title: Reorganization of a synthetic microbial consortium for one-step vitamin C fermentation.
abstract: BACKGROUND
  In the industry, the conventional two-step fermentation method was used to produce 2-keto-L-gulonic acid (2-KGA), the precursor of vitamin C, by three strains, namely, Gluconobacter oxydans, Bacillus spp. and Ketogulonicigenium vulgare. Despite its high production efficiency, the long incubation period and an additional second sterilization process inhibit the further development. Therefore, we aimed to reorganize a synthetic consortium of G. oxydans and K. vulgare for one-step fermentation of 2-KGA and enhance the symbiotic interaction between microorganisms to perform better.
  
  
  RESULTS
  During the fermentation, competition for sorbose of G. oxydans arose when co-cultured with K. vulgare. In this study, the competition between the two microbes was alleviated and their mutualism was enhanced by deleting genes involved in sorbose metabolism of G. oxydans. In the engineered synthetic consortium (H6 + Kv), the yield of 2-KGA (mol/mol) against D-sorbitol reached 89.7 % within 36 h, increased by 29.6 %. Furthermore, metabolomic analysis was used to verify the enhancement of the symbiotic relationship and to provide us potential strategies for improving the synthetic consortium. Additionally, a significant redistribution of metabolism occurred by co-culturing the K. vulgare with the engineered G. oxydans, mainly reflected in the increased TCA cycle, purine, and fatty acid metabolism.
  
  
  CONCLUSIONS
  We reorganized and optimized a synthetic consortium of G. oxydans and K. vulgare to produce 2-KGA directly from D-sorbitol. The yield of 2-KGA was comparable to that of the conventional two-step fermentation. The metabolic interaction between the strains was further investigated by metabolomics, which verified the enhancement of the mutualism between the microbes and gave us a better understanding of the synthetic consortium.
authors.affiliation: Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China. enxuwang@tju.edu.cn.|SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, 300072, People's Republic of China. enxuwang@tju.edu.cn.
authors.forename: En-Xu
authors.initials: EX
authors.lastname: Wang
authors.affiliation: Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China. mzding@tju.edu.cn.|SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, 300072, People's Republic of China. mzding@tju.edu.cn.
authors.forename: Ming-Zhu
authors.initials: MZ
authors.lastname: Ding
authors.affiliation: Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China. qianma1987@tju.edu.cn.|SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, 300072, People's Republic of China. qianma1987@tju.edu.cn.
authors.forename: Qian
authors.initials: Q
authors.lastname: Ma
authors.affiliation: Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China. dongxiutao@126.com.|SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, 300072, People's Republic of China. dongxiutao@126.com.
authors.forename: Xiu-Tao
authors.initials: XT
authors.lastname: Dong
authors.affiliation: Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, People's Republic of China. yjyuan@MIT.EDU.|SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, 300072, People's Republic of China. yjyuan@MIT.EDU.
authors.forename: Ying-Jin
authors.initials: YJ
authors.lastname: Yuan
mesh_terms: D001205:Ascorbic Acid / Q000378:metabolism*; D005285:Fermentation / Q000502:physiology; D059013:Microbial Consortia / Q000502:physiology
chemical_list: D001205:Ascorbic Acid
references.citation: Proc Natl Acad Sci U S A. 2013 Sep 3;110(36):14592-7
references.pmid: 23959872
references.citation: Science. 2009 Jan 9;323(5911):272-5
references.pmid: 19131632
references.citation: OMICS. 2012 Jul-Aug;16(7-8):387-96
references.pmid: 22734896
references.citation: Nat Biotechnol. 2015 Apr;33(4):377-83
references.pmid: 25558867
references.citation: Science. 2015 Aug 28;349(6251):924-5
references.pmid: 26315419
references.citation: Nat Protoc. 2011 Jun;6(6):743-60
references.pmid: 21637195
references.citation: Nat Rev Microbiol. 2012 Aug;10(8):538-50
references.pmid: 22796884
references.citation: Proc Natl Acad Sci U S A. 2012 Nov 20;109(47):19079-86
references.pmid: 23091010
references.citation: Nat Chem Biol. 2012 Jan;8(1):26-35
references.pmid: 22173357
references.citation: J Biotechnol. 2011 Dec 10;156(3):182-7
references.pmid: 21924300
references.citation: J Biotechnol. 2012 Jan 20;157(2):320-5
references.pmid: 22192513
references.citation: Front Microbiol. 2012 Jun 05;3:203
references.pmid: 22679443
references.citation: Appl Environ Microbiol. 2010 Nov;76(22):7514-20
references.pmid: 20889773
references.citation: Science. 2015 Aug 28;349(6251):986-9
references.pmid: 26315440
references.citation: Appl Environ Microbiol. 2003 Mar;69(3):1499-503
references.pmid: 12620835
references.citation: Proc Natl Acad Sci U S A. 2007 Feb 6;104(6):1877-82
references.pmid: 17267602
references.citation: Chem Soc Rev. 2014;43(20):6954-81
references.pmid: 25017039
references.citation: Appl Microbiol Biotechnol. 2004 Aug;65(2):163-7
references.pmid: 15293031
references.citation: PLoS One. 2011;6(10):e26108
references.pmid: 22016820
references.citation: Bioresour Technol. 2011 Feb;102(3):2623-8
references.pmid: 21036604
references.citation: J Bacteriol. 2007 Jul;189(13):4800-8
references.pmid: 17468249
references.citation: Nat Chem Biol. 2012 Jun;8(6):527-35
references.pmid: 22596204
references.citation: PLoS One. 2008;3(7):e2623
references.pmid: 18612424
references.citation: PLoS One. 2014;9(4):e94889
references.pmid: 24728527
references.citation: Genome Announc. 2013 Jan;1(1):null
references.pmid: 23472221
references.citation: Appl Microbiol Biotechnol. 2010 Mar;86(2):469-80
references.pmid: 19902207