超临界CO2杀灭大肠杆菌过程中菌体蛋白变化的研究

通过SDS-聚丙烯酰胺凝胶电泳,结合超临界CO₂对大肠杆菌的杀菌曲线,研究超临界压力、温度和处理时间对大肠杆菌菌体蛋白的影响。结果表明：超临界CO₂在杀灭大肠杆菌过程中,可显著降低菌体碱溶性（pH8.0）蛋白的溶解性,但对菌体总蛋白含量和种类没有影响;37 ℃下超临界CO2处理大肠杆菌30 min,压力为10MPa时,大肠杆菌存活率为2.8%,菌体碱溶性蛋白的溶解性显著降低,但当压力增加到50MPa时,大肠杆菌存活率和碱溶性蛋白溶解性变化不明显;超临界温度和处理时间对菌体碱溶性蛋白溶解性的影响与大肠杆菌在超临界CO₂中的存活趋势基本一致可,随处理时间的延长和温度的增加大肠杆菌存活率逐渐降低到0,碱溶性蛋白溶解性逐渐降低,直至部分蛋白带消失,但菌体总蛋白含量和种类并没有明显变化;升高温度比增加压力更能显著地导致菌体碱溶性蛋白变性,溶解性下降。

The Protein Change During the Inactivation of Escherivhia coli by Supercritical CO2

The influences of supercritical CO2 on the total protein and alkali-soluble protein of E. coli was studied by SDS-PAGE analysis and the inactivation curve of E. coli by supercritical CO2. The results showed that the solubility of E.coli alkali-soluble protein(pH8.0) significantly decreased when E. coli was inactivated by supercritical CO2, but there was no change of the species and content of total protein of E.coli after supercritical CO2 treatment. The solubility of alkali-soluble protein significantly decreased and the survival rate of E. coli was only 2.8% when the E.coli was treated 30min by supercritical CO2 at 37 ℃ and 10MPa, but the survival rate of E. coli and the solubility of alkali-soluble protein did not decreased observably when the pressure increased up to 50MPa.The survival trend of E. coli was same as the change of the solubility of alkali-soluble protein under the different temperature and treating time of supercritical CO2. The survival rate of E. coli and the solubility of alkali-soluble protein dropped off with the increase of treating time and temperature, but there was no change of the species and content of total protein of E. coli. The increasing temperature could strengthen the denaturalization and the insolubility of E. coli alkali-soluble protein more obviously than increasing pressure.