香蕉假茎中产碱性果胶酶细菌的筛选发酵优化与酶学性质

Isolation,fermentation optimization and enzymatic properties of a pectinase producing strain from banana pesudostem

利用果胶酶处理天然纤维对环境污染小,然而筛选高产量的菌株仍是降低成本获得果胶酶的关键。本文利用以果胶为唯一碳源的培养基,从香蕉假茎中分离筛选出了一株具有较高果胶酶活性的菌株。经16S r DNA序列分析表明,该菌株与枯草芽孢杆菌(Bacillus substilis)具有99%的相似性,将该菌株命名为Bacillus sp.ZLXH-5。该菌株最佳发酵时间为2天,最佳发酵温度是37℃,最佳初始p H值是5,最佳转速是180r/min,最佳葡萄糖浓度为15g/L。通过发酵条件优化,果胶酶产量提高了56.6%。对粗酶液的性质进行分析,其在55℃下达到最佳反应速率,最适催化p H值是8.5,不同的离子对于果胶酶的活性起到不同的效果。由于该菌株具有较高的果胶酶活性,可以利用该菌株对香蕉假茎进行生物脱胶。

The use of pectianase in natural fiber processing causes less pollution to environment. The key to get pectinase is to isolate a highly producing pectinase strain. A bacterial strain with high production of pectinase had been isolated and screened from banana pesudostem with a selective medium. The phylogenetic analysis based on 16S rDNA showed thatBacillussp.ZLXH-5 was close to Bacillus substiliswith 99% sequence identity. It was named asBacillussp.ZLXH-5. The optimal fermentation condition was as follows,time of 2d,temperature of 37℃,pH value of 5,rotary speed of 180r/min,and glucose concentration of 15g/L. Studies on enzymatic properties showed that optimal temperature for pectinase was 55℃,and optimal pH value for pectinase was 8.5. Different ions showed different impacts on pectinase activity. This strain can be used to process banana pesudostem because of its high pectinase production.