极地产适冷脂肪酶菌株的酶学性质研究

Research of enzyme characters of cold-adapted lipase-produced bacteria from the polar

从南北极环境样品中分离到7株产脂肪酶的细菌,经16SrDNA序列分析表明,这些细菌分别属于假交替单胞菌属(Pseudoa lteromonas)和嗜冷杆菌属(Psychrobacter).采用p-NPP法对这7株细菌所产的脂肪酶进行酶学性质研究,结果显示这些酶的最适作用温度在30～40℃、最适作用pH值在7～8之间,在低温下能保持较高的剩余活力,对热敏感,属于适冷脂肪酶.其中假交替单胞菌(Psychrobacter sp.7342)所产脂肪酶具有低温下酶的剩余活力高、有效作用温度和pH范围广、热稳定性较好及对多种金属离子抗性强等特点.该菌株能利用多种单一氮源和碳源产酶,最适产酶温度为25℃.在此基础上进行正交实验分析得到了该菌株的最佳发酵条件为:蛋白胨和淀粉含量各为1.33%,酵母膏含量为0.3%,温度为25℃.

Seven strains of lipase-produced bacteria were isolated and cultured from soil samples of Antarctic and arctic. The results of 16S rDNA sequence analysis showed that 7 bacteria belong to Pseudoalteromonas sp. and Psychrobacter sp. Their enzyme products of bacteria were analysed by p-NPP method. The results showed that optimal temperature of enzyme was 30 - 40℃, the optimal pH was 7 - 8. The enzyme maintained a high surplus vitality at low temperature and was heat-sensitive. So the enzyme belonged to low-temperature lipases. The lipase produced by Psychrobacter sp. 7342 maintained high enzyme activity at low temperature, had an effective role in a wide range of temperature and pH. It also had better thermal stability and was resisted to a variety of metal ions. The strain can use a variety of single carbon and nitrogen produce enzyme, the optimum temperature for enzyme production is 25℃. Based on the orthogonal experiment, the best fermentation condition of the strain was preliminarily found to be：Tryptone i. 33% ,starch 1.33% ,yeast 0. 3% ,at 25℃.