Molecular characterization of a β-1,4-endoglucanase from an endophytic Bacillus pumilus strain

Abstract

Endophytes comprise mainly microorganisms that colonize inner plant tissues, often living with the host in a symbiotic manner. Several ecological roles have been assigned to endophytic fungi and bacteria, such as antibiosis to phytopathogenic agents and plant growth promotion. Nowadays, endophytes are viewed as a new source of genes, proteins and biochemical compounds that may be used to improve industrial processes. In this study, the gene EglA was cloned from a citrus endophytic Bacillus strain. The EglA encodes a beta-1,4-endoglucanase capable of hydrolyzing cellulose under in vitro conditions. The predicted protein, EglA, has high homology to other bacterial cellulases and shows a modular structure containing a catalytic domain of the glycosyl hydrolase family 9 (GH9) and a cellulose-binding module type 3 (CBM3). The enzyme was expressed in Escherichia coli, purified to homogeneity, and characterized. EglA has an optimum pH range of 5-8, and remarkable heat stability, retaining more than 85% activity even after a 24-h incubation at pH 6-8.6. This characteristic is an important feature for further applications of this enzyme in biotechnological processes in which temperatures of 50-60 degrees C are required over long incubation periods.

Purification and Characterization of Cellulase from Termite Ametermes eveuncifer (Silverstri) Soldiers

“…It was observed that the optimum condition of enzyme activity by the soldier termites was pH 8 and temperature 50 °C which are in agreement with that reported by Lima et al (2005) for Bacillus pumilus strain. The optimum temperature value was the same in comparison to that obtained with the cellulase from the Reticulitermes speratus (Kolbe), a Japanese Subterranean Termite (Watanabe et al, 1997) and very close to that from the digestive tract of the termite Macrotermes mulleri, in which an optimum temperature of 55 o C was observed (Rouland et al, 1988).…”

PRODUCTION AND CHARACTERIZATION OF THERMOPHILIC CARBOXYMETHYL CELLULASE SYNTHESIZED BY Bacillus sp. GROWING ON SUGARCANE BAGASSE IN SUBMERGED FERMENTATION

“…The search for new cellulases with properties more suitable for industrial application remains a constant effort (Lima et al, 2005). In addition, new thermophilic cellulases are being exploited in order to make the relevant industrial processes more efficient and economical (Liang et al, 2009).…”

Structural characterization of the bglH gene encoding a beta-glucosidase-like enzyme in an endophytic Bacillus pumilus strain

“…Endophyte microorganisms colonize inner plant tissues, living symbiotically with the host species (Azevedo et al, 2000). These microorganisms have been investigated as a source of new genes and proteins for use in industrial processes (Stamford et al, 2001(Stamford et al, , 2002Pleban et al, 1997;Reddy et al, 1996;Moy et al, 2002;Lima et al, 2004).…”

“…isolated from Citrus were evaluated for cellulolytic activity (Lima et al, 2004). The Bacillus pumilus strain CL16 showed high cellulase activity and was selected for further studies.…”