Evaluation of Simultaneous Saccharification and Fermentation of Oil Palm Empty Fruit Bunches for Xylitol Production

Abstract

The biological process route of xylitol production from lignocellulosic materials, via enzymatic hydrolysis which is followed by fermentation, offers a more sustainable or greener process than the chemical process route. Both the enzymatic hydrolysis and the fermentation processes are conducted at moderate process condition and thus require less energy and chemicals. However, the process proceeds slower than the chemical one. In order to improve process performance, the enzymatic hydrolysis and the fermentation processes can be integrated as Simultaneous Saccharification and Fermentation (SSF) configuration. This paper discusses the evaluation of SSF configuration on xylitol production from Oil Palm Empty Fruit Bunches (OPEFB). To integrate two processes which have different optimum temperature, the performance of each process at various temperature was first evaluated. Later, SSF was evaluated at various hydrolysis and fermentation time at each optimum temperature. SSF showed better process performance than the separated hydrolysis and fermentation processes. The best result was obtained from configuration with 72 hours of prior hydrolysis followed by simultaneous hydrolysis and fermentation, giving yield of 0.08 g-xylitol/g-OPEFB. Copyright © 2019 BCREC Group. All rights reserved

Modelling Based Analysis and Optimization of Simultaneous Saccharification and Fermentation for the Production of Lignocellulosic-Based Xylitol

“…xylitol productivity of 0.047 g/L [19]. Compared to this, this ideal simulation showed faster processing time and resulted in higher xylitol productivity.…”

“…In his research, the duration of the prior hydrolysis process was varied to achieve the optimum results. Overall, at the same total processing time, up to 4-fold increase of the xylitol yield from OPEFB when compared with that of SHF was obtained [19]. Prior hydrolysis is necessary to provide sufficient substrate for initializing the fermentation.…”

“…This conventional xylitol production method has several disadvantages: the process uses a lot of energy as it is conducted at relatively high pressure and temperature (50-60 bar and 140-200 o C); the process requires delicate purification of the hydrolysate to obtain pure xylose; and need more investment in types of equipment, considerable intermediate purification, product recovery, catalyst deactivation, and recycling process [15][16][17]. An alternative method of producing xylitol from lignocellulose-based materials involves a bioprocessing system that includes enzymatic hydrolysis using xylanase to obtain xylose containing hydrolysate, and microbial fermentation to convert xylose in hydrolysate into xylitol [16,18,19]. The hydrolysis and fermentation processes are normally conducted in different reactors or better known as separate hydrolysis and fermentation (SHF) because they have different operating conditions.…”

“…Alternatively, the bioprocess route for xylitol production, that is the hydrolysis and the fermentation, can be conducted simultaneously or better known as simultaneous saccharification and fermentation (SSF). In principle, both the hydrolysis and fermentation processes take place simultaneously in the same reactor, providing direct utilization of hydrolysis product, that is the monomeric sugar, as the carbon source for the fermenting agentform the desired product [19][20][21]. Consequently, both processes are conducted at the same operating condition.…”

“…Previous studies showed that the use of SSF combined with prior hydrolysis in ethanol production was able to increase the ethanol yield than the SSF only [24,25]. Burhan et al [19] reported the implementation of SSF for xylitol production from oil palm empty fruit bunch (OPEFB). In his research, the duration of the prior hydrolysis process was varied to achieve the optimum results.…”