title: Metabolic engineering of Candida glabrata for diacetyl production.
abstract: In this study, Candida glabrata, an efficient pyruvate-producing strain, was metabolically engineered for the production of the food ingredient diacetyl. A diacetyl biosynthetic pathway was reconstructed based on genetic modifications and medium optimization. The former included (i) channeling carbon flux into the diacetyl biosynthetic pathway by amplification of acetolactate synthase, (ii) elimination of the branched pathway of α-acetolactate by deleting the ILV5 gene, and (iii) restriction of diacetyl degradation by deleting the BDH gene. The resultant strain showed an almost 1∶1 co-production of α-acetolactate and diacetyl (0.95 g L(-1)). Furthermore, addition of Fe3+ to the medium enhanced the conversion of α-acetolactate to diacetyl and resulted in a two-fold increase in diacetyl production (2.1 g L(-1)). In addition, increased carbon flux was further channeled into diacetyl biosynthetic pathway and a titer of 4.7 g L(-1) of diacetyl was achieved by altering the vitamin level in the flask culture. Thus, this study illustrates that C. glabrata could be tailored as an attractive platform for enhanced biosynthesis of beneficial products from pyruvate by metabolic engineering strategies.
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China; Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, Jiangsu, China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China; Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, Jiangsu, China.
authors.forename: Nan
authors.initials: N
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China; Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, Jiangsu, China.
authors.forename: Shubo
authors.initials: S
authors.lastname: Li
authors.affiliation: State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China; Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, China; Laboratory of Food Microbial-Manufacturing Engineering, Jiangnan University, Wuxi, Jiangsu, China.
authors.forename: Liming
authors.initials: L
authors.lastname: Liu
mesh_terms: D000094:Acetoin Dehydrogenase / Q000378:metabolism; D000095:Acetolactate Synthase / Q000378:metabolism; D000429:Alcohol Oxidoreductases / Q000378:metabolism; D041221:Candida glabrata / Q000254:growth & development / Q000378:metabolism*; D057486:Carbon Cycle / Q000187:drug effects; D003470:Culture Media; D003653:Decarboxylation / Q000187:drug effects; D003931:Diacetyl / Q000378:metabolism*; D005285:Fermentation / Q000187:drug effects; D017353:Gene Deletion; D007501:Iron / Q000494:pharmacology; D007773:Lactates / Q000378:metabolism; D060847:Metabolic Engineering / Q000379:methods*; D053858:Metabolic Networks and Pathways / Q000187:drug effects; D009243:NAD / Q000378:metabolism; D009525:Niacin / Q000494:pharmacology; D019289:Pyruvic Acid / Q000378:metabolism; D013831:Thiamine / Q000378:metabolism
chemical_list: D003470:Culture Media; D007773:Lactates; D009243:NAD; D009525:Niacin; C006359:alpha-acetolactate; D019289:Pyruvic Acid; D007501:Iron; D000429:Alcohol Oxidoreductases; D000094:Acetoin Dehydrogenase; C019801:butanediol dehydrogenase; D000095:Acetolactate Synthase; D003931:Diacetyl; D013831:Thiamine