乙醇胁迫对乳酸杆菌关键酶活力的影响

The effect of ethanol stress on the key enzymes of Lactobacillus

分别以面包乳杆菌(Lactobacillus crustorum D2-5)和植物乳杆菌(Lactobacillus plantarum D5-5)为研究对象,进行不同乙醇体积分数胁迫后菌体活力的对比,测定了乙醇胁迫后菌体中己糖激酶(HK)、丙酮酸激酶(PK)、乳酸脱氢酶(LDH)及ATP酶的活力变化,分析了乙醇胁迫后造成菌体失活的主要因素。结果表明:5%乙醇胁迫处理有助于提高菌体存活率,但是效果不显著;8%乙醇胁迫后的菌体存活率明显降低,面包乳杆菌D2-5和植物乳杆菌D5-5存活率依次仅为26.61%和23.50%,菌体的生长受到严重抑制,致使相关酶活力降低。乙醇胁迫对乳酸杆菌己糖激酶影响不显著,对其丙酮酸激酶、乳酸脱氢酶及ATP酶具有极显著的影响。这一结果说明,丙酮酸激酶、乳酸脱氢酶及ATP酶是影响乙醇胁迫损失的关键酶,酶活力变化与菌体活力相关。

In order to analyze the main factors causing the loss of the survival rates of bacteria, this paper stud- ied the activity changes of hexokinase （ HK）, pyruvate kinase （ PK）, lactate dehydrogenase （LDH） and ATPase with ethanol stress. Taking Lactobacillus crustorum D2-5 and Lactobacillus plantarum D5-5 as experimental objects, the survival rates of Lactobacillus after treatment with different concentrations of ethanol were compared. The experiment results demonstrated that 5% （V/V） ethanol stress treatment increased the viability of the survival rate, but the effect was not significant. The survival rate had the maximum decline with 8% （V/V） ethanol concentration of stress, wherein the survival rates of LactobaciUus crustorum I）2-5 and Lactobacillus plarttarum D5-5 were only 26.61% and 23.50% respectively. It also suggested that the differences in HK during different ethanol concentration treatments were not significant but the activities of PK, LDH and ATPase were significant. The above results indicated that PK, LDH and ATPase were the key enzymes resulting in the activity loss by ethanol stress and the activity changes were as- sociated with strains viability.