BIODEGRADATION OF FEATHER WASTE BY EXTRACELLULAR KERATINASE FROM SPORULATING MICROORGANISMS

Chicken feathers, consists of about 90% keratin (a recalcitrant protein) which cannot be easily hydrolyzed by common proteolytic enzymes. These feathers constitute a sizable waste disposable problem. Hence an eco-friendly alternative to this problem is mandatory. In the present investigation, the feather degrading microorganisms were isolated from feather dumped soil in Namakkal District. The preliminary study on the enrichment culture technique was performed in order to isolate the keratin degrading Bacillus species. The primary screening on skim milk and keratin agar revealed that only two Bacillus sp (FD1 and FD2) exhibited prominent growth and clear zone on agar plates. These efficient proteolytic bacteria were identified as Bacillus sp on the basis of phenotypic and physiological characteristics. The results were compared in accordance with the Bergey’s manual of Determinative Bacteriology. These two bacteria were identified as Bacillus cereus and Bacillus licheniformis. Further investigation, the degradation of chicken feathers was performed in feather minimal medium (pH 7.5) in which chicken feather acts as the sole carbon and nitrogen sources. Both the organisms effectively degraded the chicken feathers within 17 days. Both the isolates were assayed for its keratinolytic activity. The molecular weight of the keratinases for both Bacillus cereus and Bacillus licheniformis was done in SDS-PAGE. The effects of pH, temperature, carbon sources, nitrogen sources and metal ions / inhibitors on keratinase activity of both the organisms were studied. Analysis of HPLC or Monitoring the formation or disappearance of peaks obtained due to biodegradation of keratin was analyzed and recorded. Simultaneouslsy, pertaining to FTIR on keratin degradation indicated a pronounced difference between control and experimental treated feather samples. The application of keratinase enzymes obtained from Bacillus cereus and Bacillus licheniformis were studied. The above results indicated that both the Bacillussp produced appreciable levels of keratinase enzyme using feather as substrate and this could open new opportunities to reduce these recalcitrant feather waste and thereby reducing the pollution.