Improving oil biodegradability of aliphatic crude oil fraction by bacteria from oil polluted water

Abstract

Water samples were collected from three oil polluted stations, two replicates for each station, from southern region of Shatt Al-Arab estuary, and southern of Basrah city during the period from September to October 2011. The mineral salts medium was used to isolating oil biodegrading bacteria. Four bacterial species were identified according to their morphological and biochemical profiles as: Aeromonas hydrophila, Bacillus subtilis, Pseudomonas aeruginosa and Pseudomonas fluorescens. The percentage of biodegrading   ability of B. subtilis and the mixture of these bacteria to n-alkanes and isoprenoids (pristine, phytane) were measured and compared with control. Crude oil is used as a sole source of energy and the incubation period was 24 days, the hydrocarbons loss are detected each 6 day interval using capillary gas chromatography. Bacterial species were exposed to biological mutation by using Maillard reactions to improve the n-alkanes and isoprenoids (pristine, phytane) biodegradability. For this, a mixture of glucose-lysine in a concentration of 4 M was used to mutate B. subtilis and A. hydrophila while for P. aeruginosa and P. fluorescens a mixture of glucose-arginine in a concentration of 9 M. Biodegradability percentage was increased for B. subtilis from 60.6 to 92.5% and ranged from 37 to 72.3% for the other species. Also the bacterial mixture biodegradability for oil increased from 78 to 87.5%.

Keywords: Oil biodegradation, Aeromonas hydrophila, Bacillus subtilis, Pseudomonas aeruginosa,  Pseudomonas fluorescens, n-alkanes, Maillard reactions

African Journal of Biotechnology, Vol 13(11), 1243-1249