Isolation, identification and aflR gene analysis of industrial Aspergillus fungi

One hundred and forty-six strains of Aspergillus sp. were isolated and identified from 27 commercial koji which were used in producing fermented foods in Taiwan. None was found to produce aflatoxin. The genomic DNA of 17 randomly selected Aspergilli were extracted and amplified by PCR using a pair of primers, which annealed part of the coding region of aflR gene, to investigate whether the non-production of aflatoxin is caused by the absence of an aflR gene. The results indicate that all the examined nonaflatoxigenic isolates contained the regulatory gene aflR. Gene analysis revealed that the two distinct patterns of fingerprints, T-GA- A-*-C and C-C-C-C-C-T at position –90, –89, –72, –61, –43, and 102, described by Chang et al. (1995), could not differentiate all the examined strains that were classified in the Aspergillus Section Flavi.