Aspergillus flavus and Aspergillus oryzae are very closely related species (just as A. parasiticus is with respect to A. sojae). However, A. flavus is pathogenic and A. oryzae is GRAS. It has been widely accepted that, through domestication, A. oryzae lost the ability to produce alfatoxins (though biosynthetic clusters are present in its genome), nevertheless little has been signaled about the genomic gains compared to A. flavus, specially regarding its exohydrolytic apparatus. My question, for you mycologists and -hopefully- Japanese food biotechnologists, is whether A. flavus has the same hydrolytic potential to turn gelatinized cereal grains into koji. Some authors (Shurtleff & Aoyagi) claim that one would be able to make koji by spontaneous fermentation, and I am thus wondering if the substrate poses a sort of axenic pressure. Also, if A. oryzae is a millenary domesticated ecotype of A. flavus, is it plausible for it to become of cosmopolitan distribution? I am going bananas suspecting there are aflatoxins in my koji.
The aflatoxin producer Aspergillus flavus and the koji mold Aspergillus oryzae are morphologically similar species that belong to the Aspergillus section Flavi. Scientists have used amplified fragment length polymorphism ( AFLP ) to differentiate the two species. From the results obtained it found that AFLP technique is a reliable and reproducible tool with the ability to differentiate A. flavus from A. orzyae and should be generally useful in distinguishing between closely related species or strain. For detailed information consult Bot. Bull. Acad. Sin. ( 2014 ) 45: 61 - 68
Hi,
Some properties were similarity between species . But note, Aspergillus oryzae are not Aflatoxin producing
Aspergillus oryzae produces many enzymes that degrade various biomolecules of high molecular mass such as carbohydrate, polypeptide, and nucleic acids.Aspergillus flavus is capable of producing cellulase enzyme.
Aspergillus flavus & A oryzae are well known for their multi enzyme producing capabilities hydrolyzing polysaccharides and proteins. These capabilities differ not only from species to species but there are variations among their strains also.
One need to select a suitable strain of these molds for getting higher activity of the required enzyme.
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