Enzymatic hydrolysis from carbohydrates of barley straw pretreated by ionic liquids

Abstract

Lignocellulosic biomass offers many potential advantages in comparison with the traditionally used sugars or starchy biomass since it’s vastly available and it does not compete with food and feed production. The abundance and high carbohydrates content of barley straw make it a good candidate for bioethanol production in Europe. Since biomass must be pretreated before enzymatic hydrolysis to improve the digestibility of both the cellulose and the hemicellulose biomass, the use of ionic liquids (IL) has been proposed as an environmental friendly pretreatment of biomass.Different pretreatment conditions were investigated to determine the effects of the experimental conditions (temperature and time) on the enzymatic digestibility of pretreated material. The pretreatment of barley straw with 1-ethyl-3-methyl imidazolium acetate treatment resulted in up to a 9-fold increase in the cellulose conversion and a 13- 22 fold increase in the xylan conversion when compared with the untreated barley straw.Ionic liquid pretreatment of barley straw at 110 ºC for 30 minutes, 24 followed by enzymatic hydrolysis, leads to a sugar yield of 53.5 g/100 g raw material. 25 It’s then ready available for conversion into ethanol and is equivalent to more than 86%from potential sugars. The increase in saccharification was possible due to the rupture in lignin-hemicellulose linkages with treatment of 1-ethyl-3-methyl imidazolium acetate