酸性异淀粉酶产生菌的筛选及鉴定

Screening and identification of acidic isoamylase producing strain

从淀粉厂附近的土壤中分离出产脱枝酶的菌株,通过初筛和复筛,得到1株产偏酸性异淀粉酶活力较高的菌株YDF30。其发酵56h时酶活力最大,达到16．4U/mL。所产生的异淀粉酶最适反应温度为55℃,最适pH值为5．2,在低于50℃和pH5．2～9．6条件下较稳定。依据其形态特征和生理生化实验结果,初步鉴定该菌株为芽孢杆菌(Bacillus sp．)。

The debranching enzyme producing strain was isolated from the soil nearby the starch factory in Qiqihaer. YDF30, a strain producing acidic isoamylase of high activity was acquired. Enzyme activity could get the highest 16.4 U/ml after fermentation for 56 h. The optimum conditions were： temperature 55℃, optimum pH 5.2, and enzyme activity was stable below 55℃ and pH 5.2-9.6. The strain was primarily identified as Bacillus spp. according to the morphology and physiology characteristics.