High Enzymatic Recovery and Purification of Xylooligosaccharides from Empty Fruit Bunch via Nanofiltration

Abstract

Xylooligosaccharides (XOS) are attracting an ever-increasing amount of interest for use as food prebiotics. In this study, we used efficient membrane separation technology to convert lignocellulosic materials into a renewable source of XOS. This study revealed a dual function of nanofiltration membranes by first achieving a high yield of xylobiose (a main component of XOS) from alkali-pretreated empty fruit bunch (EFB) hydrolysate, and then by achieving a high degree of separation for xylose as a monosaccharide product. Alkali pretreatment could increase the xylan content retention of raw EFB from 23.4% to 26.9%, which eventually contributed to higher yields of both xylobiose and xylose. Nanofiltration increased the total amount of XYN10Ks_480 endoxylanase produced from recombinant Streptomyces lividans 1326 without altering its specific activity. Concentrated XYN10Ks_480 endoxylanase was applied to the recovery of both xylobiose and xylose from alkali-pretreated EFB hydrolysate. Xylobiose and xylose yields reached 41.1% and 17.3%, respectively, and when unconcentrated XYN10Ks_480 endoxylanase was applied, those yields reached 35.1% and 8.3%, respectively. The last step in nanofiltration was to separate xylobiose over xylose, and 41.3 g.L−1 xylobiose (90.1% purity over xylose) was achieved. This nanofiltration method should shorten the processes used to obtain XOS as a high-value end product from lignocellulosic biomass.

A hemicellulose-first approach: one-step conversion of sugarcane bagasse to xylooligosaccharides over activated carbon modified with tandem plasma and acid treatments

“…Thus, this investigation revealed that the synthesized catalyst could be used up to four times before a small loss in catalytic activity occurs. XOS recovery from water can be achieved by the use of nanofiltration membranes 61 or ethanol/water extraction process. 62…”

Improved Glucose Recovery from Sicyos angulatus by NaOH Pretreatment and Application to Bioethanol Production

“…In lignocellulosic biomass pretreatment process, alkaline concentration is a significant factor affecting degradation of the ester bonds between lignin-carbohydrate matrix [35]. Various study reported that the NaOH was suitable to remove lignin barrier, which increase the accessibility of enzyme to carbohydrate [37][38][39]. Carbohydrates of lignocellulosic biomass were comprised of cellulose and hemicellulose such as glucan, xyloglucan, xylan, arabinoxylan, mannan, gluco-or galactomannan [40].…”

Optimised Fractionation of Brewer’s Spent Grain for a Biorefinery Producing Sugars, Oligosaccharides, and Bioethanol

“…The monomer arabinose and (A)XOS could be separated by different membrane and chromatographic methods in order to obtain pure arabinose-rich and an (A)XOS-rich solutions [57,58]. A promising method for that was investigated by Wijaya et al [59] and it included the combination of ultra-and nanofiltrations. After the filtration steps, 90.1% xylose recovery was achieved from a xylooligosaccharides-rich, empty fruit brunch hydrolysate [59].…”

“…A promising method for that was investigated by Wijaya et al [59] and it included the combination of ultra-and nanofiltrations. After the filtration steps, 90.1% xylose recovery was achieved from a xylooligosaccharides-rich, empty fruit brunch hydrolysate [59]. Hence, the first acidic hydrolysate of BSG might be further processed by membrane technology to obtain pure arabinose and AXOS-rich solutions [59] for the production of crystalline arabinose and AXOS preparation, respectively.…”

“…After the filtration steps, 90.1% xylose recovery was achieved from a xylooligosaccharides-rich, empty fruit brunch hydrolysate [59]. Hence, the first acidic hydrolysate of BSG might be further processed by membrane technology to obtain pure arabinose and AXOS-rich solutions [59] for the production of crystalline arabinose and AXOS preparation, respectively. Arabinose can be used as a platform molecule for drug synthesis in the pharmaceutical industry or as a healthy sweetener in the food industry [51], while AXOS might be used as prebiotic substance in functional foods, among other possible applications [60,61].…”