High yield and cost‐effective production of poly(γ‐glutamic acid) with Bacillus subtilis |
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Authors: | Jin Huang Yinming Du Guohua Xu Huili Zhang Fan Zhu Lei Huang Zhinan Xu |
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Affiliation: | 1. Institute of Bioengineering, Department of Chemical Engineering and Bioengineering, Zhejiang University, Hangzhou, P. R. China;2. Shandong Fufeng Fermentation Co. Ltd, Shandong, P. R. China |
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Abstract: | Poly(γ‐glutamic acid) (γ‐PGA) is a promising biopolymer with many potential industrial and pharmaceutical applications. To reduce the production costs, the effects of yeast extract and L ‐glutamate in the substrate for γ‐PGA production were investigated systematically at shake flask scale. The results showed that lower concentrations of yeast extract (40 g/L) and L ‐glutamate (30 g/L) were beneficial for the cost‐effective production of γ‐PGA in the formulated medium. By maintaining the glucose concentration in the range of 3–10 g/L via a fed‐batch strategy in a 10‐L fermentor, the production of γ‐PGA was greatly improved with the highest γ‐PGA concentration of 101.1 g/L, a productivity of 2.19 g/L·h and a yield of 0.57 g/g total substrate, which is about 1.4‐ to 3.2‐fold higher than those in the batch fermentation. Finally, this high‐density fermentation process was successfully scaled up in a 100‐L fermentor. The present work provides a powerful approach to produce this biopolymer as a bulk chemical in large scale. |
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Keywords: | Bacillus subtilis Biopolymers Fed‐batch Poly(γ ‐glutamic acid) Scale‐up |
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