Enzymatic saccharification of wheat straw for bioethanol production by a combined cellulase xylanase and feruloyl esterase treatment

Abstract

The focus of this study was to improve conditions of use of fungal lignocellulolytic enzymes for conversion of lignocellulosic biomass to fermentable sugars for the production of bioethanol. Wheat straw was pre-treated by acid treatment with diluted sulfuric acid followed by steam explosion. Several enzymatic treatments implementing hydrolases (cellulases and xylanases from Trichoderma reesei, recombinant feruloyl esterase (FAE) from Aspergillus niger and oxidoreductases (laccases from Pycnoporus cinnabarinus) were investigated to the saccharification of exploded wheat straw. A synergistic effect between cellulases, FAE and xylanase was proven under a critical enzymatic concentration (10 U/g of cellulases, 3 U/g of xylanase and 10 U/g of FAE). The yield of enzymatic hydrolysis was enhanced by increasing the temperature from 37 °C to 50 °C and addition of a non-ionic surfactant, Tween 20. Optimisation of enzymatic hydrolyses allowed the use of lower quantities of enzymes and improved the cost effectiveness of the process. © 2006 Elsevier Inc. All rights reserved.