title: Combinational expression of sorbose/sorbosone dehydrogenases and cofactor pyrroloquinoline quinone increases 2-keto-L-gulonic acid production in Ketogulonigenium vulgare-Bacillus cereus consortium.
abstract: The expression levels of sorbose/sorbosone dehydrogenase genes (sdh and sndh) and the synthesis genes (pqqABCDEN) of the adjoint cofactor pyrroloquinoline quinone (PQQ) were genetically manipulated in Ketogulonigenium vulgare to increase the production of 2-keto-l-gulonic acid (2-KLG), the precursor of vitamin C, in the consortium of K. vulgare and Bacillus cereus. We found that overexpression of sdh-sndh alone in K. vulgare could not significantly enhance the production of 2-KLG, revealing the cofactor PQQ was required for the biosynthesis of 2-KLG. Various expression levels of PQQ were achieved by differential expression of pqqA, pqqABCDE and pqqABCDEN, respectively. The combinatorial expression of sdh/sndh and pqqABCDEN in K. vulgare enabled a 20% increase in the production of 2-KLG (79.1±0.6gl(-1)) than that of the parental K. vulgare (65.9±0.4gl(-1)) in shaking flasks. Our results demonstrated the balanced co-expression of both the key enzymes and the related cofactors was an efficient strategy to increase chemicals' biosynthesis.
authors.affiliation: Key Laboratory of Systems Bioengineering, Ministry of Education and Department of Pharmaceutical Engineering, School of Chemical Engineering and Technology, Tianjin University, P.O. Box 6888, Tianjin 300072, PR China.
authors.forename: Jin
authors.initials: J
authors.lastname: Du
authors.forename: Wei
authors.initials: W
authors.lastname: Bai
authors.forename: Hao
authors.initials: H
authors.lastname: Song
authors.forename: Ying-Jin
authors.initials: YJ
authors.lastname: Yuan
mesh_terms: D001205:Ascorbic Acid / Q000096:biosynthesis / Q000235:genetics; D001409:Bacillus cereus / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D002237:Carbohydrate Dehydrogenases / Q000096:biosynthesis* / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D060847:Metabolic Engineering; D045542:PQQ Cofactor / Q000235:genetics / Q000378:metabolism*; D013013:Sorbose / Q000031:analogs & derivatives / Q000235:genetics / Q000378:metabolism; D013400:Sugar Acids / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D013400:Sugar Acids; C013686:sorbosone; D045542:PQQ Cofactor; D002237:Carbohydrate Dehydrogenases; C104557:sorbose dehydrogenase; C011491:provitamin C; D013013:Sorbose; D001205:Ascorbic Acid
keywords: 2-Keto-l-gulonic acid; Cofactor engineering; Consortium; Pyrroloquinoline quinine