Screening of High-Yield Vitamin K2 Strain Based on ARTP Technology and Optimization of Fermentation Medium

Abstract:

This study aimed to obtain the vitamin K₂ dominant mutant and to further improve its yield via the fermentation medium optimization using response surface design. The mutagenesis breeding of bacillus natto was carried out through room temperature plasma (ARTP) in combination with the structural analog resistance screening under atmospheric pressure, subsequently rescreened by 24 bore plates fermentation. The fermentation medium was then optimized by Box-Behnken design. A dominant mutant strain of vitamin K₂ was obtained by ARTP mutagenesis with a yield of 3.23 times higher than that of the original strain. The optimal values based on Box-Behnken design were 0.69 g/L of K₂HPO₄, 66.01 g/L of glycerol and 25.12 g/L of yeast powder, with an increase of 56.7% of vitamin K₂ yield. A dominant mutant strain of vitamin K₂ was achieved by ARTP mutagenesis and the fermentation medium was effectively optimized by response surface methodology. The experimental results showed that the mutant strain has potential value in production and application, establishing the breeding method with a beneficial reference for the selection and breeding of other industrial microorganisms, which is of great significance to improve human health.