Isolation and Identification of Bacteria Capable of Binding to Aflatoxin Download PDF

Aflatoxin is one of the most dangerous mycotoxins produced under favorable conditions of relative humidity and high temperature by Aspergillus funguses. It rapidly disperses in the environment and causes a lot of damage to the food. Various microorganisms, including different types of Lactic Acid Bacteria, are capable of binding mycotoxins, such as Aflatoxins. Lactic Acid Bacteria are bound to the mycotoxins by polysaccharide and peptidoglycan components presenting in the cell wall, and lead to detoxicity and excretion of them. In the present study, Coumarin, due to its chemical structure similar to Aflatoxin, was used to isolate the bacteria with the ability to bind to mycotoxins. 20 isolates of lactobacillus were isolated and purified using the enrichment and serial dilution techniques in the MRS(de Man, Rogosa and Sharpe) media. The ability of these isolates to bind to the Coumarin was evaluated using a spectrophotometer. Based on microscopic observations and biochemical tests, these isolates were classified as Lactic Acid Bacteria. 3 of 20 Lactic Acid Bacteria isolates had the highest ability to reduce 50 ppm of Coumarin after a week. The isolate Entrococcus faecium 2 showed the highest percentage of reduction in Coumarin (%19.6) than other isolates and the isolates E. faecium 1 and E. casseliflavus can reduce the Coumarin as much as %14 after a week. By examining Non-living biomass of bacteria, Non-living of the isolate E. casseliflavus showed the highest percentage of reduction in the Coumarin than other isolates. In addition, the isolates E. faecium 1 and E. faecium 2 reduced the Coumarin as much as %14 after a week. Based on 16S rDNA gene sequencing of the isolates with the ability to reduce Coumarin, two isolates of E. faecium and one isolate of E.casseliflavus were identified. Based on the results, it was observed that the samples collected from livestock and poultry farms can be a suitable source for isolating the bacteria which have the capability of decomposing mycotoxins in the environment, since these bacteria present in the digestive system of livestock and poultry, they can be used in the diet of them in order to reduce mycotoxins.