Isolation and Molecular Identification of Keratinase-Producing Bacteria from the Sludge of Qeshm Island

ABSTRACT           Background and Objectives: Keratinase is an enzyme commonly used in the production of detergents, cosmetics, drugs, leather, and other industries. Considering the high cost of traditional methods for decomposition of feather, hair, hooves, nails, and wool that contain high levels of keratin, their biodegradation with keratinase-producing bacteria can be a valuable solution. The present study aimed for isolation and molecular identification of keratinase-producing bacteria in Qeshm Island and Peyposht village in Iran.           Methods: Water and sludge samples from the Qeshm Island and Peyposht village were collected. The bacteria isolates were screened for keratinase production using the Lowry method. Effect of pH and temperature was assessed on the production of keratinase and on the growth of the isolates. Colony-polymerase chain reaction was used for molecular identification of the isolates.           Results: Bacillus berevis and Enterobacter cloacae were isolated in this study. Keratinase production in B. berevis was highest at pH 7.5 and 35 °C. In addition, the highest level of enzyme production by E. cloacae was observed at pH 7 and 37 °C.           Conclusion: It seems that the bacterial strains isolated from sludge in the study area have relatively favorable keratinase production capacity.           Keywords: Bacteria, Colony PCR, Identification, Keratinolytic protein, Sewage.