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Cloning and characterization of thermo-alkalistable and surfactant stable endoglucanase from Puga hot spring metagenome of Ladakh (J&K)

Gupta, Puneet, Mishra, Arjun K., Vakhlu, Jyoti
International journal of biological macromolecules 2017 v.103 pp. 870-877
affinity chromatography, amino acids, barley, beta-glucans, cetyltrimethylammonium bromide, copper, detergents, endo-1,4-beta-glucanase, enzyme activity, gene overexpression, genes, genomic libraries, hot springs, iron, manganese, mercury, metagenomics, pH, polyacrylamide gel electrophoresis, polysorbates, screening, substrate specificity, surfactants, temperature, zinc
A thermo-alkalistable and surfactant stable endoglucanase (PHS) gene consisting of 554 amino acids was identified from metagenomic library of Puga hot spring using functional screening. PHS gene was overexpressed and purified to homogeneity using affinity chromatography The purified PHS protein presented a single band of 60kDa on the SDS-PAGE gel and zymogram. The recombinant PHS exhibited activity over a broad range of pH and temperature with optima at pH 8.0 and 65°C, respectively and having optimum stability at 60°C and pH 8.0, respectively. The recombinant PHS showed highest substrate specificity using CMC (218.4U/mg) as compared with Barley β-glucan (89.2U/mg) and Avicel (0.8U/mg). The Km and Vmax of recombinant PHS for CMC were 3.85mg/ml and 370.37μmolmin−1mg−1, respectively. The activity of the recombinant PHS was enhanced by treatment with 10mM non-ionic detergents such as Tween 20, Tween 40, Tween 80, Triton X- 100 and PEG and was inhibited by CTAB, SDS. Its functionality was stable in the presence of Fe3+ but inhibited by Cu2+, Hg2+, Mn2+ and Zn2+. These properties make PHS endoglucanase a potential candidate for use in laundry, textile,paper and pulp industries