Spring 2001 -- Vol. 18, No. 1

Extremophiles Make Impact: From Farm to Far, Far Beyond

Growing up on a dairy farm in northcentral Pennsylvania, not far from the New York state border, Jean Brenchley understood the importance of microorganisms--even if she did not know how they worked or what they were.  After all, microorganisms were essential to fermentation, which created things such as pickles and sauerkraut for Brenchley's family and silage for her family's herd of cows.

Later, she became fascinated by the unseen world of microorganisms, and she has since taken that fascination to the extremes.  Extremophiles, microoganisms that thrive in environments that could not sustain typical life, whether for reasons of chemical composition or temperature, represent Brenchley's major research focus.  Those extremophiles have an impact far beyond the farm.  With abundant research funding available and immense interest at the applied and basic levels, extremophiles represent a growing and important area of scientific study.

"There are a lot of microorganisms living around us that nobody has even bothered to discover," says Brenchley, professor of microbiology and biotechnology at Penn State.  "Who knows? Some of those may make the next great antibiotic.  Some may have enzymes that are important for industrial processes and others may help us understand some basic biological principles.

"When you stop to think about all the microorganisms out there, and all the complicated biochemical reactions that are going on inside a cell that is too small for us to see, it is absolutely phenomenal."

With her research, Brenchley focuses on a special group of extremophiles--psychrophiles, or cold-loving, microorganisms.  The psychrophiles Brenchley studies occupy what she calls a "sliding scale" of cold, from cooler than room temperature to below freezing.  Her initial work focused on applications with milk in regard to lactose intolerance, and that project has now grown, through the use of a number of different enzymes, to other beverages and products.  For example, cold-active enzymes could be used to remove pectins from fruit juices and to create household cleaning products that work at cool temperatures.

In contrast to Brenchley's somewhat broad-based approach to extremophiles, Greg Ferry, Stanley Person Professor of Molecular Biology at Penn State, studies one specific type of microorganism.  He focuses on better understanding methane-producing microbes that do their work in anaerobic environments, and he does so with his own abundant curiosity, determination, energy, and enthusiasm.

While Brenchley estimates scientists have uncovered only one-tenth of one percent of all the microbes in our world, Ferry believes he and his counterparts understand only one-1,000th of a percent about the biochemistry and molecular biology of all the known microbes.

"We have to strive to understand the fundamentals if we want to be able to truly utilize the microbes that we know exist," says Ferry.  "We cannot study an organism in the environment unless we know a lot more about its fundamental processes.  There's no way to know what to ask unless we know their composition."

Using microbes from a sewage sludge digestor in Southern California, Ferry's laboratory studies microbes that thrive in an oxygen-free environment.  Such methane-producing anaerobes play an important role in the global carbon cycle, and Ferry, with an eye on ecology, describes his work as part of an ecological cycle as well.

By tapping into the muck at the bottom of a pond, researchers can find enough methane--produced by extremophiles as they breakdown biomass--to ignite a flame. The methane represents just one resource researchers hope to learn how to harness through their study of extremophiles.

"We give ecologists information they can use to understand what's going on in the environment," says Ferry.  "The environment is so complex you cannot treat it as a black box and see what comes out.  But, if you take the black box apart in the laboratory and find out what's inside--the fundamentals of the organisms--you can use that information to go back and make intelligent experimental designs to determine what's happening in the environment."

In the larger carbon cycle, anaerobic microbes decompose biomass into methane and carbon dioxide.  Those microbes make it possible, for example, for leaves and other animal and plant remains trapped in the muck at the bottom of a pond to eventually decompose and produce the same carbon dioxide that their living counterparts produce through aerobic respiration.

Anaerobically produced methane is a potentially valuable byproduct.  Some third-world countries have already harnessed the power of methane produced by anaerobic microbes for heat and energy, and some communities in the United States hope to move in that direction.  Many areas of the country have abundant sources of such methane.  Any place where animal and plant materials are broken down in an anaerobic environment and transformed into carbon and methane--coal mines, swamps, and especially landfills--could become an energy source as scientists learn more about the extremophiles involved in the process.  Those sites could be extremely valuable energy sources, too.  According to Ferry, nature produces more than 400 million metric tons of methane each year.  If science can help find a way to help harness that energy, it would supply about a quarter of the energy needs in the United States.  Not surprisingly, the Department of Energy provides support for Ferry's research.

Still, the importance and potential impact of extremophiles goes far beyond the Earth--especially at Penn State.  As home of the NASA-funded Astrobiology Research Center, the University ranks as just one of five in the nation that receive research support to look for life on other planets and to study early life on Earth.  Conducting that search requires a reliance on clues provided by research on extremophiles.  Using genetic information from living organisms, members of the research center work to determine a timetable for the origin of life on Earth and to better understand the conditions that made life possible in order to understand if similar conditions exist elsewhere in the universe.

Through the two-year-old research center, faculty members and scientists who have been studying the topic for years come together with others who have only recently expanded their research into this area.  Working with the Life Sciences Consortium and the College of Earth and Mineral Sciences Environment Institute, the research center fosters abundant interdisciplinary interaction and study.  It also benefits from an affiliation with the Pennsylvania Space Grant Consortium.

"The main goal of the NASA Mars missions is to investigate the possibility that life exists there," says Blair Hedges, associate professor of biology and member of the Astrobiology Research Center.  "It's unlikely we're going to find complex life, but we're talking about microscopic life, something like bacteria, and many people would agree that at least simple microscopic life has to exist somewhere else in the universe."

Extremophiles hold the key to such research because heat-loving bacteria and microorganisms are thought to have been among the first bits of life to appear on Earth more than three million years ago.  Understanding how those forms of life have evolved provides insights into both a timetable, or molecular clock, for life on our planet and a template for life in general.

Whether the extremophiles are the heat-loving type that seem best associated with the creation of life, the cold-loving kind that could be useful in milk and other beverages, or some other type that somehow survives in an environment that is highly acidic, highly toxic, or even totally without oxygen, they all have a special place in the hearts of scientists.

"The main thing they've shown us is that life can exist in all sorts of extreme conditions," says Hedges.  "They've shown us that the niche for life is bigger than we previously believed.  When you consider the coldest, hottest, most extreme conditions, a lot of times something has adapted and can live there--and that's amazing, humbling, and fascinating."

-- By Steve Sampsell

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