English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Protease production by thermophilic Bacillus sp strain SMIA-2 cultivated in liquid cultures containing 1% maltose as a carbon source and supplemented with whey protein (0.1%) and corn steep liquor (0.3%) reached a maximum at 14 h, with levels of 42 U/mg protein. The microorganism was capable of utilizing a wide range of carbon sources, but protease activity varied according the carbon source. Starch and maltose were the best carbon sources in the present study for protease secretion, while lactose and sucrose were less effective. Increasing maltose concentration in the medium until 1%, improved the growth of the organism and the enzyme activity. Regarding the amounts of corn steep liquor and whey protein in the medium, the concentrations of 0.2% and 0.1% respectively, were considered the most effective for protease secretion by the organism. Studies on the protease characterization revealed that the optimum temperature of this enzyme was 70ºC. Thermostability profile indicated that the enzyme retained 80% of the original activity after 2 h heat treatment at 60ºC. At 70ºC, 70% of the original activity was retained after 15 min heat treatment. The optimum pH of the enzyme was found to be 8.5. After incubation of crude enzyme solution at room temperature for 2 h at pH 6.0-10.0, a decreased of about 15% of its original activity at pH 8.5 was observed. At pH 10.0, the decrease was 24%. In the presence of 1.0 M and 5.0 M NaCl, 76% and 37% of protease activity was retained after 2 h incubating at 45ºC respectively. A produção de proteases pelo termofílico Bacillus sp cepa SMIA-2 cultivado em culturas líquidas contendo maltose (1%) e suplementada com proteínas de soro (0,1%) e água de maceração de milho (0,3%) alcançou o máximo em 14 h, com níveis de 42 U/mg proteína. O microrganismo foi capaz de utilizar várias fontes de carbono, mas a atividade da protease variou com cada fonte. Amido e maltose foram as melhores fontes para a secreção da protease, enquanto lactose e sacarose não foram muito efetivas. O aumento da concentração de maltose no meio de cultura até 1% melhorou o crescimento do organismo e a atividade da enzima. Em relação à concentração de proteínas do soro e da água de maceração de milho no meio de cultura, 0,1% e 0,2% respectivamente, foram as mais efetivas para a secreção da enzima pelo organismo. Estudos sobre a caracterização da protease revelaram que a temperatura ótima desta enzima foi 70ºC. Em relação a termoestabilidade da enzima, a protease manteve 80% de sua atividade original após 2 h de tratamento a 60ºC. A 70ºC, 70% de sua atividade original foi mantida após 15 min. O pH ótimo para atividade da enzima foi 8,5. Após a incubação da solução enzimática bruta a pH 6,0-10.0 por 2 h a temperatura ambiente, foi observado um decréscimo de em torno de 15% da sua atividade original a pH 8,5. A pH 10,0 o decréscimo na atividade foi de 24%. Na presença de 1.0 M e 5.0 M NaCl, 76% e 37% da atividade da protease foi mantida após 2 h de incubação a 45ºC respectivamente

brazilian journal of microbiology

Effect of the culture conditions on the production of an extracellular protease by thermophilic Bacillus sp and some properties of the enzymatic activity