Abstract:The effect of heat combined with ethanol on the spore killing efficacy and permeability of inner membrane was studied in this paper. The survival rate, inner membrane fluidity, OD600 value and inner membrane permeability of Bacillus subtilis spores treated by heat combined with ethanol were studied by plate counting, fluorescence polarization, spectrophotometry and flow cytometry. The results showed that heat combined ethanol could kill the spores, and the survival concentration of spore decreased by about one logarithm at 80 ℃ combined with 75% ethanol. The fluorescence polarization degree of spore suspension decreased by 0.31 at 60 ℃ and 80 ℃ combined with 75% ethanol, indicating that the fluidity of spore inner membrane increased greatly. The OD600 value decreased the most after 80 ℃ and 75% ethanol treatment, and the permeability of spore inner membrane changed significantly. The results of flow cytometry showed that the positive area changed 93.69%. The results showed that the change of endomembrane permeability was one of the important reasons of spore death.
