June 18, 1996

Oil and Gas Industries Could Benefit from Researcher's Work with Extremozymes

Extremophiles--microorganisms that thrive in brutally harsh environments such as volcanoes, arctic pools or the Dead Sea--can be very helpful little creatures. Soon, their enzymes could make medical therapies more effective and feed for chickens easier to digest --and even make milkshakes thicker.

In the past few years, researchers around the world have begun to intensely explore the wide-ranging possibilities of the enzymes, but Dr. Robert M. Kelly, professor of chemical engineering at North Carolina State University, has focused his research in this area of biology and biotechnology since the early 1980s.

For years, Kelly has investigated the potential of enzymes from thermophilic--or heat-loving--bacteria, which live at temperatures up to and exceeding 100 degrees Celsius. His work has captured the attention of several large companies and governmental agencies that now sponsor his research, including DuPont, Kraft Foods, Dowell Schlumberger, the Department of Energy and the National Science Foundation.

His recent work has yielded an extremozyme, a name that he and Dr. Michael W. W. Adams of the University of Georgia coined for enzymes from extremophiles, that could facilitate extraction of oil from the earth.

Enzymes are proteins produced by living cells and can act as catalysts in biochemical processes. In recent years, an array of industries have sought to replace costly and hazardous chemical catalysts with enzymes; however, enzymes from microorganisms that live in moderate environments cannot stand up to the extreme conditions required by some industrial processes.

According to Kelly, researchers are discovering more and more extremozymes with potential for commerical application, learning how to find them more efficiently, and then clone them using recombinant DNA technologies--i.e., using microorganisms that grow at moderate temperatures as factories to produce large amounts of these biocatalysts much more easily than can be done directly with extremophiles.

The potential of his work for the oil and gas industry has been recognized by Recombinant BioCatalysis Inc. (RBI), a small company headquartered in Sharon Hill, Pa., that aims to find, produce and market extremozymes.

"Our enzyme discovery program at Recombinant BioCatalysis has yielded a number of novel cellulases and hemicellulases," said Eric J. Mathur, director of RBI's Molecular Diversity Program in La Jolla, Calif. "In collaboration with Bob Kelly, we have recently cloned and expressed the genes encoding the hemicellulases identified by his group."

Kelly sits on the board of advisers for RBI and is a consultant for the company. Their joint efforts--with Kelly performing the basic science and RBI pursuing commercialization--have drawn the attention of several oil and gas well companies.

Coaxing oil and gas from a well often involves injecting a viscous solution of enzymes, guar gum, sand and water into the bore, setting off an explosion and forcing the solution into resulting cracks in the surrounding rock. These cracks are propped open by the sand to permit the flow of oil and gas. Activated by the heat in the well, the enzymes break down the guar gum and thin the solution so that oil and gas can flow freely around the grains of sand.

Although gas and oil companies now use enzymes for these operations, they function well only to about 70 C and can even begin to break down the guar gum before the solution is pumped into the bore. Temperatures in the wells often reach 100 C and higher, so producers need an enzyme that can withstand the extreme heat yet does not become active at lower temperatures.

Kelly and his research group have identified a potential candidate for this application: a mixture of extremozymes that functions well over 100 C. Dr. Saad Khan of NC State and Dr. Robert Prud'homme of Princeton University, both specialists in the flow of viscous polymer solutions, worked with Kelly on the problem, and both universities were recently awarded a patent for this technique.

Kelly says, "This mixture of high temperature hemicellulases, which can break down guar gum, may be important for oil and gas well stimulation at much greater depths--that is, temperatures--than ever envisioned for this application. This, of course, could have a significant impact on the efficiency of oil and gas production."

RBI is assessing the market potential for this application.

According to Mathur, "evaluation of the economic feasibility of large-scale production of the recombinant enzymes for the hydraulic fracturing application is currently in progress."

Kelly acknowledges that scientists need to learn more about how the enzymes are able to flourish in such unrelenting environments so that the applications for them can be expanded. He says a critical goal at this point is producing sufficient quantities of extremozymes through recombinant DNA technology to assess their usefulness for a variety of purposes.

"The intrinsic basis for the extraordinary stability of extremozymes is not likely to be understood for some time. It is also doubtful that their stabilizing properties can be conferred upon enzymes from less extreme environments," Kelly notes. "The fact is we now know they are there and available. The challenge before us is to be creative in finding new ways to use enzymes that go well beyond the moderate conditions that have severely limited their use as catalysts."

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