Simultaneous cloning and expression of two cellulase genes from Bacillus subtilis newly isolated from Golden Takin (Budorcas taxicolor Bedfordi)

A bacterial strain with high cellulase activity was isolated of feces sample of Golden Takin (Budorcas taxicolor Bedfordi). The bacterium was classified and designated Bacillus subtilis LN by morphological and 16SrDNA gene sequence analysis. Two putative cellulase genes, CelL15 and CelL73, were simultaneously cloned from the isolated strain by PCR. The putative gene CelL15 consisted of an open reading frame (ORF) of 1470 nucleotides and encoded a protein of 490 amino acids with a molecular weight of 54 kDa. The CelL73 gene consisted of an open reading frame (ORF) of 741 nucleotides and encoded a protein of 247 amino acids with a molecular weight of 27 kDa. Both genes were purified and cloned into pET-28a for expression in Escherichia coli BL21 (DE3). The ability of E. coli to degrade cellulose was enhanced when the two recombinants were cultured together.