Pulsed light was used for the inactivation of Bacillus subtilis NG-2 and its spores.Morphological characteristics of the irradiated cells and spores were explored by scanning electron microscope and transmission electron microscope, the leakage of intracellular contents was determined by ultraviolet spectrophotometry, and intracellular calcium ion concentration and nonspecific esterase activity were investigated by fluorescence spectroscopy. The results showed that the optimal pulsed light parameters were determined as 5 cm and 5 cycles/s for distance and flash frequency, respectively. Under the optimized conditions, the total number of bacterial colonies was killed by more than 50% and 99.98% at 15 and 40 s of irradiation time, respectively. The structures of the cell and spore wall were damaged, and intercellular nucleic acid, proteins, diethyl 2,6-pyridinedicarboxylate, Ca2+and non-specific esterase activity were decreased after irradiation. The findings may provide a theoretical basis for the industrial application of pulsed light.%采用脉冲强光对枯草芽孢杆菌NG-2及芽孢进行灭活并研究其机理.在脉冲强光辐照枯草芽孢杆菌NG-2菌体及其芽孢后,利用扫描电子显微镜和透射电子显微镜观察形态特征变化,利用紫外分光光度法测定细胞内物质含量,利用荧光光谱法检测细胞内Ca2+浓度和非特异性酯酶活力.结果表明,辐照距离为5 cm,闪照频率为5次/s,辐照15 s时,脉冲强光对NG-2菌体及其芽孢灭活率超过50%;辐照40 s时,脉冲强光对NG-2菌体及其芽孢灭活率超过99.98%.辐照枯草芽孢杆菌及芽孢后菌体结构损伤,芽孢壁破裂,细胞内核酸、蛋白质、Ca2+和2,6-吡啶二羧酸含量显著减少,非特异性酯酶活力降低,研究结果为脉冲强光对枯草芽孢杆菌及芽孢灭活机理提供理论依据.
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