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Lactobacillus vini is a bacterial contaminant found in industrial environments of winemaking and fuel-ethanol fermentation. However, there has been no standard analysis of its physiology that can pinpoint its adaptive traits to these kinds of environments. In view of this lack of information, the aim of this study is to determine the nutritional factors that lead to the growth of L. vini in the industrial plants of fuel-ethanol. First of all, the limited growth of this bacterium was studied in the industrial substrate, which was improved by nutritional supplementation with amino acids, and its homofermentative status was confirmed. Metabolite analysis showed that citrate is a growth factor of paramount importance for this bacterium in industrial processes through pyruvate metabolization, and increases ATP production and biomass formation. Furthermore,e acetate uptake, either from the medium or generated from citrate metabolism, was assimilated for biomass production. Hence, a metabolic model was designed to describe the role of citrate and acetate in the growth of L. vini that could be tested on other lactobacilli.

ABSTRACT. This study investigated the effect of seasonality on the Cyanobacteria community in two tropical eutrophic reservoirs in northeastern Brazil. Monthly samplings were conducted in the sub-surface of reservoirs. The following abiotic variables were analyzed: apparent color, turbidity, conductivity, alkalinity, calcium, magnesium, sodium, potassium, sulfate, total phosphorous, ammonia, nitrate, nitrite, chlorides, total hardness and chlorophyll-a, according to APHA (2012). Cyanobacteria density was quantified through biomass. Data were analyzed using one-way ANOVA and Redundancy Analysis (RDA). Higher mean values of Cyanobacteria biomass occurred in the dry (9.9mm ) season in Jucazinho and Carpina reservoirs, respectively, especially Planktothrix agardhii, Cylindrospermopsis raciborskii and Geiterinema amphibium, which occurred in 100% of the samples. RDA analysis revealed that the variables nitrite, ammonia, conductivity, calcium, sulfate, chlorides and alkalinity influenced most the Cyanobacteria community in both reservoirs. High trophic state index was observed throughout the year. Seasonality affected both biotic and abiotic variables.Keywords: abiotic parameters, phytoplankton, seasonality.Comunidade de cianobactérias em dois reservatórios eutróficos e tropicais no nordeste do Brasil RESUMO. Este estudo investigou o efeito da sazonalidade sobre a comunidade de cianobactérias em dois reservatórios eutróficos tropicais no nordeste do Brasil. Mensalmente, amostras foram coletadas na subsuperfície dos reservatórios. Foram analisados os seguintes fatores abióticos: cor aparente, turbidez, condutividade, alcalinidade, cálcio, magnésio, sódio, potássio, sulfato, fósforo total, amônia, nitrato, nitrito, cloretos, dureza total e clorofila-a, de acordo com APHA (2012). A densidade de cianobactérias foi quantificada por meio de sua biomassa. Os dados foram analisados usando Anova (one-way) e Análise de Redundância (RDA). Maiores valores médios de biomassa de cianobactérias ocorreram na estação seca (9,9 mm ) nos reservatórios de Jucazinho e Carpina, respectivamente, especialmente Planktothrix agardhii, Cylindrospermopsis raciborskii e Geitlerinema amphibium que ocorreram em 100% das amostras. A análise de RDA revelou que os parâmetros nitrito, amônia, condutividade, cálcio, sulfato, cloretos e alcalinidade foram mais influentes na comunidade de Cyanobacteria em ambos os reservatórios. Elevado índice de estado trófico foi detectado durante todo o ano. A sazonalidade exerceu influência tanto nas variáveis bióticas como abióticas.Palavras-chave: parâmetros abióticos, fitoplâncton, sazonalidade.