title: Rhamsan gum production by Sphingomonas sp. CGMCC 6833 using a two-stage agitation speed control strategy.
abstract: Varying the agitation speed could greatly affect rhamsan gum production by Sphingomonas sp. CGMCC 6833. Batch fermentations at agitation speeds of 400, 600, 800, and 1,000 rpm were therefore carried out. The time course of specific cell growth rate, specific glucose consumption rate, and specific rhamsan gum formation rate was subsequently determined. Based on the results, a novel two-stage agitation speed control strategy was developed. From 0 to 13 H, the high specific cell growth and glucose consumption rates were achieved by setting the agitation speed of the fermenter at 800 rpm. From 13 H onward to the end of fermentation, the glucose consumption rate and specific cell growth rate were high at the agitation speed of 600 rpm. Using this method, the maximum concentration and productivity of rhamsan gum reached 21.63 ± 1.76 g L(-1) and 0.338 ± 0.028 g L(-1)  H(-1) , respectively, which were both higher than the optimum results obtained at constant agitation speeds.
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Nanjing, People's Republic of China.|College of Food Science and Light Industry, Nanjing University of Technology, Nanjing, People's Republic of China.|College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing, People's Republic of China.
authors.forename: Xiao Ying
authors.initials: XY
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Nanjing, People's Republic of China.|College of Food Science and Light Industry, Nanjing University of Technology, Nanjing, People's Republic of China.
authors.forename: Ping
authors.initials: P
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Nanjing, People's Republic of China.|College of Food Science and Light Industry, Nanjing University of Technology, Nanjing, People's Republic of China.
authors.forename: Sha
authors.initials: S
authors.lastname: Li
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Nanjing, People's Republic of China.|College of Food Science and Light Industry, Nanjing University of Technology, Nanjing, People's Republic of China.
authors.forename: Xiao Ye
authors.initials: XY
authors.lastname: Chen
authors.affiliation: College of International Education, Nanjing University of Technology, Nanjing, People's Republic of China.
authors.forename: Xing Huan
authors.initials: XH
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing University of Technology, Nanjing, People's Republic of China.|College of Food Science and Light Industry, Nanjing University of Technology, Nanjing, People's Republic of China.
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
mesh_terms: D001709:Biotechnology; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis*; D020578:Sphingomonas / Q000166:cytology / Q000378:metabolism*
chemical_list: D011135:Polysaccharides, Bacterial; C071623:rhamsan; D005947:Glucose
keywords: Sphingomonas sp. CGMCC 6833; agitation speed control; batch fermentation; rhamsan gum; two-stage strategy