Cellulose hydrolysis and bioethanol production from various types of lignocellulosic biomass after microwave-assisted hydrotropic pretreatment

Abstract

This study examined the impact of microwave-assisted hydrotropic pretreatment using sodium cumene sulfonate on the enzymatic hydrolysis of cellulose contained in pine chips, beech chips and wheat straw biomasses as well as the effectiveness of the production of bioethanol from the obtained hydrolysates. The effectiveness of enzymatic hydrolysis of cellulose contained in beech chips and wheat straw subjected to pretreatment in optimised process conditions amounted to ca. 55–60%. As a result of this, hydrolysates containing glucose in the concentration of 76–84 g/L were acquired, which is a significant achievement in the case of cellulosic hydrolysates. A lower efficiency of the process was recorded when cellulose from pine chips was used (maximum hydrolysis efficiency was 17.21 ± 0.09%), which confirms a higher resistance of softwood biomass to the process of biodegradation. The highest concentration of ethanol, at the level of 41.44 ± 0.55 g/L, was achieved through the fermentation of the medium being a hydrolysate of wheat straw after microwave-assisted hydrotropic pretreatment. The developed raw material and hydrolysate preparation method indicates the possibility of using wheat straw after microwave-assisted hydrotropic pretreatment for efficient cellulosic ethanol production using high-gravity (HG) technology.