English

Dombou Armelle Leslie Sileu,Yanou Nicolas Njintang,Emmanuel Jong Nso,Ngoune Leopold Tatsadjieu,Zangue Henriette Adjia

doi:10.5897/ajb2019.16948

Abstract

This study aims at characterizing new chicken feather-degrading bacteria isolated from soils of keratinic waste collected from four dumping sites of Ngaoundere. Fifteen proteolytic bacteria were isolated with three (D1, D2 and F1) showing the capacity to degrade feather in Basal Salt Media. Highest degradation rate (71.11 ± 3.05%) of feather was obtained from isolate D2 from Municipal slaughterhouse. The partial characterization of the strain D2 based on morphological and biochemical tests revealed that it is a Bacillus sp. The keratinolytic activity was positively correlated to the bacterial growth with the highest value (13.76 U.ml-1) obtained at the stationary phase after 120 h of incubation. The optimal conditions for the keratinolytic activity of this isolate were determined to be pH 8.0 and temperature of 45°C. Thus, the Bacillus strain (D2) isolated is a promising strain for the management and valorization of feather wastes.   Key words: Chicken feather-degrading bacteria, keratinolytic enzyme activity, characterization, Ngaoundere, Cameroon.

Highlights

Proteases are enzymes consisting of one or more polypeptide chains that catalyze the hydrolysis of proteins by cleaving the peptide bond that binds two amino acids and belong to the class of peptidases (Drouin, 2005)
The high temperatures and pressures used in these treatments require large amounts of energy and the drastic conditions used lead to the degradation of many essential amino acids, giving a product with poor and variable nutritional quality (Cai et al, 2008)
The chemical composition of chicken feather indicated that it is a proteinaceous substrate, which can constitute a principal source of carbon and energy for many microorganisms

Summary

Introduction

Proteases are enzymes consisting of one or more polypeptide chains that catalyze the hydrolysis of proteins by cleaving the peptide bond that binds two amino acids and belong to the class of peptidases (Drouin, 2005) They are the most produced and used industrial enzymes in the world, accounting for about 65% of the global. The high temperatures and pressures used in these treatments require large amounts of energy and the drastic conditions used lead to the degradation of many essential amino acids (lysine, methionine, tryptophan), giving a product with poor and variable nutritional quality (Cai et al, 2008) This has prompted researchers to consider new possibilities, especially biological treatments in mild conditions through the use of microorganisms producing keratinases which will facilitate the disruption of disulfide bridges of keratins (Papadopoulos et al, 1986). It has been shown that keratinases produced can have a variety of applications, in production of animal feed (Suntornsuk and Suntornsuk, 2003), in the detergent (Gessesse et al, 2003), leather, textiles and wool industries (Alexandre et al, 2005)

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