期刊
BIOMED RESEARCH INTERNATIONAL
卷 2013, 期 -, 页码 -出版社
HINDAWI LTD
DOI: 10.1155/2013/584207
关键词
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资金
- Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)
- Coordenacao de Aperfeicoamento de Pessoal do Ensino Superior (CAPES)
- Financiadora de Estudos e Projetos (FINEP)
Streptomyces misionensis strain PESB-25 was screened and selected for its ability to secrete cellulases. Cells were grown in a liquid medium containing sugarcane bagasse (SCB) as carbon source and corn steep liquor (CSL) as nitrogen source, whose concentrations were optimized using response surface methodology (RSM). A peak of endoglucanase accumulation (1.01 U.mL(-1)) was observed in a medium with SCB 1.0% (w/v) and CSL 1.2% (w/v) within three days of cultivation. S. misionensis PESB-25 endoglucanase activity was thermoacidophilic with optimum pH and temperature range of 3.0 to 3.6 and 62 degrees to 70 degrees C, respectively. In these conditions, values of 1.54 U mL(-1) of endoglucanase activity were observed. Moreover, Mn2+ was demonstrated to have a hyperactivating effect on the enzyme. In the presence of MnSO4 (8 mM), the enzyme activity increased threefold, up to 4.34 U.mL(-1). Mn2+ also improved endoglucanase stability as the catalyst retained almost full activity upon incubation at 50 degrees C for 4 h, while in the absence of Mn2+, enzyme activity decreased by 50% in this same period. Three protein bands with endoglucanase activity and apparent molecular masses of 12, 48.5 and 119.5 kDa were detected by zymogram.
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