Xylose enhances furfural tolerance in Candida tropicalis by improving NADH recycle

- C. tropicalis shows stronger furfural tolerance in xylose medium.
- Process of xylose metabolism improves the recycle of NAD+.
- C. tropicalis is a promising host for utilization of hemicellulose hydrolysate.

Furfural is one of the typical inhibitors present in hemicellulose hydrolysate. Furfural is harmful to cell growth and biofuel production in microbes. As one of the microbes that could use xylose in hemicellulose hydrolysate, Candia. tropicalis shows a promising potential for metabolic engineering to produce biofuels and value-added chemicals. In this study, we found that the rate of furfural degradation and half maximal inhibitory concentration for furfural of C. tropicalis in xylose medium increased 1.68-fold and 1.19-fold, respectively, compared with those in glucose medium, indicating that C. tropicalis obtained better furfural tolerance in xylose medium. The dehydrogenation of xylitol, which produces coenzyme NADH, promotes the recycle of NAD+ and facilitates the reduction of furfural. This study provides important information for metabolic regulation and metabolic engineering of efficient lignocellulose fermentation strains.

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