Forschungs- & Entwicklungsinformationsdienst der Gemeinschaft - CORDIS

Method for the creation of permissive and suppressive culture conditions for the production of ochratoxin A in species of black aspergilli

Influence of culture parameters (trace metals, carbon source, nitrogen source) on the production of ochratoxin A in cultures of A. ochraceus has been intensively studied. No correlation between biomass production and OTA biosynthesis was observed under neither condition. OTA production depended on initial pH of the culture medium at inoculation.

Production of OTA was observed reproducibly at an initial pH of 6.5 whereas no OTA was produced in cultures inoculated at pH 5.0. Biomass production was not depending on the initial pH at inoculation. Observations could be used to trigger production of OTA in a non-producing culture by shifting pH to 6.5 during cultivation. Onset of toxin production was observed with a time delay of about 20 h after pH shift.

The result has no direct commercial application but has serious impact on basic research in the field of biosynthesis of OTA as well as on studies of its genetics and regulation. A practical output from this result may be that processing of food and feed in which OTA production by A. ochraceus might be critical, should be run under OTA suppressive conditions, e.g. at pH lower than 5.0 at start of the process.

More information on the DETOX-FUNGI project can be found at:

Reported by

Technische Universität München, Lehrstuhl für Technische Mikrobiologie
Welhenstephaner Steig 16
85350 Freising
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