Phospholipid fatty acids analysis-fatty acid methyl ester (PLFA-FAME) changes during bioremediation of crude oil contamination soil

Abstract

This study aims to develop certain perspectives based on the principle of on-site remediation of the soil through biological means known as "bioremediation" against soil pollution issues resulting from fuel contamination in our country and to reveal the fatty acid profile in the final soils. The fatty acid profile of the soils was pointed out by testing the activity of three basic bioremediation applications (biological multiplication, biological excitation and the combined application of these two approaches) established in the laboratory condition. Under biological multiplication applications, six of the selected bacterial strains (Pseudomons aeruginosa, Pseudomonas putida biotype A, Citrobacter amalonaticus-GC subgroup A, Acinetobacter genomospecies) exhibit the highest growth in crude oil environment isolated from oil-contaminated soils of Adana, Batman and Adıyaman, and they also have the highest levels of crude oil degradation. Under biological excitation applications, the organic materials being humic-fulvic acid and, in combined applications, different combinations of bacteria mixture and organic materials were examined as to the amount of crude oil they degrade in an incubation period of 120 days by qualitative hydrocarbon-type analyses. The highest level of oil degradation, being 56%, occurred under biological multiplication applications where the bacteria mixture was applied. Under biological excitation conditions where various organic materials were applied to the contaminated soil, degradation to 18% was observed. In combined applications, oil degradation was achieved to 30%. The most common fatty acids were found to be 15:0 iso, 15:0 anteiso, 16:0, 16:1 w7c, 17:0ai, 18:2w6,9 and 18:1w9c fatty acids detected in both unpolluted and oil-contaminated soils. Determination of high level 18:1w9c fatty acid in oil contaminated and clean soils may indicate the presence of Pseudomonas spp. However, fatty acid 15:0 anteiso was determined to be higher in oil-contaminated soils than in unpolluted soils. It may be explained that Gram positive bacteria were predominant in oil-contaminated environment.

Key words: Soil, crude oil, bacteria, bioremediation, phospholipid fatty acids analysis-fatty acid methyl ester (PLFA-FAME).