title: Utilization of D-Lactate as an Energy Source Supports the Growth of Gluconobacter oxydans.
abstract: d-Lactate was identified as one of the few available organic acids that supported the growth of Gluconobacter oxydans 621H in this study. Interestingly, the strain used d-lactate as an energy source but not as a carbon source, unlike other lactate-utilizing bacteria. The enzymatic basis for the growth of G. oxydans 621H on d-lactate was therefore investigated. Although two putative NAD-independent d-lactate dehydrogenases, GOX1253 and GOX2071, were capable of oxidizing d-lactate, GOX1253 was the only enzyme able to support the d-lactate-driven growth of the strain. GOX1253 was characterized as a membrane-bound dehydrogenase with high activity toward d-lactate, while GOX2071 was characterized as a soluble oxidase with broad substrate specificity toward d-2-hydroxy acids. The latter used molecular oxygen as a direct electron acceptor, a feature that has not been reported previously in d-lactate-oxidizing enzymes. This study not only clarifies the mechanism for the growth of G. oxydans on d-lactate, but also provides new insights for applications of the important industrial microbe and the novel d-lactate oxidase.
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China.
authors: Binbin
authors: B
authors: Sheng
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China.
authors: Jing
authors: J
authors: Xu
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China.
authors: Yingxin
authors: Y
authors: Zhang
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China.
authors: Tianyi
authors: T
authors: Jiang
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China.
authors: Sisi
authors: S
authors: Deng
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China.
authors: Jian
authors: J
authors: Kong
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China jieerbu@sdu.edu.cn.
authors: Chao
authors: C
authors: Gao
authors: State Key Laboratory of Microbial Technology, Shandong University, Jinan, People's Republic of China.
authors: Cuiqing
authors: C
authors: Ma
authors: State Key Laboratory of Microbial Metabolism and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
authors: Ping
authors: P
authors: Xu
mesh_terms: D055162:Biocatalysis; D004734:Energy Metabolism; D017353:Gene Deletion; D005816:Genetic Complementation Test; D020600:Gluconobacter oxydans / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D007700:Kinetics; D045022:Lactate Dehydrogenases / Q000145:classification / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D019344:Lactic Acid / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D013379:Substrate Specificity
chemical_list: D019344:Lactic Acid; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D045022:Lactate Dehydrogenases; C021497:lactate 2-monooxygenase; D010100:Oxygen