Effects of sulfuric acid promoter on biopolymer-derived fractions from empty plam fruit bunch under solvothermal fractionation process

Abstract

A single step sulfuric acid catalyzed (H2SO4) under the organosolv process was studied for fractionation of empty palm fruit branches. The use of H2SO4 as an acid catalyst showed higher efficiency of the removal of hemicellulose with an increase in lignin removal from native EPFB into organic phase and leave glucan in solid fraction. The optimal condition showed the maximum glucan yields of 2.45 g and the highest lignin yields of 1.86 g was at 180oC, with 15 min residence time. The addition of H2SO4 catalyzed enhanced hemicellulose and lignin removal. 0.05% H2SO4 led to improve glucan yields of 3.17 g with the lower degradation of glucan and pentose in the aqueous phase. Under this condition, a 1.28 g recovery of lignin was obtained from the organic phase. Physicochemical analysis revealed intact cellulose fibers with the decrease in crystallinity, while the hemicellulose was partially recovered as mono- and oligomeric sugar. High-purity organosolv lignin with < 2% sugar cross-contamination was obtained with no major structural modification according to Fourier-transform infrared spectroscopy. This work represents an alternative process for efficient fractionation of lignocellulosic biomass in biorefineries.