The gene coding for the cellulase from Streptomyces G12 strain similar to GH12 family cellulase from Streptomyces xylophagus (D2D3J0) was synthesized by PCR on Streptomyces G12’s genomic DNA using as primers both degenerate oligonucleotides whose sequences were designed on the basis of sequences of peptides identified by proteomics or sequences of peptides in similar proteins and specific oligonucleotides whose sequences were designed on the basis of sequence of amplified central region (Table 1), to amplify three overlapped fragments.