Abstract

The pretreatment is a critical step for lignocellulosic biomass enzymatic hydrolysis, bearing a significant economic weight on the process of producing biomass sugar syrups. This study carried out a thorough investigation of the effect of a prior biological pretreatment (BPT) on the hydrothermal pretreatment (HPT) efficiency, carried out under different severity conditions, to promote the enzymatic hydrolysis of sugarcane straw. Among the microorganisms studied for BPT, Pleurotus ostreatus was more effective, as it showed high selectivity for removing lignin and promoted higher cellulose digestibility, being selected to be combined with HPT. The sole effect of the HPT treatment, at 170 degrees C for 40 min (combined severity factor of 0.446), promoted high hemicellulose removal and the following enzymatic hydrolysis resulted in a 68.3% glucose yield. Nonetheless, the efficiency of the HPT was improved by performing BPT prior to HPT, even under lower severity conditions (160 degrees C for 40 min, combined severity factor of 0.073), resulting in an increased glucose yield of 78.5%, 1.2-fold higher than the HPT carried out solely. These results indicate that BPT is an interesting aid for HPT pretreatment of sugarcane straw. [GRAPHICS]