Classificação das cepas de leveduras dominantes de processos fermentativos utilizando parametros fermentativos e taxonomia numerica

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

In fermentatives processes for alcohol production is common the development of yeasts that are not the one which were selected as inoculum. These yeasts, when present, can show good fermentatives qualities or not. Thus, the microbiological control in the alcoholic fermentation is important for the detection of the wild yeasts, together with the evaluation of its fermentative behavior and its identitication. Through this procedure, it is possible to prevent and to detect problems related with the loss of industrial efficiency, that are very often due to the presence of wild yeasts that show low fermentative qualities. Still it is possible to identify, among the isolated yeasts, the one that presents fermentatives qualities that are suitable to the processo This work had the objective to study the population behavior of industrial fermentatives processes that use different substracts (cane broth and orange broth) and that had as inoculum a strain of Saccharomyces cerevisiae (Y904) produced by Mauri of Brazil. Samples of fermented wine of Usina Alvorada and Citrosuco Paulista Site Matão were collected. The samples were spread on plates in diferencial medium for yeasts (WLN), for the isolation and counting of the dominant yeasts. The isolated yeasts were evaluated through the F ermentative Capacity methodology, where kinetic, yield and pruductivity characteristics are considered (ANDRJETTA et al., 1999). In this classitication system, six different parameters are used for the detinition of the group of each strain: specific cell production (YXlS), substract consumption rate (VCS), substract conversion (NCO), maximum specific growth rate (Jlmáx), productivity (PROD) and specific ethanol production (YP/S). With these parameters it was possible to do the evaluation and classification of the dominant yeasts isolated in different periods of crop of the fermentative units. The isolated yeasts were also evaluated with respect to total nitrogen and were identified by Numerical Taxonomy. In Usina Alvorada the 26 strain isolated in the 11 collections made were distributed in 12 groups through the Fermentative Capacity methodology, where the groups I and 11 were the ones of larger relevance due to the fact of being present repeatedly during the crop. Concerning the concentration profile of total nitrogen, the isolated yeasts had show predominantly low percentages. From the total of the isolated yeasts, 10 could be identified as Saccharomyces chevalieri (Saccharomyces cerevisiae). Among the 26 isolated yeasts, 4 different groups were identified. The group A is characterized by its ability of assimilating the maltose and the melibiose. The group B is characterized by the ability to assimilate the maltose and inability of assimilating the melibiose. The group C is characterized by the inability of assimilating either the maltose or the meliobiose. The group D is characterized by the inability of assimilating the maltose and ability of assimilating the melibiose. In Citrosuco Paulista - Site Matão, in 5 collections made, a total of 10 yeasts were isolated, and were classified through the Fermentative Capacity methodology in 8 different groups. The isolated yeasts had shown predominantly low percentages of total nitrogen. Through the numerical taxonomy it was possible to identify 7 isolated yeasts as Saccharomyces chevalieri (Saccharomyces cerevisiae). The isolated ones were identified as belonging to group A - maltose and melibiose assimilation, and B - assimilation of maltose and non assimilation of melibiose

ASSUNTO(S)

alcool - industria levedos taxonomia numerica fermentação

ACESSO AO ARTIGO

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