Isolation and Characterization of Endophytic Bacilli Bacterium from Maize Grains Able to Detoxify Aflatoxin B1

Author： El-Deeb Bahig Altalhi Abdulla Khiralla Ghada Hassan Sabry Gherbawy Youssuf

ISSN： 0890-5436

Source： Food Biotechnology, Vol.27, Iss.3, 2013-07, pp. : 199-212

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Abstract

Aflatoxins are commonly found in cereals worldwide and bring significant threats to the food industry and animal food production. Among a collection of aflatoxin-degradative endophytic bacteria isolated from grains of corn plant, the strain TUBF1 was selected based on its high-ability to utilize aflatoxin B1 (AFB1) (10 μg/mL) as the sole carbon source. The morphological, physiological, and phylogenetic studies indicated that strain TUBF1 belonged to the Bacillus sp. group. HPLC was used to determine the reduction in AFB1 concentrations. Bacillus sp. TUBF1 had the strongest ability to detoxify toxin, where the degradation percentages of AFB1 was 81.5% and 100% after 48 and 72 h, respectively. The degradation of AFB1 was mainly in the culture supernatant of TUBF1 rather than its cells. About 90% of AFB1 was degraded within the first 12 h and reduced to the undetectable level after 24 h. The supernatant was characterized by considerable activity at wide range of temperatures (10-40°C) with optimal activity at 32°C and pH 6.5-7.5. Biosafety assessment test indicated that the crude enzymes had the high ability to detoxify AFB1. In conclusion, this is the first report on AFB1 detoxification using an endophytic Bacillus isolated from grains.