BIODEGRADATION ABILITY OF FUNGAL STRAINS ISOLATED FROM ANTARCTICA TOWARDS PAH

The capability of Antarctic microorganisms, including filamentous fungi to exist in some of the most severe climatic conditions known to Earth is the reason of the increasing interest to their metabolic characteristics. The study of species diversity characteristic of this region, and their metabolic capabilities can be useful when searching for new solutions in the industry and the environment. The aim of this study was to test the possible ability of new isolated Antarctic fungal strains to grow and develop on phenanthrene, anthracene, and naphthalene as sole carbon and energy sources in the medium. Sixteen fungal strains isolated from Livingston Island Antarctica were studied for their ability to degrade phenanthrene, naphthalene and anthracene. Cultures were stored on beer agar medium, pH 6.3 in glass vials with screw caps at 4 degrees C. The strains were grown in a solid or liquid mineral medium Czapek Dox containing 10 g/l glucose and/or various concentrations of the investigated polycyclic aromatics. The temperature of cultivation was 23 degrees C. In the solid medium experiments a spray-plate technique was applied. PAH were distributed evenly as a thin visible overlay by pipetting 0.6 ml of a filter-sterilized acetone solution (0.5%) and stirred up on the agar surface. Plates were dried overnight at 30 degrees C to allow the acetone evaporation. In experiments in liquid media PAH were ultra sounded ex tempore to a fine dispersion in small aliquots of liquid medium and then inoculated in the corresponding cultivating media. Although there were found five representatives of Penicillium and Aspergillus which did not show any development in the presence of such compounds most of the investigated strains demonstrated good tolerance to the presence of anthracene and naphthalene. A good tolerance to phenanthrene in the culture medium was obtained only for Altemaria maritima strain AL10. Two other strains: Aspergillus glaucus AL1 and Penicillium waksmanii AL14 showed slight growth in phenanthrene presence. The degradation experiments carried out in a media containing each one of the tested compounds as a single source of carbon and energy demonstrated the ability of Penicillium rugolosum AL7 and Penicillium waksmanii AL14 to degrade 0.3 g/l anthracene. Strains Altemaria maritima AL10 and Penicillium waksmanii AL14 showed capacity to utilize 0.3 g/l phenanthrene. Aspergillus fumigatus AL9, Penicillium chtysogenum AL12 and Mucor sp. AL13 degraded 0.3 g/l naphthalene. As a result of the research it could be concluded that the most toxic effect was exerted by phenanthrene followed by anthracene, and naphthalene. We see also that different species of fungi genera show different abilities to adapt and to utilize each one of the polycyclic aromatic compounds used in this study.