氯灭活水中枯草芽孢杆菌的效果

以枯草芽孢杆菌(ATCC6633)作为难灭活微生物的代表,研究了氯对水体中芽孢的灭活效果,考察了氯浓度、作用时间、反应体系pH值、温度以及芽孢初始浓度等因素的影响。结果表明,氯对芽孢的灭活过程可分为延滞期和灭活期;初始氯浓度在2.06~10.30 mg·L^-1,反应时间0~166 min,pH值6~9,温度1~30℃,初始芽孢浓度10²~10¹² cfu·ml^-1范围内,消毒剂浓度和反应时间共同影响着氯对芽孢的灭活效果,提高消毒剂投量或延长消毒反应时间,均可提高灭活率;酸性条件下氯灭活芽孢的能力强于碱性条件下;随着温度的上升,氯对芽孢的灭活能力增强;芽孢的初始浓度对氯灭活芽孢的效能影响不大。初始氯投量为8.30 mg·L^-1,pH=7,芽孢初始浓度10⁶ cfu·ml^-1,温度分别为5℃和25℃下,枯草芽孢杆菌对氯消毒剂的抗性强于炭疽芽孢杆菌。

Inactivation of Bacillus subtilis spores in water with chlorine

Spores of Bacillus subtilis(ATCC6633)could be used as a potential model for the resistant microorganisms.The inactivation effect of the spores in drinking water by chlorine was studied,and such factors as chlorine concentration,contact time,pH,temperature,and initial density of spores,which might influence the inactivation were evaluated.The results showed that the inactivation process of spores by chlorine was characterized by a lag phase and a logarithmic phase of inactivation.With chlorine concentration from 2.06 to 10.30 mg·L^-1,reaction time from 0 to 166 min,pH from 6 to 9,temperature from 1 to 30℃,and initial density of spores from 10² to 10¹² cfu·ml^-1,both chlorine concentration and reaction time influenced the inactivation effect of spores,and rate of inactivation would increase at either higher chlorine concentration or longer reaction time.The inactivation ability of chlorine was stronger under acidic condition than that under alkali condition.With increasing temperature,the inactivation ability of chlorine was enhanced,while initial density of spores nearly had no effect.This study indicated that Bacillus subtilis spores were more resistant to chlorine than Bacillus anthracis spores.