During investigation of fungal flora in imported and domestic cereal products many isolates of
Penicillium were obtained. Of the representative 20
Penicillium strains, the MicroLog system was tested for species identification. The MicroLog system is a 96 well microplate with 95 different carbon sources selected to include all of the important biochemical groups: sugers, carboxylic acids, amino acids, fattyacids, etc. The FF MicroPlate was used in this study and purchased from BIOLOG, Inc. One plate is inoculated with one isolate conidial suspension. After incubation, plates were evaluated with a microplate reader, which measures the turbidity in each well. The microplate reader connected to a computer, using the MicroLog software. During the incubation of the MicroPlates it was observed that most of the isolates produced colored soluble pigments on some of the carbon sources. Some species of the genus
Penicillium are difficult to separate based on morphology alone, and the differentiation between species of this genus is difficult without the aid of physiological tests, i.e, assimilation of carbon sources and secondary metabolic profiles. We found that the MicroLog system could distinguish between the limited number of mycotoxigenic Penicillia such as
P. citreonigrum,
P. citrinum,
P. expansum,
P. islandicum and
P. verrucosum. In addition, we examined to distinguish among the members of aflatoxigenic section
Flavi species, including
Aspergillus flavus,
A. parasiticus and
A. nomius isolates from imported peanuts and sugarcane field soil collected from Okinawa by the MicroLog system. Our results indicate that difficult of separate of these species.
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