ABSTRACT
Saccharomyces cerevisiae strains from different regions of Minas Gerais, Brazil, were isolated and characterized aiming at the selection of starter yeasts to be used in the production of cachaça, the Brazilian sugar cane spirit. The methodology established took into account the screening for biochemical traits desirable in a yeast cachaça producer, such as no H2S production, high tolerance to ethanol and high temperatures, high fermentative capacity, and the abilities to flocculate and to produce mycocins. Furthermore, the yeasts were exposed to drugs such as 5,5',5"-trifluor-D,L-leucine and cerulenin to isolate those that potentially overproduce higher alcohols and esters. The utilization of a random amplified polymorphic DNA-PCR method with primers based on intron splicing sites flanking regions of the COX1 gene, as well as microsatellite analysis, was not sufficient to achieve good differentiation among selected strains. In contrast, karyotype analysis allowed a clear distinction among all strains. Two selected strains were experimentally evaluated as cachaça producers. The results suggest that the selection of strains as fermentation starters requires the combined use of biochemical and molecular criteria to ensure the isolation and identification of strains with potential characteristics to produce cachaça with a higher quality standard.
Subject(s)
Alcoholic Beverages/microbiology , Saccharomyces cerevisiae/classification , Saccharomyces cerevisiae/isolation & purification , Saccharum/microbiology , Brazil , Culture Media , DNA, Fungal/analysis , Fermentation , Industrial Microbiology/methods , Karyotyping , Mycological Typing Techniques , Polymerase Chain Reaction , Random Amplified Polymorphic DNA Technique , Reproducibility of Results , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/growth & developmentABSTRACT
Comparou-se o método de contagem em placas com o método do Número mais Provável (NMP), na detecçäo de clostrídios redutores de sulfito em produtos de origem vegetal (condimentos) e de origem animal (lingüica frescal). A contagem em placas, utilizando-se o agar sulfito polimixina sulfadiazina, detectou microrganismos em 47,7 por cento e 50,0 por cento das amostras de condimentos e lingüiça, respectivamente. Pelo método de NMP, em caldo sulfito polimixina sulfadiazina, os índices de detecçäo foram, respectivamente, 56,8 e 66,7 por cento. Os resultados indicaram maior efetividade do NMP, independentemente da origem da amostra.
