Abstract: Atmospheric and room temperature plasma(ARTP) was used to mutate Bacillus velezensis CY30 for improving the production of spores and fungicidal activity. The most optimal condition for the ARTP mutagenesis was working flow rate at 10 L/min, treating distance of 2 mm and electrical power of 100 W. The mutants were selected based on microscopic morphology of the colonies, the spore counts and antifungal activity of the cultures from shake-flask fermentation. A mutant with code of CY30-314 was obtained through 3 rounds of microscopic checking of the slants and shake-flask fermentation. The spore counts of the mutant in shake-flask fermentation was 12.23 billion spores/mL, and the corresponding cultures inhibited the growth of fungus for 75.58%. The mutant also showed genetic stability. The mutant produced 25.3% more spores in shake-flask fermentation which resulted in the increase of antifungal activity at 15.6%. The duration of the mutant was shorted for 2 h.

Key words: Atmospheric and room temperature plasma(ARTP), Bacillus velezensis, spore count, antifungal activity