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. 2012 May 20;2(1):28.
doi: 10.1186/2191-0855-2-28.

Influence of pH and carbon to nitrogen ratio on mycotoxin production by Alternaria alternata in submerged cultivation

Katrin Brzonkalik  1 , Dominik Hümmer, Christoph Syldatk, Anke Neumann
Affiliations

Influence of pH and carbon to nitrogen ratio on mycotoxin production by Alternaria alternata in submerged cultivation

Katrin Brzonkalik et al. AMB Express. .

Abstract

Production of the Alternaria mycotoxins alternariol (AOH), alternariol monomethylether (AME) and tenuazonic acid (TA) by Alternaria alternata DSM 12633 was influenced by pH and carbon to nitrogen (C:N) ratio of the growth medium both in shaking flasks and bioreactor cultivation. The impact of medium pH on mycotoxin production was studied in the range of pH 3.5 - 8. pH values above 5.5 led to a decreased mycotoxin production or inhibited mycotoxin formation completely whereas an acidic pH in the range of 4.0-4.5 was optimal for mycotoxin production. The influence of the C:N ratio was evaluated over the range of 24 to 96. Glucose was used as carbon source and its concentration was altered while nitrogen concentration was kept constant. Growth kinetics and mycotoxin production parameters were studied depending on different C:N ratios. With increasing initial glucose concentration fungal biomass did increase but the maximum specific growth rate was not influenced. The optimal initial C:N ratio for attaining highest mycotoxin concentrations was 72. A higher C:N ratio did not further enhance mycotoxin production.

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Figures

Figure 1
Figure 1
Chemical structure of the best studiedAlternariamycotoxins: alternariol (A), alternariol monomethylether (B) and tenuazonic acid (C).
Figure 2
Figure 2
pH variation (A) and mycotoxin production (B) during shaking flask cultivation ofA. alternataDSM 12633 in modified Czapek-Dox medium depending on initial pH. Data is given as an average of 3 independent samples.
Figure 3
Figure 3
Glucose consumption (A), biomass production (B) and mycotoxin formation (C) during shaking flask cultivation ofA. alternataDSM 12633 in modified Czapek-Dox medium depending on C:N ratio. Data is given as an average of 3 independent samples.
See this image and copyright information in PMC

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