Microbial Degradation of Hydrocarbons from Petrochemical Waste Using Food Waste Amendments

Polycyclic aromatic hydrocarbons (PAHs) are an organic pollutant that is abundant in petrochemical waste. Bioremediation can be an alternative way for the remediation of such hydrocarbon-contaminated soil. Therefore, this study determined the PAHs degradation activity by soil bacteria amended with food waste in a shake flask system. Diesel oil that was amended with various types of food wastes was inoculated with hydrocarbon-contaminated soil and incubated for 5 weeks at 30 °C, 150 rpm. The PAH extraction was conducted by using a liquid–liquid extraction procedure, and the diesel oil degradation compound was analyzed using gas chromatography–mass spectrometry (GC-MS). Bacteria from the enrichment culture flasks were isolated and identified based on colony morphology and biochemical tests using the BBL Crystal Identification Kit. As a result, the degradation rates of diesel oil compounds were higher in the flasks amended with food wastes as compared to the flask unamended with food wastes. A total of 11 hydrocarbon-degrading bacteria were successfully isolated and preliminary identified to be Acinetobacter baumannii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Pseudomonas fluorescens, Klebsiella pneumoniae, Shewanella putrefacien, Enterobacter aerogenes, Brevibacillus brevis, Bacillus cereus, Staphylococcus saprophyticus and Corynebacterium sp. The results of this study demonstrated the potential of food wastes to be harnessed for enhancing the bioremediation of diesel-contaminated soil instead of being disposed of as a waste.