Research On The Optimum Conditions For The Germination Of Bacillus Subtilis Spores Induced By Heat And Chemicals

Spores are extremely resistant to various treatments, but germinated spores could be inactivated easily.There are many factors that induce the germination of spores.This article studied the germination effects of Bacillus subtilis spores by temperature pretreatment combined with chemicals.This article treated the spores with different chemicals, different combinations of chemicals, temperature pretreatment combined with chemicals, combinations of germination inducers and inhibitors. The germination rate was used as the research index, and the germination effects of Bacillus subtilis spores treated with various schemes were researched systemically.The study results are as follows:(1)At first, this article studied germination-inducing effects of chemicals on spores. It was found that DPA, inosine, dodecylamine, L-alanine and D-glucose could quickly induce spore germination. OD600 value and refractility of spores decreased quickly.At 37℃, the germination-inducing effects of DPA, D-glucose and inosine were higher than that of 25℃. However, at 25℃, the germination-inducing effects of L-alanine and dodecylamine were higher than that of 37℃, and the germination efficiency of DPA was significantly higher than that of other chemical substances. With the increase of processing time, the germination rate of spores during the first 10 minutes increased rapidly. After 10 minutes, it tended to be stable and the change of germination rate was not significant.(2)The effects of the combination of thermal pretreatment and chemical substances on the germination of spores were studied. It was found that after pretreatment at 60℃ for 15 min, the germination rate of spores treated with DPA was increased significantly. Its germination rate could reach more than 98%. Thermal pretreatment could increase the germination rate of Bacillus subtilis spores treated with the combination of L-alanine and dodecylamine, and the spores germination rates with pretreatment at 40℃ were higher than that of 60℃. TME results indicated that treatment of DPA combined with pretreatment could further reduce the refractility of the spores.(3)The spore germination was induced by a combination of different spore germination-inducing agents. It was found that combination of DPA and dodecylamine, and combination of DPA and L-alanine could induce spore germination. However, the germination rates of spores treated with these combinations were lower than that of DPA alone. However, the germination-inducing effects of some combinations of chemicals were not significantly. Some combinations of chemicals even could not induce spore germination.(4)This article studied the germination-inhibiting effects of the combination of D-alanine、HgCl2、 NaHCO3 and germination inducers on spores. It was found that the germination-inhibiting effects of HgCl2 was much higher than that of D-alanine and NaHCO3, and the inhibitng effects of D-alanine were higher than that of NaHCO3. The spore germination was not inhibited when it was treated with the combination of dodecylamine and NaHCO3, and combination of L-alanine and NaHCO3. With the increase of treatment time, the germination-inhibiting effects of D-alanine、HgCl2 and NaHCO3 didn’t change significantly.