Palm oil mill effluent as the pretreatment solvent of oil palm empty fruit bunch fiber for fermentable sugars production

Pretreatment is an essential upstream process to deconstruct oil palm empty fruit bunch fiber (OPEFBF) prior to sugars production. This study aimed to investigate the efficiency of OPEFBF pretreatment using palm oil mill effluent (POME) as solvent. The effect of alkali catalyst (5%w/w NaOH and ammonia), temperature (90,120,135 °C) and time (60,120,180 min) on the efficiency of pretreatment (OPEFBF-to-solvent ratio of 1:25) was also investigated. The results indicated that POME-pretreatment (135 °C, 180 min) enhanced glucose yield by only ~56%. Glucose production was increased about 5.8-fold to 495.3 ± 5.9 mg g-1 OPEFBF when NaOH was added in POME-pretreatment (Na-P). The xylose production from OPEFBF was increased about 3.7-fold after ammonia-catalyzed POME-pretreatment. About 12.1 ± 0.2 g L-1 of ethanol was produced from Na-P-hydrolysate at molar conversion of 59.4 ± 1.4%. This research provides new insight into the use of POME as a cost-effective pretreatment solvent of OPEFBF to reduce upstream process cost by cutting down water usage.