David Cooper

Research interests and projects

The research projects involve one or more of the themes; fermentation development, bioremediation/environment and bioproducts (e.g. biosurfactants, biopharmaceuticals).

Lately, the environmental research has concentrated on the fate of xenobiotic compounds. In particular, this has involved the co-metabolism of plasticizers and pharmaceuticals by microorganisms or mammalian cells already growing on easily used substrates. The patterns of biodegradation are different from those reported for direct metabolism of the xenobiotics as a sole carbon source. We have found many examples in which a xenobiotic is only partially degrade to yield stable metabolites and we have shown that, in some cases, these metabolites are more toxic than the original material. There is a range of possible metabolites depending on both the plasticizer or other xenobiotic added and the microorganism used. These metabolites are resistant to further degradation and we have found some of them in samples taken from the environment.

Several projects have been developing a technique called self-cycling fermentation (SCF). This uses feedback control to maintain a stable series of batch fermentations. After several cycles, this growth becomes synchronized and the cycle time is identical to the doubling time of the microorganism. The system is robust and has a high throughput because growth is always in the exponential phase. The most recent projects are concerned with applying this technique to the large scale production of bacteriophages. This has required work to develop monitoring systems for feed back control, improved methods of level detection and more sophisticated control strategies allowing for the integration of a two step process. One of these steps is the growth of the host bacterium. The other is the infection of the harvest from the first stage to produce the bacteriophage after infecting the host. Uses for the bacteriophage would include the selective treatment of pathogenic bacteria, diagnostic tools to monitor the presence and concentration of these bacteria and the use of these systems for recombinant protein production.

Projects

• Interaction of cells with plasticizers, pharmaceuticals and other xenobiotics
• The development of green plasticizers that do not lead to toxic metabolites
• Biodegradation mechanisms of pharmaceuticals during co-metabolism
• Field study of xenobiotic metabolites in Quebec
• Endocrine disruption by metabolites of xenobiotics
• Alternative control strategies for SCF
• Enhanced yields of bacteriophage and other bioproducts using SCF
• Effect of biosurfactants of the co-metabolism of xenobiotics

Specialized laboratory facilities

The laboratories are completely equipped for the maintenance, growth and monitoring of microbial systems. The following demonstrates the specialized equipment in my laboratories, but they also contain the usual balances, ovens, refrigerators, fumehoods (5), etc. As well, there are a number of other useful analytical tools in the departmental equipment laboratories (eg. GC-MS, AA, ICP).

• laminar hood, -70oC freezer, large autoclaves, incubators
• controlled temperature incubator shakers (6)
• computer-controlled fermentors (4), CO2 and O2 online analysis
• large centrifuges, microcentrifuges, microscope
• gas chromatographs, UV-visible, Autotensiomat (surface tension)
• HPLC, capillary electrophoresis, fluorescence spectroscopy
• equipment for molecular biology – PCR, SDSPAGE, DGGE

Collaborators

• Prof R. Leask, Chem. Eng., McGill
• Prof J. Nicell, Civil Eng., McGill
• Prof S. Coulombe, Chem. Eng., McGill
• Prof M. Maric, Chem. Eng., McGill
• Prof. V. Yargeau, Chem. Eng., McGill

Research group

MEng candidates

• Zachary Storms
• Hervé Gauthier
• Andrea McGlynn
• Nicolas Firlotte

PhD candidates

• Dominic Sauvageau
• Azadeh Kermanshi pour

Visiting student

• Hanno Erythripol