Abstract: A 1.4 kb keratinase gene(kerB) was isolated from Bacillus licheniformi s L-25 strain by a polymerase chain reaction(PCR) with L-25 genomic DNA as the template. Amplified keratinase gene was directly cloned into a cloning vector PC R2.1. Then the keratinase gene within PCR2.1 was excised by restriction endo nuclease XbaI-SpeI, and inserted into the plasmid of PUB18-P43 for expressing. This new plasmid(PLK18) was transformed into protease-deficient strain Bacillus s ubtilis DB104 competent cells. The FD-8(DB104/PLK18) strain could grow rapidly o n feather-medium and completely hydrolyze all feathers in the medium.

Key words: keartinase, Bacillus licheniformis L-25 strain, kerB gene