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In Colombia, knowledge of the yeast and yeast-like fungi community is limited because most studies have focused on species with clinical importance. Sediments and water represent important habitats for the study of yeast diversity, especially for yeast species with industrial, biotechnological, and bioremediation potential. The main purpose of this study was to identify and compare the diversity of yeast species associated with sediment and water samples from two artificial lakes in Universidad del Valle (Cali-Colombia). Yeast samplings were performed from fifteen sediment samples and ten water samples. Grouping of similar isolates was initially based on colony and cell morphology, which was then complemented by micro/mini satellite primed PCR banding pattern analysis by using GTG5 as single primer. A representative isolate for each group established was chosen for D1/D2 domain sequencing and identification. In general, the following yeast species were identified: Candida albicans, Candida diversa, Candida glabrata, Candida pseudolambica, Cryptococcus podzolicus, Cryptococcus rajasthanensis, Cryptococcus laurentii, Williopsis saturnus, Hanseniaspora thailandica, Hanseniaspora uvarum, Rhodotorula mucilaginosa, Saccharomyces cerevisiae, Torulaspora delbrueckii, Torulaspora pretoriensis, Tricosporon jirovecii, Trichosporon laibachii and Yarrowia lypolitica. Two possible new species were also found, belonging to the Issatchenkia sp. and Bullera sp. genera. In conclusion, the lakes at the Universidad del Valle campus have significant differences in yeast diversity and species composition between them.

Some tropical Saccharomyces cerevisiae strains, isolated from Champús, a traditional Colombian low alcoholic fermented beverage, were characterised in order to select yeasts for aroma improvement in wine. H 2 S production, volatile acidity, β-glucosidase activity, higher alcoholesters and terpenes production were evaluated in this study. These tropical strains were characterised by a considerable production of ethyl hexanoate, 2-phenylethanol, 2-phenylethyl acetate, and geraniol, detected by SPME-GC-MS. Odor activity values were calculated to analyse the effects of yeasts strains on wine aroma, resulting in six distinctive wine groups, as evidenced by discriminant analysis. These results suggest that Saccharomyces strains isolated from Champús can be an important source for new tropical yeast biotypes with potential winemaking applications, producing a wide range of aroma compounds.

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