南大洋深海嗜冷菌2-5-10-1及其低温脂肪酶的研究

Studies on the low-temperature lipase of psychrophilic bacterium 2-5-10-1 isolated from the deep sea of the Southern Ocean

从南大洋普里兹湾的水样中筛选到一株产低温脂肪酶的深海嗜冷菌25101,对其生长及产酶情况和酶性质做了初步研究.该菌株的最适生长温度为5℃,此时分泌的胞外脂肪酶最多;添加Tween80,橄榄油可显著促进脂肪酶的产生.该脂肪酶的最适作用温度为35℃,在0～20℃均保持较高的酶活性,在0℃可保持37%的相对酶活性;酶的最适作用的pH值为7.5,在pH6～9的范围内均存在较高酶活性;对热较敏感,在60℃保温15min可丧失50%以上的酶活性.该脂肪酶的催化作用不需要金属离子的参与,Cu2+和Zn2+对酶活有着强烈的抑制作用.

A strain of psychrophilic bacteria, 2-5-10-1, which produces low-temperature lipase, was isolated from the deep sea of the Prydz Bay in the Southern Ocean. The optimal growth temperature of strain 2-5-10-1 is 5 ℃, it also produces more extracellular lipase at 5 ℃. Tween80 or olive oil in medium enhances the secretion of lipase. The optimal temperature and pH for lipase activity are 35 ℃ and 7.5 respectively. At 0 ℃, the lipase still has 37% relative enzyme activity. The lipase shows high thermolability, remaining less than 50% activity after incubation at 60 ℃ for 15 min. EDTA has no effect on lipase activity, indicating that the lipase activity is independent of divalent cation. In contrast, the lipase activity is inhibited markedly by Cu^(2+) and Zn^(2+).