Lignocellulosic Properties of Coffee Pulp Waste After Alkaline Hydrogen Peroxide Treatment

Abstract

Abstract The effect of alkaline hydrogen peroxide (AHP) treatment on reducing lignin content in coffee pulp waste (CPW) was investigated to increase the digestibility and accessibility of cellulose during production of valuable products by enzymatic and biological process. Hydrogen peroxide (H 2 O 2 ) at various concentrations (2.5, 5, and 7.5% (w/w of substrate)) was mixed into 10% (w/v) of CPW-NaOH solution at 35 °C for 24 h with pH 11.5. The concentration of lignocellulosic content was investigated. The characteristic of crystallinity index, functional groups, and surface morphology of CPW at before and after the treatment have been observed using XRD, FTIR, and SEM analysis, respectively. The results showed that the highest lignin removal was achieved at the addition of 7.5% H 2 O 2 which decreased from 16.85% to 8.5%. The concentration of cellulose and hemicellulose in CPW increased from 53% to 64% and 11% to 24%, respectively. The crystallinity index of AHP-treated CPW has increased from 30.83% to 42.08%. A surface morphological destruction on the CPW was getting worse as along with the increase of H 2 O 2 concentration. This would be useful to increase the porosity of biomass to give cellulose accessibility by enzyme for further processes.