Agricultural Waste to Value-Added Xylooligosaccharides: The Potential of Banana Pseudostem

Abstract

Lignocellulosic biomass is a sustainable and renewable resource to be used as feedstock for high value biochemicals especially xylooligosaccharides (XOS) which are attracting great interest because of its well-established prebiotic functionality. Banana pseudostem is an agro industrial residue available in high quantities and presents a moderate xylan content which makes it potential substrate for XOS production within integrated biorefinery systems. The following review evaluates the current advancement on strategies to valorize banana pseudostem generating XOS specifically addressing the effects of physicochemical pretreatment approaches on biomasses deconstruction and xylan accessibility. In this connection pretreatment procedures exemplified by alkaline dilute acid and steam explosion leading to lingo cellulosic structural changes as well as hemicellulose solubilisation with effect on downstream enzymatic digestibility are reviewed. Furthermore, the evaluation of endo-β-1,4-xylanases as an important biocatalytic step ruling the XOS yield and product specificity for the enzymatic depolymerization of xylan is discussed. It also synthesizes the effects of process parameters reaction temperature pH enzyme loading on hydrolysis efficiency and degree of polymerization of resultant oligosaccharides as reported in individual studies. Although new findings have been published on XOS biosynthesis from lignocellulose confounding factors such as feedstock heterogeneity low substrate selectivity and lack of techno economic validation impede optimization efforts for banana pseudostem derived systems. Integrated & synergistic pretreatment enzymatic conversion strategies along with scale up studies and life cycle assessment must become the focus of future studies to develop economically feasible and environmentally friendly XOS production routes. The valorization of banana pseudostem may promote the implementation of circular bioeconomy models by collaborating with agricultural residues being transformed into functional food ingredients