The huge amounts of keratinous waste generated daily in various industries, slaughterhouses and processing plants must be properly destroyed. Most research related to keratin degradation focuses on keratin from bird feathers and only a few studies on keratin from sheep wool. In this PhD thesis, we describe the isolation, identification and characterization of novel keratinolytic bacteria and fungi capable of degrading sheep wool and their use to accelerate the composting process and anaerobic methanogenic degradation. We describe the isolation of 16 isolates with high keratinolytic activity belonging to five known bacterial species (Bacillus altitudinis, B. mycoides, B. subtilis, B. wiedmannii, Streptomyces coelicoflavus) and one fungal species (Aphanoascus reticulisporus). The ability to degrade sheep wool has not been described for most isolates, but for B. mycoides and B. wiedmannii this is the first description of keratinolytic activity in the literature. The keratinases of the new isolates are active over a wide range of temperatures (25–85 °C) and pH values (6.0–10.0), so all isolates have a high potential for further biotechnological use in industry and various environmental and agricultural applications for the reduction and recycling of keratin-rich waste such as sheep wool and used wool textiles. The new keratinolytic isolates were used as a starter culture in the composting of sheep wool waste and accelerated the long-term degradation of the complex keratin structure compared to the control compost pile. However, we were not able to increase the biogas production yield from aerobic microbially or enzymatically pre-treated sheep wool in the experiment with biomethane potential.
|
