Evaluation of Aflatoxin B1 Biosynthesis in A. flavus Isolates from Central India and Identification of Atoxigenic Isolates

Abstract

Present study describes the effect of temperature and pH on biosynthesis of aflatoxin B1 (AFB1) to identify atoxigenic (aflatoxin non-producer) isolates of Aspergillus flavus. An indigenous detection method for AFB1 was developed using tandem mass spectrometric method. Detection of AFB1 was carried out in positive polarity using triple quadrapole mass spectrometer with electrospray ionization interface in Multiple Reaction Monitoring (MRM) mode. A total of four A. flavus isolates were selected for screening of AFB1 biosynthesis at pH 4.0, 5.5, 7.0, and 8.5 at 27°C. Highest AFB1 biosynthesis in MTCC11866 was found at pH 6.5 while in MTCC9367 it was at pH 7.0. On screening AFB1 biosynthesis in A. flavus culture at various temperatures a significant suppression in AFB1 biosynthesis was found at 37°C in comparison to 24 and 27°C in MTCC11866 and MTCC9367. AFB1 was not detected in other two A. flavus isolates MTCC11580 and MTCC11588 at any temperature and pH tested. AFB1 nonproducing isolates, MTCC11580 and MTCC11588 could be used as potent biocontrol agent. Additionally, present standardized method for AFB1 detection may find its application in qualitative and quantitative analysis of AFB1 contamination in food crop and other products.