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KMID : 1094720210260040630
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Biotechnology and Bioprocess Engineering
2021 Volume.26 No. 4 p.630 ~ p.640
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Combining Genome Shuffling with Streptomycin Resistance to Improve Poly-γ-L-diaminobutanoic Acid Production in Bacillus pumilus
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Li Shu
Wang Liang
Wang Nan
Cong Wei
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Abstract
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A breeding approach combining genome shuffling with streptomycin resistance was developed in this research to improve the poly-γ-L-diaminobutanoic acid (γ-PAB) production in Bacillus pumilus LS-1. By this unique strategy, recombinants from the third round of genome shuffling could tolerate 18 μg/L of streptomycin and exhibited higher γ-PAB yield as 152.2 mg/L in shake-flask fermentation, 3-fold over the parent. In batch fermentation, B. pumilus GS3-9 could produce γ-PAB as high as 1284.7 mg/L in two days, 2.4-fold higher than the control, which was the highest productivity ever reported. In addition, the optimal pH in B. pumilus for γ-PAB synthesis was changed after atmospheric and room temperature plasma (ARTP) mutagenesis and protoplast fusion, because lower pH environment is favorable for accumulation of intracellular ATP. Some key enzymes in GS3-9 showed higher activities than those in parent, suggesting a greater flux to TCA circle and DAP pathway, which was a reason for enhanced γ-PAB production.
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KEYWORD
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poly-γ-L-diaminobutanoic acid, genome shuffling, streptomycin resistance, fermentation
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