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Comparison of the Keratinase Gene Sequences of Fast, Slow and Intermediate Feather Degrading Strains of Bacillus licheniformis

Gerald Goldstein, Patricia BS Celestino-Soper, Allison K Morrell Dailey, Sara Fitzgerald-Butt


Feathers are composed of beta keratin which is an insoluble protein resistant to degradation. Bacillus licheniformis has a gene that codes for a keratinase enzyme that hydrolyzes feathers. The DNA sequences of the genes coding for keratinase enzymes of various strains of B. licheniformis were compared. Some strains of the bacteria hydrolyze feathers rapidly, some slowly, and some at an intermediate rate. The mature keratinase enzyme is composed of 274 amino acids three of which, aspartic acid, histidine, and serine, are specific for activity at the catalytic site. The keratinase enzyme amino acid sequences from strains of the bacteria that degrade feathers rapidly, slowly and intermediately all contain the three specific amino acids of the catalytic site in their respective positions. Genetic mutations that resulted in changes in the amino acid sequence of the mature keratinase enzymes did not correspond to differences in the ability of the enzymes to degrade feathers. The −10 and −35 sequences of the bacterial promoter site of the keratinase enzyme genes were found to be essentially identical in all three classes of feather degrading strains of bacteria. Subtilisin is a closely related serine protease enzyme produced by B. subtilis. Control of expression of subtilisin is mediated by at least 15 regulator proteins and is still not completely understood. The differences in the feather degrading abilities of various strains of B. licheniformis are probably due to complex patterns of regulation of expression of secreted protease enzymes of the Bacillus genus +.



Keywords: Keratinase genes, feathers, Bacillus licheniformis


Cite this Article


Goldstein Gerald, Celestino-Soper Patricia BS, Morrell Dailey Allison K, et al. Comparison of the keratinase gene sequences of fast, slow and intermediate feather degrading strains of Bacillus licheniformis. Research & Reviews: Journal of Microbiology and Virology. 2015; 5(3): 1–9p.


keratinase genes, Bacillus licheniformis, feathers

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