葡甘聚糖酶高产菌株Q1发酵条件优化及酶的分离纯化

该研究以海洋来源的枯草芽孢杆菌(Bacillus subtilis) Q1为出发菌株，通过单因素实验对葡甘聚糖酶产生菌Q1发酵条件进行优化，并将菌株Q1发酵所得上清液经硫酸铵沉淀、透析、超滤离心和Sephadex G-100凝胶过滤层析，得到电泳纯的葡甘聚糖酶，并研究其部分酶学性质。结果表明，最佳发酵条件为魔芋粉添加量0.75%、牛肉膏添加量为0.2%，蛋白胨添加量为0.4%、氯化钠添加量0.4%、培养温度26 ℃、转速160 r/min、接种量5%、初始pH 7.0、装液量100 mL/250 mL。在此条件下，葡甘聚糖酶酶活为241.61 U/mL。葡甘聚糖酶相对分子质量为41.3 ku；酶最适作用底物为葡甘聚糖。

Optimization of fermentation conditions of high glucomannanase-producing strain Q1 and separation and purification of the enzyme

Using Bacillus subtilis Q1 from marine as original strain, the fermentation conditions of the glucomannanase-producing strain Q1 were optimized by single factor experiments. The glucomannanase from the supernatant liquor was purified using ammonium sulfate precipitation, dialysis, ultrafiltration and gel filtration chromatogram of Sephadex G-100, and its enzymatic properties were researched. The results showed that the optimum fermentation conditions were as follows: konjaku flour 0.75%, beef extract 0.2%, peptone 0.4%, sodium chloride 0.4%, culture temperature 26 ℃, rotate speed 160 r/min, inoculum 5%, initial pH 7.0, liquid volume 100 ml/250 ml. Under the conditions, the enzyme activity was up to 241.61 U/ml. The relative molecular mass of the glucomannanase was determined to be 41.3 ku. The optimum substrate of the enzyme was glucomannan.