Recently, a research paper titled Identification and Application of a Novel Patulin Degrading Enzyme from Meyerozyma guilliermondii by Prof. Zhang Hongyin's Research team from School of Food and Biological Engineering of Jiangsu University (JSU) was published in the Advanced Science. Doctoral Candidate Yu Zhang is the first author, and Prof. Zhang Hongyin and Associate Prof. Yang Qiya are the co-corresponding authors. Qianhua Zhao, Solairaj Dhanasekaran, Esa Abiso Godana, Le Zhang and Xue Bai contributed to this work.
Patulin (PAT) is a highly toxic fungal secondary metabolite mainly produced by Penicillium expansum, which contaminates apples, pears, grapes and other fruits and their derived products. The primary hazards of PAT to animals and humans include carcinogenicity, immunotoxicity, reproductive toxicity, skin toxicity, intestinal toxicity, hepatotoxicity and nephrotoxicity. Traditional physical and chemical methods to control PAT contamination face limitations, whereas biological methods have attracted significant attention due to their safety and efficiency. Biological methods primarily detoxify PAT through microorganisms or enzymes produced by these microorganisms. Among these methods, enzymatic detoxification technology avoids secondary microbial contamination and demonstrates superior potential for industrial applications. However, current literature reports on PAT degrading enzymes remain limited in diversity, abundance, and functional characterization. There is an urgent need to screen novel high-efficiency degradation enzymes, elucidate their enzymatic properties and catalytic mechanisms, and engineer high-performance immobilized enzymes to advance their industrial production and application.
In this study, RNA-seq and molecular docking techniques were employed to analyze the molecular mechanism of PAT degradation by Meyerozyma guilliermondii. The results indicated that M. guilliermondii mitigated the harmful effects of PAT stress by enhancing gene expression related to antioxidant stress, GSH metabolism, DNA damage repair, DNA replication, growth and reproduction, drug resistance, potential degradation enzymes, and zinc finger transcription factors. A novel PAT degrading enzyme (short-chain dehydrogenase/reductase, MgSDR1) was screened in this study. MgSDR1 can convert 10 μg/mL PAT into non-toxic E-ascladiol within 2 h. And the biodegradation process had no negative effect on the quality of fresh pear juice. In addition, the effects of catalytic triads (Ser174, Tyr188 and Lys192) on the degradation of PAT by MgSDR1 were analyzed by molecular docking and amino acid site-directed mutagenesis. After the above three amino acid residues were mutated to alanine, the mutant protein could hardly degrade PAT, indicating that the catalytic triad of MgSDR1 plays an important role in the degradation of PAT.
