P3-120 Biodegradation of Aflatoxin B1 by Edible Mushroom Cultures and Their Cell-free Extracts

Wednesday, July 12, 2017
Exhibit Hall (Tampa Convention Center)
Min Jung Choo , Korea University, Department of Integrated Biomedical and Life Science , Seoul , South Korea
Kyu Ri Lee , Korea University, Department of Integrated Biomedical and Life Science , Seoul , South Korea
Sung Min Cho , Korea University, Department of Integrated Biomedical and Life Science , Seoul , South Korea
Min Jung , Korea University, Department of Integrated Biomedical and Life Science , Seoul , South Korea
Sung-Yong Hong , Korea University, Department of Integrated Biomedical and Life Science , Seoul , South Korea
Soo-Hyun Chung , Korea University, Department of Integrated Biomedical and Life Science , Seoul , South Korea
Introduction: Aflatoxins are highly toxic secondary metabolites predominantly produced by toxigenic Aspergillus flavus and Aspergillus parasiticus. Of these aflatoxins, aflatoxin B1 (AFB1) is the most potent carcinogen. It has been reported that edible mushrooms including Pleurotus ostreatus, have AFB1 biodegradation activity.

Purpose: The purpose of this study was to investigate the AFB1-degrading activity of edible mushroom cultures and their cell-free extracts.

Methods: Twenty edible mushrooms in Basidiomycota were obtained from mushroom farms in Gyung-gi province in Korea. AFB1-degrading activity was screened using potato dextrose broth (PDB) containing 50 ng/mL of AFB1. To find out AFB1 degradation mechanism, cell-free extracts and cell-free culture broth were spiked with 0.1 1 μg/mL of AFB1 and incubated at 25°C for 2 days. AFB1 reduction in the samples was analyzed by HPLC-FLD.

Results: AFB1 in PDB was reduced by 5 mushrooms; Auricularia auricular-judae, Bjerkandera adusta, Hericium erinaceus, Lentinula edodes, and Poria cocos. The cell-free extract of the mushrooms showed significant AFB1-degrading activity; AFB1 (initial concentration of 1 μg/mL) was reduced by more than 98% by A. auricular-judae, 70% by B. adusta, 37% by H. erinaceus, and 50% by L. edodes,  respectively, within 24 hr. The AFB1 biodegradation was enhanced in the presence of NADPH and NaIO4. No growth of the 5 AFB1-degrading mushrooms was observed on cumarin agar plates and no decolorization of Remazol Brilliant Blue R agar plates was found from 4 mushrooms except B. adusta.

Significance: These results indicate that the extracts from the selected mushrooms, especially edible Auricularia auricular-judae and Lentinula edodes, which are major mushrooms produced commercially in Korea, have potentials for biodegradation of AFB1in food and feed.