Acremonium纤维素酶在玉米芯糖化中的应用

Application of Acremonium cellulase in saccharification of corncobs

玉米芯作为一种木质纤维素类农业废弃物,同时也是生产生物乙醇的潜在原料。在玉米芯糖化过程中,纤维素酶的作用是十分关键的。本研究比较了里氏木霉纤维素酶、绿色木霉纤维素酶和Acremonium纤维素酶各相关酶活。其中Acremonium纤维素酶的滤纸酶活约是里氏木霉纤维素酶的6倍,是绿色木霉纤维素酶的8倍。其羧甲基纤维素酶活和绿色木霉纤维素酶基本相等。Acremonium纤维素酶的β-葡萄糖苷酶酶活是里氏木霉纤维素酶的38倍,以及绿色木霉纤维素酶的41倍。而Acremonium纤维素酶的木聚糖酶活只相当于绿色木霉纤维素酶的70%。这说明Acremonium纤维素酶降解纤维素的能力可能强于另两种纤维素酶,而降解半纤维素类物质的能力要弱于绿色木霉纤维素酶。在玉米芯糖化实验中,使用Acremonium纤维素酶的糖化液中产生的最高葡萄糖浓度比里氏木霉纤维素酶的高14%,比绿色木霉纤维素酶的高58%。Acremonium纤维素酶用量在10 FPU/g时,反应16 h就基本可以达到最佳效果,而另两种酶用量则需达到30 FPU/g,反应48h才能达到最佳效果。使用Acremonium纤维素酶的糖化液中产生的最高木糖浓度与里氏木霉纤维素酶相等,比绿色木霉纤维素酶低42%。而同时使用Acremonium纤维素酶及绿色木霉纤维素酶时,其糖化液中最高木糖浓度有所提高,比绿色木霉纤维素酶的高31%。Acremonium纤维素酶可以有效地应用于玉米芯糖化,为玉米芯的资源化提供一种可能的方案。

Not only is corncob a lignocellulosic agricultural waste, but also it can be considered as a potential feedstock for ethanol production. Cellulase is crucial to the saccharification of corncob. The activities of the cellulase from Trichoderma reesei, the cellulase from Trichodern viride and the cellulase from Acremonium cellulolyticus were assayed respectively in this research. The filter paper activity of the cellulase from Acremonium cellulolyticus was about 6 times and 8 times higher than those of the cellulase from Trichoderma reesei and the cellulase from Trichoderma viride, respectively, while carboxymethyl cellulase of the cellulase from Acrernonium cellulolyticus was similar to that of the cellulase from Trichoderma viride. glucosidase activity of the cellulase from Acremonium cellulolyticus was 38 times and 41 times higher than those of the cellulases from Trichoderma reesei and Trichoderma viride, respectively. Xylanase activity of the cellulase from Acremo- nium ceUulolyticus was only about 70% of that from Trichoderma viride. This indicated that the ability of the cellulase from Acremonium cellulolyticus to degrade cellulose would be better than those of the other two cellulases, while the ability to degrade hemicellulose may be worse than that of the cellulase from Trichoderma viride. In the experiment of corncob sac- charification, the glucose concentration of saecharification liquid of the cellulase from Acremonium cellulolyticu was 14% and 58% higher than those of the cellulases from Trichoderrna reesei and Trichoderma viride, respectively. The maximum efficiency could be obtained at 16 h with the cellulase from Acrernonium cellulolyticus of 10 FPU/g, while at 48 h with the other two cellulases of 30 FPU/g. The highest xylose concentration in the saccharifieation liquid of the cellulase from Acremoniura cellulolyticus was similar to that of the cellulase from Trichoderma reesei, while it was about 42% lower than that of the cellulase from Trichoderrna viride. The xylose concentration could be improved with both the cellulases from Acremonium cellulolyticus and Trichoderma viride, resulting in the xylose yield increased by 31% , compared to that with the cellulase from Trichoderma viride alone. The cellulase from Acrernonium cellulolyticus could be applied to the saccharification of corncob, providing a possible method for resource of corncob.