Enzymatic hydrolysis enhancement of oil palm empty fruit bunch by Peracetic-Sulfuric acid pretreatment

Abstract The use of Oil palm empty fruit bunch (OPEFB) for bioethanol production requires lignin and hemicellulose removals to provide more enzyme accessibility during the subsequent enzymatic hydrolysis of cellulose to glucose. The well-known Dilute sulfuric acid (DS)-pretreatment degraded mainly the hemicellulose with minimal delignification. Oppositely, Peracetic acid (PA) degraded selectively the lignin, leaving most of the hemicellulose. In this study, the addition of PA 200 mM to H2SO4 100 mM (called PS) under electromagnetic irradiation (140 °C for 5 min) led to the high effectiveness of not only hemicellulose removal (88.5%) but also delignification (81.3%). This effective pretreatment enriched the OPEFB quality (cellulose composition) to 83.5% from 49.9% in unpretreated, compared to 62.9% in DS-pretreated OPEFB. The PS-pretreatment enhances the enzymatic digestibility to 77.0% (at 35 EGU cellulase and 30 U β-glucosidase/g cellulose), 1.8- and 11.9-times higher than those of DS-pretreated and unpretreated OPEFB, respectively. This high effectiveness of PS-pretreatment provides a potential way towards economically feasible bioethanol production from OPEFB.