title: [Enhancement of 2-keto-L-gulonic acid production using three-stage pH control strategy].
abstract: The aim of this study was to improve the 2-keto-L-gulonic acid (2-KLG) production efficiency by Ketogulonicigenium vulgare and Bacillus megaterium by using multi-stage pH control strategy. The effect of pH on the cell growths and 2-KLG production showed that the optimum pH for K. vulgare and B. megaterium cell growth were 6.0 and 8.0, respectively, while the optimum pH for 2-KLG production was 7.0. Based on the above results, we developed a three-stage pH control strategy: the pH was kept at 8.0 during the first 8 h, then decreased to 6.0 for the following 12 h, and maintained at 7.0 to the end of fermentation. With this strategy, the titer, productivity of 2-KLG and L-sorbose consumption rate were achieved at 77.3 g/L, 1.38 g/(L x h) and 1.42 g/(L x h), respectively, which were 9.7%, 33.2% and 25.7% higher than the corresponding values of the single pH (pH 7.0) control model.
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Jingwen
authors.initials: J
authors.lastname: Zhou
authors.forename: Liming
authors.initials: L
authors.lastname: Liu
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Kejie
authors.initials: K
authors.lastname: Chen
authors.forename: Guocheng
authors.initials: G
authors.lastname: Du
authors.forename: Jian
authors.initials: J
authors.lastname: Chen
mesh_terms: D001410:Bacillus megaterium / Q000254:growth & development / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D041902:Rhodobacteraceae / Q000254:growth & development / Q000378:metabolism*; D013013:Sorbose / Q000378:metabolism*; D013400:Sugar Acids / Q000378:metabolism*
chemical_list: D003470:Culture Media; D013400:Sugar Acids; C011491:provitamin C; D013013:Sorbose