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[ES] En la vinificación de vinos tintos de Burdeos, la cepa principal de levadura empleada para completar la fermentación es S. cerevisiae. La razón de utilizar esta cepa en vinos tintos secos es que produce efectos agradables y seguros, con una baja incidencia de defectos. Cada vez son más comunes los vinos fermentados con levaduras nativas o inoculadas con cepas no tradicionales para la búsqueda de vinos más diversos, interesantes y complejos. Este trabajo se estudia la composición de vinos de la variedad Merlot de la denominación Pomerol en Burdeos, que han realizado la fermentación tras ser inoculados de forma secuencial con las levaduras K. Thermotolerans y S. cerevisiae, comparados con vinos fermentados con una cepa de S. cerevisiae de una selección local y otra comercial. Una vez completadas las fermentaciones alcohólica y maloláctica, se hizo un análisis sensorial, y se determinaron los parámetros convencionales y polifenólicos de los vinos. Se concluyó que los tres grupos presentaron perfiles muy parecidos en su análisis sensorial, aunque el análisis químico mostró diferencias significativas en color, contenido de antocianos y calidad de taninos. La fermentación secuencial con K. Thermotolerans y S. cerevisiae dio lugar a concentraciones más altas de acidez volátil y antocianos, con una tonalidad más alta, pero con copigmentación más baja. Los polifenoles fueron los más afectados, con niveles medios entre los dos tipos de S. cerevisiae. Los componentes menos afectados fueron los taninos, aunque la fermentación con K. Thermotolerans produjo niveles más bajos de taninos astringentes en comparación con las otras dos muestras. En resumen, hay poca evidencia de que esta combinación particular de K. Thermotolerans/S. cerevisiae produzca un vino significativamente diferente en la evaluación organoléptica, pero el análisis químico indica un vino más apropiado para consumirlo joven, con más color y taninos más suaves que los producidos únicamente con S. cerevisiae., [EN] In the vinification of red wines in Bordeaux, the principal fermenting agent is the yeast strain Saccharomyces cerevisiae for its security and predictability in producing a dry wine with low instances of faults. Increasingly as winemakers look for ways to diversify their wines with elements of complexity and uniqueness, non Saccharomyces yeast components are employed in either in a wild ferment or a controlled seeding of the ferment. This work is focused on a set of Merlot wines from the Bordeaux appellation of Pomerol that are fermented in sequence with K. Thermotolerans and S cerevisiae in comparison with those fermented with a locally selected and a commercial S. Cerevisiae strain. Following the completion of alcoholic and malolactic fermentation, samples of wines were taken and analyzed in various sensorial, conventional and polyphenolic parameters. It was concluded that while the three sets of wines were exceedingly similar when judged by a tasting panel, their chemical analysis showed statistical differences in color, anthocyanin content, and tannin quality, while polyphenolic analysis revealed relatively little difference. The Concerto/Saccharomyces sequential ferment resulted in the highest level of volatile acidity, tonality and anthocyanin content in the wines although with lower copigmentation levels. The polyphenols were the most affected with the sequential ferment producing levels between the two strictly S. cerevisiae ferments. The least affected component were the tannins as the yeast variety did not seem to significantly affect the amount of tannins in the wine, although the K thermotolerans ferment produced the lowest levels of astringent tannins when compared to the other two. In summary, there is little evidence that this particular Concerto/F33 combination used in sequence produces a significantly altered wine when judged organoleptically, although the chemical analysis points to a wine more apt to drink young with more color and softer tannins than the solely Saccharomyces ferments.

This study examined the effects of honey varieties and non-Saccharomyces cerevisiae (Torulaspora delbrueckii and Kluyveromyces thermotolerans) on the flavor volatiles of mead. Five different types ...

Spirogyra peipingensis algae is a microscopic green algae which is one of an alternative raw material to producing bioethanol because it has a high carbohydrate about 64%. This study aims to discover the growth of various types of yeast in S. peipingensis algae medium in producing bioethanol. This study uses hydrolysis methods and fermentation methods. In this study, the hydrolysis method using α-amylase enzyme as much as 150 KNU/L. The type of yeast used was Saccharomyces cerevisiae, Pichia kudriavzevii and Kluyveromyces thermotolerans. The result shown that the optimal yeast growth in producing ethanol is S. cerevsisiae was 0,49 g ethanol/g sugar at 10 hours fermentation duration. Based in the result shown that S. peipingensis algae can be used as raw material for producing bioethanol by using Saccharomyces cerevisiae.

충남 금산군과 전남 완도군, 제주도 송악산 등지에서 서식하고 있는 야생화들로부터 Rhodosporidium fluviale 201-C-1과 Kluyveromyces thermotolerans 150-JE-2(1), Rodosporidium paludigenum과 Candida sp. 80-J-3등의 국내 미기록 효모들을 분리, 선발하여 이들의 미생물학적 특성들을 조사하였다. Rhodosporidium fluviale 201-C-1은 내염성의 무포자 효모로 의균사를 형성하였고 urease 활성을 갖고 있었다. Kluyveromyces thermotolerans 150-JE-2(1)는 내당성과 내염성을 가진 무포자효모로서 $30^{\circ}C$ , pH 4.0~6.0에서 잘 생육하였다. Candida sp. 80-J-3과 Rhodosporidium paludigenum 86-J-1 균주들은 모두 무성생식을 하는 무포자 효모들이었고 YPD 배지, Vitamin-free 배지와 5% NaCl을 함유한 YPD 배지 등에서 잘 생육하였다. 또한 Candida sp. 80-J-3 균주의 urease 활성은 음성이었으나 Rhodosporidium paludigenum 86-J-1 균주는 urease 활성이 양성이면서 pH 7.0~8.0에서 잘 생육하였다. 【Rhodosporidium fluviale 201-C-1 and Kluyveromyces thermotolerans 150-JE-2(1) were isolated from wild flowers in Geumsan-gun, Chungcheongnam-do and Wando-gun, Jeollanam-do, respectively. Rhodosporidium paludigenum 86-J-1 and Candida sp. 80-J-3 were also isolated from flowers in Jeju island, Korea. Characteristics for these yeasts were not reported before. Therefore, morphological and physiological characteristics for these yeasts were investigated in this study. R. fluviale 201-C-1 was halophilic asporogenous yeast and formed pseudomycelium. It also grew at $30^{\circ}C$ and pH 4.0-6.0. K. thermotolerans 150-JE-2(1) was sugar-tolerant and halotolerant asporogenous yeast. It formed pseudomycelium and showed positive urease activity. Candida sp. 80-J-3 and R. paludigenum 86-J-1 were asporogenous yeasts, and grew well in yeast extract-peptone dextrose(YPD) medium, potato-dextrose medium as well as vitamin-free medium and YPD medium containing 5% NaCl.】

The efficacy of two strains of Kluyveromyces thermotolerans in preventing the growth and ochratoxin A (OTA) accumulation of ochratoxigenic fungi both "in vitro" and "in situ" was evaluated. The data from this study showed that both yeast strains were able to control Aspergillus carbonarius and A. niger aggregate species growth and ochratoxin A accumulation. The inhibitory effects were dependent on the ochratoxigenic species, yeast strains, a(w) and temperature evaluated and their interactions. Over all conditions assayed, ochratoxin A accumulation was reduced from 3% to 100% and the growth rate from 11% to 82.5%, depending on conditions. These results are promising for future development of a bio-pesticide.

Objectives: The aim of this study was to compare the prevalence of yeast-like fungi and yeasts on the mucous membranes of a group of students of Natural Sciences and Medicine. Materials and methods: The study involved 156 students of the Faculty of Biology and Biotechnology (FB&B) and 37 students of the Faculty of Medical Sciences (FMS). Material samples were collected with sterile cotton swab from the nose, mouth and throat. The identification of fungi was carried out by the evaluation of macrocultures and microcultures on Nickerson agar and biochemical features. Results: Yeast-like fungi and yeast were isolated from 41.97% of the subjects (81 people). The fungal colonization of the mucous membrane was observed in 59 students of the Faculty of Biology and Biotechnology (37.82%) and 22 students (56.46%) of the Faculty of Medical Sciences. The obtained fungi were classified into 31 taxonomic units. The predominant species were Candida dubliniensis and Lachancea thermotolerans (syn. Kluyveromyces thermotolerans). 14 species with defined status of BSL were recorded. Conclusions: Yeast and yeast-like fungi were more frequent among students of Biology and Biotechnology, than students of Medical Sciences. In students of FB&B greater taxonomic diversity of fungi was found than in students of FMS. The species diversity and prevalence of fungi observed in students of the Life Sciences are determined not only by lifestyle, but mainly by the possibility and frequency of contact with a variety of reservoirs and sources of potentially pathogenic fungi. The occurrence in human ontocenoses of 14 species classified to 1st and 2nd class of Biosafety Level is also very important.

Kluyveromyces thermotolerans strain NBRC 1674 was selected for the simultaneous production of sphingolipids and ethanol from beet molasses. The strain gradually synthesized ethanol with fermentation periods and attained a level slightly higher than that of the strain of Saccharomyces cerevisiae usually used for ethanol production. The sphingolipids accumulated in the cells were composed of almost equal amounts of free ceramides and glucosylceramides. The sphingoid bases and fatty acids of the two sphingolipids differed from each other and changed under aerobic and anaerobic growth conditions. Oxygen limitation may cause accumulation of sphinganine by inhibiting sphingolipid desaturases and enhance its proportion in both the sphingolipids.

During the single culture fermentation of grape must K. thermotolerans, strain TH941, isolated in a wine-producing region in northern Greece, reached a very high cell concentration of 8.4 log (c.f.u ml−1), followed by a rapid decline of the viable cells. The yeast produced 9.6 g L-lactic acid l−1 during the growth phase, 7.58% v/v of ethanol and showed a limited degradation of L-malic acid as well as a low production of volatile acidity. In the presence of 3% v/v and 6% v/v of ethanol the K. thermotolerans isolate was able to grow. At 9% v/v of ethanol it could not grow but showed no loss of viability for 10 days.

The growth and glucose uptake of single cultures of the wine-related yeasts Kluyveromyces thermotolerans, Torulaspora delbrueckii, and Saccharomyces cerevisiae were investigated. The yeasts had different specific glucose uptake rates (qs) that depended on the residual glucose concentration and the oxygen availability. In mixed cultures, the qs values of the yeasts were not subject to any interaction effects over a wide range of glucose concentrations. Our results strongly indicate that the relative glucose uptake abilities of both non-Saccharomyces yeasts, i.e. the qs(non-Saccharomyces)/qs(S. cerevisiae) ratios, regulated their abilities to compete for space in mixed cultures with S. cerevisiae, which, in turn, regulated their early deaths. This hypothesis enabled us to explain why K. thermotolerans was less able than T. delbrueckii to coexist with S. cerevisiae in mixed cultures. Furthermore, it enabled us to explain why oxygen increased the abilities of K. thermotolerans and T. delbrueckii to coexist with S. cerevisiae in the mixed cultures.

International audience; Transfer of fragments of mtDNA to the nuclear genome is a general phenomenon that gives rise to NUMTs (NUclear sequences of MiTochondrial origin). We present here the first comparative analysis of the NUMT content of entirely sequenced species belonging to a monophyletic group, the hemiascomycetous yeasts (Candida glabrata, Kluyveromyces lactis, Kluyveromyces thermotolerans, Debaryomyces hansenii and Yarrowia lipolytica, along with the updated NUMT content of Saccharomyces cerevisiae). This study revealed a huge diversity in NUMT number and organization across the six species. Debaryomyces hansenii harbors the highest number of NUMTs (145), half of which are distributed in numerous large mosaics of up to eight NUMTs arising from multiple noncontiguous mtDNA fragments inserted at the same chromosomal locus. Most NUMTs, in all species, are found within intergenic regions including seven NUMTs in pseudogenes. However, five NUMTs overlap a gene, suggesting a positive impact of NUMTs on protein evolution. Contrary to the other species, K. lactis and K. thermotolerans harbor only a few diverged NUMTs, suggesting that mitochondrial transfer to the nuclear genome has decreased or ceased in these phylogenetic branches. The dynamics of NUMT acquisition and loss are illustrated here by their species-specific distribution.

Three types of structure of the ascospore wall were found among the haploid Saccharomyces species examined: a warty wall (S. rouxii), a smooth wall with a single electron-light inner layer (S. bailii) and a smooth wall with a double light inner layer (S. montanus, S. florentinus). The latter type also occurred in Kluyveromyces thermotolerans and K. waltii. In K. fragilis spores the wall had a single light inner layer. The taxonomic implications of these findings were discussed.

DNA base compositions (GC content) of Saccharomyces species are reported and discussed. Several amendments of the four groups given by van der Walt are suggested, viz. the transfer of S. kluyveri to group 1, and of S. eupagycus, S. cidri, S. montanus, S. microellipsodes and S. florentinus to group 2. The synonomy of S. amurcae and S. cidri is suggested. The DNA base compositions revealed two possible pairs of sibling species: S. elegans and S. bailii, with a difference in GC content of 4.1%; S. dairensis and S. servazzii with a difference in GC content of ca. 3%. S. mrakii had a GC content of 47.3-48.5% the highest encountered in this genus and similar to that of Kluyveromyces thermotolerans.

The ability of Kluyveromyces marxianus IMB3 to decolorize Remazol Black-B dye was investigated. The effect of environmental conditions, such as pH and temperature were examined. No noticeable effects on decolorization were observed when pH varied from 3.0–5.5. Maximum colour removal, 98%, was achieved at 37°C. Little or no colour removal was detected when K. marxianus IMB3 was incubated under anaerobic conditions. Further investigation, in which decolorization was monitored under extreme temperatures and low pH (to inhibit growth) and using ten fold dense inoculum, revealed that decolorization was due to biosorption to the yeast cells and not due to a metabolic reaction. Keywords: Bioremediation, Biosorption, Textile dyes, Decolorization, Pollution removal, Kluyveromyces marxianus, Dye decolorization by yeast