PRODUCTION AND CHARACTERIZATION OF KERATINASE OF A FEATHER-DEGRADING BACILLUS-LICHENIFORMIS PWD-1

The keratinase produced by Bacillus licheniformis PWD-1 was induced by feather powder, Maximal enzyme production could be achieved by cultur ing in a medium containing 1% hammer-milled feather powder (100 mesh) at 45 degrees C for 30 h, Maximal growth of PWD-1 was achieved at 50 d egrees C, and maximal enzyme induction was at 45 degrees C, The molecu lar mass and isoelectric point of this enzyme were 31.4 kDa and 8.5, r espectively, This enzyme was stable from pH 5 to 12, The optimal react ion pHs for feather powder and casein were 8.5 and 10.5 to 11.5, respe ctively, The optimal reaction temperature was 50 degrees C to 55 degre es C, The relative activity of this enzyme toward casein, feather powd er, keratin, elastin, and collagen was 100:52:41:18:7, and 100:55:32:3 for Suc-AAPL-pNA, Suc-AAPF-pNA, Suc-AAPM-pNA, and Suc-AAVA-pNA (Suc, succinyl; pNA, p-nitrophenylanilide).