Fibrous Keratin Powder as by-Product of Keratinase Fermentation under Solid State Fermentation using Chicken Feathers as Substrate

Abstract

Billion tons of chicken feathers are being generated every year from the poultry industry. Ironically, although egg white is one important source of proteins for a human, it only contains 57% of protein, while chicken feathers contains about 980% of protein. However, due to its complex structure, chicken feathers are not consumable by the human. This makes chicken feathers are classified as biowaste material which causes environmental problems. The huge amount of this biomaterial offers a potential raw material for polypeptide and amino acids source. Chicken feathers contains a highly fibrous protein called keratin. X-ray diffraction model of keratin architecture showed supercoiled of helical proteins. The structure is also strengthened by disulphide bonds which make keratin insoluble in water and an organic solvent. Many attempts have been tried to break down the chemical bonds and convert chicken feathers into simple structural materials for sustainable uses. Currently, hydrothermal degradation is a preferable technique to concert chicken feathers into keratin powder because it is cheap for industrial purposes. Enzymatic degradation offers a greener process. We have successfully isolated a Gram-positive bacterium named Bacillus sp. MD24 which is capable of producing keratinase, an enzyme that degrades chicken feathers. In this paper, we described fibrous keratin powder as a by-product of keratinase fermentation by Bacillus sp. MD24 under solid-state fermentation (SSF). Scanning electron micrograph showed a tremendous reduction in the size of keratin after fermentation.