Development of Sterilization Strategy for Thermoduric Bacterial Spores in Photoreaction System with Solar Source

在光催化杀菌系统中，发现TiO_2颗粒能有效地杀灭微生物。在本研究中，使用了不同类型的微生物，即酿酒酵母（细胞）、大肠杆菌（细胞）和嗜热脂肪B.stearothermophilus（孢子）。在高压汞灯（波长范围：365- 579 nm）照射下，为了获得有效的孢子/细胞灭活率，TiO_2颗粒和溶解氧的存在是必要的。此外，溶解氧可能提供了氧化自由基的形成，这些氧化自由基随后攻击孢子/细胞。 ...更多信息 应用二级反应速率方程描述光激发TiO_2粒子产生的细胞浓度和氧化自由基浓度。基于单次击中多目标模型和串联事件模型定量描述了光照强度对芽孢/细胞灭活率的影响。4.为实现连续杀菌，将TiO_2颗粒固定在玻璃板表面，进行了大肠杆菌的光催化杀菌实验。实验结果表明，TiO_2悬浮和固定化体系的杀菌效率都很高，TiO_2悬浮体系和固定化体系的杀菌动力学参数基本一致。5. TiO_2悬浮体系和固定化体系的表观失活速率常数与光照强度呈线性关系。光催化剂的表观失活速率常数随TiO_2浓度或固定量的变化存在一个最大值，表明TiO_2光催化剂对不同类型的微生物都有较好的杀菌效果。对TiO_2固定化体系微生物杀菌的连续运行有一定的认识。少

In the photocatalytic sterilization system using the semiconductive photocatalysts, it was found that the effective sterilization of microbes could be obtained with TiO_2 particles. In this study, different types of microbes namely, S.cerevisiae (cells) , E.coli (cells) and B.stearothermophilus (spores) were used. The sterilization of these microbes were performed in either the TiO_2 suspended or immobilized system and the following findings were obtained :1.The presence of TiO_2 particles and dissolved oxygen was necessary in order to obtain the effective deactivation rate of spores/cells in a system illuminated with a high pressure Hg lamp (wavelengthrange : 365-579nm) .2.Spore deactivation rates were promoted with the increase in the average light intensities inside the photoreactor. In addition, the dissolved oxygen was presumed to provide the formation of oxidative radicals which subsequently attacked the spores/cells.3.The spore/cell deactivation kinetics could be described by ap … More plying the second-order reaction rate equation with respect to the concentrations of cells and oxidative radicals generated by light excitation of TiO_2 particles. Further, the effect of light intensity on spore/cell deactivation rates was expressed quantitatively based on a single-hit multitarget model or a series-event model.4.To achieve the continuous sterilization, TiO_2 particles were immobilized on a glass plate surface and the photocatalytic sterilization experiment of E.coli was performed. It was then found that the effective rate of sterilization was obtained even with the TiO_2 immobilized system, and that the values of parameteres obtained from the kinetic analyzes based on a series-event model were identical in both the TiO_2 suspended and immobilized systems.5.A linear relation was obtained between the apparent deactivation rate constant and light intensity in both the TiO_2 suspended and immobilized systems. It was also found that there existed a maximum value for the apparent deactivation rate constant with respect to TiO_2 concentration or its amount immobilized.In conclusion, photochemical sterilization with semiconductive photocatalysts was effective for various types of microbes. A basic knowledge on the continuous operation of microbe sterilization could be obtained in the TiO_2 immobilized system. Less