草鱼肠道一菌株产纤维素酶的分离纯化及性质研究

Purification and Properties of a Cellulase Produced by a Strain from the Intestinal of Grass Carp

从草鱼肠道分离出1株枯草芽孢杆菌,有较强的活性。该菌产生的纤维素酶粗酶液,经盐析、透析,并通过葡聚糖凝胶层析柱SephadexG-75分离纯化,经SDS-PAGE后表明第2峰已纯化,得到一种相对分子质量约为62.43kD纤维素酶。分离纯化后该酶的比活力提高了2.924倍,回收率为6.38%。酶学试验研究表明:该酶的最适反应温度为55℃,最适pH值为7.0;Lineweaver-Burk法求得动力学参数,Km和Vmax分别为1.02×10-3g/mL、2.727×10-2mg/(mL·min)。

A strain of bacillus subtilis isolated from the intestinal of Grass Carp has strong activity. The crude cellulase extraction from this strain was separated and purified by the ammonium sulfate precipitation, dialysis and column chromatography of Sephadex G - 75. The protein was purified in second peak of Sephadex G - 75 after SDS - PAGE, and its molecular mass was estimated as 62.43 kD. The specific activity of the cellulase increased 2.924 fold, and coefficient of recovery was 6.38%. The optimal reaction temperature of the cellulase was 55℃ ,and the optimal pH was 7.0. The values of Km and Vmax calculated from Lineweaver - Burk plots were 1.02 × 10^-3 g/mL and 2.727× 10^-2 rag/（ mL . min） respectively.