Discovery of two novel ß-glucosidases from an Amazon soil metagenomic library.

An Amazon soil microbial community metagenomic fosmid library was functionally screened for ß-glucosidase activity. Contig analysis of positive clones revealed the presence of two ORFs encoding novel ß-glucosidases, AmBGL17 and AmBGL18, from the GH3 and GH1 families, respectively. Both AmBGL17 and AmBGL18 were functionally identified as ß-glucosidases. The enzymatic activity of AmBGL17 was further characterized. AmBGL17 was tested with different substrates and showed highest activity on pNPßG substrate with an optimum temperature of 45 °C and an optimum pH of 6. AmBGL17 showed a Vmax of 116 mM s(-1) and Km of 0.30 ± 0.017 mM. This is the first report of ß-glucosidases from an Amazon soil microbial community using a metagenomic approach.