Purification and identification of an aflatoxin B1 degradation enzyme from Pantoea sp. T6.

Aflatoxin B1 (AFB1) is a secondary metabolite produced by Aspergillus flavus and other fungi. Soil, crops, food, feed, etc. were susceptible to aflatoxin B1 contamination, which caused adverse economic and health consequences. It is necessary to search for microorganisms or microbial enzymes that can degrade AFB1. The degradation activity of AFB1 by cell-free supernatant (68.30%) of isolate Pantoea sp. T6 was significantly higher (P < 0.05) than viable bacterial cells (4.87%) and intracellular cell extracts (3.68%). The supernatant's AFB1 degradation activity was reduced from 68.30% to 5.33% in treatment with protease K and sodium dodecyl sulphate (SDS). An extracellular enzyme from the supernatant was secreted by Pantoea sp. T6 and was named as Pantoea aflatoxin degradation enzyme (PADE), which was obtained using Diethylaminoethanol (DEAE)-Sepharose chromatography. PADE was further purified by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The PADE, outer membrane protein A, was identified by mass spectrometry and molecular mass was 38180.1Da. The optimum temperature and pH for the reaction of PADE with AFB1 were 40 °C and 7.0, respectively. These finding showing that the PADE, which was isolated from the supernatant of Pantoea sp. T6, has the ability to degrade AFB1, and may have potential application for aflatoxin B1 reduction in the food and feed industry.