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United States Department of Agriculture

Agricultural Research Service

Title: Yeast Microflora of Illinois Corn

Authors
item Nout, M J - AGRIC UNIV, NETHERLANDS
item Wicklow, Donald

Submitted to: International Cereal and Bread Congress Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: June 12, 1996
Publication Date: N/A

Technical Abstract: Microflora in woundsites of preharvest corn (maize) may include bacteria and yeasts, as well as filamentous fungi. The bacteria and yeasts may play a role in attracting insects by the formation of volatile metabolites. Bacteria and yeasts may also interact with the growth and/or mycotoxin production of the filamentous fungi. As little data are available about the yeasts occurring on corn from the US corn belt, approximately 250 strains of yeasts were isolated from samples of milled corn, harvested in 1988, 1989, 1990 and 1991 from distinct experimental corn plots at the University of Illinois River Valley Sand Farm, Kilbourne, IL. Based on morphological criteria, a representative subsample of 27 strains was fully characterized for identification. The majority of the yeasts encountered are Candida guilliermondii, Candida zeylanoides, Debaryomyces hansenii, and Candida shehatae. Also present were Trichosporon cutaneum and Pichia membranaefaciens. The occurrence of killer yeasts was evaluated using hypersensitive yeast strains as indicator strains. Only 4 isolates were killer yeasts; 3 were identified as Trichosporon cutaneum; the remaining is a Candida zeylanoides. The majority of yeasts found were unable to ferment the major sugars of corn, i.e. sucrose and maltose. Certain yeasts (e.g. Candida zeylanoides) were not even able to assimilate these sugars. These properties appear to be of importance in relation with insect attraction.

Last Modified: 7/28/2014
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