Hydrothermal pre-treatment of rapeseed straw

Abstract

As a first step for ethanol production from alternative raw materials, rapeseed straw was studied for fermentable sugar production. Liquid hot water was used as a pre-treatment method and the influence of the main pre-treatment variables was assessed. Experimental design and response surface methodology were applied using pretreatment temperature and process time as factors. The pretreated solids were further submitted to enzymatic hydrolysis and the corresponding yields were used as pretreatment performance evaluation. Liquid fractions obtained from pre-treatment were also characterized in terms of sugars and no-sugar composition. A mathematical model describing pre-treatment effects is proposed. Results show that enzymatic hydrolysis yields near to 100% based on pretreated materials can be achieved at 210-220ºC for 30-50 min, equivalent to near 70% of glucose present in the raw material. According to the mathematical model, a softer pre-treatment at 193ºC for 27 min results in 65% of glucose and 39% of xylose available for fermentation.