Science Alliance Annual Report
2008–2009
UT-ORNL Distinguished Scientists
Georges Guiochon
Separation science – separating substances in chemical compounds
Single-celled algae are a promising alternative biofuel resource, but not all species produce the oils (lipids) used in biodiesels equally well. Just understanding the complex, metabolic processes of living organisms challenges current scientific knowledge and technology, let alone identifying the metabolites specific to increased lipid production.
An expert in the art of separating chemical compounds Georges Guiochon joined forces with others searching for better biodiesel resources. He turned his team’s extensive expertise with multidimensional chromatography to the study of four different species of blue-green algae that appear on a Department of Energy list of species with potentially high-yield.
Unraveling the thousands of metabolic compounds involved in lipid production requires separation methods far more powerful than any individual technique currently available. Such complexity even defies the most powerful analytical methods—liquid chromatography (HPLC), which separates chemicals but is limited to a few hundred per column; mass spectrometry (MS), which identifies molecular structure but only on relatively simple mixtures of up to a dozen compounds; and nuclear magnetic resonance (NMR), which identifies spatial arrangements, but only if the sample is pure or nearly so.
To address the problem, Guiochon says, the burden to separate the highly concentrated metabolite mixtures falls to a two-dimensional, or two-step, HPLC technique, where the hundreds of compounds collected at the exit of one column are sorted by a second column, which separates them according to different characteristics. These simpler mixtures can then be analyzed using mass spectrometry. Significant information on the behavior and physiology along with limited, but promising, data about lipid metabolism in the chosen algal species is already available. These organisms produce long linear alkyl alcohols or carboxylic acids with properties similar to the hydrocarbons used to power diesel engines. Once Guiochon’s group has identified the lipid producing metabolites, they can use their results to identify those algae with the greatest diesel-fuel-like lipid production.
This research will help identify renewable resources that use solar energy to convert carbon dioxide into diesel fuel.
Guiochon received the Csaba Horvath Memorial Award of the Connecticut Chromatography Council in April 2009. This medal is given to a person in the field of separation science whose work has exemplified, and will continue to enhance the advancement of, separation science.