ASPERGILLUS-OCHRACEUS PRODUCTION OF 5,6-DIHYDROPENICILLIC ACID IN CULTURE AND FOODS

The production of 5,6-dihydropenicillic acid (DHPA) and penicillic aci d (PA) by Aspergillus ochraceus was-studied. DHPA has been revealed to be genotoxic in the Drosophila DNA-repair test in our previous report . The two compounds were produced by various type strains of A; ochrac eus and related strains of Aspergillus ih nutrient cultures. When A. o chraceus cells were inoculated into nutrient medium, PA was rapidly pr oduced followed by a steady increase of DHPA and a decrease in the PA level. On the contrary, A. ochraceus produced almost exclusively PA in potato dextrose agar medium, which is low in nutrients. A, ochraceus cells produced DHPA when inoculated into grain, especially in rice flo ur at 20 to 24 degrees C, and the DHPA level increased as the incubati on was prolonged. These results suggested that PA was Converted to DHP A under highly nutritive conditions. In vitro mutagenicity tests, the Ames test and the unau test, showed that DHPA was not mutagenic.