Bioconversion of Agro-Industrial Byproducts Using Bacillus sp. CL18: Production of Feather Hydrolysates for Development of Bioactive Polymeric Nanofibers

Microbial fermentation represents an interesting strategy for the management and valorization of agro-industrial byproducts. In this study, the proteolytic strain Bacillus sp. CL18 was used to produce bioactive hydrolysates during submerged cultivation with various protein-containing substrates, including byproducts from the poultry (feathers), cheese (whey), fish (scales), and vegetable oil (soybean meal) industries. The bioactive feather hydrolysates (BFHs) showing high antioxidant activity were incorporated in poly(vinyl alcohol) (PVA) and poly-epsilon-caprolactone (PCL) nanofibers by the electrospinning technique. The PVA nanofibers containing 5% BFH reached antioxidant activities of 38.7% and 76.3% for DPPH and ABTS assays, respectively. Otherwise, the PCL nanofibers showed 49.6% and 55.0% scavenging activity for DPPH and ABTS radicals, respectively. Scanning electron microscopy analysis revealed that PVA and PCL nanofibers containing BFH had an average diameter of 282 and 960 nm, respectively. Moreover, the results from thermal analysis and infrared spectroscopy showed that the incorporation of BFH caused no significant modification in the properties of the polymeric matrix. The bioconversion of feathers represents an interesting strategy for the management and valorization of this byproduct. Furthermore, the effective incorporation of BFH in polymeric nanofibers and validation of the biological activity suggest the application of these materials as antioxidant coatings and packaging.