Purification and characterization of a novel neutral β-glucanase and an alkaline β-glucanase from an alkaliphilic Bacillus isolate

Abstract

A relatively high b-glucanase-producing strain Bacillus sp. III-3 was isolated from soda lakes in Neimenggu, China. This alkaliphilic strain was found to produce two thermostable b-glucanases including a novel neutral b-glucanase III-3-A and an alkaline b-glucanase III-3-B. The b-glucanases were purified to homogeneity from the culture supernatant with a two-step column chromatographic procedure. III-3-A and III-3-B had molecular mass of approximately 45 and 85 kDa, respectively. Mass spectrometry analysis indicated that III-3-A was probably different from the b-glucanases reported, whereas III-3-B showed high homology with those of family A5 alkaline b-glucanases from alkaliphilic bacilli. The optimum pH of III-3-A was about 7.0, while that of III-3-B was 8.0-10.0. Both enzymes exhibited maximum activity at 45°C and were stable up to 50°C. Ca 2+ ion stimulated the activity of III-3-A but enhanced the thermostability of III-3-B. The two enzymes were resistant to most metal ions and reagents examined.

A Novel Alkaline, Highly Thermostable and Oxidant Resistant Carboxymethyl Cellulase (Cmcase) Produced by Thermophilic Bacillus sonorensis CY-3

“…The results are quite similar to that reported for this enzyme from other source (Chang et al, 2011). Co 2+ ions caused a significant increase (Mansfield et al, 1998;Christakopoulos et al, 1999;Chang et al, 2011) while Mn 2+ caused a decrease in the activity of enzymes (Mawadza et al, 2000;Liu et al, 2008). In this study enzyme activitiy was stimulated by Ca 2+ ions to 131%.…”

“…Isolate CY-3 was showed the largest zone of hydrolysis and was selected for cellulase production. The diameter of halo directly reflected the ability to produce cellulases and the bigger the diameter of halo, the higher the enzyme concentration for liquid culture have been reported by Liu et al, (2008), Theather and Wood (1982). The isolate was Gram positive, rod shaped, spore forming bacterium and aerobic.…”

“…The activity was stimulated by Ca 2+ ions rather than Co 2+ ions. These results suggest that the enzymes required Ca 2+ and Co 2+ ions for thermal stability (Ito, 1997 ions has been reported very unusual for alkaline endoglucanases (Christakopoulos et al, 1999;Liu et al, 2008;Lee et al, 2008). However, Mansfield et al (1998) reported that Ca 2+ ions required by enzymes with the former increasing the substrate binding affinity of the enzyme, protecting them from conformational changes and stabilizing the conformation of the catalytic site.…”

A Novel Neutral Endoglucanase from Streptomyces sp. H31 with Wide-pH-range Stability

“…The Method and assay of enzyme activity was used as described previously (Liu et al, 2008). Streptomyces sp.…”

“…One unit of the enzyme activity was defined as the amount of enzyme that produced 1mg product per hour. The Method was used as described previously (Liu et al, 2008).…”