Optimization of Xylose Recovery in Oil Palm Empty Fruit Bunches for Xylitol Production

Diah Meilany,Raj Boopathy,Made Tri Ari Penia Kresnowati,Tjandra Setiadi

doi:10.3390/app10041391

Abstract

The hardest obstacle to make use of lignocellulosic biomass by using green technology is the existence of lignin. It can hinder enzyme reactions with cellulose or hemicellulose as a substrate. Oil palm empty fruit bunches (OPEFBs) consist of hemicellulose with xylan as the main component. Xylitol production via fermentation could use this xylan since it can be converted into xylose. Several pretreatment processes were explored to increase sugar recovery from lignocellulosic biomass. Considering that hemicellulose is more susceptible to heat than cellulose, the hydrothermal process was applied to OPEFB before it was hydrolyzed enzymatically. The purpose of this study was to investigate the effect of temperature, solid loading, and pretreatment time on the OPEFB hydrothermal process. The xylose concentration in OPEFB hydrolysate was analyzed using high-performance liquid chromatography (HPLC). The results indicated that temperature was more important than pretreatment time and solid loading for OPEFB sugar recovery. The optimum temperature, solid loading, and pretreatment time for maximum xylose recovery from pretreated OPEFB were 165 °C, 7%, and 60 min, respectively, giving a xylose recovery of 0.061 g/g of pretreated OPEFB (35% of OPEFB xylan was recovered).

Highlights

Xylitol can be found naturally in some fruits and vegetables in a small amount, and it is widely consumed by diabetic patients as a sugar substitute since it does not need insulin to be metabolized [1,2].Xylitol has low potential to produce tooth decay; it is widely applied in toothpaste and confectionery
The effects of Solid loading (SL), temperature, and time on xylose recovery in the hydrolysate of solid and liquid pretreated Oil palm empty fruit bunches (OPEFBs) are shown in Figure 1a,b, respectively
Other studies stated that the pretreatment of sugarcane bagasse, sugarcane straw, wood, and OPEFB at temperatures higher than 165 ◦ C resulted in dissolved hemicellulose [37,38,39,40]

Summary

Introduction

Xylitol can be found naturally in some fruits and vegetables in a small amount, and it is widely consumed by diabetic patients as a sugar substitute since it does not need insulin to be metabolized [1,2]. Xylitol has low potential to produce tooth decay; it is widely applied in toothpaste and confectionery. Xylitol can be biologically synthesized from xylan, the part of hemicellulose in lignocellulosic biomass. The lignocellulosic biomass should be hydrolyzed enzymatically to obtain xylose as the main substrate for xylitol fermentation. Oil palm empty fruit bunches (OPEFBs) represent the main lignocellulosic biomass waste from the palm oil industry. For every ton of crude palm oil (CPO) produced, 0.96 tons of OPEFB is generated [3,4]

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Discussion

Conclusion