Isolation, Identification and Characterization of Paenibacillus pabuli E1 to Explore Its Aflatoxin B₁ Degradation...

Aflatoxin B₁ (AFB₁) contamination in feed and food seriously threatens the healthy growth of animals and humans, and it may lead to huge economic losses in livestock and poultry production. Therefore, screening of high-efficient AFB₁-degrading bacteria is necessary to ensure the safety of feed and food. The study aims to isolate and characterize bacteria from various sources to explore its AFB₁ degradation potential. Fifteen bacterial were obtained using a medium containing coumarin as the sole carbon source; only one strain showed a good-degrading ability in culture media by adding AFB₁ and it was selected for further studies. A gram-negative and spore-forming, designated E1, was identified as Paenibacillus pabuli, with the highest sequence similarity to P. pabuli NBRC13638^T (98.97%). The growth of the strain E1 was observed under 22-47 °C, pH 5.5-9.5 and NaCl concentration 0-6% (w/v), with optimum growth at 37 °C, pH 7.5 and 1% NaCl. The biodegradation characteristics of object strain were detected by high performance liquid chromatography (HPLC). The degradation ratio of AFB₁ reached 55% at 24 h and 70.2% at 48 h. After 96 h, the degradation rate of AFB₁ reached 85.9%. The active degradation components were present in the cell-free supernatant of strain E1, and the degradation ratio of AFB₁ reached 80.0% after 96 h. It is the first report that genus Paenibacillus could degrade AFB₁. Moreover, E1 has highly adaptable to diverse environmental conditions. It will be a potential candidate for biodegradation of mycotoxins in feed and food.