Potential of bacteria isolated from diesel-contaminated seawater in diesel biodegradation

Abstract

Abstract The purpose of this study was to analyze the potential of bacteria isolated from diesel-contaminated seawater for diesel biodegradation. Samples of diesel-contaminated seawater were collected from a ship dismantling facility in Madura Island, Indonesia. Bacteria were isolated using the serial dilution method. Bacteria with potential for diesel degradation were screened using nutrient agar and mineral salt medium (MSM) with 0%, 5%, 10%, and 15% (v/v) diesel as carbon source. Diesel degradation test was performed by inoculating potential bacterium into MSM with the optimum concentration selected from the screening stage. Diesel degradation percentage was analyzed by gas chromatography–mass spectrometry (GC–MS). In this research, six bacterial species were isolated and used in the screening stage. The optimum concentration was 10% diesel (v/v) based on the screening stage, and the bacteria coded as MFI5 exhibited the highest growth with 8.13 ± 0.19 log colony forming unit/mL after 7 days of incubation. The bacteria coded as MFI5 was identified as Vibrio alginolyticus. Results showed that V. alginolyticus was able to degrade diesel up to 26.78% after 14 days of incubation at 10% initial diesel concentration (v/v). V. alginolyticus can potentially degrade diesel in a contaminated environment with further investigation using the biostimulation and bioaugmentation techniques.