01. Universidade Federal Rural de Pernambuco - UFRPE (Sede)
URI permanente desta comunidadehttps://arandu.ufrpe.br/handle/123456789/1
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Resultados da Pesquisa
Item Prospecção da atividade antimicrobiana de polissacarídeos extraídos das paredes celulares das leveduras Kluyveromyces marxianus, Kluyveromyces lactis e Saccharomyces cerevisiae(2021-02-26) Araújo, Isabelle Maria Feitosa de; Ferreira, Éder Galinari; http://lattes.cnpq.br/7670722046479986; http://lattes.cnpq.br/5044579569126838Polysaccharides from the most diverse sources, may have pharmacological activities such as, for example, antioxidant, immunomodulatory, anticoagulant and antimicrobial. Bearing in mind that this last activity has not yet been evaluated, according to our bibliographic survey, for the cell wall polysaccharides of the yeasts Kluyveromyces marxianus and Kluyveromyces lactis, the objective of this study was to verify the antimicrobial activity of polysaccharides extracted from the cell walls of the yeasts Kluyveromyces marxianus CCT7735 and Kluyveromyces lactis CBS2359 and compare them to a non-Kluyveromyes yeast like Saccharomyces cerevisiae CAT-1. The susceptibility tests were performed in Petri dishes (90 x 15 mm) using the Kirby-Bauer disc-diffusion method as recommended by the M 100 supplement of the 29th edition of the Clinical & Laboratory Standards Institute. Ten microliters of the polysaccharide solution (10 mg/mL) solubilized in distilled water and sterilized by filtration were deposited on sterile paper discs (6 mm). Polysaccharides were tested against Escherichia coli ATCC 25922 (positive control: 100/10 μg of piperacillin-tazobactam); Staphylococcus aureus ATCC 29213 (positive controls: 30 μg of cefoxitin and 10 units of penicillin); Pseudomonas aeruginosa ATCC 27853 (positive controls: 100/10 μg of piperacillin-tazobactam and 10 μg of gentamicin); Klebsiella pneumoniae ATCC 700603 (positive control: 10 μg gentamicin) and Enterococcus faecalis ATCC 29212 (positive controls: 30 μg tetracycline and 10 units of penicillin). None of the cell wall polysaccharide samples evaluated inhibited the growth of the pathogenic bacteria strains tested. Thus, at least in native molecules, polysaccharides did not show antimicrobial activity. We suggest that further studies be carried out with the samples evaluated, either for other pharmacological applications/activities or with the chemical modification or modification of the concentration of these polysaccharides, followed by a new test for antimicrobial activity, among others.Item Avaliação de parâmetros de crescimento das leveduras Kluyveromyces marxianus, Kluyveromyces lactis e Saccharomyces cerevisiae(2022-05-31) Veiga, Luísa Helena Farias Alves; Ferreira, Éder Galinari; http://lattes.cnpq.br/7670722046479986; http://lattes.cnpq.br/3226662191542782The microorganisms most used in industries are yeasts. Kluyveromyces lactis is used in the production of proteins and the enzyme β-galactosidase by the pharmaceutical industry, in addition to the production of heterologous proteins of biotechnological importance. Kluyveromyces marxianus has metabolic diversity, thermotolerance, assimilates lactose as a source of energy and carbon and has the highest maximum growth rate (μmax) known among eukaryotic microorganisms. S. cerevisiae is widely used in fermented products, such as breads and alcoholic beverages, and can also be used in the bioremediation of heavy metals, such as zinc, mercury, lead, cadmium, nickel, arsenic, gold, chromium, uranium, and platinum. To produce yeast biomass on anindustrial scale, it is important to know some parameters such as the maximum growth rate and the saturation constant, as well as to determine the biomass production quickly. In this case, it is possible to correlate the biomass with the cell optical density. Thus, the objective of this work wasto compare the growth of K. marxianus, K. lactis and S. cerevisiae yeasts in YP medium with different glucose concentrations [2.5 g/L, 5.0 g/L, 10.0 g/L, and 20.0 g/L (w/v)], determining their maximum growth rates, the saturation constant and correlating biomass production with cellular optical densities. K. marxianus was incubated at 37 °C and K. lactis and S. cerevisiae at 30 °C in ashaker at 200 rpm. The cell optical density (OD) was determined in a spectrophotometer (600 nm).The optical density was measured after 2, 3, 4, 5 and 6 h of incubation. The maximum growth rates and saturation constants obtained for K. marxianus, K. lactis and S. cerevisiae were, respectively, 0.69 h-1 and 0.17 g/L, 0.45 h-1 and 0.385 g /L, 0.47 h-1 and 0.54 g/L. To calculate the correlation of biomass with cell optical densities, dilutions were prepared from a mother microbial suspension of each yeast species, obtaining dilutions 1:0, 1:1, 1:2, 1:4, 1:8 and 1:16. Considering these dilutions, respectively, the OD and biomass obtained for K. marxianus were 53.15 and 23.0 g/L, 27.68 and 12.0 g/L, 12.76 and 6.7 g/L, 7, 33 and 4.4 g/L, 4.04 and 2.9 g/L, 2.1 and 1.7 g/L. Likewise, for K. lactis the OD and biomass determined were 59.35 and 21 g/L, 28.80 and 11 g/L, 13.95 and 6.3 g/L, 8.16 and 3.4 g/L, 4.53 and 1.9 g/L, 2.25 and 1.2 g/L. And yet, for S. cerevisiae the OD andbiomass calculated were 39.3 and 16 g/L, 19.13 and 8.5 g/L, 9.04 and 4.7 g/L, 4.82 and 3, 4 g/L, 2.55 and 1.4 g/L, 1.39 and 1.2 g/L. It is concluded that, under the conditions evaluated, the yeast K. marxianus exhibited higher maximum growth velocity and biomass, with a lower saturation constant of glucose transporters when compared to K. lactis and S. cerevisiae.Item Uso de leveduras para o controle da podridão da escama em cebola(2018) Ribeiro, Bárbara Gomes; Gama, Marco Aurélio Siqueira da; http://lattes.cnpq.br/6842187820744212; http://lattes.cnpq.br/2575317444139542