title: Streptomyces misionensis PESB-25 produces a thermoacidophilic endoglucanase using sugarcane bagasse and corn steep liquor as the sole organic substrates.
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, Mn(2+) 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). Mn(2+) also improved endoglucanase stability as the catalyst retained almost full activity upon incubation at 50 °C for 4 h, while in the absence of Mn(2+), 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.
authors.affiliation: Departamento de Microbiologia Geral, Instituto de Microbiologia Paulo de Góes, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, Avenida Carlos Chagas Filho 373, Bloco I, Laboratório 055, 21941-902 Rio de Janeiro, Brazil.
authors.forename: Marcella Novaes
authors.initials: MN
authors.lastname: Franco-Cirigliano
authors.forename: Raquel de Carvalho
authors.initials: Rde C
authors.lastname: Rezende
authors.forename: Mônica Pires
authors.initials: MP
authors.lastname: Gravina-Oliveira
authors.forename: Pedro Henrique Freitas
authors.initials: PH
authors.lastname: Pereira
authors.forename: Rodrigo Pires
authors.initials: RP
authors.lastname: do Nascimento
authors.forename: Elba Pinto da Silva
authors.initials: EP
authors.lastname: Bon
authors.forename: Andrew
authors.initials: A
authors.lastname: Macrae
authors.forename: Rosalie Reed Rodrigues
authors.initials: RR
authors.lastname: Coelho
mesh_terms: D002244:Carbon / Q000378:metabolism*; D002480:Cellulase / Q000378:metabolism*; D002482:Cellulose / Q000737:chemistry; D003470:Culture Media; D004795:Enzyme Stability; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D009584:Nitrogen / Q000378:metabolism*; D031786:Saccharum / Q000737:chemistry; D013302:Streptomyces / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D013696:Temperature; D003313:Zea mays / Q000737:chemistry
chemical_list: D003470:Culture Media; D002244:Carbon; D002482:Cellulose; C027433:bagasse; D002480:Cellulase; D009584:Nitrogen