• beta-glucosidase;
  • functional screen;
  • GH1;
  • GH3;
  • metagenomic library


An Amazon soil microbial community metagenomic fosmid library was functionally screened for β-glucosidase activity. Contig analysis of positive clones revealed the presence of two ORFs encoding novel β-glucosidases, AmBGL17 and AmBGL18, from the GH3 and GH1 families, respectively. Both AmBGL17 and AmBGL18 were functionally identified as β-glucosidases. The enzymatic activity of AmBGL17 was further characterized. AmBGL17 was tested with different substrates and showed highest activity on pNPβG 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 β-glucosidases from an Amazon soil microbial community using a metagenomic approach.