FeCl3 Pretreatment of Three Lignocellulosic Biomass for Ethanol Production

Bioethanol from lignocellulosic biomass bioconversion is a promising alternative to fossil fuels. Pretreatment plays an important role in this bioconversion. Recyclable ferric chloride was employed for pretreating three kinds of biomass species, including bagasse, rice straw, and wood fiber, in this study to make a comparison. The results showed that FeCl3 was suitable for pretreating biomass species, especially the rice straw, which contains a high hemicellulose content and has a weak matrix structure. The enzymatic saccharification of rice straw pretreated by FeCl3 could reach 95.1% with the highest ratio (83.3%) of removed hemicellulose to raw cellulose. A favorable conversion (81.9%) of cellulose could be attained; the pretreated rice straw was conducted in high solid loading (20%, w/v) hydrolysis. At the same cost with a lower pretreatment combined severity factor (CSF), FeCl3 pretreated rice straw could achieve a higher conversion than HCl. Meanwhile, FeCl3 could realize more than 90% recovery during the pretreatment, resulting in low environmental pollution. This suggests that FeCl3 pretreatment was competitive for biomass bioconversion.