一株产耐高温碱性脂肪酶菌株的筛选及产酶条件优化

Screening of a thermostable alkaline lipase producing strain and optimization of fermentation condition for Lipase production

摘要: 用Tween平板法从采集自河北省的122份土样中筛选到一株脂肪酶活性较高的菌株Lipa1318。综合其形态学和生理生化特征以及16S r DNA的序列比对结果,确定该菌株为粘质沙雷氏菌（Serratia marcescens）。其所产胞外脂肪酶的最适反应温度为60℃,最适p H为8.0,是一种耐热的碱性脂肪酶。摇瓶发酵实验证明该菌株的最适产酶条件为:葡萄糖1.0%,牛肉膏1.0%,Triton X-100 1.5%,橄榄油0.50%,Ca Cl20.50mmol/L,发酵液初始p H为8.0,30℃培养96h,通过发酵条件的优化使酶活提高了3.6倍。

Abstract: Using the plate assay method with Tween 80 as substrate of lipase,122 soil samples collected from Hebei province were screened and a bacterial strain Lipa1318 with high lipase activity was obtained. The results of morphological features,the physiological and biochemical characteristics and 16 S r DNA sequence alignment analysis demonstrated that the isolate was Serratia marcescens. The optimal temperature and p H of the extracellular lipase were 60℃ and 8.0,which indicated that the lipase was a thermostable alkaline lipase. The optimal fermentation condition for high lipase production in flask were as follows: glucose 1.0%,beef extract 1.0%,Triton X-100 1.5%,olive oil 0.50%,Ca Cl20.50 mmol / L,the initial p H( 8.0) and temperature( 30℃),culture time( 96h).Under these conditions,the lipase activity was increased by 3.6 times.