Bacterial community profiles on feathers during composting as determined by terminal restriction fragment length polymorphism analysis of 16S rDNA genes

Composting is one of the more economical and environmentally safe methods of recycling feather waste generated by the poultry industry, since 90% of the feather weight consists of crude keratin protein, and feathers contain 15% N. However, the keratin in waste feathers is resistant to biodegradation and may require the addition of bacterial inocula to enhance the degradation process during composting. Two keratin-degrading bacteria isolated from plumage of wild songbirds and identified as Bacillus licheneformis (OWU 1411T) and Streptomyces sp. (OWU 1441) were inoculated into poultry feather composts (1.13×10⁸ cfu g⁻¹ feathers) and co-composted with poultry litter and straw in 200-l compost vessels. Composting temperatures, as well as CO₂ and NH₃ evolution, were measured in these vessels to determine the effects of inoculation on the rate and extent of poultry feather decomposition during composting. Terminal restriction fragment length polymorphisms of 16S rRNA genes were used to follow changes in microbial community structure during composting. The results indicated that extensive carbon conversion occurred in both treatments (55.5 and 56.1%). The addition of the bacterial inocula did not enhance the rate of waste feather composting. The microbial community structure over time was very similar in inoculated and uninoculated waste feather composts.