Conversion of Zearalenone to β-Zearalenol and Zearalenone-14,16-diglucoside by Candida parapsilosis ATCC 7330

Abstract

Zearalenone (ZEN), mainly produced by Fusarium species in many crops worldwide, is an estrogenic mycotoxin that causes reproductive disorders in livestock. In this study, we developed a different degradation mode by choosing specific microorganisms to catalyze directional reactions to produce less toxic or non-toxic target products. One promising strain, Candida parapsilosis ATCC 7330, with high reductase activity was evaluated for its ability to directly convert ZEN to less toxic β-Zearalenol (β-ZOL). Glucose was added to trigger ZEN glucosylation by yeast. Thin layer chromatography (TLC) combined with liquid chromatography-mass spectrometry (LC-MS) revealed that ZEN exposed to C. parapsilosis ATCC 7330 was transformed into β-ZOL and zearalenone glucosides ([M+H]+ at 643.2581), and it was proposed to be ZEN-14,16-diglucoside according to NMR analysis, which was stable under digestive conditions. Furthermore, kinetic analysis indicated that the ZEN level (20 μg/mL) decreased by 97% within 5 h, which relied on enzymes on the cell membrane. In addition, C.parapsilosis ATCC 7330 also exhibited glucosyltransferase activities toward β-ZOL, α-Zearalenol (α-ZOL) and Zearalanone (ZAN) with yields of 100%, 76%, and 100%, respectively. Considering the estrogenic toxicity of target metabolites after complex transformation without coenzyme addition, detoxification by specific biodegradable microorganisms may open new opportunities and innovations for mycotoxin detoxification.