Effects of Cultivation Conditions on the Production of γ-PGA with Bacillus subtilis ZJU-7

• DOI: 10.1007/s12010-008-8307-z
• Publication Date: 2008-07-30T13:51:19Z
• Authors: Jie Chen; Feng Shi; Bin Zhang; Fan Zhu; Weifeng Cao; Zhinan Xu; Guohua Xu; Peilin Cen
• Keywords: Bacillaceae

Poly-gamma-glutamic acid (gamma-PGA) is a kind of water-soluble and biodegradable polymer made from D- and L-glutamic acid units, which are linked by amide bonds formed between alpha-amino and gamma-carboxylic acid groups. As a potential targeted biopolymer that can be refined from biomass directly, gamma-PGA has been increasingly applied to food, cosmetic, and pharmaceutical industries. In this work, a suitable nitrogen source was screened out for the high and cost-effective production of gamma-PGA in Bacillus subtilis ZJU-7. The effects of inoculation time and initial glucose concentration on the gamma-PGA production were investigated systematically in both shake flasks and a bench-top 15-l fermentor. Under the optimized culture conditions, a high gamma-PGA productivity (46.4 g/l) was obtained after 48 h cultivation at 37 degrees C. Finally, the large-scale fermentation of gamma-PGA production was successfully scaled up to a 100-l fermentor, with the highest gamma-PGA productivity for over 54.0 g/l.