7 超音波殺菌の熱量測定による定量・定性評価(医学的・生化学的応用)

抄録

It is well known that cavitation effect of ultrasound is applicable to disinfection of the wastewater. Moreover, the combination of ultrasound and other techniques is interesting to develop efficient disinfection system. To do this, detail study on the growth activity of microorganisms treated by ultrasonic irradiation should be important. However the colony counting and the turbidity measurements of the growth medium are insufficient to evaluate the quantitative and qualitative change of microbial growth. In this study, to evaluate the growth activity of the yeast cells, calorimetric analysis was carried out in addition to the colony counting. Using a heat conduction type multiplex calorimeter equipped with 24 calorimetric units the heat evolution on the growing of treated yeast cells was detected in the form of growth thermograms. It can provide not only the quantitative information for the microbial growth activity but also the characteristic features about the bactericidal and bacteriostatic effect due to the chemical or physical action to microorganisms. It was shown that the longer irradiation time, the more peak shift toward a longer incubation time, which means bactericidal effect of ultrasound. On the other hand, growth rate constant of yeast was decreased according to increase of the concentration of NaClO.