Mechanisms of patulin biodegradation by Wickerhamomyces anomalus XL1 in apple juice

Abstract

Patulin (PAT), a mycotoxin primarily produced by Penicillium species, presents a serious food safety challenge due to its widespread occurrence and harmful health effects. Among current detoxification approaches, yeast-based degradation is particularly promising, offering high efficiency, environmental sustainability, and preservation of food quality—key attributes for industrial application. However, the enzymatic pathways involved and the potential for concurrent quality enhancement remain poorly understood. In this study, Wickerhamomyces anomalus XL1—selected from 15 yeast strains for its superior PAT-degrading capacity—completely eliminated 5 μg/mL PAT to undetectable levels (<0.06 μg/mL) within 24 h under optimal conditions (pH 3–7, 20–35 °C). Mechanistic analysis confirmed that degradation is mediated by intracellular enzymes, indicating an enzymatic rather than adsorptive mechanism. UPLC-Q-TOF/MS identified the major degradation products as non-toxic E/Z-ascladiol isomers. Importantly, XL1 demonstrated practical efficacy in both fresh and commercial apple juice, achieving complete PAT removal within 24 h. Additionally, it enhanced juice quality by increasing total phenolic content (from 243.25 to 397.17 mg/L) and enriching volatile aroma profiles through the synthesis of novel compounds. This dual functionality—efficient PAT detoxification and concurrent improvement of product quality—positions W. anomalus XL1 as a highly promising biological agent for industrial-scale food safety applications.