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Cellulose is one of the world's most abundant natural organic matter, is a cheap and renewable resources, the development and utilization of far-reaching significance. The cellulase degradation of cellulose is an effective and environmentally sound way, and a wide range of applications of the cellulose enzyme. Therefore, cellulase and its application has gradually become the focus of attention. Present internal endoglucanase more. Sun Lun completed the screening and separation of a high cellulase activity of Bacillus subtilis bacteria, its molecular identification, and name of Bacillus Sp bs-1, and successfully cloned endoglucanase enzyme gene. In this study, based on building different prokaryotic expression vector, and soluble expression in E. coli. The purpose of this study was to compare the expression vector, to study their expression efficiency, as well as to optimize the expression conditions, endoglucanase soluble overexpression of laying the foundation. This study has successfully build into three different expression vectors, i.e., the pQE-30-C, pET-30a-C, pET-28a-C, and compared to effect its expression. By fumble suitable expression conditions, the pET-30a-C is determined, the best of the pET-28a-C Expression of endoglucanase soluble inducible expression conditions. pET-30a-C Expression of endoglucanase was induced with 1 mM of IPTG for 3 hours at 25 ℃, can achieve the best amount of soluble expression. pET-28a-C Expression of endoglucanase at 25 ℃, induced with 0.8mM IPTG was 5 hours, to be able to achieve the optimum amount of soluble expression. Construction of pET-30a-C, pET-28a-C Expression of endoglucanase activity were measured, and to determine the optimum reaction conditions. pET-30a-C Expression of endoglucanase in the substrate buffer (CMC-Na as a substrate and incubated at pH 7.0) 50 ° C for 30min, the enzyme activity highest activity was 1489U/mL, pET- 28a-C expression of the endoglucanase in substrate buffer (CMC-Na as a substrate, and incubation at pH 3.0) 55 ° C for 30min, the enzyme activity highest activity was 683U/mL. PET-30a-C was purified using Ni-NTA resin, pET-28a-C Expression of endoglucanase protein, to obtain a single target protein, and measuring the specific activity of the purified endoglucanase. endoglucanase purified after expression of pET-30a-C 723U/mg the specific activity of the enzyme activity of the enzyme in the pET-28a-C Expression of endoglucanase purified 808U/mg. This results from Bacillus subtilis endoglucanase provide a theoretical basis for industrial applications.
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