Identification of a positive β-glucosidase functional clone 135B12 from metagenomic library of Miscanthus sinensis fed cattle’s ruminal inhabitants. A. Strategy of obtaining of new β-glucosidase from metagenomic library. B. The volume of metagenomic library. C. Stability of exogenous gene in the library after subcultures (A, B, C: digestive pattern of fosmid DNA of three indipendent clones from the library by EcoR I and Hind III; 1-4: mean four times of subcultures).