Bioconversion of oil palm empty fruit bunches waste into prebiotic xylooligosaccharides using a genetic modified cross-linked endoxylanase aggregates immobilization

Abstract

Recent progress has been achieved towards more environmentally friendly and productive approaches using xylanolytic enzyme in producing prebiotic xylooligosaccharides (XOS) from inexpensive lignocellulosic biowaste. The cost of hydrolyzing XOS from appropriate materials high in xylan and the lack of xylanase enzyme activity after several treatment cycles are among the most pressing problems faced by the industries. In this study, XOS was produced utilizing a cross-linked mutated endoxylanase aggregates (CLmXynA) immobilization from an oil palm empty fruit bunches (OPEFB) waste. OPEFB was pretreated using sodium hydroxide-peracetic acid two-stage process which successfully removed 61.1% of lignin and 78.4% of extractives. From 28.4% of hemicellulose recovered, the highest hydrolysis activity (19.3%) was optimized using one-factor at one time approach where a total of 11.01 mg/g of XOS was produced. X3 (70.5%) was shown to be a major product meanwhile, this study presented longer XOS oligomers (X4 = 5.1% and X5 = 6.1%) hydrolyzed compared to a common major of X2 and X3 from a previous report. Moreover, CLmXynA maintained 29% of its initial XOS hydrolysis after five cycles, each of 48 h of reaction and depicted 1.6-fold higher activation energy (33.1 kJ mol⁻¹ K⁻¹) than its apparent kinetic model when the heterogenous kinetic hydrolysis were assessed using a modified Prout-Tompkin equation. As a conclusion, immobilized CLmXynA shown to be an efficient and stable biocatalyst while OPEFB which is a markedly large agriculture biowaste produced especially in Southeast Asia demonstrated a promise alternative of low-cost natural substrate for XOS production as a valuable prebiotic.