Cloning and expression of a new cellulase gene from the metagenomic library of the goat rumen
Six positive clones with cellulase activities were isolated from a metagenomic library of the goat rumen using a functional screening method. One positive clone was subject to further subcloning and sequence analysis and a new cellulase gene open reading frame was obtained. After blast analysis, it was found that the cellulase gene showed 51% sequence similarity and 65% homology compared with the hypothetical protein of Bacteroides cellulosilyticus DSM 14838. Using p ET28a(+) as a carrier, Escherichia coli BL21(DE3) as a host strain, the new gene was recombined and expressed efficiently and the expression conditions of the newly-cloned gene were optimized.