Abstract: In order to improve the γ-PGA fermentation yield of glutamate-independent strains through metabolic engineering methods, and to maximize the potential of this type of Bacillus biosynthetic system. Aglutamate-independent strain of Bacillus amyloliquefaciens C10 preserved in the laboratory that can produce γ-PGA was used as the research object, and the upp gene was selected as the reverse selection marker to construct a traceless gene knockout of Bacillus amyloliquefaciens C10 in addition to the system, the oxdC gene in the C10 genome of Bacillus amyloliquefaciens was quickly and seamlessly knocked out, and the yield of the mutant strain γ-PGA was verified by fermentation. The results showed that the OD₆₀₀ values of C10ΔuppΔoxdC and control C10Δupp were 13.96, 15.56 after 36 h of fermentation, respectively, and the mutant strain's growth ability decreased;the yield of γ-PGA was 12.33, 22.22 g/L, and the yield of fermentation product γ-PGA was also lower. The initial strains indicate that if oxalic acid was not degraded, it was not conducive to the growth of the bacteria and the synthesis of γ-PGA.

Key words: B.amyloliquefaciens, upp gene, Gene knockout, γ-PGA, Fermentation

CLC Number: 

• S432.4