Influence of surfactant-free ionic liquid microemulsions pretreatment on the composition, structure and enzymatic hydrolysis of water hyacinth.

This study investigated the pretreatment performance of surfactant-free ionic liquid microemulsions (ILMs) on water hyacinth. Pretreatment effects were evaluated in terms of lignocellulosic composition, structure and enzymatic hydrolysis. Analysis of the regenerated water hyacinth indicated that the content of the lignocellulosic composition changed, and the surface became more porous. After being pretreated with ILM(a) (mass ratio of toluene: ethanol: 1-ethyl-3-methylimidazolium acetate ([Emim]Ac)=0.35:0.3:0.35) at 70°C for 12h, the maximum delignification of 63.6% was observed. The cellulose of the water hyacinth was well protected and retained during the pretreatment process. After being enzymatically hydrolyzed for 48 h, the reducing sugar yield of the water hyacinth pretreated with ILM(a) at 70°C for 6 h was 563.7 mg/g, and its hydrolysis yield (86.1%) was nearly four and a half times of that of the untreated one (20.2%). In conclusion, the designed surfactant-free ILMs exhibit promising potential application in biomass pretreatment.