Assessing the effect of protic ionic liquid pretreatment of Pinus radiata from different perspectives including solvent-water ratio

Abstract

In this study, pine (Pinus radiata) pretreated with PIL, triethylammonium hydrogen sulfate (TEAHSO4) at different water-PIL ratios (1:9, 1:4 and 3:7), biomass loadings (10–60%) and biomass particle sizes (<1.18 mm, 1.18–1.76 mm and 1.76–2.40 mm) was enzymatically transformed into fermentable sugars. TEAHSO4 removed 52% lignin with pretreatment at 170 °C, 20% loading and 1:4 water-PIL ratio for 3 h, from biomass with the largest particle size. Reducing the water content of PIL solution enhanced delignification performance of PIL under the same conditions; cellulose content of the biomass increased 2-fold by extracting 59% lignin from pine. Compositional changes were supported with saccharification and characterization analyses. Utilizing 1:4 water-PIL ratio introduced more constructive pretreatment conditions with respect to the changes in lignin particle size distribution. Attaining favorable compositional changes for pine as a recalcitrant softwood motivated the contribution of PILs to IL based biorefineries.