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Produção de fenóis voláteis por isolados de Dekkera bruxellensis da fermentação etanólica e efeitos sobre uma linhagem industrial de Saccharomyces cerevisiae
(Universidade Federal de São Carlos, 2018-05-02) Silva, Lincon Felipe Lima; Ganga Muñoz, María Angélica; Ceccato-Antonini, Sandra Regina; https://lattes.cnpq.br/7600793543184032; https://lattes.cnpq.br/6770132100603523
One of the main contaminant yeast is Dekkera bruxellensis being known its ability to produce volatile phenolic compounds such as 4-vinylphenol (4-VP) and 4-ethylphenol (4-EP) from hydroxycinnamic acids through the activity of the enzymes cumarate decarboxylase (CD) and vinylphenol reductase (VR), respectively. Hydroxycinnamic acids are present in the sugarcane juice as well as molasses and, thus, 4-EF could be synthesized during Brazilian ethanol fermentation conditions and act as metabolism inhibitors of Saccharomyces cerevisiae. The objective of this work was initially quantify the specific activities of the enzymes CD and VR of three strains of D. bruxellensis isolated from the ethanolic fermentation and two industrial strains of S. cerevisiae (PE-2 and CAT-1). Following the production of 4-EP in fermentations with and without cell recycle utilizing molasses and sugarcane juice as fermentation media by the strains of D. bruxellensis and one industrial strain of S. cerevisiae (PE-2) was evaluated. The effect of p-coumaric acid, 4-VP and 4-EP on the growth of S. cerevisiae PE-2 was also evaluated in semi-synthetic medium. The D. bruxellensis strains showed maximum specific enzymatic activity (U/mg protein) CD of 184.44 up to 215.52 and VR of 101.94 up to 154.26. Although the S. cerevisiae strains also showed CD and VR enzymatic activities, that there was no 4-EP production under fermentation conditions. The fermentative tests without cell recycle showed that the highest values for 4-VP and 4-EP occurred after 24 h during the exponential phase of growth and were stable until 72 h of fermentation in sugarcane juice and molasses. Comparatively the concentrations of 4-EP were higher in the fermentations with cell recycle especially in molasses, with D. bruxellensis CCA077 being the largest producer, 9.47 mg/L, in the first 12-h fermentative cycle already. There was no inhibitory effect of p-coumaric acid, 4-VP and 4-EP at concentrations of 4 to 20 mg/L, 2 to 10 mg/L and 3 to 15 mg/L, respectively, on the maximum specific growth rate of the S. cerevisiae PE-2 strain.
Estudo químico e ecológico de Escovopsis spp., invasor do jardim de fungos de formigas cortadeiras
(Universidade Federal de São Carlos, 2018-05-02) Santos, Ana Carolina Alves do; Vieira, Paulo Cezar; https://lattes.cnpq.br/8923844563320377; https://lattes.cnpq.br/6169045230374129
Microorganisms associated to leaf cutting ants comprise an important source of antifungal and antibacterial compounds due to the environment they are inserted in. The fungal garden is composed by a complex microbial network in which, can be found, at least, a mutualistic fungus (Leucoagaricus gongylophorus), a specialized parasite (Escovopsis spp.), symbionts actinomycetes (Pseudonocardia and Streptomyces spp.) and many other microbes with still unknown ecological functions. Among these, we highlight the fungi belonging to the genus Escovopsis, due to their ability to bring nests to death when infected. In spite of its potential to produce antimicrobial agents, until now there is no reports about the chemical mediators produced by Escovopsis that are involved in this ecological relationship. Thus, aiming to better understanding the chemical-ecology of Escovopsis spp., two species from this genus (E. microspora and E. weberi) were investigated on their metabolomics and chemical-ecology aspects. Through metabolomics studies, it was possible to isolate and identify several secondary metabolites such as anthraquinones, aza-anthraquinones, polyketides, diketopiperazines, terpene-indole alkaloid, among others. On the other hand, coculture experiments between E. weberi and L. gongylophorus led to the isolation and identification of two compounds (melinacidin IV and shearinine D) which are upregulated in the presence of the symbiont fungus. Despite the fact they don’t display antifungal activity against L. gongylophorus, these metabolites inhibit the growth of bacteria responsible for the nest protection (Pseudonocardia spp.). Therefore, these substances may play a role in the ecological war between the microorganisms living in the leaf-cutting ants fungal garden.
A matemática e o futebol: aprendendo matemática com as cobranças de pênaltis
(Universidade Federal de São Carlos, 2018-05-02) Zola, Fausto Lombardo; Caetano, Paulo Antônio Silvani; https://lattes.cnpq.br/0370219014539994
In this work, having as a guideline the football penalty kicks, is presented the idealization, the development, the application and the results analysis of a didactic sequence in order to teach and recover some mathematical concepts. As final product a penalty simulator in GeoGebra and five activity sheets were obtained, which were applied in two classes of the second year of high school in a private school in Bebedouro/SP.
Microplanejamento de estradas florestais por meio de geotecnologias
(Universidade Federal de São Carlos, 2018-05-02) Américo, Carla; Thiersch, Claudio Roberto; https://lattes.cnpq.br/8791966697254106; Valente, Roberta Averna; https://lattes.cnpq.br/1582627535733911; https://lattes.cnpq.br/8373522066888211
Forest roads, when are not well structured and allocated, can become potential sources of environmental impacts, mainly related to water dynamics and sediment production. The environmental analyses subsidize the land-use planning which contributes to the control of the undesirable geodynamic processes as the erosion. In this context, the study aimed at the definition of critical areas to forest roads allocation, considering relief, hydrography, and soil characteristics of a landscape (i.e. forest farm of study). We mapped these aspects, that supported the following criteria map generation: slope, erodibility, distance to the flow accumulation water, and aspect. Some criteria were aggregated through Weighted Linear Combination (WLC), a Multicriteria Method (MCE), producing the final map of critical areas to allocated roads, which had its accuracy verified by ROC (Receiver Operating Characteristic) analysis. According to the mapping, the farm was classified in the following levels of criticality: 39,46% high, 29,68% average, 15,61% low, 10,90% very high, 4,14% very low, 0,14% extremely low, and 0,06% extremely high. Yet the roads currently located in the area were classified as the following criticality levels: 37,79% high; 21,78% average; 17,43% low, 15,23% very high; 6,97% very low, 0,43% extremely low, and 0,36% extremely high. The ROC analysis showed a statistically significant accuracy of the mapping, indicating that the criteria represented the critical characteristics of the landscape. We concluded that WLC method can be used in the forest road network planning, considering the critical aspects of the landscape, ensuring its soil and water conservation.