高压CO_2处理对枯草芽孢杆菌芽孢杀灭及协同作用的影响

Effect of High-pressure Carbon Dioxide Treatment on the Inactivation of Bacillus subtilis Spores

选用枯草芽孢杆菌为研究对象,以磷酸盐缓冲液为基质,研究高压(5～25MPa)CO2协同热处理对其芽孢杀灭作用的影响。结果表明:20MPa高压CO2处理前在45℃预热处理30min时枯草芽孢杆菌芽孢的失活率达到了3.84个数量级,单纯20MPa高压CO2处理30min时枯草芽孢杆菌芽孢的失活率达到2.44个数量级。采用连续式和间歇式两种不同的施压方式考查其对枯草芽孢杆菌芽孢的灭活及萌发影响,结果表明:10MPa、50℃连续30min高压CO2处理对枯草芽孢杆菌芽孢的杀灭使其数量下降了0.67个数量级,间歇施压(低压10MPa施压10min,高压30MPa施压10min)循环1次时枯草芽孢杆菌芽孢的失活率达到2.55个数量级。选择添加3种组合的营养发芽诱导因子考察在不同的压力条件下(10MPa 30℃、10MPa 50℃、30MPa 30℃、30MPa 50℃)与高压CO2处理相结合对芽孢发芽的影响。结果表明:添加的营养发芽诱导因子在低压(10MPa)时的诱导作用不如高压(30MPa)时明显。

Bacillus subtilis spores were suspended in phosphate buffer and treated by high-pressure carbon dioxide（HPCD） at the range of 5-25 MPa combined with mild heating.The results showed that Bacillus subtilis spores were inactivated by 3.84 magnitude orders after heating treatment for 30 min at 45 ℃ followed by treatment at 20 MPa for another 30 min.HPCD treatment alone resulted in an inactivation by 2.44 magnitude orders.Continuous HPCD treatment at 10 MPa for 30 min could result in a decrease in the viable spore count of Bacillus subtilis by 0.67 magnitude orders.After the first cycle of intermittent HPCD treatment（held at 10 MPa for 10 min and then at 30 min for another 10 min）,Bacillus subtilis spores were inactivated by 2.55 magnitude orders.Meanwhile,the combined effects of each of three combinations of germination inducers and different combinations of heating and subsequent HPCD treatment（30 ℃ plus 10 MPa or 30 MPa and 50 ℃ plus 10 MPa or 30 MPa） were investigated.The inducing effect of germination inducers at 10 MPa was not so obvious as at 30 MPa.