This study aims to evaluate the capability of extracellular protease to hydrolyze keratin substrates of local poultry feathers and observing the amino acid profile. The indigenous strains (Bacillus cereus TD5B, Bacillus cereus LS2B, and Pseudomonas sp. PK4) were used in this study, and the obtained data were analysed descriptively. Bacillus cereus TD5B has a maximum activity at 0.003849062 unit/ml and 0.000310042 unit/ml on casein and commercial keratin substrates. Each hydrolyzed consisted of Aspartic Acid, Glutamic Acid, Serine, Glycine, Valine, Phenylalanine, Ileucine, Leucine, and Lysine. The differences between the three feather meals were on the amino acid’s concentration, the specific amino acid (Threonine) in the hydrolyzed kampung chicken feather meals, and the amino acid Alanine in the hydrolyzed layer feathers and also the goose feather meals. The SDS-PAGE results showed that the molecular weight of keratinase in the three hydrolyzed feather meals was observed at 100 kDa. In this study, the highest substrate degradation was observed by Bacillus cereus TD5B at chicken layer feathers (21.25%). During 21 days, Bacillus cereus LS2B could hydrolyze kampung feather at 38.8% during 23 days, and Pseudomonas sp. PK4 hydrolyzed kampung feather at 39.8% for 24 days.

Feather waste is a poultry by-product that is abundant, difficult to degrade, and creates an environmental problem. Feather protein is mainly composed of keratin, a structural protein with low digestibility. The effect of poultry feather meal prepared by NaOH as a Nitrogen source on the growth of the indigenous keratinolytic strain in the agar and the liquid medium was evaluated in this research. This study shows that all strains (Pseudomonas sp. PK-4, Bacillus cereus TD5B, and Bacillus cereus LS2B) can grow and produce clear zones around the colony. Medium containing 1% skim milk, commercial keratin, kampung, layer chicken feathers, and goose feathers were used to indicate that all strains could produce extracellular casein and keratinase enzymes. The strains can grow optimally in a liquid medium with feather hydrolysates, indicated by the increased turbidity (OD600) with a higher absorbance value. The highest growth occurred when strains grew with kampung chicken feather hydrolysate. Therefore, it can be concluded that the feather meals from local poultry feathers had potential as N-source for bacterial growth.