Determination of Keratinase Enzyme Activity by Bacillus megatrium SKH14 Strain

Background & objectives : Billions of chickens are consumed annually in the world and about billions of tons of chicken feathers are produced. About 5 to 7 percent of the chicken's weight is feather and about 90 percent of the feathers are keratin. Feather is a pure keratin protein that is highly insoluble and difficult to break down. Some bacteria have the ability to produce the keratinase enzyme to break down keratin. The aim of this study was to determine the factors affecting the growth of SKH14-isolated bacilli megatrium strain SKH14 and to measure the enzymatic activity of keratinase. Methods: Soil samples were collected in sterile plastic containers. Seven bacterial isolates were grown on a specific environment, of which 5 showed clear decomposition and were selected for biochemical tests, 16S rRNA sequencing and keratin measurement activity. These five bacteria were then sequenced and GeneBank accession number was assigned for each of them as a new strain. Five bacteria were tested for keratinase production and the strongest strain was optimized for keratinase production. Results: Five isolates were belonged to different strains of bacilli, and all five isolates were feather decomposer at different times. The highest enzymatic activity was reported in Bacillus megaterium SKH14 with 18.01 units per ml and the lowest in Bacillus felexus SKH4 with 10.81 units per ml. Conclusion: The complete decomposition of Bacillus megaterium SKH14 isolate showed that this bacterium has high protease activity and is able to decompose complete keratin.