Protease- and keratinase-producing microbial strains for compost bioaugmentation

Microbial inocula that generate extracellular proteases and keratinases are potentially of value for enhancing the industrial composting of poultry wastes. In this study we have isolated new feather- and poultry-waste-degrading bacteria with proteolytic activities that belong to diverse genera including: Chryseobacterium, Rhodococcus, Bacillus, Pseudomonas, Stenotrophomonas, and Achromobacter. Feather keratin and model poultry carcass wastes were then composted in replicated experiments to determine whether composting of two different model poultry wastes could be enhanced by different bioaugmentation strategies. Strategies included using combinations of isolated bacteria, microbial communities enriched from natural sources, as well as uninoculated controls reliant on associated microbial populations. The study revealed that composting activity was maintained across all treatments, showing that degradation in the model wastes were clearly not limited by the associated microbial population in the test material.