title: Biological treatment of chicken feather waste for improved biogas production.
abstract: A two-stage system was developed which combines the biological degradation of keratin-rich waste with the production of biogas. Chicken feather waste was treated biologically with a recombinant Bacillus megaterium strain showing keratinase activity prior to biogas production. Chopped, autoclaved chicken feathers (4%, W/V) were completely degraded, resulting in a yellowish fermentation broth with a level of 0.51 mg/mL soluble proteins after 8 days of cultivation of the recombinant strain. During the subsequent anaerobic batch digestion experiments, methane production of 0.35 Nm3/kg dry feathers (i.e., 0.4 Nm3/kg volatile solids of feathers), corresponding to 80% of the theoretical value on proteins, was achieved from the feather hydrolyzates, independently of the pre-hydrolysis time period of 1, 2 or 8 days. Cultivation with a native keratinase producing strain, Bacillus licheniformis resulted in only 0.25 mg/mL soluble proteins in the feather hydrolyzate, which then was digested achieving a maximum accumulated methane production of 0.31 Nm3/kg dry feathers. Feather hydrolyzates treated with the wild type B. megaterium produced 0.21 Nm3 CH4/kg dry feathers as maximum yield.
authors.affiliation: School of Engineering, University of Borås, 501 90 Borås, Sweden. gergely.forgacs@hb.se
authors.forename: Gergely
authors.initials: G
authors.lastname: Forgács
authors.forename: Saeid
authors.initials: S
authors.lastname: Alinezhad
authors.forename: Amir
authors.initials: A
authors.lastname: Mirabdollah
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Feuk-Lagerstedt
authors.forename: Ilona Sárvári
authors.initials: IS
authors.lastname: Horváth
mesh_terms: D000818:Animals; D001410:Bacillus megaterium / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D056804:Biofuels / Q000032:analysis*; D002645:Chickens; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005241:Feathers / Q000737:chemistry* / Q000378:metabolism / Q000382:microbiology; D010447:Peptide Hydrolases / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D056804:Biofuels; D004269:DNA, Bacterial; D011994:Recombinant Proteins; D010447:Peptide Hydrolases; C035855:keratinase