Cloning and biochemical characterization of a glucosidase from a marine bacterium Aeromonas sp. HC11e-3.

By constructing the genomic library, a β-glucosidase gene, with a length of 2,382 bp, encoding 793 amino acids, designated bgla, is cloned from a marine bacterium Aeromonas sp. HC11e-3. The enzyme is expressed successfully in the recombinant host Escherichia coli BL21 (DE3) and purified using glutathione affinity purification system. It shows the optimal activity at pH 6, 55 °C and hydrolyzes aryl-glucoside specially. Ca(2+), Mn(2+), Zn(2+), Ba(2+), Pb(2+), Sr(2+) can activate the enzyme activity, whereas SDS, EDTA, DTT show slight inhibition to the enzyme activity. Homologous comparing shows that the enzyme belongs to glycosyl hydrolase family 3, exhibiting 46 % identity with a fully characterized glucosidase from Thermotoga neapolitana DSM 4359. Such results provide useful references for investigating other glucosidases in the glycosyl family 3 as well as developing glucosidases using in suitable industrial area.