固定化纤维二糖酶在纤维原料水解中的应用

Application of immobilized cellobiase in cellulosic material hydrolysis

纤维原料(木糖渣)经里氏木霉(Trichoderma reesei)纤维素酶水解后,水解液中含有大量的纤维二糖,利用固定化纤维二糖酶将其迅速转化成葡萄糖.在重复分批酶解条件下,纤维素水解液中的葡萄糖质量浓度由起始的26.3 g/L提高到46.7 g/L;在连续酶解工艺中,当稀释率为 0.3 h-1时,酶柱出口处的纤维二糖质量浓度降为零.将T.reesei纤维素酶和固定化纤维二糖酶的水解反应有机耦连,协同降解纤维原料,从而有效解除酶解过程中因纤维二糖累积所形成的反馈抑制作用,酶解得率达88.2%,比单独采用T.reesei纤维素酶提高了31%.进一步采用分批添料协同酶解工艺,将纤维底物的最终质量浓度增加到200 g/L,水解液中还原糖质量浓度上升至128.5 g/L,酶的利用率得到了明显提高.

In the process of cellulosic material hydrolysis by the cellulase of Trichoderma reesei, cellobiose accumulated in the hydrolysate and caused the feed back inhibition to the cellulase reaction. The immobilized cellobiase was used to convert cellobiose to glucose effectively. Under repeated batch hydrolysis processes, the glucose concentration in the hydrolysate increased from 26.3 g/L to 46.7 g/L. In continuous hydrolysis process, the cellobiose in the hydrolysate was totally hydrolyzed to glucose under 0.3 h-1 dilution rate. The synergetic hydrolysis process on corncob residue was carried out by the cellulase of T. reesei and the immobilized cellobiase. The feedback inhibition caused by cellobiose was eliminated and the hydrolysis yield of corncob residue reached 88.2%, which was 31% higher than that in the process using only T. reesei cellulase. By using fed-batch technique in the synergetic hydrolysis process, the final concentration of cellulosic substrate increased to 200 g/L, and the concentration of reducing sugar in the hydrolysate reached 128.5 g/L, and the cost of enzyme was reduced obviously.