No abstract

No abstract

As lignocellulosic biomass, Oil Palm Empty Fruit Bunch (OPEFB)

The biological route to produce xylitol from Oil Palm Empty Fruit Bunches (EFBs) comprises of EFBs pretreatment, enzymatic hydrolysis, fermentation, and downstream separation of the produced xylitol. Due to the specificity in the hemicellulose composition of EFBs, a xylanase enzyme that has a high affinity to EFBs is required to hydrolyze the EFBs into xylose. In this research, the influences of aeration, humidity, and mixing in xylanase production were mapped. The xylanase production was performed by Aspergillus fumigatus ITBCCL170 in a solid-state fermentation using a tray fermenter with EFBs as the substrate. The optimal configuration was further scaled up into xylanase production using 1000 g of EFBs as the substrate. The results showed that the highest enzyme activity was 236.3 U/g EFB, obtained from the use of humid air airflow of 0.1 LPM, and mixing was performed once a day. The scaling up resulted in a lower xylanase activity and call for a better design of the fermenter.Keywords: aeration, humidity, mixing, OPEFBs, tray fermenter, xylanase, xylitol

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).