Affiliation:
1. ”Bio-Ekološki Centar” DOO, Zrenjanin
2. Institut za kukuruz “Zemun Polje”, Beograd-Zemun
Abstract
Nine isolates of fungi of genera Aspergillus, Fusarium, Paecilomyces and
Penicillium were cultured on the modified Vogel?s medium with the addition
of crude ochratoxin A (OTA) extract. This crude OTA extract was derived from
a natural solid substrate on which Aspergillus ochraceus strain CBS 108.08
was cultivated. OTA was isolated, partially purified, dried by evaporating
and dissolved in ethanol (1 mg ml-1), and added to the test medium up to the
final concentration of 10 ?g ml-1. The presence of OTA residues was
determined after 7 and 14 day cultivation of fungi in the test medium at
27?1?C. The Paecilomyces lilacinus isolate (Inf. 2/A), which completely
degraded OTA (150 ?g) after only seven days, was selected for further
studies. Wet sterile rice grains (50 g + 25 ml distilled water) were
inoculated with individual isolates of fungi A. ochraceus (strain CBS
108.08) and P. lilacinus (isolate Inf. 2/A), and with their combination. In
the case of P. lilacinus monoculture, 0.9 mg of crude OTA was also added
into cultivation substrate. Each test was done in three replications. After
the four week cultivation of individual and combined fungi at 27?1?C,
inoculated rice grains were dried to the constant weight and pulverized. OTA
was determined in these samples by the application of standard TLC method
for fodder analysis. OTA in the amount of 61.310 ?g kg-1 dry matter (DM) was
determined only in the samples inoculated with a producer of ochratoxin A
(A. ochraceus, strain CBS 108.08). On the other hand, a much smaller amount
of OTA (80 ?g kg-1 DM) was detected in samples inoculated with combined
cultures of A. ochraceus and P. lilacinus isolates. Gained results indicate
that P. lilacinus degraded, on average, 99.8% of OTA. After four week
cultivation, the same fungal isolate in the samples of wet sterile rice
kernels with the addition of 0.9 mg of crude OTA, completely degraded added
crude OTA (<8 ?g kg-1).
Publisher
National Library of Serbia
Cited by
1 articles.
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