Better Biomass Pretreatment Streamlines Ethanol Production

A biomass pretreatment process that uses biobased tetrahydro­furan (THF) as a cosolvent could significantly reduce the cost of making cellulosic ethanol biofuel (ChemSusChem 2015, DOI: 10.1002/cssc.201403045). A team led by Charles E. Wyman of the University of California, Riverside, determined that THF’s miscibility with water enhances aqueous dilute sulfuric acid pretreatment to break down recalcitrant plant material such as corn stover and hardwood. The cosolvent further facilitates separating cellulose from hemicellulose and lignin, producing a material that is more easily diced up by enzymes into fermentable sugars. The researchers were therefore able to use smaller amounts of enzymes and carry out sugar fermentation using yeast simultaneously in the same reactor. The new cosolvent-enhanced lignocellulosic fractionation (CELF) pretreatment “has the potential to be truly game changing,” Wyman says. The researchers show that CELF removes about 90% of the lignin from biomass and achieves higher yields of ethanol compared with acid pretreatment alone. CogniTek, a clean energy company based in Northbrook, Ill., has acquired rights to commercialize the technology through a subsidiary called MG Fuels.