Feather is high in protein (keratin) and is not easily degradable in nature. It is produced in large amounts as waste through poultry activities all over the world. In order to provide sufficient use for this keratin-rich waste the keratin present in feather can serve as keratinase inducer. Hence this study focuses on the production, purification and characterisation of keratinases from isolated keratin-degrading Bacillus licheniformis-K51, Bacillus subtilis-K50 and Bacillus sp.-K53. Bacillus licheniformis-K51 gave highest keratinolytic activity (24.76±0.91 U/mL) at pH 7.8, 37 o C, agitation rate 150 rpm and 0.3% (NH 4) 2 SO 4 on day 7, while Bacillus subtilis-K50 had 19.03±0.74 U/mL at pH 7.5, 37 o C, agitation rate 200 rpm and 1.4% cellulose on day 4. Bacillus sp.-K53 gave least activity (18.41±0.60 U/mL) at pH 7.2, 37 o C and agitation rate 150 rpm on day 5. Molecular mass of purified keratinases was determined using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis and was obtained between 33-36 kDa. Purified enzyme of Bacillus licheniformis-K51 (EZYKer-51) contained Glutamate (18.2%), Alanine (14.9%) and showed highest activity (26.31 U/mL) at 60 o C and pH 8 with K M and V max kinetic constants of 25.60 mM and 74.46 U/mL, respectively. The optimal conditions tested in this study can be useful parameters in the production of keratinases and also in applications that require the breakdown of keratin proteins

Aim: This study focuses on the screening and characterisation of keratin-degrading Bacillus species from feather waste. Methods: Nine bacteria were isolated from feather waste obtained from a poultry layout at Egbeda local government secretariat, Ibadan, Nigeria. These bacteria were grown in basal medium with feather as primary source of carbon, nitrogen, sulfur and energy. Feather degrading bacteria were screened for both proteolytic activity and keratin degradation on skimmed milk agar and keratin azure medium respectively. They were also screened for their ability to degrade other keratin substrates such as hair and nail. Results: Three of the isolates with higher feather degradation levels also showed high proteolytic activity and release of azure dye. They were selected and identified phenotypically and genotypically using 16S rRNA sequencing as Bacillus licheniformis-K51, Bacillus subtilis-K50 and Bacillus sp.-K53. The bacteria were capable of degrading other keratin-containing substrates such as nail and hair. Bacillus subtilis-K50 and Bacillus licheniformis-K51 showed significant difference (P) in degradation among the three different keratin sources used yielding higher degradation with feather as keratin source with respective optical densities of 0.07 and 0.11 followed by hair and least in nails with optical densities of 0.05 and 0.07 respectively. Highest degradation of all the three keratin substrates was observed in Bacillus licheniformis-K51. Conclusion: The three isolated bacteria possess the ability to degrade keratin and utilize feather as keratin substrate. As a result, these can be considered as potential candidates for degradation and utilization of feather keratin.

Keratins are tough, fibrous proteins found as the major protein component in hair. Chemical hair removal is harsh and results in severe toxicity and pollution, hence, a need for a non-chemical enzymatic hair removal process. The aim of this study is to characterise keratinase from isolated keratin-degrading Bacillus licheniformis-K51, Bacillus subtilis-K50 and Bacillus sp.-K53 and investigate its potential in hair removal. The collagenolytic ability of keratin-degrading keratinases obtained from Bacillus licheniformis-K51, Bacillus subtilis-K50 and Bacillus sp.-K53 was determined using standard methods. The depilatory potential of keratinase (directly and as part of the constituent of formulated depilatory cream) was determined in vitro on goat skin and in vivo on Wistar rat. Purified keratinases from Bacillus licheniformis-K51 (EZYKer-51), Bacillus subtilis-K50 (EZYKer-50) and Bacillus sp.-K53 (EZYKer-53) did not show significant collagenolytic activities. In vitro treatment of goat skin with EZYKer-51 showed total hair removal within 24 hours and partial hair removal with EZYKer-50 and EZYKer-53. The formulated depilatory cream containing EZYKer-51 showed highest keratinolytic activity (22.20±0.63 U/mL) followed by EZYKer-50 (20.52±0.46 U/mL) and EZYKer-53 (17.06±0.81 U/mL). In vivo depilatory action using formulated cream took 40 min, while that of commercial cream was achieved within 20 min. Keratinase from Bacillus licheniformis-K51 exhibited complete hair-removal function which makes it potentially suitable in industrial processes involving removal of hair. ARTICLE INFO

The aim of this study was to determine the potential of keratinases produced by Bacillus species isolated from poultry feather waste in stain removal. The effect of individual and combined detergent components on the keratinase activity of EZYKer-51, EZYKer-50 and EZYKer-53 enzymes produced from keratin degrading Bacillus licheniformis-K51, Bacillus subtilis-K50 and Bacillus sp.-K53 respectively was determined. EZYKer-51, which had the least enzyme inhibition in the presence of the detergent component was used as the enzyme component in detergent formulation and a wash performance analysis test was carried out to compare the stain removal capacity of DETKER 51 (detergent formulated using EZYKer-51 as enzyme component) with a commercial enzyme. Data were analyzed using descriptive statistics. EZYKer-51 showed a significantly higher (P≤0.05) enzyme activity in the presence of the detergent ingredients for both the crude and purified forms of the enzyme compared with the activities of EZYKer-50 and EZYKer-53, except for the activities (8.02±1.32 U/mL and 7.94±0.63 U/mL) in the presence of 15% LAS and 5% liquid paraffin. Visually, better stain removal was achieved when endogenous protease of commercial enzyme was replaced with EZYKer-51. These results suggest that keratinase EZYKer-51 may be a useful alternative for applications in detergent formulation.