Nutrient effects on biocontrol of Penicillium roqueforti by Pichia anomala J121 during airtight storage of wheat.
نویسندگان
چکیده
The biocontrol yeast Pichia anomala inhibits the growth of a variety of mold species. We examined the mechanism underlying the inhibition of the grain spoilage mold Penicillium roqueforti by the biocontrol yeast P. anomala J121 during airtight storage. The biocontrol effect in a model grain silo with moist wheat (water activity of 0.96) was enhanced when complex medium, maltose, or glucose was added. Supplementation with additional nitrogen or vitamin sources did not affect the biocontrol activity of the yeast. The addition of complex medium or glucose did not significantly influence the yeast cell numbers in the silos, whether in the presence or absence of P. roqueforti. Mold growth was not influenced by the addition of nutrients, if cultivated without yeast. The products of glucose metabolism, mainly ethanol and ethyl acetate, increased after glucose addition to P. anomala-inoculated treatments. Our results suggest that neither competition for nutrients nor production of a glucose-repressible cell wall lytic enzyme is the main mode of action of biocontrol by P. anomala in this grain system. Instead, the mold-inhibiting effect probably is due to the antifungal action of metabolites, most likely a combination of ethyl acetate and ethanol, derived from glycolysis. The discovery that sugar amendments enhance the biocontrol effect of P. anomala suggests novel ways of formulating biocontrol yeasts.
منابع مشابه
Biocontrol of mold growth in high-moisture wheat stored under airtight conditions by Pichia anomala, Pichia guilliermondii, and Saccharomyces cerevisiae.
Pichia anomala inhibits the growth of Penicillium roqueforti and Aspergillus candidus on agar. In this investigation, antagonistic activity on agar against 17 mold species was determined. The abilities of Pichia anomala, Pichia guilliermondii, and Saccharomyces cerevisiae to inhibit the growth of the mold Penicillium roqueforti in nonsterile high-moisture wheat were compared by adding 10(3) Pen...
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متن کاملInfluence of ethyl acetate production and ploidy on the anti-mould activity of Pichia anomala.
A diploid and a haploid strain of Pichia anomala were tested for their biocontrol ability against the spoilage mould Penicillium roqueforti in glass tubes filled with grain at two water activities (aw). At aw 0.98, the two yeast strains grew and inhibited mould growth equally well and showed similar patterns of ethyl acetate production, reaching maximum values of 10-14 microg ml(-1) headspace. ...
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ورودعنوان ژورنال:
- Applied and environmental microbiology
دوره 71 4 شماره
صفحات -
تاریخ انتشار 2005