Use of Poultry Byproduct for Production of Keratinolytic Enzymes

The production of keratinolytic enzymes by Chryseobacterium sp. isolated from the poultry industry was tested on different growth substrates: casein, peptone, yeast extract, gelatin, soybean meal, fish meal, feather meal, raw feathers, and cheese whey. Raw feather, an important byproduct from the poultry industry, was the selected growth substrate to test the effect of three variables (temperature, initial pH, and feather concentration) on keratinase production by response surface methodology. A 2³ central composite design was performed with the central point chosen as: temperature 30 °C, initial pH 8.0, and feather concentration 20 g l⁻¹. Statistical analysis of results showed that, in the range studied, temperature had a strong effect on keratinase production. The interaction between temperature and feather concentration and between temperature and initial pH had a significant effect on enzyme production. Response surface data showed maximum keratinase production at 23 °C, initial pH 9.0, and 30 g l⁻¹ of raw feathers. Under these conditions, the model predicted a keratinase activity of 1,559 U ml⁻¹.