Culture Media and Factors Influencing Ochratoxin A Production by Two Species of Penicillium Isolated from Poultry Feeds

Penicillium verrucosum and Penicillium nordicum produced a nephrotoxic metabolite, ochratoxin A (OTA). The OTA production was significantly influenced by media, pH, temperature, microbial nutrients, incubation periods and trace elements by P. verrucosum and P. nordicum were investigated. Among different media tried, Czapek yeast autolysate medium induced maximum amount of OTA production of both the species under study. Yeast extract sucrose, Blakeslee malt extract autolysate and rice flour (food based) medium were next preferred substrates. The pH of 5.5–6.5, temperature 25–30 °C and yeast extract (1 %) was optimum for both mycelial growth and OTA production. The kinetics of OTA production over 1 month incubation period with riveted 12th and 15th day incubation to be optimum for P. verrucosum and P. nordicum respectively. Out of trace elements Zn2+, Mg2+ was strongly influence OTA production, but Cu2+ and Fe3+ reduced the OTA production 30–40 %. The OTA production was analyzed by high performance liquid chromatography and results are presented in this communication.