Student Abstracts: Biology at INEEL

Partial Purification of a Thermophilic Catalase from Thermus brockianus.. LEANNE MCFARLAND (Knox College, Galesburg, IL 61401) VICKI THOMPSON (Idaho National Engineering and Environmental Laboratory, Idaho Falls, ID 83415) .
Extremozymes are enzymes isolated from microorganisms that thrive in extreme conditions such as: temperatures as high as 100°C to temperatures below 0°C, immense pressures found on the ocean floor, high salt environments like the Great Salt Lake, even acidic condition with pH values less than 2. One of the driving forces behind research on extremozymes is the possibility of application for industrial processing. The enzyme of interest, catalase, catalyzes the breakdown of peroxide protecting cells from its toxic effects. Paper mills often use peroxide to bleach paper, but a normal catalase cannot degrade peroxide at the high temperatures at which the process is run. A catalase enzyme from a thermophilic or "heat-loving" organism would be ideal at such high temperatures. Thermus brockianus, a thermophilic bacterium isolated from Yellowstone National Park was chosen for catalase isolation. Cells were grown up in a rich lactate media, pelleted by centrifugation, and lysed by French Press. The resulting cell extract was run on an ion-exchange column followed by a hydrophobic interaction column and a gel filtration column. The protein has been partially purified from an original specific activity of 24 units/mg to 4,723 units/mg by the three chromatographic steps. Catalase positive fractions from the final column resulted in approximately four proteins of similar size and properties. Future experiments to purify catalase from Thermus brockianus will be conducted on the PerSeptive Biosystems Vision Workstation with new columns. After purification effects of temperature and pH, enzyme kinetics, and metal inhibition will be tested.