产蛋白酶菌株的鉴定及其对虾壳的脱蛋白研究

Identification of a protease-producing strain and deproteinization on shrimp shell

从虾塘沉积物中分离到一株产蛋白酶的菌株C1,采用菌落形态、生理生化特征和16S rDNA基因序列分析相结合的方法进行鉴定,进一步探究其在提取虾壳甲壳素工艺中脱蛋白的应用,并与枯草芽孢杆菌(Bacillus subtilis)对虾壳蛋白脱除效果进行比较分析。结果表明,菌株C1被鉴定为一株蜡样芽孢杆菌(Bacillus cereus),其对虾壳的脱蛋白能力高于枯草芽孢杆菌。当发酵培养基中葡萄糖添加量为50 g/L,虾壳粉添加量为20 g/L,酵母膏添加量为1 g/L时,枯草芽孢杆菌和蜡样芽孢杆菌发酵5 d的蛋白酶活力分别为145.7 U/mL、220.8 U/mL,脱蛋白率分别达到80.4%、90.8%。

A protease-producing strain C1 from the shrimp pond sediment was isolated and identified based on morphology,physiological and biochemical characteristics and 16S rDNA gene sequencing.The application of deproteinization of the strain for chitin extraction from shrimp shell was studied and the deproteinization effect was compared with Bacillus subtilis.The results indicated that the strain C1 was identified as Bacillus cereus,and its deproteinization effect on shrimp shell was better than B.subtilis.When the fermentation medium was composed of glucose 50 g/L,shrimp shell powder 20 g/L and yeast extract 1 g/L.Under such fermentation conditions of B.subtilis and B.cereus for 5 d,respectively the protease activity was 145.7 U/ml and 220.8 U/ml,respectively,and the deproteinization rate were 80.4%and 90.8%,respectively.