Produção de protease alcalina porCellulosimicrobium cellulans

Cellulosimicrobium cellulans is one of the microorganisms that produces a wide variety of yeast cell wall-degrading enzymes, &#946;-1,3-glucanase, protease and chitinase. Dried cells of Saccharomyces cerevisiae were used as carbon and nitrogen source for cell growth and protease production. The medium components KH2PO4, KOH and dried yeast cells showed a significant effect (p<0.05) on the factorial fractional design. A second design was prepared using two factors: pH and percentage of dried yeast cells. The results showed that the culture medium for the maximum production of protease was 0.2 g/l of MgSO4.7H2O, 2.0 g/l of (NH4)2SO4 and 8% of dried yeast cells in 0.15M phosphate buffer at pH 8.0. The maximum alkaline protease production was 7.0 ± 0.27 U/ml over the center point. Crude protease showed best activity at 50°C and pH 7.0-8.0, and was stable at 50°C.Cellulosimicrobium cellulans é um microrganismo que produz uma variedade de enzimas que hidrolisam a parede celular de leveduras: &#946;-1,3-glucanase, protease e quitinase. Células desidratadas de Saccharomyces cerevisiae foram usadas como fonte de carbono e nitrogênio para o crescimento celular e produção de protease. Os componentes do meio de cultura: KH2PO4, KOH e células de levedura desidratadas mostraram efeitos significativos (p<0,05) no planejamento experimental fracionário. Um segundo planejamento foi preparado usando dois fatores: pH e porcentagem de células de levedura desidratadas. Os resultados mostraram que o meio de cultura para a produção máxima de protease foi 0,2 g/L de MgSO4.7H2O; 2,0 g/L de (NH4)2SO4 e 8% de células de levedura desidratadas em tampão fosfato 0,15M e pH 8,0. A produção máxima de protease alcalina foi 7,0 ± 0,27 U/mL no ponto central. A protease bruta apresentou atividade ótima a 50 °C e pH 7,0-8,0; e foi estável a 50°C.546

Caracterização da toxina killer da linhagem de Saccharomyces cerevisiae Y500-4L

The strain Saccharomyces cerevisiae Y500-4L, selected from the must of alcohol producing plants, liberates a toxin which is lethal to the commercial yeast produced by Fleischmann Royal Nabisco and other strains of yeast. This toxin was characterized, and the maximum production was obtained after 24 hours of incubation at 25ºC in YEPD medium. The maximum activity was achieved between pH 4.1 and 4.5 and between 22 and 25ºC and maximum stability in the pH range 3.8 to 4.5 at -10ºC. The killer toxin was inactivated by heating at 40ºC for 1 hour at pH 4.1. After concentration by ultrafiltration of culture supernatants and purification by gel filtration chromatography, the molecular weight of the purified toxin was estimated by SDS-PAGE to be about 18-20 kDa.A linhagem de Saccharomyces cerevisiae Y500-4L, selecionada de mosto de fermentação de usina de álcool, produz toxina killer, letal à levedura comercial Fleischmann Royal Nabisco e outras linhagens de leveduras. Esta proteína foi caracterizada, verificando-se que a produção máxima foi obtida após 24 horas de incubação a 25ºC em meio YEPD. A toxina killer apresentou maior atividade na faixa de pH 4,1-4,5 e temperatura de 22-25ºC; e maior estabilidade na faixa de pH 3,8-4,5 a -10ºC, sendo totalmente inativada após 1 hora de incubação a 40ºC em pH 4,1. Após concentração a partir do sobrenadante do meio de cultura através de ultrafiltração e purificação por cromatografia de filtração em gel, estimou-se, através de SDS-PAGE, que o peso molecular desta toxina é cerca de 18 a 20 kDa.291297Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Sequential optimization strategy for maximum l-asparaginase production from aspergillus oryzae CCT 3940

l-asparaginase is an enzyme that catalyzes the deamination free l-asparagine to yield aspartic acid and ammonia, and it is used in the food industry to reduce the levels of acrylamide that are formed when starchy foods are fried, baked and cooked. In this work, a sequential optimization strategy was used to determine the effect of carbon sources, nitrogen sources, l-asparagine inducer, inoculum concentration, initial medium pH, temperature and agitation rate in the production of l-asparaginase from Aspergillus oryzae CCT 3940 in submerged fermentation. The micro-organism was fermented at 30 °C in modified Czapeck medium composed of proline (2%), glucose (0.5%), l-asparagine inducer (0.2%), yeast extract (0.5%), KH2PO4 (0.152%), KCl (0.052%), MgSO4·7H2O (0.052%), CuNO3·3H2O (0.0001%), ZnSO4·7H2O (0.0001%) and FeSO4.7H2O (0.0001%) adjusted to pH 8.0 using a concentration of 3×107 spores and 72 h of fermentation at 150 rpm at 30 °C. A final activity of 67.49 U mL−1 was achieved, which represents an increase of 225% in relation to the initial non-optimized conditions63339CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPSem informação2012/24046-