanotroph Methylomonas sp. ZR1. World J Microbiol Biotechnol 2021; 37:29. [PMID: 33452942 DOI: 10.1007/s11274-021-02995-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 01/05/2021] [Indexed: 10/22/2022]
Abstract
Methylomonas sp. ZR1 was an isolated new methanotrophs that could utilize methane and methanol growing fast and synthesizing value added compounds such as lycopene. In this study, the genomic study integrated with the comparative transcriptome analysis were taken to understanding the metabolic characteristic of ZR1 grown on methane and methanol at normal and high temperature regime. Complete Embden-Meyerhof-Parnas pathway (EMP), Entner-Doudoroff pathway (ED), Pentose Phosphate Pathway (PP) and Tricarboxy Acid Cycle (TCA) were found to be operated in ZR1. In addition, the energy saving ppi-dependent EMP enzyme, coupled with the complete and efficient central carbon metabolic network might be responsible for its fast growing nature. Transcript level analysis of the central carbon metabolism indicated that formaldehyde metabolism was a key nod that may be in charge of the carbon conversion efficiency (CCE) divergent of ZR1 grown on methanol and methane. Flexible nitrogen and carotene metabolism pattern were also investigated in ZR1. Nitrogenase genes in ZR1 were found to be highly expressed with methane even in the presence of sufficient nitrate. It appears that, higher lycopene production in ZR1 grown on methane might be attributed to the higher proportion of transcript level of C40 to C30 metabolic gene. Higher transcript level of exopolysaccharides metabolic gene and stress responding proteins indicated that ZR1 was confronted with severer growth stress with methanol than with methane. Additionally, lower transcript level of the TCA cycle, the dramatic high expression level of the nitric oxide reductase and stress responding protein, revealed the imbalance of the central carbon and nitrogen metabolic status, which would result in the worse growth of ZR1 with methanol at 30 °C.
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Ren J, Lee HM, Thai TD, Na D. Identification of a cytosine methyltransferase that improves transformation efficiency in Methylomonas sp. DH-1. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:200. [PMID: 33372613 PMCID: PMC7720504 DOI: 10.1186/s13068-020-01846-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 11/30/2020] [Indexed: 05/10/2023]
Abstract
BACKGROUND Industrial biofuels and other value-added products can be produced from metabolically engineered microorganisms. Methylomonas sp. DH-1 is a candidate platform for bioconversion that uses methane as a carbon source. Although several genetic engineering techniques have been developed to work with Methylomonas sp. DH-1, the genetic manipulation of plasmids remains difficult because of the restriction-modification (RM) system present in the bacteria. Therefore, the RM system in Methylomonas sp. DH-1 must be identified to improve the genetic engineering prospects of this microorganism. RESULTS We identified a DNA methylation site, TGGCCA, and its corresponding cytosine methyltransferase for the first time in Methylomonas sp. DH-1 through whole-genome bisulfite sequencing. The methyltransferase was confirmed to methylate the fourth nucleotide of TGGCCA. In general, methylated plasmids exhibited better transformation efficiency under the protection of the RM system than non-methylated plasmids did. As expected, when we transformed Methylomonas sp. DH-1 with plasmid DNA harboring the psy gene, the metabolic flux towards carotenoid increased. The methyltransferase-treated plasmid exhibited an increase in transformation efficiency of 2.5 × 103 CFU/μg (124%). The introduced gene increased the production of carotenoid by 26%. In addition, the methyltransferase-treated plasmid harboring anti-psy sRNA gene exhibited an increase in transformation efficiency by 70% as well. The production of carotenoid was decreased by 40% when the psy gene was translationally repressed by anti-psy sRNA. CONCLUSIONS Plasmid DNA methylated by the discovered cytosine methyltransferase from Methylomonas sp. DH-1 had a higher transformation efficiency than non-treated plasmid DNA. The RM system identified in this study may facilitate the plasmid-based genetic manipulation of methanotrophs.
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Affiliation(s)
- Jun Ren
- Department of Biomedical Engineering, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Hyang-Mi Lee
- Department of Biomedical Engineering, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Thi Duc Thai
- Department of Biomedical Engineering, Chung-Ang University, Seoul, 06974, Republic of Korea
| | - Dokyun Na
- Department of Biomedical Engineering, Chung-Ang University, Seoul, 06974, Republic of Korea.
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Hydrogen Production from Methane by Methylomonas sp. DH-1 under Micro-aerobic Conditions. BIOTECHNOL BIOPROC E 2020. [DOI: 10.1007/s12257-019-0256-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Bioproduction of Isoprenoids and Other Secondary Metabolites Using Methanotrophic Bacteria as an Alternative Microbial Cell Factory Option: Current Stage and Future Aspects. Catalysts 2019. [DOI: 10.3390/catal9110883] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Methane is a promising carbon feedstock for industrial biomanufacturing because of its low price and high abundance. Recent advances in metabolic engineering and systems biology in methanotrophs have made it possible to produce a variety of value-added compounds from methane, including secondary metabolites. Isoprenoids are one of the largest family of secondary metabolites and have many useful industrial applications. In this review, we highlight the current efforts invested to methanotrophs for the production of isoprenoids and other secondary metabolites, including riboflavin and ectoine. The future outlook for improving secondary metabolites production (especially of isoprenoids) using metabolic engineering of methanotrophs is also discussed.
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Nguyen AD, Park JY, Hwang IY, Hamilton R, Kalyuzhnaya MG, Kim D, Lee EY. Genome-scale evaluation of core one-carbon metabolism in gammaproteobacterial methanotrophs grown on methane and methanol. Metab Eng 2019; 57:1-12. [PMID: 31626985 DOI: 10.1016/j.ymben.2019.10.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 09/18/2019] [Accepted: 10/14/2019] [Indexed: 11/29/2022]
Abstract
Methylotuvimicrobium alcaliphilum 20Z is a promising platform strain for bioconversion of one-carbon (C1) substrates into value-added products. To carry out robust metabolic engineering with methylotrophic bacteria and to implement C1 conversion machinery in non-native hosts, systems-level evaluation and understanding of central C1 metabolism in methanotrophs under various conditions is pivotal but yet elusive. In this study, a genome-scale integrated approach was used to provide in-depth knowledge on the metabolic pathways of M. alcaliphilum 20Z grown on methane and methanol. Systems assessment of core carbon metabolism indicated the methanol assimilation pathway is mostly coupled with the efficient Embden-Meyerhof-Parnas (EMP) pathway along with the serine cycle. In addition, an incomplete TCA cycle operated in M. alcaliphilum 20Z on methanol, which might only supply precursors for de novo synthesis but not reducing powers. Instead, it appears that the direct formaldehyde oxidation pathway supply energy for the whole metabolic system. Additionally, a comparative transcriptomic analysis in multiple gammaproteobacterial methanotrophs also revealed the transcriptional responses of central metabolism on carbon substrate change. These findings provided a systems-level understanding of carbon metabolism and new opportunities for strain design to produce relevant products from different C1-feedstocks.
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Affiliation(s)
- Anh Duc Nguyen
- Department of Chemical Engineering, Kyung Hee University, Yongin-si, Gyeonggi-do, 17104, South Korea
| | - Joon Young Park
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea
| | - In Yeub Hwang
- Department of Chemical Engineering, Kyung Hee University, Yongin-si, Gyeonggi-do, 17104, South Korea
| | - Richard Hamilton
- Biology Department, San Diego State University, San Diego, CA, 92182-4614, United States
| | - Marina G Kalyuzhnaya
- Biology Department, San Diego State University, San Diego, CA, 92182-4614, United States
| | - Donghyuk Kim
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea.
| | - Eun Yeol Lee
- Department of Chemical Engineering, Kyung Hee University, Yongin-si, Gyeonggi-do, 17104, South Korea.
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Kabimoldayev I, Nguyen AD, Yang L, Park S, Lee EY, Kim D. Basics of genome-scale metabolic modeling and applications on C1-utilization. FEMS Microbiol Lett 2019; 365:5106816. [PMID: 30256945 DOI: 10.1093/femsle/fny241] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 09/23/2018] [Indexed: 12/11/2022] Open
Abstract
It is fundamental to understand the relationship between genotype and phenotype in biology. This requires comprehensive knowledge of metabolic pathways, genetic information and well-defined mathematic modeling. Integration of knowledge on metabolism with mathematical modeling results in genome-scale metabolic models which have proven useful to investigate bacterial metabolism and to engineer bacterial strains capable of producing value-added biochemical. Single carbon substrates such as methane and carbon monoxide have drawn interests and they assumed one of next-generation feedstocks because of their high abundance and low price. The methylotroph and acetogen-based biorefineries hold promises for bioconversion of C1 substrates into biofuels and high value compounds. As an effort on expanding our knowledge on C1 utilization approaches, in silico computational framework of C1-metabolism in methylotrophic and acetogenic bacteria has been developed. In this review, genome-scale metabolic models for C1-utilizing bacteria and well-established analysis tools are presented for potential uses for study of C1 metabolism at the genome scale and its application in metabolic engineering.
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Affiliation(s)
- Ilyas Kabimoldayev
- Department of Genetic Engineering and Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin 17104, South Korea
| | - Anh Duc Nguyen
- Department of Chemical Engineering, Kyung Hee University, Yongin 17104, South Korea
| | - Laurence Yang
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA.,The Novo Nordisk Foundation Center for Biosustainabiliy, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Sunghoon Park
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
| | - Eun Yeol Lee
- Department of Chemical Engineering, Kyung Hee University, Yongin 17104, South Korea
| | - Donghyuk Kim
- Department of Genetic Engineering and Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin 17104, South Korea.,School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea.,School of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of Korea
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Metabolic engineering of the type I methanotroph Methylomonas sp. DH-1 for production of succinate from methane. Metab Eng 2019; 54:170-179. [DOI: 10.1016/j.ymben.2019.03.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Revised: 03/21/2019] [Accepted: 03/31/2019] [Indexed: 12/20/2022]
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Nguyen AD, Kim D, Lee EY. A comparative transcriptome analysis of the novel obligate methanotroph Methylomonas sp. DH-1 reveals key differences in transcriptional responses in C1 and secondary metabolite pathways during growth on methane and methanol. BMC Genomics 2019; 20:130. [PMID: 30755173 PMCID: PMC6373157 DOI: 10.1186/s12864-019-5487-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 01/28/2019] [Indexed: 12/21/2022] Open
Abstract
Background Methanotrophs play an important role in biotechnological applications, with their ability to utilize single carbon (C1) feedstock such as methane and methanol to produce a range of high-value compounds. A newly isolated obligate methanotroph strain, Methylomonas sp. DH-1, became a platform strain for biotechnological applications because it has proven capable of producing chemicals, fuels, and secondary metabolites from methane and methanol. In this study, transcriptome analysis with RNA-seq was used to investigate the transcriptional change of Methylomonas sp. DH-1 on methane and methanol. This was done to improve knowledge about C1 assimilation and secondary metabolite pathways in this promising, but under-characterized, methane-bioconversion strain. Results We integrated genomic and transcriptomic analysis of the newly isolated Methylomonas sp. DH-1 grown on methane and methanol. Detailed transcriptomic analysis indicated that (i) Methylomonas sp. DH-1 possesses the ribulose monophosphate (RuMP) cycle and the Embden–Meyerhof–Parnas (EMP) pathway, which can serve as main pathways for C1 assimilation, (ii) the existence and the expression of a complete serine cycle and a complete tricarboxylic acid (TCA) cycle might contribute to methane conversion and energy production, and (iii) the highly active endogenous plasmid pDH1 may code for essential metabolic processes. Comparative transcriptomic analysis on methane and methanol as a sole carbon source revealed different transcriptional responses of Methylomonas sp. DH-1, especially in C1 assimilation, secondary metabolite pathways, and oxidative stress. Especially, these results suggest a shift of central metabolism when substrate changed from methane to methanol in which formaldehyde oxidation pathway and serine cycle carried more flux to produce acetyl-coA and NADH. Meanwhile, downregulation of TCA cycle when grown on methanol may suggest a shift of its main function is to provide de novo biosynthesis, but not produce NADH. Conclusions This study provides insights into the transcriptomic profile of Methylomonas sp. DH-1 grown on major carbon sources for C1 assimilation, providing in-depth knowledge on the metabolic pathways of this strain. These observations and analyses can contribute to future metabolic engineering with the newly isolated, yet under-characterized, Methylomonas sp. DH-1 to enhance its biochemical application in relevant industries. Electronic supplementary material The online version of this article (10.1186/s12864-019-5487-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anh Duc Nguyen
- Department of Chemical Engineering, Kyung Hee University, Yongin, 17104, Republic of Korea
| | - Donghyuk Kim
- School of Energy and Chemical Engineering & School of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
| | - Eun Yeol Lee
- Department of Chemical Engineering, Kyung Hee University, Yongin, 17104, Republic of Korea.
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Lee JK, Kim S, Kim W, Kim S, Cha S, Moon H, Hur DH, Kim SY, Na JG, Lee JW, Lee EY, Hahn JS. Efficient production of d-lactate from methane in a lactate-tolerant strain of Methylomonas sp. DH-1 generated by adaptive laboratory evolution. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:234. [PMID: 31583020 PMCID: PMC6767647 DOI: 10.1186/s13068-019-1574-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/22/2019] [Indexed: 05/17/2023]
Abstract
BACKGROUND Methane, a main component of natural gas and biogas, has gained much attention as an abundant and low-cost carbon source. Methanotrophs, which can use methane as a sole carbon and energy source, are promising hosts to produce value-added chemicals from methane, but their metabolic engineering is still challenging. In previous attempts to produce lactic acid (LA) from methane, LA production levels were limited in part due to LA toxicity. We solved this problem by generating an LA-tolerant strain, which also contributes to understanding novel LA tolerance mechanisms. RESULTS In this study, we engineered a methanotroph strain Methylomonas sp. DH-1 to produce d-lactic acid (d-LA) from methane. LA toxicity is one of the limiting factors for high-level production of LA. Therefore, we first performed adaptive laboratory evolution of Methylomonas sp. DH-1, generating an LA-tolerant strain JHM80. Genome sequencing of JHM80 revealed the causal gene watR, encoding a LysR-type transcription factor, whose overexpression due to a 2-bp (TT) deletion in the promoter region is partly responsible for the LA tolerance of JHM80. Overexpression of the watR gene in wild-type strain also led to an increase in LA tolerance. When d form-specific lactate dehydrogenase gene from Leuconostoc mesenteroides subsp. mesenteroides ATCC 8293 was introduced into the genome while deleting the glgA gene encoding glycogen synthase, JHM80 produced about 7.5-fold higher level of d-LA from methane than wild type, suggesting that LA tolerance is a critical limiting factor for LA production in this host. d-LA production was further enhanced by optimization of the medium, resulting in a titer of 1.19 g/L and a yield of 0.245 g/g CH4. CONCLUSIONS JHM80, an LA-tolerant strain of Methylomonas sp. DH-1, generated by adaptive laboratory evolution was effective in LA production from methane. Characterization of the mutated genes in JHM80 revealed that overexpression of the watR gene, encoding a LysR-type transcription factor, is responsible for LA tolerance. By introducing a heterologous lactate dehydrogenase gene into the genome of JHM80 strain while deleting the glgA gene, high d-LA production titer and yield were achieved from methane.
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Affiliation(s)
- Jong Kwan Lee
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826 Republic of Korea
| | - Sujin Kim
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826 Republic of Korea
| | - Wonsik Kim
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826 Republic of Korea
| | - Sungil Kim
- Department of Chemical and Biomolecular Engineering, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul, 04107 Republic of Korea
| | - Seungwoo Cha
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826 Republic of Korea
| | - Hankyeol Moon
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826 Republic of Korea
| | - Dong Hoon Hur
- Department of Chemical Engineering, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin, 17104 Republic of Korea
| | - Seon-Young Kim
- Personalized Genomic Medicine Research Center, KRIBB, 125 Gwahag-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Jeong-Geol Na
- Department of Chemical and Biomolecular Engineering, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul, 04107 Republic of Korea
| | - Jin Won Lee
- Department of Chemical and Biomolecular Engineering, Sogang University, 35 Baekbeom-ro, Mapo-gu, Seoul, 04107 Republic of Korea
| | - Eun Yeol Lee
- Department of Chemical Engineering, Kyung Hee University, 1732 Deogyeong-daero, Giheung-gu, Yongin, 17104 Republic of Korea
| | - Ji-Sook Hahn
- School of Chemical and Biological Engineering, Institute of Chemical Processes, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul, 08826 Republic of Korea
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Bodelier PLE, Pérez G, Veraart AJ, Krause SMB. Methanotroph Ecology, Environmental Distribution and Functioning. METHANOTROPHS 2019. [DOI: 10.1007/978-3-030-23261-0_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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