Effect of keratinous waste addition on improvement of crude oil hydrocarbon removal by a hydrocarbon-degrading and keratinolytic mixed culture

The aim of this work was to evaluate the effect of keratinous waste addition on oil-hydrocarbon removal, through a mixed culture of oil-degrading bacteria, with the ability to secrete keratinases. The mixed culture was grown in the media with oil, or oil supplemented with chicken-feathers as the keratinous waste. Residual oil-hydrocarbons were determined as total petroleum hydrocarbons (TPHs) and oil fractions and then quantified by GC–FID and GC–MS.Results showed that in presence of the keratinous waste, the removal of oil-hydrocarbons was 57,400 mg l−1, meanwhile the treatment without waste presented an oil-hydrocarbons removal of 35,600 mg l−1. The aliphatic fraction was the most removed in both treatments. In addition, chromatographic profiles indicated that the aliphatic fraction showed different degradation pattern; in the presence of keratinous wastes, the C18 to C28 compounds were preferably removed over the C10 to C17. The addition of keratinous waste not only improved the oil-hydrocarbons removal but, it changed the removal pattern of the target hydrocarbons.