α-淀粉酶和糖化酶协同酶解马铃薯淀粉的工艺条件优化

Study on hydrolysis of potato starch by α-amylase and glucoamylase

【目的】探讨α-淀粉酶和糖化酶协同酶解马铃薯淀粉的工艺条件,为降低微藻生产生物柴油成本提供参考。【方法】采用α-淀粉酶和糖化酶协同酶解马铃薯淀粉,以葡萄糖含量为测定指标,选取反应温度、底物质量浓度、加酶量(m(α-淀粉酶)∶m(糖化酶)=3∶1)、反应时间4个影响因素,进行L25(54)正交试验,确定最佳酶解工艺条件;采用高效液相色谱法(HPLC)、电子扫描电镜(SEM)、X射线衍射(XRD)法对酶解产物的物理特性进行分析。【结果】最佳酶解工艺条件为:反应温度80℃、底物质量浓度0.1 g/mL、加酶量为干基底物淀粉质量的0.6%、反应时间4 h、反应pH 4.0,在此条件下,马铃薯淀粉水解液中葡萄糖含量最高,为802.9 g/L。HPLC、SEM、XRD测定结果表明,酶解产物中葡萄糖所占比例最高,酶解未破坏马铃薯淀粉晶型结构,酶解作用只在淀粉表面发生。【结论】得到了α-淀粉酶和糖化酶协同酶解马铃薯淀粉的最佳工艺条件,为微藻生产生物柴油提供了较好的碳源,节约了生产成本。

【Objective】 The optimal hydrolysis technology of potato starch by α-amylase and glucoamylase was discussed to provide a reference for reducing the costs of biodiesel.【Method】 The enzymatic hydrolysis of potato starch was carried out by α-amylase and glucoamylase.The enzymatic hydrolysis conditions were optimized with L25（54）orthogonal test and the reaction temperature,substrate concentration,enzyme dosag（m（α-amylase）∶m（glucoamylase）=3∶1） and reaction time were chosen as the factors with the yield of the glucose as determination of indicators;the potato starch hydrolysate was subjected to analysis by HPLC,SEM,XRD.【Result】 The results showed that the optimum conditions were as follows：temperature,substrate concentration,the best enzyme dosage,reaction time and pH were 80 ℃,0.1 g/mL,ratio of enzyme dosage to dry starch of 0.6%,4 h and pH 4.0 respectively,and under this condition,the percent of glucose was the highest,which reached 802.9 g/L.The results of HPLC,SEM,XRD showed that the glucose reached the highest proportion in the enzymatic hydrolyzate.The enzymatic hydrolysis did not destroy the crystal structure of potato starch,the enzymatic hydrolysis just occured on the surface of the potato starch.【Conclusion】 The optimal hydrolysis technology of potato starch by α-amylase and glucoamylase has been found.Therefore,potato starch hydrolysate is a good alternative carbon source,and is superior to glucose for biofuel in industrial processes.