Effects of germination factors on Bacillus subtilis spores in the sub(lethal) stage

The effect of food nutritional ingredient on Bacillus subtilis spores in the sub(lethal) stage germination was evaluated,which the impact of carbon,nitrogen,inorganic salts in food on spore germinate was conducted by batch culture method, and temperature, p H, inoculum size, oxygen content was studied by orthogonal experimental design. To quantitatively analyse the effect of these factors,the optical density of OD580 was determined to calculate germination rate. The results showed that maltose,whey protein were the best C source and N source of spore germination,respectively. Mg SO_4 had a significant induction effect on spore germination.Based on the best nutrients of maltose(5 mg/m L),Mg SO_4(5 mg/m L),whey protein(5 mg/m L),optimal growth conditions for spore was that an inoculum of 4% of Bacillus subtilis spores in media with p H7.0 were cultured under 37 ℃,and the dissolved oxygen was 70 m L,constant shaking for 60 min,resulted in the maximum spore germination rate was 15.27%.