Breeding of a high-cellulose degrading Bacillus subtilis by heavy ion mutagenesis

Abstract

To improve the cellulose degradation ability of Bacillus subtilis (B. subtilis), a strain with a higher cellulose degradation rate was selected from five B. subtilis strains as the starting strain in this experiment. By heavy ion irradiation mutagenesis treatment, we screened a high cellulose degradation rate strain, and optimized its fermentation conditions. The results showed that a B. subtilis CG-40-1 mutant strain cellulose degradation rate was （53.07±0.75）%, which was 17.75% higher than the starting strain and has good genetic stability. After the optimization experiment of fermentation conditions, the optimal fermentation time, culture temperature, and pH of this strain were 120 h, 45 ℃, and 6.5, respectively. And the cellulose degradation rate was (67.79±0.49)%, which was 27.74% higher than that without optimization.

Keywords

• bacillus subtilis
• heavy ion
• irradiation
• mutagenesis
• cellulose degradation rate
• optimization of fermentation process