超声协同紫外灭活大肠杆菌实验研究

应用紫外、超声、超声协同紫外对大肠杆菌进行灭活,并从生物学角度对协同机理进行探讨。结果表明:实验条件下,紫外辐照剂量与大肠杆菌灭活率之间具有良好的线性关系,各紫外辐照剂量下的E.coli均发生了光复活现象。超声功率密度对于灭活结果具有显著意义(p0.05),研究中超声灭活大肠杆菌的最大相对功效值对应的工况为7.18W/cm2作用80s。超声的协同作用使紫外线消毒动力学方程K值由0.1增至0.1358,减小了细菌对UV的抗性;与单独紫外作用比较,超声与紫外协同作用的光复活率有所降低。超声与紫外同时作用对细胞形态结构产生严重的破坏,超声作用只能改变细胞的结构,而不能破坏其DNA;利用T4-EndoⅤ对CPDs的特异性识别特性,可发现经各工况处理后,大肠杆菌DNA均被降解,产生大量CPDS,且各工况下ESS含量变化曲线与各工况下大肠杆菌灭活率曲线的相关系数达到0.92。

Synergistic Efficiency of E.coli.Inactivation under US and UV

Ultraviolet(UV),ultrasound(US)and synergistic efficiency were applied to inactivate E.coli,and the biological mechanism was investigated.Results showed that there was a good linear relation between UV irradiation dose and inactivation rate of E.coli.The power density of US had statistical significance on inactivation result.Operation condition of the maximum relative efficacy value was 7.18W/cm2 for 80s.The reaction rate constant increased from 0.1 to 0.1358 and photo reactivation rate of E.coli.decreased under the synergistic effect of US and UV.The cell structure of E.coli.was destroyed seriously under the synergistic effect of US and UV.US could not change DNA of E.coli.By specific recognition characteristics of T4 endonuclease V to thymine dimmer,DNA of E.coli.was found degradation under every operation condition and lots of CPDs were produced,and content of ESS produced by T4-Endo V digestion could embody inactivation rate of E.coli.under every operating condition.