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A yeast strain identified as Geotrichum sp. JR1 was able to use acetonitrile as the sole carbon and nitrogen source. The strain grew in 0.5 to 2M acetonitrile. Ammonia generation as enzymatic product during the strain growth indicates the presence of an acetonitrile degrading enzyme. Acetic acid and acetamide were detected during assays with the resting cells cultivated in acetonitrile, indicating the presence of nitrile and amide degrading enzymes. This paper is the first to describe the use of acetonitrile as the sole carbon and nitrogen source by a yeast. Uma linhagem de levedura identificada como Geotrichum sp. JR1 foi capaz de utilizar acetonitrila, em concentrações de 0,5 a 2M, como única fonte de carbono e de nitrogênio. A geração de amônia durante o crescimento do microrganismo indica a presença de sistema enzimático capaz de degradar acetonitrila. Durante os ensaios enzimáticos, com células cultivadas em acetonitrila, foram detectados ácido acético e acetamida como produtos indicando a presença de sistema enzimático capaz de degradar acetonitrila e acetamida. Este trabalho é o primeiro a descrever a utilização de acetonitrila como única fonte de carbono e de nitrogênio por uma levedura.

An outbreak of staphylococcal food poisoning involving 42 people who had eaten a meal at a restaurant in the Municipality of Passos, Minas Gerais, Brazil, is reported. Thirty-one of the individuals became ill with vomiting, diarrhea and dizziness within 30 minutes after eating the meal. The foods suspected were: chicken pancake, rice, beans, tomato sauce and mashed chick-peas. Large numbers (> 2.0x10(8) CFU/g) of enterotoxigenic staphylococci were present in the chicken pancake. These strains produced enterotoxins A, B and D. Swabs from the nasal cavity and throat and from under the fingernails of food handlers were cultured for the detection of enterotoxigenic staphylococci carriers. Four out of five of them were healthy carriers of enterotoxin A, B, C and D producing Staphylococcus aureus at the sites cultured and one of them was also a nasal carrier of TSST-1 toxin producing S. aureus. These results indicate that the food handlers would have been the source of the food contamination.Um surto de toxinfecção alimentar envolvendo 42 pessoas, ocorrido após a ingestão de uma refeição servida num restaurante do município de Passos, Minas Gerais, Brasil, é relatado. Trinta minutos após a ingestão dos alimentos, 31 pessoas adoeceram apresentando tontura, vômito, cólica e diarréia. Os alimentos suspeitos foram panqueca de frango, arroz, feijão, molho de tomate e pasta de grão de bico. Foram isolados na panqueca de frango contagens superiores a 2,0x10(8) UFC de estafilococos produtores de enterotoxinas A, B e D por grama do alimento. Culturas isoladas a partir da região orofaríngea, sub-ungüeal e mucosa nasal dos manipuladores de alimentos revelaram serem estes, portadores assintomáticos de cepas de S. aureus produtores de enterotoxinas A, B, C e D. Na mucosa nasal de um dos manipuladores foi isolada a cepa de S. aureus produtora de TSST-1. Os resultados obtidos indicam os manipuladores como prováveis fontes de contaminação dos alimentos.

Yeast strains of the genera Aureobasidium, Rhodotorula and Trichosporon were isolated from stainless steel effluents and tested for their ability to utilize phenol as the sole carbon source. Fourteen strains grew in the presence of up to 10 mm phenol. Only the strain Trichosporon sp. LE3 was able to grow in the presence of up to 20 mm phenol. An inhibitory effect was observed at concentrations higher than 11 mm, resulting in reduction of specific growth rates. Phenol degradation was a function of strain, time of incubation and initial phenol concentration. All strains exhibited activity of catechol 1,2-dioxygenase and phenol hydroxylase in free cell extracts from cells grown on phenol, suggesting that catechol was oxidized by the ortho type of ring fission. Addition of glucose and benzoate reduced the phenol consumption rate, and both substrates were used simultaneously. Glucose concentrations higher than 0.25% inhibited the induction of phenol oxidation by non-proliferating cells and inhibited phenol oxidation by pre-induced cells.

Different encapsulation matrices were tested for immobilized cells of Candida guilliermondii UFMG-Y65 used for acetonitrile degradation. Acetonitrile degradation by free cells and cells immobilized in Ba-alginate, kappa-carrageenan and citric pectin was studied. The rate of acetonitrile degradation was monitored for 120 h by measuring yeast growth and ammonia concentration. Different alginate concentrations did not affect cell viability, but the period of incubation in BaCl2 solution reduced the number of viable cells. Likewise, the gel nature and the matrix structure of the support resulting from the cell immobilization conditions were of fundamental importance for biocatalyst activity and performance, affecting substantially the patterns of microbial growth and enzymatic activity. Alginate-immobilized cells degraded acetonitrile more efficiently than kappa-carrageenan or citric pectin-immobilized cells. Na degradação de acetonitrila, foram testadas células livres de Candida guilliermondii UFMG-Y65 e imobilizadas em diferentes suportes, quais sejam, Ba-alginato, kapa-carrageno e pectina cítrica. A velocidade de degradação da acetonitrila foi monitorada por 120 h, mediante o crescimento da levedura e geração de amônia. Diferentes concentrações de alginato não afetam a viabilidade das células; mas o período de incubação, em solução de BaCl2, reduziu o número de células vivas. Da mesma forma, a natureza do gel e a estrutura da matriz do suporte, ambas resultantes das condições de imobilização das células, foram de fundamental importância para a atividade catalisadora e sua performance; afetando assim, os padrões de crescimento microbiano e a de atividade enzimática. As células imobilizadas em alginato degradaram acetonitrila com maior eficácia do que as imobilizadas em kapa-carrageno ou as células imobilizadas em pectina cítrica.

Different encapsulation matrices were tested for immobilized cells of Candida guilliermondii UFMG-Y65 used for acetonitrile degradation. Acetonitrile degradation by free cells and cells immobilized in Ba-alginate, kappa-carrageenan and citric pectin was studied. The rate of acetonitrile degradation was monitored for 120 h by measuring yeast growth and ammonia concentration. Different alginate concentrations did not affect cell viability, but the period of incubation in BaCl2 solution reduced the number of viable cells. Likewise, the gel nature and the matrix structure of the support resulting from the cell immobilization conditions were of fundamental importance for biocatalyst activity and performance, affecting substantially the patterns of microbial growth and enzymatic activity. Alginate-immobilized cells degraded acetonitrile more efficiently than kappa-carrageenan or citric pectin-immobilized cells.Na degradação de acetonitrila, foram testadas células livres de Candida guilliermondii UFMG-Y65 e imobilizadas em diferentes suportes, quais sejam, Ba-alginato, kapa-carrageno e pectina cítrica. A velocidade de degradação da acetonitrila foi monitorada por 120 h, mediante o crescimento da levedura e geração de amônia. Diferentes concentrações de alginato não afetam a viabilidade das células; mas o período de incubação, em solução de BaCl2, reduziu o número de células vivas. Da mesma forma, a natureza do gel e a estrutura da matriz do suporte, ambas resultantes das condições de imobilização das células, foram de fundamental importância para a atividade catalisadora e sua performance; afetando assim, os padrões de crescimento microbiano e a de atividade enzimática. As células imobilizadas em alginato degradaram acetonitrila com maior eficácia do que as imobilizadas em kapa-carrageno ou as células imobilizadas em pectina cítrica.

Yeast strains from the genera Candida, Debaryomyces, Aureobasidium, Geotrichum, Pichia, Rhodotorula, Tremella, Hanseniaspora, and Cryptococcus were isolated from samples of a gold mine from liquid extraction circuit. These strains were tested for their ability to utilize acetonitrile at 12 mM as the sole nitrogen source. The yeasts that grew using acetonitrile at 12 mM were tested in the presence of acetonitrile, isobutyronitrile, methacrylnitrile, and propionitrile at concentrations of 12, 24, 48, 97, and 120 mM. One strain was selected for each nitrile and the concentration of nitrile in which the best growth occurred. Cryptococcus sp. strain UFMG-Y28 had a better growth on 120 mM propionitrile and 97 mM acetonitrile, Rhodotorula glutinis strain UFMG-Y5 on 48 mM methacrylnitrile, and Cryptococcus flavus strain UFMG-Y61 on 120 mM isobutyronitrile. The utilization of different nitriles and amides by yeast strains involves hydrolysis in a two-step reaction mediated by both inducible and intracellular nitrile hydratase and amidase.

Aspergillus niger was grown in an industrial gold mining solution containing cyano-metal complexes. Gold, silver, copper, iron and zinc were accumulated, and the major mechanism of metal uptake involved metal precipitation on the cell surface. This could be achieved by the extensive application of instrumental analyses combined to the study of the chemical composition of the solutions, before and after contact with the fungus.

Strains of Saccharomyces spp. from tropical substrates tolerated temperatures up to 40 ° C, sucrose concentrations up to 50% (w/v) and ethanol concentrations up to 20 g/L in fermentation conditions. Strain TD200 tolerated 20 g/l of ethanol. The ethanol produced by strain DR1459 was comparable to that of industrial strain HTYM-81. These strains have potential use for the production of fuel alcohol.

Yeast cells immobilized by entrapment in Ba-alginate gel were investigated for growth pattern and respiratory activity. The oxygen uptake rates (OUR) of cells entrapped in gels with 4% alginate were 5.2 and 23% lower than the OUR of 2% alginate and free cells, respectively. The mass-transfer resistance offered by the matrix and growth of the entrapped cells determine a gradient of nutrients throughout the gel which is responsible for both a lower specific growth rate of immobilized cells with respect to that of free ones, and a heterogeneous biomass distribution, with progressively increasing cellular density from the inside to the outside of the matrix. Gel-matrix polymer concentration affected the maximum oxygen uptake of immobilized growing yeast cells.

Yeast communities and genetic polymorphism of prevalent Saccharomyces cerevisiae strains isolated from the spontaneous fermentation of the sugarcane juice during the production of aguardente in three distilleries in the state of Minas Gerais, Brazil, were studied. S. cerevisiae was the prevalent species during the process of aguardente production, but Schizosaccharomyces pombe was predominant in old fermentations in one distillery. Transient yeast species were found in a variable number, probably due to the daily addition of sugarcane juice, and they were different for each of the three distilleries studied. PFGE and PCR analysis of the predominant strains of S. cerevisiae isolated from the fermented must showed a high degree of genetic polymorphism among the three distilleries. A high molecular variability of S. cerevisae strains was also observed among strains isolated from the same vat at different fermentation ages. Our results showed that there was a succession of geneticly different strains of S. cerevisae during the process of aguardente production.

A variant of a yeast strain identified as Candida famata isolated from gold mine effluent was able to grow on acetonitrile, acrylonitrile, butyronitrile, isobutyronitrile, methacrylnitrile, propionitrile, succinonitrile, valeronitrile, acetamide, isobutyamide, and succinamide as sole nitrogen source, after acclimatization. The yeast grew on acetonitrile and acetamide at concentrations up to 4%. The utilisation of acetonitrile and acetamide by the C. famata strain probably involves hydrolysis in a two-step reaction mediated by both inducible and intracellular nitrile hydratase and amidase.