Effect of pretreatment and enzymatic hydrolysis for oligosaccharide production from oil palm mesocarp Fibre

Abstract

In this study, oil palm mesocarp fibre (SM) was converted into oligosaccharides as a value-added product. The objective of this study was to determine the effect of pretreatment and hydrolysis time for oligosaccharide production using a commercial Celluclast (1.5 L) enzyme complex. Pretreatment with 5% (v/v) sodium hydroxide (NaOH) and 5% (v/v) acetic acid solution (CH3COOH) was performed before enzyme hydrolysis. Pretreatment using concentrations of 5, 10 and 15% (v/v) NaOH solution was carried out in an autoclave at 120 °C for 30 min. Hydrolysis of the alkaline pretreated SM was performed at 0, 3, 6, and 24 h. Enzymatic hydrolysis results indicated that pretreatment of SM with 5% NaOH produced a higher amount of reducing sugar compared to raw SM and 5% CH3COOH SM pretreatment, producing 351.94 mg/g compared to 181.44 and 183.15 mg/g amount of reducing sugar per mass of biomass, respectively. The increased amount of sugars for alkali pretreatment was due to the removal of lignin and hemicellulose portions in SM. Increased NaOH concentration resulted in a higher percentage of saccharification. Hydrolysis of pretreated SM for 3 to 24 h produced oligosaccharides with 2, 3 and 4 glucose units. No differences in the number of glucose units were observed when hydrolysis time was increased from 3 to 24 h. This study demonstrated the ability of oligosaccharide production from SM by manipulating hydrolysis time.