Biodegradation of PAHs in Soil by Two Deuteromycete Fungi

Abstract

The fungal strains used is this work, namely, 984 and 1040, were isolated fr om soil samples collected at the Jureia -Itatins Ecological Reserve, Sao Paulo-Brazil. Following microscopical examinations these strains were classified as Aspergillus sp. (984) and Verticillium sp. (1040). The degradation of PAHs in soil contaminated with 5 mg naphthalene/g soil; 1,0 mg anthracene/g soil or 0,5 mg pyrene and/or benzo[a]pyrene/g soil, was verified. These strains were grown in wheatbran:water for 3 days, inoculated in sterilized and non- sterilized soil, and cultivated for 2,4, 6, and 8 weeks. The PAHs were then extracted and degradation was determined by HPLC. The best degradation, in sterilized soil was obtained after 8 weeks for the two strains: naphthalene (64.50 - 65.43%), anthracene (77.35 - 85.83%) and pyrene (73.01 - 78.78%). When benzo[a]pyrene was used the best degradation shown by strain 984 was 89.62% in six weeks and 78.06% by strain 1040 in eight weeks. In non-sterilized soil the strains exhibited lower growth and degradation than in sterilized soil, with the exception for benzo[a]pyrene (82.3 - 82.6%). Our results indicate that these two fungal strains have potential for application in the bioremediation of soils contaminated with PAHs.