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- Forgács, Gergely, 1983, et al.
(författare)
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Biological treatment of chicken feather waste for improved biogas production
- 2011
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Ingår i: Journal of Environmental Sciences. - : Elsevier BV. - 1001-0742 .- 1878-7320. ; 23:10, s. 1747-1753
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Tidskriftsartikel (refereegranskat)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 Nm(3)/kg dry feathers (i.e., 0.4 Nm(3)/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 Nm(3)/kg dry feathers. Feather hydrolyzates treated with the wild type B. megaterium produced 0.21 Nm(3) CH(4)/kg dry feathers as maximum yield.
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