超声预处理强化紫外线消毒效果的研究

采用超声预处理强化紫外线消毒效果,并从分子生物学的角度探讨了其强化机理.结果表明,无论是单独紫外辐照还是超声预处理/紫外辐照,紫外辐照剂量与大肠杆菌灭活率之间均具有良好的线性关系;进行超声灭活时,超声功率、作用时间及菌悬液体积对灭活率均无显著意义(P>0.05),按影响大小排序为:菌悬液体积>超声功率>作用时间;当单独超声处理200 mL大肠杆菌悬液时,超声功率为200 W、作用时间为20 S条件下的灭活率最高(0.22-1g),该条件下继续进行紫外辐照,灭活率最高达到2.75-1g,1 h光复活后灭活率仍高达1.72-1g,超声/紫外协同作用的灭活率大于二者单独作用的灭活率之和,表明该条件下超声预处理起到了强化紫外线消毒的作用;超声处理只能改变细胞的结构,不能破坏其DNA;酶敏感位点数量与大肠杆菌的灭活率具有较强的相关性,相关系数约为0.88.

Ultrasound Pretreatment for Strengthening Ultraviolet Disinfection Effect

Ultrasound pretreatment was applied to strengthen the effect of ultraviolet (UV) disin-fection, and the mechanism was investigated based on molecular biology. The results show that whether for single UV irradiation or ultrasonic pretreatment/UV irradiation, there is a good linear relation between the UV irradiation dose and the inactivation rate of E. coli. During ultrasonic inactivation, the ultrasonic power, action time and volume of bacterial liquid have no statistical significance to inactivation rate (p> 0.05), and the arrangement in order of importance is the bacterial liquid volume > the ultrasonic power > the action time. When ultrasound is used to pretreat 200 mL E. coli liquid, the maximal inactivation rate is 0.22-1g under the conditions of 200 W ultrasonic power and 20 s action time. Under above condi-tions, when it is followed by UV irradiation, the maximal inactivation rate is 2.75-1g, even after 1 h pho-toreactivation, the inactivation rate remains at 1.72-1g. The inactivation rate in the synergistic system of ultrasound and UV is more than the total sum of the two separate inactivation rates, demonstrating that ul-trasonic pretreatment can strengthen the effect of UV disinfection. Ultrasound only can change the cell structure and can not destroy the DNA. There is positive relation between ESS and the inactivation of E. coli, and the correlation coefficient is about 0.88.