Aflatoxin biotransformation by commercial peroxidase and its application in contaminated food

Abstract

BACKGROUND Aflatoxin B1 (AFB1) is the most commonly occurring and the most toxic of all aflatoxins (AFs). It is responsible for liver cancer in animals and it is listed as a Group I carcinogen by the International Agency for Research on Cancer. Thus, it is necessary to find decontamination methods that show efficiency, specificity, low cost, and that allow the disposal of contaminated raw materials into the environment. This study evaluated the effects of enzyme concentration, pH, temperature and reaction time on AFB1 biotransformation by commercial peroxidase (POD) in a model solution (100 mmol L−1 phosphate buffer). RESULTS When 0.015 U mL−1 was used to treat 0.5 µg L−1 of AFB1, at pH 7.0–8.0 and 30–40 °C, for 8.0 h, the AFB1 biotransformation reached its maximum (97%). KM value of POD for the biotransformation of AFB1 was 0.0160 µmol L−1 (5 µg L−1) with a VMAX of 6.4 µmol L−1 min−1, which were determined based on Lineweaver‐Burk's plot. POD (0.015 U mL−1) effectively reduces AFB1 (97%) and M1 (65%) in UHT milk and AFB1 (24%) in lager beer samples acquired in markets of Rio Grande‐RS (Brazil). CONCLUSION The use of POD may be a strategy to mitigate the impact of AFs found in food to reduce the risk of consumer exposure. © 2018 Society of Chemical Industry

Enzymes for Detoxification of Various Mycotoxins: Origins and Mechanisms of Catalytic Action

“…Aflatoxin dialdehyde aldo-keto reductase AKR7A1 (Figure 2 [15,16], Table 1 [17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58]) was isolated from rat liver, and its structure in complex with NADP + was solved [59]. This enzyme is assumed to reduce both aldehyde groups of dialdehyde of hydroxy aflatoxin B 2a , forming from 8,9-dihydrodiol aflatoxin B 1 , resulted in dihydroxy derivative.…”

“…90 kDa to open the lactone ring according to measurements of biotransformed mycotoxin fluorescence. Other authors [25] went further and supposed (so far without experimental confirmation) that not only the lactone ring but also the coumarin ring can be opened. The commercial horseradish peroxidase showed the highest affinity for aflatoxin B 1 compared to aflatoxin M 1 .…”

“…The commercial horseradish peroxidase showed the highest affinity for aflatoxin B 1 compared to aflatoxin M 1 . Such enzyme successfully decontaminates milk and beer from the aflatoxins [25] by mechanism still being unknown.…”

Co-Immobilization of Enzymes and Metals on the Covalent-Organic Framework for the Efficient Removal of Mycotoxins

“…Aflatoxin B 1 (AFB 1 ) is one of the most hazardous mycotoxins and has been classified as a class A carcinogen by the International Agency for Research on Cancer. AFB 1 is commonly found in cereals and animal products. − Conventional methods for the detoxification of mycotoxins include physical adsorption and chemical treatments. However, these conventional methods have limitations, such as secondary pollution and the residue of reagents or material. − Moreover, due to the high stability of mycotoxins, traditional methods for their removal often require strong oxidants, high temperatures, and high pressure. − Therefore, exploring strategies for the removal of mycotoxins in green, efficient, and environmentally friendly manners is a meaningful and challenging issue.…”

Whole-Genome Sequencing and Bioinformatics Analysis of Apiotrichum mycotoxinivorans: Predicting Putative Zearalenone-Degradation Enzymes

“…This biotransformation is essential in eliminating aflatoxin’s tumorigenicity. Enzymes that cut the aflatoxin coumarin ring was also identified, although the involved mechanisms are still unknown because of the lack of protein complex structures ( Marimón Sibaja et al, 2019 ). In recent years, computer modeling technology has become more and more popular in the search for the next generation of aflatoxin degrading enzymes ( Dhakal et al, 2017 ; Zarev et al, 2020 ).…”