Dan Lefebvre - Associate Professor
Research: My lab's current research involves studies in bioremediation, including microbial fermentation and phytoremediation of both inorganic and organic contaminants, as well as polyculture and plant culturing techniques. These include laboratory investigations as well as fieldwork.
Polyculture. Polyculture studies are being performed in collaboration with fish biologists at Queen’s and the local aquaculture industry. In these studies plants are being assessed for their ability to clean water used in the culture of fish and for their growth rates as horticultural crops under these conditions.
Mercury Biotransformation. Recent scientific publications include those in the area of mercury biotransformation where it was discovered by using bioreactors that a range of microbes can convert metal ions into sulfides with the desirable outcome of low mercury bioavailability to other organisms.
Phytoremediation. Field work includes using tree species such as poplars and willows to remove contaminants from, and stop the migration of contaminated groundwater. Of particular interest is the removal of dioxane, that is destroyed by light after it has been volatilized from tree leaves. Furthermore, groundwater movement can be attenuated by high rates of evapotranspiration from trees that have deep root systems.
Biodegradation. Another research area in bioremediation is exploiting the genetic variation in fungal species that use the enzymes, laccase and peroxidase, to degrade organic chemicals. From these studies we developed a practical laboratory for our fourth year bioremediation course that was such a success, it was recently published in the journal of biological education, Bioscene.
Culturing for High Root Production. We have published a very effective means of growing plants to produce large root systems, which can then be easily used for studies at the biochemical and molecular levels. This study employed the model plant species, Arabidopsis thaliana.
Some Recent Publications:
- D.D. Lefebvre, D. Kelly, and K. Budd. (2007) Biotransformation of Hg(II) by cyanobacteria. Applied and Environmental Microbiology. 73: 243-249.
- D.J.A. Kelly, K. Budd, and D.D. Lefebvre. (2007) Biotransformation of mercury in pH-stat cultures of eukaryotic freshwater algae. Archives of Microbiology 187(1): 45-53.
- D.J.A. Kelly, K. Budd, and D.D. Lefebvre. (2006) Mercury analysis of acid- and alkaline-reduced biological samples: identification of β-HgS as the major biotransformed compound in algae. Applied and Environmental Microbiology 72(1): 361-367.
- D.J.A. Kelly, K. Budd, and D.D. Lefebvre. (2006) The Biotransformation of Mercury in pH-Stat Cultures of Microfungi. Canadian Journal of Botany 84: 254-260.
- M.-F. Hetu, L. Tremblay and D.D. Lefebvre. (2005) High root biomass production in anchored Arabidopsis plants grown in axenic sucrose supplemented liquid culture. Biotechniques 39: 345-349.