细菌纤维素微球固定化α-淀粉酶的研究

Immobilization ofα-amylase on bacterial cellulose pellets

由本实验室分离保存的葡糖醋杆菌(Gluconacetobacter intermedius)G-29摇瓶培养产生的细菌纤维素微球作为载体,采用戊二醛交联法固定化α-淀粉酶.通过正交实验确定了固定化的最佳条件:pH 6.4,3%戊二醛浓度,给酶量12.5 mL(1 mg/mL),固定化时间12 h.研究了固定化酶的性质,与游离酶相比,α-淀粉酶经细菌纤维素微球固定化后,抗酸碱和温度变化的能力提高,最适pH向酸性区偏移0.4个单位(从6.0降到5.6),最适温度升高10℃(从60℃升高到70℃),并在较宽的pH和温度范围内也能保持较高的活性,保藏性和重复使用性较稳定,说明细菌纤维素微球在工业上作为酶载体支持物有较大潜力.

Bacterial cellulose pellets were produced in shaking flasks by Gluconacetobacter interrnedius G- 29 which was isolated and preserved by our laboratory. Activated bacterial cellulose pellets by the method of glutaraldehyde cross-linking were used as the support of a-amylase for its immobilization. The optimal conditions for immobilization were determined by orthogonal experiment, the result was as following. pH 6.4, 3% of glutaraldehyde concentration, 12.5 mL（1 mg/mL） of enzyme amount, 12 h. The properties of free and immobilized a-amylase were also investigated and compared, the optimal pH of im- mobilized a-amylase was descended by 0.4 to the acid region （from 6.0 to 5.6） arid the optimal temperature was 70 ℃, 10 ℃ higher than that of free α-amylase, immobilized a-amylase could maintain high activity in a wider range of pH and temperature; the operational and storage stability of immobilized α-am- ylase were improved significantly. We can infer that the bacterial cellulose pellets have the potential to be used as a new support for enzyme immobilization in industry.