Assesment of diesel degrading potential of fungal and bacterial isolates from Egypt

摘要

Two naturally occurring fungal and bacterial species, Aspergillus flavus and Bacillus sp.H6 strains, were capable of utilizing diesel oil as a sole source of carbon in syntheticmicrocosoms. The initial diesel oil contamination of 1666 mg kg-1 dry soil was reduced to166.667 mg kg-1 after 150 days of incubation in fungal-bacterial consortium microcosm. That ismean 89.9%, of the initial oil concentration was removed. Abiotic process reduced the diesel oilcontamination to about 616 mg kg-1dry soil at the end of the experiment. Seven microcosmswere set up to fulfill the experiments. The decontamination activity follow this order; Bacillussp. H6 + A. flavus consortium Bacillus sp. H6 natural control A. flavus cycloheximidetreated benzyl Penicillin-Streptomycin treated poisoned control. Gas chromatographicanalysis data revealed that both A. flavus and Bacillus sp. H6 treatment led to completeutilization of carbon-17 compounds. Other biodegradation products such as C-15, 16, 20, 21, and24 appears in the chromatogram after 150 days incubation. Increase of C-20, 21 and C-24compounds also noticed. The fungal- and bacterium consortium treatment depicted a decrease ofall detected n-alkanes. The microbial success in biodegradation was evaluated by determiningthe number of germinating seeds of Phaseolus vulgaris. The highest level of germination (92 %)was detected in consortium microcosms after 150 days incubation. The treatment with A. flavusand Bacillus sp. H6 separately led to a lower percentage of germination (86%). The othertreatments showed variable results except the poisoned control that showed negative germinationand minor chemical degradation of diesel oil. Thus, bacterial-fungal consortium treatment iseffective in bioremediation of contaminated oils than separate treatment.