Improvement of poly-γ-glutamic acid biosynthesis in a moving bed biofilm reactor by Bacillus subtilis NX-2

Yongxiang Jiang, Bao Tang, Zongqi Xu, Kun Liu, Zheng Xu, Xiaohai Feng, Hong Xu

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

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 ± 0.86 g/L and productivity of 0.59 ± 0.06 g/(L h) 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 74.2 g/L and 1.24 g/(L h) 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.

Original languageEnglish
Pages (from-to)360-366
Number of pages7
JournalBioresource Technology
Volume218
DOIs
StatePublished - 1 Oct 2016

Keywords

  • Bacillus subtilis NX-2
  • CFD simulation
  • DO-stat
  • Moving bed biofilm reactor
  • Poly(γ-glutamic acid)

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