title: Two-stage pH control strategy based on the pH preference of acetoin reductase regulates acetoin and 2,3-butanediol distribution in Bacillus subtilis.
abstract: Acetoin reductase/2,3-butanediol dehydrogenase (AR/BDH), which catalyzes the interconversion between acetoin and 2,3-butanediol, plays an important role in distribution of the products pools. This work characterized the Bacillus subtilis AR/BDH for the first time. The enzyme showed very different pH preferences of pH 6.5 for reduction and pH 8.5 for oxidation. Based on these above results, a two-stage pH control strategy was optimized for acetoin production, in which the pH was controlled at 6.5 for quickly converting glucose to acetoin and 2,3-butanediol, and then 8.0 for reversely transforming 2,3-butanediol to acetoin. By over-expression of AR/BDH in the wild-type B. subtilis JNA 3-10 and applying fed-batch fermentation based on the two-stage pH control strategy, acetoin yield of B. subtilis was improved to a new record of 73.6 g/l, with the productivity of 0.77 g/(l · h). The molar yield of acetoin was improved from 57.5% to 83.5% and the ratio of acetoin/2,3-butanediol was switched from 2.7:1 to 18.0:1.
authors.affiliation: The Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, P. R. China.
authors.forename: Xian
authors.initials: X
authors.lastname: Zhang
authors.affiliation: The Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, P. R. China.
authors.forename: Teng
authors.initials: T
authors.lastname: Bao
authors.affiliation: The Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, P. R. China.
authors.forename: Zhiming
authors.initials: Z
authors.lastname: Rao
authors.affiliation: The Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, P. R. China.
authors.forename: Taowei
authors.initials: T
authors.lastname: Yang
authors.affiliation: School of Medicine and Pharmaceuticals, Jiangnan University, Wuxi, Jiangsu, P. R. China.
authors.forename: Zhenghong
authors.initials: Z
authors.lastname: Xu
authors.affiliation: Department of Chemical Engineering, Ohio State University, Columbus, Ohio, United States of America.
authors.forename: Shangtian
authors.initials: S
authors.lastname: Yang
authors.affiliation: The Key Laboratory of Industrial Biotechnology of Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu, P. R. China.
authors.forename: Huazhong
authors.initials: H
authors.lastname: Li
mesh_terms: D000093:Acetoin / Q000378:metabolism*; D000429:Alcohol Oxidoreductases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D001412:Bacillus subtilis / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology; D002072:Butylene Glycols / Q000378:metabolism*; D002417:Cattle; D004492:Edetic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005285:Fermentation / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D007477:Ions; D007700:Kinetics; D053858:Metabolic Networks and Pathways / Q000187:drug effects; D008670:Metals / Q000494:pharmacology; D012710:Serum Albumin, Bovine / Q000378:metabolism; D013379:Substrate Specificity / Q000187:drug effects; D013696:Temperature; D013997:Time Factors
chemical_list: D002072:Butylene Glycols; D004791:Enzyme Inhibitors; D007477:Ions; D008670:Metals; D012710:Serum Albumin, Bovine; C026978:2,3-butylene glycol; D004492:Edetic Acid; D000093:Acetoin; D000429:Alcohol Oxidoreductases; C019801:butanediol dehydrogenase