Bioprospecção de leveduras da kombucha para produção de cerveja

• Ano de defesa: 2020
• Autor(a) principal: Clausen, Willyan Alex Prochera
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Positivo; Brasil; Pós-Graduação; Programa de Pós-Graduação em Biotecnologia Industrial; UP
• Palavras-chave em Português: Biotecnologia; Microbiologia; Fermentação; Sulfeto de hidrogênio; CNPQ::CIENCIAS BIOLOGICAS::BIOLOGIA GERAL
• Link de acesso: https://repositorio.cruzeirodosul.edu.br/handle/123456789/2769

Beer is a hoppy drink with different alcoholic grades, obtained through the fermentation of cereal malt by yeasts like Saccharomyces cerevisiae. Beer production in Brazil was 14.1 billion liters in 2017, making it the third largest producer in the world. There is a growing consumer and industry demand for beer with new flavors and aromas, which can be obtained through new strains of yeast to be used in fermentation. A potential source for isolation and prospecting for yeasts is kombucha, which is an Asian drink from the fermentation of black or green tea made by a consortium of yeasts and acetic bacteria, with a great variation in the species of microorganisms according to the source of the kombucha. The strains involved in the fermentation of the kombucha contribute to the sensory quality of the drink, so that it is possible to introduce some flavors and aromas of the kombucha in other fermented drinks, such as beer, if the microorganisms from the production of the kombucha are used. The main objective of the present work was to prospect kombucha yeasts for beer production. Evaluating different selection methods in order to obtain strains capable of growing in beer must and that can be used for beer production, specifically yeasts that are capable of growing in beer must in conditions similar to those of the beer production process. For this, a single sample of kombucha tea from the infusion of mate tea was used in the laboratory of Universidad Positivo. From the sample, the yeast was directly isolated from this sample and the yeast pre-selection method, inoculating aliquots of the sample in brewing wort and in YPD8E5 liquid medium (composed of yeast extract, peptone, glucose and ethanol), at in order to select yeasts adapted to the wort composition and the presence of ethanol, respectively. Colonies were obtained by plating in YPD medium supplemented with chloramphenicol to inhibit bacteria, totaling 27 isolated yeast strains, which underwent characterization tests for tolerance to hops 30 IBU (international bitterness unit), which corresponds to an average bitterness of hop. an Ale type beer, and H2S production test. The best performing strain was subjected to a 3% (v/v) ethanol tolerance test. At the end, it was possible to obtain a yeast using the tolerance tests for hops and ethanol, with the mass loss technique, the strain coded as MC-7-BR01 had greater loss of mass compared to others obtained in the tests.