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 (M-r 148 kDa) was purified and characterized. Optimum activity occurred at 50degreesC; 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.