title: Enhanced welan gum production using a two-stage agitation speed control strategy in Alcaligenes sp. CGMCC2428.
abstract: Batch fermentative production of welan gum by Alcaligenes sp. CGMCC2428 was investigated under various oxygen supply conditions using regulating agitation speed. Based on a three kinetic parameters analysis that includes specific cell growth rate (μ), specific glucose consumption rate (q (s)), and specific welan formation rate (q (p)), a two-stage agitation speed control strategy was proposed to achieve high concentration, high yield, and high viscosity of welan. During the first 22 h, the agitation speed in 7.5 L fermenter was controlled at 800 rpm to maintain high μ for cell growth. The agitation was then reduced step-wise to 600 rpm to maintain a changing profile with stable dissolved oxygen levels and obtain high qp for high welan accumulation. Finally, the maximum concentration of welan was reached at 26.3 ± 0.89 g L(-1) with a yield of 0.53 ± 0.003 g g(-1) and the welan gum viscosity of 3.05 ± 0.10 Pa s, which increased by an average of 15.4, 15.2, and 20.1% over the best results controlled by constant agitation speeds.
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, College of Food Science and Light Industry, Nanjing University of Technology, No. 5 Xinmofan Road, Gulou District, Nanjing 210009, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
authors.forename: Hao
authors.initials: H
authors.lastname: Xu
authors.forename: Sha
authors.initials: S
authors.lastname: Li
authors.forename: Han-Jie
authors.initials: HJ
authors.lastname: Ying
authors.forename: Ping-Kai
authors.initials: PK
authors.lastname: Ouyang
mesh_terms: D000421:Alcaligenes / Q000254:growth & development / Q000378:metabolism*; D019149:Bioreactors; D003470:Culture Media; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D007218:Industrial Microbiology / Q000379:methods*; D007700:Kinetics; D010100:Oxygen / Q000378:metabolism; D011135:Polysaccharides, Bacterial / Q000032:analysis / Q000096:biosynthesis*
chemical_list: D003470:Culture Media; D011135:Polysaccharides, Bacterial; C068570:welan; D005947:Glucose; D010100:Oxygen