Identification and characterization of aldo-keto reductase responsible for patulin degradation in Saccharomyces cerevisiae

Patulin (PAT) is a hazardous mycotoxin that contaminates fruits and their products, causing significant economic losses. An aldo-keto reductase from Saccharomyces cerevisiae ( Sc AKR) was expressed in Escherichia coli in this study. The purified Sc AKR converted PAT to E -ascladiol with NADPH as a cofactor. The Sc AKR exhibited a strong degradation activity on PAT and the optimal degradation conditions were pH 7 and 37 °C. Molecular docking and site-specific mutagenesis indicated that the amino acids in Sc AKR interacting with PAT aldehyde affected the degradation effect, and the mutation of Trp298 showed the most significant effect on the degradation rate. Furthermore, Sc AKR also showed a strong degradation effect on 3-keto-deoxynivalenol, a metabolite of another mycotoxin, deoxynivalenol (DON). The findings offer new insights on the detoxification mechanism of PAT by S. cerevisiae and for the development and application of bioenzymes with broad-spectrum mycotoxin degradation properties.