一株乳酸乳球菌对棒曲霉素的去除作用

以筛选得到的可有效去除棒曲霉素的食品生产用菌株乳酸乳球菌MG1363为实验材料,通过改变环境温度、pH对其降解特性进行研究,并通过灭活菌体、提取粗酶液等手段,对乳酸乳球菌MG1363降解棒曲霉素的机理进行初步探究。结果表明,温度、pH对乳酸菌去除棒曲霉素活力的影响显著(P<0.05),去除棒曲霉素的较佳反应环境为30 ℃、pH值5.5~6.0。乳酸乳球菌MG1363既能物理吸附棒曲霉素,也能通过酶解作用降解棒曲霉素,且发挥降解活性的酶为胞内酶。乳酸乳球菌MG1363酶解棒曲霉素为其自身固有的特性,但棒曲霉素可诱导乳酸乳球菌的降解活性。

Patulin reduction by Lactococcus lactis strain

In the present study, a strain of food-grade microorganism Lactococcus lactis MG1363 was screened for its ability of patulin degradation. The effects of environmental temperature and pH value on patulin degradation by L. lactis MG1363 were assessed, and the mechanisms of patulin degradation were also studied by bacterial cells inactivation and crude enzyme extraction. The results indicated that temperature and pH influenced patulin degradation significantly (P<0.05), and the optimal condition was 30 ℃, pH value 5.5-6.0. The mechanisms of patulin degradation by L. lactis MG1363 involved both physical adsorption and enzymatic degradation, and the degradation relevant enzymes were located inside the bacterial cells. The property of patulin-degrading by L. lactis MG1363 was constitutive, nevertheless, the enzymatic activity of patulin degradation was enhanced by low amount of patulin.