This work was performed to verify the potential of yeast strains isolated from cachaça distilleries for two specific biotechnological applications: beer and bioethanol production. In the beer production, the strains were tested for characteristics required in brewery practices, such as: capacity to ferment maltose and maltotriose, ability to grow at lowest temperatures, low HS production, and flocculation profile. Among the strains tested, two of them showed appropriate characteristics to produce two different beer styles: lager and ale. Moreover, both strains were tested for cachaça production and the results confirmed the capacity of these strains to improve the quality of cachaça. In the bioethanol production, the fermentation process was performed similarly to that used by bioethanol industries: recycling of yeast biomass in the fermentative process with sulfuric acid washings (pH 2.0). The production of ethanol, glycerol, organic acids, dry cell weight, carbohydrate consumption, and cellular viability were analyzed. One strain presented fermentative parameters similar to PE2, industrial/commercial strain, with equivalent ethanol yields and cellular viability during all fermentative cycles. This work demonstrates that cachaça distilleries seem to be an interesting environment to select new yeast strains to be used in biotechnology applications as beer and bioethanol production.

This study suggests that the use of selected yeast strains could contribute to obtain a cachaça similar to those produced traditionally, while getting wide acceptation in the market, yet presenting more homogeneous organoleptic characteristics, and thus contributing to the PDO implementation.

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Resumo -O objetivo deste trabalho foi quantificar a população de Gluconactobacter diazotrophicus presente em plântulas de 34 variedades de cana-de-açúcar, e caracterizar os isolados quanto à capacidade de utilizar diversas fontes de carbono e formar pigmento róseo em presença de luz. A população de G. diazotrophicus foi quantificada pela técnica do número mais provável e isolada em meios de cultura semi-seletivos. A população de G. diazotrophicus foi maior no sistema radicular do que na parte aérea, e maior nas variedades brasileiras de cana-de-açúcar. Os isolados utilizaram poucas fontes de carbono, e aqueles obtidos do sistema radicular utilizaram maior número de fontes, em comparação aos da parte aérea. Apenas a estirpe padrão Ppe-4 e quatro outros isolados formam pigmento róseo em presença de luz. A baixa variação observada pode estar relacionada com o habitat ou com a adaptação dessa população às condições específicas do interior das plantas e, por isso, a estrutura genética da população dessas bactérias é limitada e conservada.Termos para indexação: diversidade, bactérias diazotróficas, endófitos. Use of different carbon sources by strains of Gluconacetobacter diazotrophicus isolated from sugarcaneAbstract -The objective of this work was to quantify the population of Gluconacetobacter diazotrophicus present in plantlets of 34 sugarcane varieties and to characterize the isolates according to their capacity to use carbon sources and produce pink pigments under light. G. diazotrophicus population was estimated using the most probable number technique, and then, isolated in semi-selective culture media. The highest population number of G. diazotrophicus was found in the roots; Brazilian varieties presented the highest population. The isolates used little carbon sources, and those strains obtained from the root used the highest number of carbon sources. Only the strain Ppe-4 and four other ones produce pink pigments under light. The low variation observed may be related to the habitat or to the adaptation of this population to specific internal plant conditions, and for this reason, the genetic structure of these bacteria is limited and preserved.

In natura sugarcane juice or garapa is one of the derivatives of sugarcane and is a tasty and energetic drink. The addition of acid fruits to the sugarcane juice is quite common, giving the product a refreshing flavor and softening its sweetness. The present study aimed to evaluate the sensorial quality of beverages elaborated by mixing sugarcane juice and fruits pulp, among high school students at IFNMG – campus Salinas. The samples were prepared for the flavors of passion fruit, tamarind, and caja, adding pulp in the proportions of 5, 7.5 and 10 mL per 100 mL of sugarcane juice, and a preference-ranking test was applied to 30 untrained panelists. Based on the result of this test, samples of the beverage with the preferred pulp concentration for each flavor were prepared. The acceptance test was applied to 88 panelists in the same study group. For the preference-ranking test, this analysis showed that there was no significant difference (p ≥ 0.05) between the samples in any of the three flavors and concentrations evaluated. However, the highest absolute values were obtained by the samples of passion fruit and tamarind at 5% of pulp and caja at 7.5% of pulp. Regarding the acceptance test, there was no significant difference (p ≥ 0.05) between samples. In the evaluation of the overall impression, the scores were between “like moderately” and “like extremely”, which shows a great acceptance for these products. Also, the most accepted flavor was caja at 7.5%. The purchase intention was evaluated as “probably buy” and “certainly buy” and the highest purchase intention was also for the sample of caja at 7.5%. Therefore, this study contributes to a greater appreciation of the fruits from the semi-arid and to adding value to the sugarcane juice.