Use of a Mixture of Thermophilic Enzymes Produced by the Fungus Thermoascus aurantiacus to Enhance the Enzymatic Hydrolysis of the Sugarcane Bagasse Cellulose | Science Publications

American Journal of Agricultural and Biological Sciences

J. R. Monte¹  W. Carvalho¹  A. M.F. Milagres¹ 

关键词: Xylanase;    cellulose;    Thermoascus aurantiacus;    purification;    enzymatic hydrolysis;    lignocellulose;   

DOI  :  10.3844/ajabssp.2010.468.476

学科分类：农业科学（综合）

来源: Science Publications

【 摘 要 】

Problem statement: The production of hydrolytic enzymes by T. aurantiacus has beenperformed under solid-state fermentations using lignocellulosic materials. The influences of theinoculum size and of the fermentation medium on the production of hemicellulases and cellulases werestudied. Filtrates from the cultures were used to hydrolyze a pulp of sugarcane bagasse and theproduced enzymes were shown to be candidates for use as co-adjuvants in plant saccharification.Aproach: The present study focuses on the effect of different culture conditions on production ofcellulases and hemicellulases by T. aurantiacus. It is also provides a possible application ofT. aurantiacus enzymes in the degradation of sugarcane bagasse pulp, considering that thisthermophilic fungus is a potential source of thermostable enzymes. Results: T. aurantiacus wascultivated on four different agricultural residues: sugarcane bagasse, sugarcane straw, wheat straw andcorn cob. Xylanase was produced with much more expressive activity than cellulases. The highest titreof xylanase was obtained on sugarcane straw at 9 days (1679.8 IU g⁻¹); the same was observed for β-glucosidase (29.9 IU g⁻¹) at 6 days. With an inoculum load of 10⁸ spores g⁻¹, the amount ofexoglucanase produced by the fungus considerably exceeds that produced with 10⁴ spores g⁻¹.Xylanases and cellulases purified from filtrates of the cultures were investigated to hydrolyze abagasse pulp prepared with alkaline peroxide. Xylanase or sulphuric acid were used as pretreatmentsfor xylan removal, increasing the cellulase performance on pulp bagasse. However, results revealedthat the removal of hemicellulose is not the only main factor limiting the cellulose hydrolysis.Conclusion: Results indicate that the xylanase action on alkaline-pretreated sugar cane bagasseenhances the cellulolytic effect promoted by a commercial cellulase. This study thus presents anevaluation of the applicability of enzymes from Thermoascus aurantiacus to potentially improve theenzymatic cellulose hydrolysis.

【 授权许可】

Unknown