Biovalorization of Nondetoxified Corn Cob Hydrolysate into Xylitol by <i>Pichia fermentans</i> T12

High Resolution Image Download MS PowerPoint Slide Xylitol is a sugar alcohol extensively used in the food and pharmaceutical industries and can be produced via microbial fermentation processes through the reduction of xylose derived from hemicellulosic biomass. Corn cobs represent an abundant lignocellulosic resource that can serve as a raw material for xylitol production as well as the biosynthesis of other value-added compounds. The objective of the current study was to examine the novel utilization of corn cob hydrolysate (CCH), rich in xylose, as a sustainable and low-cost substrate for xylitol production by the newly isolated yeast strain Pichia fermentans T12 (GenBank number: PV876729). Acid-pretreated corn cobs, without any detoxification step, were directly employed as the feedstock for xylitol production. The process parameters were optimized to enhance the xylitol yield, and the highest xylitol accumulation was achieved at a temperature of 30 °C, an initial pH of 6, a CCH concentration of 125 mL/L, a yeast extract concentration of 2 g/L, an inoculum concentration of 7%, and an incubation time of 96 h. Under optimized batch fermentation conditions using 125 mL/L CCH (32 g/L xylose), 21.6 g/L xylitol was obtained with a yield of 0.67 g/g, as confirmed by the HPLC analysis. Following downstream processing, the functional groups of the microbial xylitol were verified by FTIR results. This research study emphasizes the potential of P. fermentans T12 for xylitol production by utilizing corn cob biomass as a microbial cell factory, offering a sustainable alternative to conventional substrates.