Xylose reductase generated by yeast Candida tropicalis purified using an aqueous two-phase system optimised by RSM.

Xylitol is a sweetener, which can be produced by Candida yeasts. Xylitol production (XP) is expensive due to the high cost of enzymes production such as xylose reductase (XR). XR can be produced with a low-cost using cashew apple waste (CAW) hydrolysed; however, methods for XR purification are expensive. This study aims to optimise an ATPS using a response surface method (RSM) for xylose reductase (XR) purification. CAW was hydrolysed. Fermentations were conducted using yeast (CCT 1516) for XR production. Then, a RSM varying ATPS composition (polyetilenglycol (PEG, 1.6-2.4 g/L) and potassium phosphate (PP, 1-1.3 g/L) was applied for XR purification. The highest concentration of xylitol (15.4 g/L) generated was achieved at 40 h. The highest XR activity (0.4 U/mg) was reached at 28 h. RSM reveals that XR purification is positively affected by PEG, in contrast, PP did not affect XR purification.