Ecologically safe method for improved feather wastes biodegradation

Twenty thermophilic actinomycetes were selected that were able to degrade feather wastes in high degree (87-91%). Increased proteolytic and lipolytic activity and exopolysaccharide production of the strains growing on feathers suggested their important role in the complex process of feathers biodegradation. Highest soluble protein content was determined in the fermented broths of the strains 3H, 8H, and 27A. Based on data obtained, a mixed culture of three selected thermoactinomycete strains - 3H, 8H and M4, has been designed that considerably improved the feathers digestion process. The addition of feathers from 0.7 to 3% and pH values from 7.5 to 8.5 provided highest soluble protein content in the fermented broth of the mixed culture. It was shown that the hydrolysate obtained after 72 h growth of the mixed culture on feathers is rich in soluble proteins and amino acids including essential ones like lysine threonine, leucine, isoleucine and valine, and rare ones like threonine, proline and serine. Therefore, the obtained value-added protein hydrolysate could be used for preparation of fertilizers or soil amendments, as well as protein source in animal feeding. To our knowledge, this is first report of using mixed culture of thermoactinomycete strains for improved feathers biodegradation. The proposed ecologically safe method is simple and economically viable thus applicable on industrial scale. (C) 2009 Elsevier Ltd. All rights reserved.