ABSTRACT

 Chicken feathers are waste products of poultry processing industries and can create a solid waste disposal problem in the environment. These wastes contain considerable amount of highly stable animal protein (keratin) which can be utilized by the keratinophilic fungi species leading to its environmentally safe disposal. This group of fungi produces the enzyme keratinase which has proteolytic ability to hydrolyze the insoluble protein keratin more efficiently than other proteases. With an increasing world-wide concern for the environment, it is possible to use these fungi for the degradation of enormous quantity of chicken feather wastes. This study deals with the isolation and identification of fungi that play significant role in the degradation of chicken feathers, their keratinase producing ability and keratin degradation ability. The chicken feathers were collected from chicken processing areas of orie-ugba market. The keratinophilic fungi were isolated using hair baiting technique. The isolated fungi were identified by lactophenol cotton blue staining method as Aspergillus niger, Mucor spp, Rhizopus spp, Aspergillus flavus, Trichoderma spp, Fusarium spp, Curvularia spp. The keratinophilic fungi were screened for keratinase activity on casein agar plates and only Aspergillus niger and Aspergillus flavus showed positive result on casein agar with Aspergillus niger having the highest zone of clearance (15 mm). The selected fungi isolated were grown in 100 ml feather meal broth using chicken feather meals as sole source of carbon and nitrogen and was incubated for 5 days. At temperature of 27°C ±2, Aspergillus flavus yielded maximum enzyme production of 19.68 ml and an optimum enzyme activity of 17.16 µml, while at the temperature of 45°C, Aspergillus niger yielded the maximum enzyme production of 18.94 j.t/ml and an optimum activity of 15.84 µml. At pH 6, Aspergillusfiavus yielded maximum enzyme production of 17.01 µml and optimum enzyme activity of 14.62 µml, while at pH 9, Aspergillus niger yielded the maximum enzyme production of 12.97 µ /ml and an optimum activity of 12.97 µml. There was a decrease in enzyme activity with time for both fungi species during incubation of the crude enzyme keratinase for that Also, a color change from a roughly colorless medium to a yellowish fermentation broth was observed after 7 weeks of incubation. Feather degradation in this study was determined visually through the level of degradation of the chicken feathers. Increase in turbidity of the chicken feathers broth was an indication of fungal growth and subsequent degradation. This is as a result of the presence of keratinophilic group of fungi which produces the enzyme keratinas Tha4grades. chicken feather wastes into value added products.