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BioMed Research International
Volume 2013 (2013), Article ID 584207, 9 pages
http://dx.doi.org/10.1155/2013/584207
Research Article

Streptomyces misionensis PESB-25 Produces a Thermoacidophilic Endoglucanase Using Sugarcane Bagasse and Corn Steep Liquor as the Sole Organic Substrates

1Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde (CCS), Universidade Federal do Rio de Janeiro (UFRJ), Avenida Carlos Chagas Filho 373, Bloco I, Laboratório 055, 21941-902 Rio de Janeiro, RJ, Brazil
2Departamento de Engenharia Bioquímica, Escola de Química, Centro de Tecnologia (CT), Universidade Federal do Rio de Janeiro (UFRJ), Avenida Athos da Silveira Ramos 149, Bloco E, sala 203, 21941-909 Rio de Janeiro, RJ, Brazil
3Departamento de Bioquímica, Instituto de Química, Centro de Ciências Matemáticas e Natureza (CCMN), Universidade Federal do Rio de Janeiro (UFRJ), Avenida Athos da Silveira Ramos 149, Bloco A, sala 539, 21941-909 Rio de Janeiro, RJ, Brazil

Received 1 October 2012; Revised 8 January 2013; Accepted 4 February 2013

Academic Editor: Divya Prakash

Copyright © 2013 Marcella Novaes Franco-Cirigliano et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

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° to 70°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°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.