Ain Farisah Mohd Dahari, Umairah Balqis Shahril, Nur Aliyah Mohd Azrin, Muhamad Noranzrian Ridzuan, Mohd Shukuri Mohamad Ali, Noor Dina Muhd Noor

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PROTEOLYTIC ACTIVITY AND CONCOMITANT ANTIOXIDANTS KERATINASE WITH FEATHER DEGRADING ABILITY FROM ENTEROCOCCUS FAECALIS STRAIN SR5

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Abstract 

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With the aim of screening proteolytic strains bacteria capable of degrading chicken feathers, we isolated a new proteolytic strain from a chicken slaughter- house. After proteolytic and keratinolytic activity screening, the sample was further identified by 16s rRNA sequencing before being analyzed by a bioinformatical approach. Sample SR5, identified as Enterococcus faecalis, showed the most prominent proteolytic and keratinolytic activity and thus was called as Enterococcus faecalis strain SR5. The protease enzyme showed optimal activity in Tris-HCl buffer (pH 7) and stability over a pH range of 7-8 for 60 minutes at 37 ̊C. The catalytic activity was enhanced in the presence of Ca2+, Zn2+, and Mg2+. The enzyme was completely inhibited by phenylmethanesulfonyl fluoride (PMSF) and ethylenediaminetetraacetic acid (EDTA), suggesting it belongs to the serine protease and metallo-protease families with a molecular weight between 25-35 kDa. SEM observation revealed the effect of feather degradation following a 4-day incubation period with the protease extract. The keratin hydrolysate exhibited antioxidant activity, reducing the Fe3+ concentration from 0.55 g/L to 1.75 g/L. In conclusion, due to proteolytic and keratinolytic activity observed from the SR5 enzyme, it has potential applications in feather meal preparation and waste feather disposal, which may provide a more cost- effective and efficient pollution control for the poultry industry.

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