Xylitol production by a Wickerhamomyces anomalus strain adapted for enhanced tolerance to sugarcane bagasse hemicellulosic hydrolysate with high content of fermentation inhibitors

Background

Xylitol, a five-carbon polyalcohol, is used in the food and pharmaceutical industries and as a building block in the synthesis of high-value chemicals. It can be sustainably produced from renewable sources through xylose assimilating microbe fermentation.

Results

We screened microbial strains for xylitol production and identified Wickerhamomyces anomalus Z1 as a key xylitol producer. Utilizing lignocellulosic biomass hydrolysates for xylitol production poses challenges due to microbial sensitivity to inhibitors from biomass pre-treatment. In this study, an adaptive laboratory evolution (ALE) of W. anomalus Z1 was performed by culturing the yeast in a mineral medium supplemented with gradual increases of sugarcane bagasse hemicellulosic hydrolysate (SCHH) obtained by intensified steam explosion pretreatment. The performance of the adapted yeast, named Wickerhamomyces anomalus ALE, was assessed in comparison to the wild-type strain regarding its capacity to produce xylitol using SCHH. The evolved yeast reached a xylitol yield of 0.11 g xylitol/g xylose whereas the wild-type strain could not produce xylitol. Removing acetic acid from SCHH enhanced W. anomalus ALE performance, with optimal results at 75% hydrolyzed hemicellulose, yielding 0.44 g xylitol/g xylose and 13.41 g/L xylitol.

Conclusions

This study demonstrates the potential of W. anomalus ALE in successfully valorizing the hemicellulosic fraction of sugarcane bagasse for sustainable xylitol production.

How to cite: Bonfiglio F, Cagno M, Nuñez L, et al. Xylitol production by a Wickerhamomyces anomalus strain adapted for enhanced tolerance to sugarcane bagasse hemicellulosic hydrolysate with high content of fermentation inhibitors. Electron J Biotechnol 2024;71. https://doi.org/10.1016/j.ejbt.2024.05.004.