BIOREMEDIATION OF DIESEL BY SOIL FUNGI

Abstract

The study attempts to bioremediation of diesel as petroleum contaminants using fungi isolated from soil of different sites in Baghdad . The three isolated fungi: Aspergillus fumigatus, Candida nonsorbophila and zygosaccharomyces bailii were identified by molecular classification (PCR) and selected for bioremediation experiments that were more predominant in the soil .The fungi tested to biodegradation of diesel in solid medium (PDA) , liquid medium (MSM) and in soil. Results of PDA experiments showed A. fumigatus was resistant to diesel fuel in 5% concentration, the colony diameter reached up to 7.1cm after 14 days. Lowest diameter 1.4 cm appeared in Z. bailii after 28 days.Regarding MSM experiment, A. fumigatus showed highest bioremediation 69.50% after 28 days in 10g/L diesel, while C. nonsorbophilii showed high biodegradation 69.0% after 28 days. To test the ability of mix fungi in MSM media, mix A. fumigatus with Z. bailii showed higher degradation 59.8% in 10g/L diesel after 28 days. While at used three fungi (A.fumigatus+ C.nonsorbophilii+ Z.bailii) showed less degradation 48.0% in 10g/L diesel after 28 days.Experiments of diesel biodegradation in soil after 60 days incubation, A. fumigatus recorded high percentage of remediation 97.70% ,while 97.20% recorded by C. nonsorbophilii. , and 94.80% by Z. bailii that was not different significance among them, but significantly higher than the minimum bioremediation of the three fungal mixture (90.70%).The study concluded that A. fumigatus could be used in bioremediation being better than the rest of the fungi on diesel pollutant biodegradation in solid, liquid and soil medium.Ability of mixed fungi to diesel biodegradation was less than using alone depended on competition and antagonisms between the fungi in the growth medium.