Enhanced saccharification of lignocellulosic biomass by pretreatment with quaternary ammonium hydroxide

BACKGROUND: As one of the most abundant natural resources, lignocellulosic biomass is usually utilized at low efficiencies because of its complicated structure and poor degradability, and pretreatments prior to utilization are therefore considered necessary. To overcome the disadvantages of traditional pretreatments for lignocellulosic biomass, a method based on the application of quaternary ammonium hydroxide was investigated. RESULTS: Remarkable structural transformation and compositional changes were detected in pretreated biomass, presenting significant removal of lignin and decreased cellulose crystallinity, which could contribute to enhanced degradability. Significant factors in this process were investigated by single-factor experiment and response surface methodology, and optimum conditions were calculated as: reaction time 7.0 h, temperature 51.6 °C, and concentration of solvent 16.8%. Biomass pretreated under these conditions presented a maximum saccharification yield of 73.71%, which was a 3-fold increase compared with the untreated sample. In addition, the solvent quaternary ammonium hydroxide was recycled five times for biomass pretreatment with high activity retained. CONCLUSIONS: Enhanced saccharification efficiency of lignocellulosic biomass was achieved by pretreatment with quaternary ammonium hydroxide.