Biosynthesis of xylitol by cell immobilization: an insight

Xylitol is one of the value-added polyalcohols with diverse applications in the food, nutraceuticals, cosmetic, and pharmaceutical industries. Commercial xylitol production is extensively carried out via chemical technology through catalytic xylose dehydrogenation under high temperatures and pressure. The biotechnological synthesis of xylitol from lignocellulosic biomass is a promising and sustainable substitute for chemical xylitol synthesis, which requires strong reaction conditions and removal of the undesirable coproducts produced during the process. Numerous reviews target culture conditions and metabolic pathways in recombinant and wild xylitol-producing organisms for enhanced xylitol accretion. However, fewer studies focus on the engineering and bioprocess aspects essential for large-scale xylitol production. This review emphasizes recent advancements in xylitol bioproduction using immobilization methods. Cell immobilization improves biocatalyst reusability, stability, and tolerance against inhibitors, decreases process costs, and denotes a fundamental prerequisite for industrial application. The main immobilization techniques, mode of operations, and bioreactors employed for xylitol bioproduction using immobilization have been comprehensively summarized in this review.