Production, purification and characterization of an extracellular keratinase from Lysobacter NCIMB 9497

AIMS: The aim of this study was to determine the keratinolytic ability of a range of bacteria and subsequently, to characterize the keratinase showing the greatest biotechnological potential. METHODS AND RESULTS: Nine bacteria, reported to produce extracellular proteases, were screened for production of keratinases. Of these, Lysobacter NCIMB 9497 exhibited the highest keratinolytic activity. The keratinase from this strain (Mr 148 kDa) was purified and characterized. Optimum activity occurred at 50 degrees C; no inhibition was demonstrated by phenylmethylsulphonyl fluoride (PMSF), but inhibition by EDTA was demonstrated. CONCLUSIONS: This study indicates that keratinase is a metalloprotease with a high degree of keratinolytic activity and stability. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first detailed report of a metalloprotease with keratinolytic activity. The novel reaction mechanism, degree of keratinolytic activity and stability indicate considerable biotechnological potential in the leather industry, and in the processing of poultry waste.