Biodegradation of diesel oil by various environmental and specialized microflorae

摘要

Biodegradation of diesel oil by various environmental microflorae was investigated in closed batch systems by hydrocarbon consumption and CO_2 production. Intrinsic biodegradation capacities of microflorae from polluted and unpolluted soils were determined and compared to those of an activated sludge from an urban waste-water treatment plant. In order to define the specific contributions of bacterial groups to diesel oil degradation, microbial culture enrichments were produced using model substrates representative of each hydrocarbon class of diesel oil as sole carbon sources. Degradation capacities of the enriched microflorae were measured and microbial compositions were determined by 16S rDNA sequence analysis. Results show that: (ⅰ) microflorae from polluted sites displayed higher degradation capacities (80% of the initial diesel oil amount) than unpolluted soil (67%) or sludge (64%), (ⅱ) n-alkanes were totally degraded whatever the microflora used, (ⅲ) biodegradation capacities and bacterial composition of enriched cultures were dissimilar and dependent on the substrate used.