Aflatoxin B1 degradation during co-cultivation of Aspergillus flavus and Pleurotus ostreatus strains on rice straw

Abstract

Aflatoxin B1 (AFB1) produced by Aspergillus flavus is known to have carcinogenic and teratogenic effects on animal health. Accidental feeding of AFB1-contaminated rice straw may be detrimental to dairy cattle. White-rot basidiomycetous fungus Pleurotus ostreatus can grow on different agronomic wastes by synthesizing different ligninolytic enzymes. These extracellular enzymes are capable of degrading many environmentally hazardous compounds including AFB1. The present study examines the ability of different strains of P. ostreatus to degrade AFB1 in contaminated rice straw. Different strains of A. flavus were inoculated on rice straw for AFB1 production. The moldy straw was then subjected to co-cultivation by different strains of P. ostreatus. The extent of AFB1 degradation was determined by high performance liquid chromatography. Results indicated the presence of AFB1 in the moldy straw samples at levels of 27.95 ± 0.23 and 21.26 ± 0.55 µg/g of dry substrate for A. flavus MTCC 2798 and A. flavus GHBF09, respectively. Co-cultivation of P. ostreatus strains on AFB1-contaminated rice straw revealed their ability to rapidly colonize the substrate by profuse hyphal ramification. Highest degradation of AFB1 (89.41 %) was recorded in the straw containing co-cultures of A. flavus MTCC 2798 and P. ostreatus GHBBF10. Natural isolate P. ostreatus GHBBF10 demonstrated higher AFB1-degradation potential than P.ostreatus MTCC 142. This basidiomycete strain can be further exploited to effectively degrade moderate concentrations of AFB1 in contaminated moldy rice straw.

Microbial degradation of aflatoxin B1: Current status and future advances

“…Chen et al 2015, Cole et al (1972), Das et al (2014), Megalla and Mohran (1984), and Wu et al (2009) Aflatoxin By applying these recommendations, we could have comparable data between the different degradation solutions. The future of those methods is the development and formulation of cocktails of AFB1 degraders to optimise efficacy and provide solutions to the agro-food chain.…”

“…For Basidiomycota, the potential of Pleurotus ostreatus to degrade AFB1 has been studied for N15 years. Recently, Das et al (2014) tested 2 strains of P. ostreatus on autoclaved rice. AFB1 was degraded between 89 and 92% after an incubation of 15 days at 30°C.…”

Mycoremediation in Soil

“…Many works on the edible mushroom P. ostreatus have been published. The biodegradation of the carcinogenic secondary metabolite aflatoxin B 1 (AFB 1 ), produced by Aspergillus flavus on rice straw [90] and on maize [91], was reported for this species. The mycoremediation of heavy metal-contaminated soils by means of different Pleurotus species was also reviewed in the work of [92].…”

Control of Aflatoxigenic Molds by Antagonistic Microorganisms: Inhibitory Behaviors, Bioactive Compounds, Related Mechanisms, and Influencing Factors

“…The biological control has been regarded as a more environmentally friendly and safer method [5,6], which was carried out generally at pre-and/or post-harvest. The post-harvest strategies focus mainly on the removal of aflatoxin [7][8][9][10][11][12]. However, once the agro-foods and feeds are contaminated, the contaminants such as aflatoxins can never be completely removed.…”