Abstract The interest for oleaginous yeasts has grown significantly in the last three decades, mainly due to their potential use as a renewable source of microbial oil or single cell oils (SCOs). However, the methodologies for cell disruption to obtain the microbial oil are considered critical and determinant for a large-scale production. Therefore, this work aimed to evaluate different methods for cell wall disruption for the lipid extraction of Yarrowia lipolytica QU21 and Meyerozyma guilliermondii BI281A. The two strains were separately cultivated in 5 L batch fermenters for 120 hours, at 26 ºC and 400 rpm. Three different lipid extraction processes using Turrax homogenizer, Ultrasonicator and Braun homogenizer combined with bead milling were applied in wet, oven-dried, and freeze-dried biomass of both strains. The treatment with the highest percentage of disrupted cells and highest oil yield was the ultrasonication of oven-dried biomass (37-40% lipid content for both strains). The fact that our results point to one best extraction strategy for two different yeast strains, belonging to different species, is a great news towards the development of a unified technique that could be applied at industrial plants.

Abstract Kefir is a product elaborated from the symbiotic fermentation of different microorganisms. The Kluyveromyces and Saccharomyces genera are the major representatives of the yeasts found in kefir microbiota. The only pobiotic yeast commercialized as an oral medication, is the Saccharomyces boulardii. The present work involved the microbiological quality examination of six kefir samples in the city of Santa Maria/RS, the yeasts isolation present in the samples and the identification of them by PCR (Polymerase chain reaction). Then, their probiotic potential was evaluated by in vitro technique. After that, microbiological analysis confirmed that kefir samples were suitable for consumption once the microbiological quality was established. Nineteen yeast strains were isolated from six different kefir samples; it was identified, by PCR analysis, but only three species were identified from these microorganisms in the present article: Saccharomyces cerevisiae, Hanseniospora uvarum and Kazachstania unispora. Nevertheless, by simulating the passage of isolated strains through the gastrointestinal environment, it was observed that they could not be considered probiotics. The results indicate that, in an isolated way, the yeast presents in kefir samples, in the city of Santa Maria, RS, can´t be considered probiotics according to the tests performed.

The purpose of this work was to study a rapid yeast DNA extraction by boiling and freeze-thawing processes without using chemical reagents or any purification procedures, to obtain a high grade PCR-product. A specific DNA fragment of the 18S region of Dekkera bruxellensis and Saccharomyces cerevisiae was chosen. The described boiling and freeze-thawing protocols generated the PCR-grade product preparations and could be used to process many samples. The amplification of the fragments could be observed after 30 and 35 cycles. These processes of extraction without using any kind of chemical reagents, especial water, and purification procedures proved to be efficient, reproducible, simple, fast, and inexpensive.

A esporotricose é uma infecção subaguda ou crônica, causada por fungos pertencentes ao Complexo Sporothrix. Relato do caso: esporotricose de localização nasal foi tratada com iodeto de potássio e como não se obteve sucesso, reiniciou-se o tratamento com associação de iodeto de potássio e itraconazol. Porém, ocorreu nova recidiva. As culturas dos exames micológicos foram submetidas a ensaios de atividade antifúngica in vitro para auxiliar no tratamento. A terbinafina foi o antifúngico que apresentou melhores resultados, por isso, o tratamento foi reiniciado com este antifúngico e, após dois anos do término do mesmo, não recidivou. Adicionalmente, ambas as culturas foram comparadas por RAPD, obtendo padrões de fragmentos distintos, indicando que os isolados são diferentes ou demonstrando um processo microevolutivo do microrganismo

Sporotrichosis is a chronic subacute infection caused by fungi belonging to the Sporothrix Complex. In the present clinical case, nasal sporotrichosis was treated with potassium iodide. This was unsuccessful, and the treatment was restarted with a combination of potassium iodide and itraconazole. This however resulted in a further recurrence of the infection. The mycological cultures were tested in vitro for antifungal activity to assist in treatment. Terbinafine, an antifungal drug, produced the best results and was therefore used for the rest of the treatment course, with no recurrence after two years of its completion. In addition, both cultures were compared using RAPD and different fragment patterns were observed. This indicated that the isolates were either different or indicated a microevolutionary process of this microorganism

The aim of this work was to study the production of functional protein in yeast culture. The cells of Saccharomyces cerevisiae Embrapa 1B (K+R+) killed a strain of Saccharomyces cerevisiae Embrapa 26B (K-R-)in grape must and YEPD media. The lethal effect of toxin-containing supernatant and the effect of aeration upon functional killer production and the correlation between the products of anaerobic metabolism and the functional toxin formation were evaluated. The results showed that at low sugar concentration, the toxin of the killer strain of Sacch. cerevisiae was only produced under anaerobic conditions . The system of killer protein production showed to be regulated by Pasteur and Crabtree effects. As soon as the ethanol was formed, the functional killer toxin was produced. The synthesis of the active killer toxin seemed to be somewhat associated with the switch to fermentation process and with concomitant alcohol dehydrogenase (ADH) activity.

The aim of this work was to evaluate the influence of Brettanomyces custersianus on the metabolic activity of Saccharomyces cerevisiae during the tumultuous stage of wine production. The Cabernet Sauvignon grape must with the skin was inoculated with individual cultures of Sacch. cerevisiae and with mixed cultures of Sacch. cerevisiae and Br. custersianus. During the 6-day tumultuous phase of fermentation, the highest ethanol production and the highest sugar consumption were obtained with the strains without B. custersianus. Fermentations carried out with the addition of Brettanomyces metabolites, acetic acid and 4-ethylphenol, showed that only the former inhibited the growth of both Sacch. cerevisiae strains used. In some cases, Br. custersianus could affect the rate higher alcohols production and their final concentrations during the tumultuous phase of vinification.