The Potential of Peroxidases Extracted from the Spent Mushroom (Flammulina velutipes) Substrate Significantly Degrade Mycotoxin Deoxynivalenol.

Ko-Hua Tso,Hsin-I Chiang,Chompunut Lumsangkul,Jyh-Cherng Ju,Yang-Kwang Fan

doi:10.3390/toxins13010072

Abstract

Little is known about the degradability of mycotoxin deoxynivalenol (DON) by the spent mushroom substrate (SMS)-derived manganese peroxidase (MnP) and lignin peroxidase (LiP) and its potential. The present study investigated the growth inhibition of Fusarium graminearum KR1 and the degradation of DON by MnP and LiP extracted from SMS. The results from the 7-day treatment period showed that mycelium inhibition of F. graminearum KR1 by MnP and LiP were 23.7% and 74.7%, respectively. Deoxynivalenol production in the mycelium of F. graminearum KR1 was undetectable after treatment with 50 U/mL of MnP or LiP for 7 days. N-acetyl-D-glucosamine (GlcNAc) content and chitinase activity both increased in the hyphae of F. graminearum KR1 after treatment with MnP and LiP for 1, 3, and 6 h, respectively. At 12 h, only the LiP-treated group had higher chitinase activity and GlcNAc content than those of the control group (p < 0.05). However, more than 60% of DON degradabilities (0.5 mg/kg, 1 h) were observed under various pH values (2.5, 4.5, and 6.5) in both MnP (50 U/g) and LiP (50 U/g) groups, while DON degradability at 1 mg/kg was 85.5% after 50 U/g of LiP treatment for 7 h in simulated pig gastrointestinal tracts. Similarly, DON degradability at 5 mg/kg was 67.1% after LiP treatment for 4.5 h in simulated poultry gastrointestinal tracts. The present study demonstrated that SMS-extracted peroxidases, particularly LiP, could effectively degrade DON and inhibit the mycelium growth of F. graminearum KR1.

Highlights

During harvest, transportation, processing, and storage, feed ingredients are susceptible to fungal infection and contamination by their toxic metabolites—mycotoxins [1].More than 25% of worldwide crops are affected by mycotoxins yearly, resulting in a huge financial loss in grain production and causing a threat to the health and life of humans and animals [2]
lignin peroxidase (LiP) treatments, and the hyphae became broken down after LiP treatment (Figure 1). These results strongly suggest that manganese peroxidase (MnP) and LiP could enhance chitinase activity and cause degradation or degeneration of hyphae
LiP, the present study has adequately provided a simplified purification procedure in turning disposed spent mushroom substrate (SMS) into a valuable by-product from the mushroom industry in an environment-friendly manner. This is the first report on the ability of MnP and LiP to inhibit the growth of F. graminearum KR1 and the production of DON

Summary

Introduction

Transportation, processing, and storage, feed ingredients are susceptible to fungal infection and contamination by their toxic metabolites—mycotoxins [1]. More than 25% of worldwide crops are affected by mycotoxins yearly, resulting in a huge financial loss in grain production and causing a threat to the health and life of humans and animals [2]. The type B trichothecene deoxynivalenol (DON) is responsible for one of the most severe pollutions in feeds and ingredients. Global climate change has resulted in an increased risk of Fusarium infection in grains, and the worldwide pollution rates of DON in ingredients and feeds have been rising over years, posing a severe threat to animal and human health [7].

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