A novel endo-glucanase from the thermophilic bacterium Geobacillus sp. 70PC53 with high activity and stability over a broad range of temperatures

Abstract

A thermophilic Geobacillus bacterium secreting high activity of endo-glucanase (EC 3.2.1.4) was isolated from rice straw compost supplemented with pig manure. A full-length gene of 1,104 bp, celA, encoding this glycosyl hydrolase family 5 endo-glucanase of 368 amino acids was isolated. No related gene from Geobacillus has been reported previously. The recombinant CelA expressed in Escherichia coli had an optimal activity at 65 degrees C and pH 5.0, and it exhibited tenfold greater specific activity than the commercially available Trichoderma reesei endo-glucanase. CelA displayed activity over a broad temperature range from 45 to 75 degrees C and was a thermostable enzyme with 90% activity retained after heating at 65 degrees C for 6 h. Interestingly, CelA activity could be enhanced by 100% in the presence of 2 mM MnSO(4). CelA had high specific activity over beta-D-glucan from barley and Lichenan, making it a potentially useful enzyme in biofuel and food industries.

Phylogenetic Diversity and Characterization of Novel and Efficient Cellulase Producing Bacterial Isolates from Various Extreme Environments

“…5,6,35) Thermal stability is another additional important characteristic of industrial enzymes. The crude cellulase of Bacillus sp.…”

“…Niches with high organic matter content such as compost, forest and marshes are the best niches for the isolation of cellulase producers, but extreme environments can also be exploited for cellulases with specific properties. Microorgansims from different extreme environments have been explored for production of cellulases, [3][4][5][6][7] but there is a paucity of information regarding the cellulase producing abilities of these microbial resources.…”

Cloning and Characterizing the Thermophilic and Detergent Stable Cellulase CelMytB from Saccharophagus sp. Myt-1

“…Because converting cellulosic waste to glucose is globally significant, cellulases are important in biomass use. Thermophilic cellulases specifically are advantageous for many industrial applications because the high processing temperatures they can endure increase the solubility of the reactants and reduce contamination [7]. Therefore, greater understanding of thermophilic cellulases could lead to new and useful industrial applications.…”

Expression and characterization of recombinant cellulases from an isolated Klebsiella

“…After determined the protein content using Coomassie brilliant blue method, 20 μl solution with protein concentration of 5 μg.μl -1 was dipped onto CMC-Na plates (the proliferation medium supplemented with 15 g.l -1 decarburization agar strip, pH7.0). After incubation for 24 h at 37°C, the plates were put at 60°C for 1 h, then stained with 0.2% (w/v) Congo red for 15 min and destained with 1 M NaCl solution (Ng et al, 2009). Two ml solution with protein concentration of 1 μg.μl -1 was transferred into 8 ml Mandel's inorganic salt solution containing FINE pieces of 1 × 4 cm decarbonization quantitative filter paper (Xinhua Paper Co., Ltd, Hangzhou, China).…”

“…After culturing for 6 h on a rotary shaker (150 r.min -1 ) at 30°C, 5 ml filtrates were transferred into 50 ml fresh LB liquid medium for overnight incubation. Then, 30 μl cultures were transferred into 30 ml medium (Mandel's inorganic salt solution (Ng et al, 2009) containing 10 g.l -1 sodium carboxylmethyl cellulose (CMC-Na) as the sole carbon source, pH7.0) for proliferation. Four days later, 100 μl of them were inoculated onto Congo red plates (proliferation medium supplemented with 15 g.l -1 decarburization agar strip, 0.2 g.l -1 Congo red, pH7.0) and were cultured upside down at 30°C for 7 days.…”