title: Improvement of poly-γ-glutamic acid biosynthesis in a moving bed biofilm reactor by Bacillus subtilis NX-2.
abstract: The production of poly-γ-glutamic acid (γ-PGA) by Bacillus subtilis NX-2 using a moving bed biofilm reactor (MBBR) system was tested for the first time in this study. Polypropylene TL-2 was chosen as a suitable carrier, and γ-PGA concentration of 42.7±0.86g/L and productivity of 0.59±0.06g/(Lh) were obtained in batch fermentation. After application of the strategy of dissolved oxygen (DO)-stat feeding, higher γ-PGA concentration and productivity were achieved than with glucose feedback feeding. Finally, the repeated fed-batch cultures implemented in the MBBR system showed high stability, and the maximal γ-PGA concentration and productivity of 74.2g/L and 1.24g/(Lh) were achieved, respectively. In addition, the promotion of oxygen transfer by an MBBR carrier was well explained by a computational fluid dynamics (CFD) simulation. These results suggest that an MBBR system could be applied to large-scale γ-PGA production.
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, China; College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China.
authors.forename: Yongxiang
authors.initials: Y
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, China; College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China.
authors.forename: Bao
authors.initials: B
authors.lastname: Tang
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, China; College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China.
authors.forename: Zongqi
authors.initials: Z
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, China; College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, China; College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China.
authors.forename: Zheng
authors.initials: Z
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, China; College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China. Electronic address: fengxiaohai@njtech.edu.cn.
authors.forename: Xiaohai
authors.initials: X
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing 211816, China; College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Xu
mesh_terms: D001412:Bacillus subtilis / Q000378:metabolism*; D061249:Batch Cell Culture Techniques; D018441:Biofilms; D019149:Bioreactors / Q000382:microbiology*; D005285:Fermentation; D005947:Glucose; D018698:Glutamic Acid / Q000378:metabolism; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000096:biosynthesis
chemical_list: C511775:poly(gamma-glutamic acid); D011099:Polyglutamic Acid; D018698:Glutamic Acid; D005947:Glucose
keywords: Bacillus subtilis NX-2; CFD simulation; DO-stat; Moving bed biofilm reactor; Poly(γ-glutamic acid)