A novel β-glucosidase from soil microbes

Abstract:

[Background] Only a small proportion of microbes can be cultured in laboratories, thereby hampering the discovery of novel β-glucosidases from microbes. Novel microbial β-glucosidases can be discovered using culture-independent metagenomic approach. [Objective] Discovery of new β-glucosidase from soil microbes by metagenomic technology. [Methods] Screening a metagenomic library on esculin-containing Luria-Bertani agar plates and the putative β-glucosidase gene derived from the active clone was heterologously expressed for characterization. [Results] We found a?β-glucosidase active clone by screening 620 000 clones in the library and an ORF (YNBG3) whose product is homologous with the third family of β-glucosidase was identified from the active clone. YNBG3 was heterologously expressed and characterized. Its optimum pH is 5.2, and optimal temperature is 53 °C. YNBG3 showed good tolerance to organic solvents including dimethyl sulphoxide, acetone and ethanol, and the activity of YNBG3 was enhanced in presence of EDTA and urea. [Conclusion] A new β-glucosidase, with thermostability and stability in the presence of organic solvents and urea, was discovery in this study.

Key words:Metagenomics, Functional screening, β-glucosidase, Enzymatic properties