Glucose and Xylose Productions From Oil Palm Empty Fruit Bunch by Hydrolysis With Enzyme and Acid Using Response Surface Methodology.

Abstract Oil palm empty fruit bunch (EFB) is a major cellulosic waste from a palm oil mill. The use of EFB for bioconversion to fuel and valuable products is possible because this biomass is a cheap, renewable and abundantly available. This study was aimed to produce sugars from the alkaline peroxide pretreated EFB (APEFB) by hydrolysis with a commercial enzyme (iKnowzyme acid 2XL cellulase) in comparison with hydrochloric acid. Response surface methodology (RSM) was applied to improve the hydrolysis process. For an enzymatic hydrolysis, the optimum enzyme dose of 40 U/g APEFB and the liquid to solid ratio of 10 ml/g APEFB were investigated at 150 rpm and 50°C for 120 h. After saccharification, glucose and xylose obtained were 65.71 g/l (0.66 g/g APEFB) and 2.14 g/l (0.02 g/g APEFB), respectively. Many acids (acetic, formic, hydrochloric (HCl), nitric, orthophosphoric and sulfuric acids) were used to hydrolyze APEFB. The result showed that HCl was the best acid to produce glucose and xylose from APEFB with low furfural and hydroxymethylfurfural productions. The optimum HCl concentration and temperature for APEFB saccharification were 5.85% (w/v) acid at 114°C for 90 min. The glucose, xylose, furfural, and hydroxymethylfurfural obtained under these conditions were 10.70 g/l (0.11 g/g APEFB), 15.30 g/l (0.15 g/g APEFB), 2.34 g/l (0.02 g/g APEFB) and 0.67 g/l (0.007 g/g APEFB), respectively.