Secretion of a trypsin-like thiol protease by a new keratinolytic strain of Bacillus licheniformis

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When cultured in feather-containing broth with a growth optimum of pH 7.0 and 47°C, a Bacillus licheniformis strain exhibited a high chicken feather-degrading activity. A trypsin-like protease was isolated from its ferment broth and was partially characterized. The enzyme was constitutively secreted and was highly active towards N-benzoyl-Phe-Val-Arg-p-nitroanilide as chromogenic substrate. Its pH optimum was 8.5 and it exhibited the highest activity at 52°C. Fractionation on Sephadex G-100 column revealed that its molecular mass was about 42 kDa. The enzyme, which is new for the genus Bacillus, is a thiol protease, as tosyl-L-phenylalanine chloromethyl ketone, tosyl-L-lysine chloromethyl ketone, phenylmethylsulfonyl fluoride and ethylenediamine tetraacetate did not inhibit it, while HgCl2 and para-chloromercuribenzoate lowered its activity.

Original languageEnglish
Pages (from-to)221-224
Number of pages4
JournalFEMS microbiology letters
Issue number2
Publication statusPublished - Dec 18 2001


  • Bacillus licheniformis
  • Keratinase
  • Protease secretion

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology
  • Genetics

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