Poster Presentations

Session Title: Environmental Biotechnology
Presentation Date: Tuesday, August 19, 2008
Poster Board Number: 0287

EFFECTS OF ENHANCED NATURAL ATTENUATION ON THE DEGRADATIVE POTENTIAL AND COMMUNITY STRUCTURE OF INDIGENOUS SOIL BACTERIAL COMMUNITIES IN POLLUTED SOIL SAMPLES

E. Adetutu¹, A. Ball¹, C. Dandie², J. Weber², A. Juhasz^2
1Flinders University, Biological Sciences, Adelaide, Australia, ²Centre for Environmental Risk Assessment and Remediation, University of South Australia, Adelaide, Australia

Hydrocarbon pollution can adversely affect soil microorganisms in the recipient ecosystem causing changes in microbial community structure and function. Ecosystem detoxification via bioremediation which aims to restore the ecosystem to near pristine state fit for human and microbial existence has therefore assumed great importance. Bioremediation processes such as biostimulation which exploit the ability of indigenous microorganisms to degrade hydrocarbons are now seen as cost effective and highly efficient options of detoxification. This research aims to assess the degradative potential of indigenous soil bacteria in hydrocarbon polluted soils under conditions of enhanced natural attenuation (ENA) and evaluate changes in bacterial community structure and dominance associated with ENA.
Soil microcosms were set up for 16 weeks with soil samples collected from sites with different levels of hydrocarbon pollution. Natural attenuation was enhanced in the microcosms by the use of a Slow Releasing Fertilizer (SRF) with equivalent controls being set up without SRF. ¹⁴C labelled isotopes were used to evaluate the mineralization potentials of the different soil samples while changes in the community structure were evaluated by PCR-T/DGGE analysis of 16S rRNA genes. Changes in microbial numbers and hydrocarbon concentration were also monitored.
¹⁴C- hexadecane mineralization showed that the hydrocarbon mineralization rates varied from sample to sample and was enhanced in certain samples by ENA. ENA also caused reduction in soil TPH concentration and changes in the soil bacterial numbers and community diversity over time in some samples. The results obtained in this study demonstrate the benefits of ENA in bioremediation.