Yeast Identification During Fermentation of Turkish Gemlik Olives.

Naturally fermented black table olives of the Gemlik variety are one of the most consumed fermented products in Turkey. The objective of this work was to identify yeast strains isolated during their natural fermentation by using Restriction Fragments Lengths Polymorphism-Polimerase Chain Reaction (RFLP-PCR) and DNA sequencing methods. The study also focused on determining the effect of regional differences on yeast microflora of naturally fermented Gemlik olives. A total of 47 yeast strains belonging to 12 different species which had been previously isolated from the natural brine of Akhisar and Iznik-Gemlik cv. olives were characterized by molecular methods. Forty-two of the tested strains could be identified by RFLP-PCR to species level. These yeast species were determined as Candida mycetangi, Candida hellenica, Candida membranaefaciens, Candida famata, Candida pelliculosa, Saccharomyces cerevisiae, and Zygosaccharomyces mrakii. Five strains were identified by DNA sequencing. These strains belonged to three different species: Aureobasidium pullulans, Kloeckera apiculate, and Cryptococcus saitoi. The most frequent species were C. famata and C. pelliculosa in both regions. PRACTICAL APPLICATION: This work studies the yeasts from Turkish table olives which could prove to be of importance to the food industry in that area. On the other hand, it compares identification by molecular and classical biochemical methods and offers an idea about the differences between the ecosystems of Gemlik olives in the Akhisar (AO) and Iznik (IO) regions. The study could be useful in characterizing a very important product and, in this way, could help to promote its marketing.

Potentially pathogenic yeasts from soil of children's recreational areas in the city of Lódz (Poland).

OBJECTIVES: Yeasts may become potential human and animal pathogens, particularly for individuals with a depressed immune system. Their presence in the environment, especially in soil, may favour their spread into human ontocenoses. MATERIALS AND METHODS: Eighty-four soil samples obtained from 21 children's recreational sites in Lódz in autumn 2010 and spring 2011 were evaluated. The yeasts were isolated by classical microbiological methods and identified on the basis of morphological and biochemical features. RESULTS: The fungi were found in 73.8% and in 69.0% of the examined samples collected in autumn and spring, respectively. Among 97 isolates of yeasts, the species potentially pathogenic to humans and animals were Candida colliculosa, C. guilliermondii, C. humicola, C. inconspicua, C. lambica, C. lusitaniae, C. pelliculosa, C. tropicalis, Cryptococcus albidus, C. laurentii, C. neoformans, C. terreus, Kloeckera japonica, Geotrichum candidum, G. penicillatum, Rhodotorula mucilaginosa, R. glutinis, Saccharomyces cerevisiae, Sporobolomyces salmonicolor and Trichosporon cutaneum. The most frequently isolated fungi included the genus Cryptococcus (38 isolates) and two species: Rhodotorula glutinis (15), Trichosporon cutaneum (14). C. neoformans, an etiological factor of cryptococcal meningitis, was present in the sandpits of 3 kindergartens. The Candida species were identified from park playgrounds and school sports fields mainly in autumn 2010 (14 isolates), in spring 2011 - only 1 isolate. The concentration of fungal species in particular samples varied considerably, but in the majority of samples, fungi were present at concentration of up to 1×10(2) CFU/1 g of soil. CONCLUSIONS: Yeasts were present in the soil of parks, schools and kindergarten recreational areas; the fact may pose a health risk to humans, especially to children, and this type of biological pollution should be regarded as a potential public health concern.

Kloeckera taiwanica sp. nov., an ascomycetous apiculate yeast species isolated from mushroom fruiting bodies.

Three apiculate yeast strains, EJ7M09(T), GJ5M15 and GJ15M04, isolated from mushrooms in Taiwan were found to represent a novel species of the genus Kloeckera. The phylogenetically closest relative of this novel species is Hanseniaspora occidentalis, but the type strain of H. occidentalis differed by 4.6 % divergence (25 substitutions; 5 gaps) in the sequence of the D1/D2 domain of the large subunit rRNA gene. This difference clearly suggests that the three strains represent a distinct species. As none of the strains that were examined in this study produced ascospores or exhibited conjugation on common sporulation medium either alone or in a pairwise mixture, this species could be considered as an anamorphic member of the genus Hanseniaspora, and a novel species, Kloeckera taiwanica sp. nov., is proposed, with EJ7M09(T) ( = BCRC 23182(T) = CBS 11434(T)) as the type strain.

Candida krusei and Kloeckera apis inhibit the causal agent of pineapple fusariosis, Fusarium guttiforme.

Studies based on microbial ecology and antagonistic interactions play an important role in the development of new alternative strategies in controlling plant pathogens and are relevant to further biotechnological applications. Antagonistic interactions between the yeasts Candida krusei and Kloeckera apis isolated from rotten pineapple fruits, and two isolates of the pathogenic filamentous fungus Fusarium guttiforme (Syn.: Fusarium subglutinans f. sp. ananas) resistant and susceptible to fungicide benzimidazole were studied in broth culture, and on plate assays. The yeasts significantly reduced Fusarium conidial germination after 24h of cocultivation in broth culture, and also mycelial growth on plate assays. Slide coculture appeared to show attachment of yeasts to the hyphal surface and also slight morphological abnormalities caused by C. krusei. Filtrates of cocultures of fungi and yeasts inhibited fungal growth, but filtrates of the yeast cultures alone did not, suggesting that the antagonistic action of the yeasts is inducible. The F. guttiforme isolate sensitive to benzimidazole was most affected by both yeasts in pineapple juice, reaching a maximum of 36.5 % germ tube inhibition. This isolate was also inhibited by yeasts in mycocinogenic plate assay. These results demonstrated that C. krusei and K. apis are effective in inhibiting F. guttiforme growth and that the mode of action is associated with hyperparasitism and mycocinogenic activity.

Three new species of bipolar budding yeasts of the genus Hanseniaspora and its anamorph Kloeckera isolated in Thailand.

In the course of a survey of yeast biodiversity in the natural substrates in Thailand, eight strains were found to represent three hitherto undescribed species of Hanseniaspora/Kloeckera. They were isolated from insect frass, flower, lichen, rotted fruit and rotted wood. Based on the morphological and physiological characteristics, and sequences of D1/D2 domain, six strains represent a single species of the genus Hanseniaspora, described as Hanseniaspora thailandica sp. nov. (type BCC 14938(T)=NBRC 104216(T)=CBS 10841(T)), and another strain as Hanseniaspora singularis sp. nov. (type BCC 15001(T)=NBRC 104214(T)=CBS 10840(T)). A further strain, which belongs to Kloeckera and does not produce ascospores, is described as Kloeckera hatyaiensis sp. nov. (type BCC 14939(T)=NBRC 104215(T)=CBS 10842(T)). Strains belonging to H. thailandica sp. nov. differed by 17-19 nucleotide substitutions from Hanseniaspora meyeri, the closest species. DNA reassociation between the two taxa showed 30-48% relatedness. Kloeckera hatyaiensis sp. nov. and H. singularis sp. nov. differed by eight and 16 nucleotide substitutions with one gap from the nearest species, Hanseniaspora clermontiae and Hanseniaspora valbyensis, respectively.