中性纤维素酶糖化中性汽爆玉米秸秆工艺优化

提出一种在非缓冲系统中水解中性汽爆秸秆的工艺。首先选取具有较好协同降解木质纤维素能力的特异腐质霉(Humicola insolens)所产中性纤维素酶进行工艺优化,确定其水解工艺可以在非缓冲体系中进行。在此基础上,通过添加β-葡萄糖苷酶、木聚糖酶、漆酶和表面活性剂与中性纤维素酶制剂中进行复配后在非缓冲体系中(自然pH值)水解中性汽爆秸秆,并用分批加酶水解提高了复合酶的酶解效率。结果表明,每克中性汽爆秸秆底物中加入10 FPU中性纤维素酶,75 IU β-葡萄糖苷酶,3 000 IU木聚糖酶和体积分数为0.5 % Triton-100,以100 g/L底物浓度水解120 h后,综合水解率为48.4 %。每克底物中复合酶以15+5 FPU,分批加酶水解120 h后综合水解率、纤维素水解率和半纤维素水解率分别为56.0 %、64.9 %和42.5 %。这有助于拓宽木质纤维素糖化工艺研究的思路,为木质纤维素材料高效糖化及后续乙醇发酵提供参考。

Process of Neutral Cellulase-based Saccharification on the Neutral Steam Exploded Corn Stover

A neutral cellulase was introduced to optimize the saccharification process of neutral steam exploded corn stover. It was found that the neutral cellulase was affected equally in the non-buffer and buffer system under the natural condition. Further investigation showed that xylase, β-glucosidase, and Tritonx-100 have positive effects on the saccharification in the system. In summary, an optimized enzymatic hydrolyzing condition for one gram neutral steam exploded corn stover (100 g/L) is obtained as follows: 10 FPU neutral cellulase complex, 75 IU β-glucosidase, 3 000 IU xylase and Triton-100 with 0.5 percent in volume. After 120 h incubation at 50 ℃ with 150 r/min,total biomass conversion is around 48.4%. The total biomass conversion and cellulose conversion rates are 56.0% and 64.9% when using two-step addition of the enzymes.