Crude oil biodegradation activity in potable water

• The presence of aliphatic and aromatic hydrocarbons in potable water in Kuwait was demonstrated.
• Presence of hydrocarbons in all water samples implied common source of hydrocarbon pollution.
• Hydrocarbons in water selected bacterial communities able to utilize a wide-range of available hydrocarbons.
• The hydrocarbon-utilizing bacteria in water demonstrated potential to utilize available hydrocarbon pollution.

A wide range of aliphatic and aromatic hydrocarbon concentrations were detected in potable water samples obtained from various locations in Kuwait city. Detected aliphatic compounds included hexadecane (2.19 μg l−1), heptadecane (2.49 μg l−1), nonadecane (2.24 μg l−1), eicosane (1.79 μg l−1), docasane (1.4 μg l−1) and pentacosane (1.48 μg l−1), while the aromatic hydrocarbons contaminants included benzene (1.62 μg l−1), phenanthrene (3.19 ng l−1) and several aromatic-degradation intermediates. Culturable microbial loads in the water samples were low, ranging from 3 CFU ml−1 to 41 CFU ml−1, but included a high proportion of hydrocarbon degrading bacteria. Hydrocarbon-utilizing bacteria isolated included Cupriavidus gilardii, Pseudomonas sp., Bacillus cereus and Paenibacillus ehimensis that constituted >30% of the total number of isolates. Under current experimental conditions, the hydrocarbon-utilizing capacities of individual isolates from the water samples were wide representing self-cleaning activity of hydrocarbons present in water samples. Interestingly, the hydrocarbon-utilizing microbial contaminants also exhibited a wide-range of antibiotic resistance characteristics.