Q to the Rescue!

Seventy-five miles west of the State House, between Worcester and Springfield, a huge reservoir built in the 1930s holds the water that ultimately gushes from Boston's showerheads every morning. On the western shore of this 39-square-mile lake, the Quabbin, near the town of Pelham, there stands a forest of hemlocks and beeches. Running through the forest is a small tributary that feeds into a stream that empties into the Quabbin. And at the bottom of that tributary is a muck of partially decayed leaves and sticks. In 1996, UMass Amherst microbiologist Thomas Warnick waded into the muck, leaned down, and dug up a tablespoonful. He scooped the black slop into a jar and sealed the lid tightly. He was holding what just might be the Holy Grail of microbiology.

At the time, of course, Warnick didn't know that. He simply climbed out of the water and an hour later was back in the Amherst lab of his colleague, professor Susan Leschine, where he stuck the jar in a pile of containers holding the finest soil from Brazil, Mexico, France, and Hawaii. Leschine was researching microbes that break down plant waste—and within the Quabbin sample, she soon isolated an unusual bug. When she looked through her microscope, she saw a single-celled microbe that wasn't round and fat like the ones collected from around the globe, but slender, with a circular spore at one end, which made it resemble a tiny lollipop. She came to call this microbe "Q," a nod to its reservoir home.

Over time Leschine discovered that Q not only looked different from any microbe she had seen, but also acted like no other microbe. It had the ability to home in on many compounds—particularly cellulose (the fibrous, insoluble molecules that form a plant's cell walls), and turn it into sugars, and then, even more surprising, transform the sugars into pure ethanol. This was huge: Currently, plant waste has to be run through machines (which consume energy of their own) in order to make ethanol, a process that carries a steep price tag. But Q could make ethanol on its own—in one step, with no machinery involved. Its ethanol would be nearly as clean a power source as solar or wind. All of which meant Q could probably make someone a lot of money, too.
 

Susan Leschine is 62, with blond hair and freckles. She's known around campus as much for her warmth as her intelligence; in her lab, she greets visitors with a smile and a touch on the arm. Leschine has the ability to explain very complicated things very easily, a useful skill for someone whose research deals with the physiology, ecology, and diversity of polymer-decomposing members of microbial communities.

Leschine has spent 30-plus years identifying new species of anaerobic bacteria—the kind that don't need oxygen to grow—and figuring out how they work. She's always been interested in microscopic bugs that eat big stuff without the benefit of a mouth. The small number of microbes that can find and feed on much larger plant material underwater actually turn themselves inside out to accomplish the trick. "Sticks and leaves obviously do break down at the bottom of a pond," Leschine says. "But how is a mystery," since the cellulose they contain won't break down on its own.

In 1996, she tested the Quabbin soil for its ability to consume plant cellulose by putting a small sample on a piece of filter paper and pouring water over it. Then she waited a few days to see whether the paper disappeared. It did. The Quabbin muck ate the paper. Intrigued, she examined the zoology in the soil in an attempt to isolate the individual microbe doing the work. It took Leschine several months of comparing microbes against textbooks and then peering back at the soil to single out Q.

She noticed that Q, trying to locate its food, released dozens of enzymes into the water; she'd never seen a microbe release so many. These enzymes attacked almost any plant cellulose, breaking it down into sugar. The microbe then "smelled" the sugar in the water, swam toward the plant, and gorged itself.

Leschine initially focused on Q's adaptability, its ability to eat any waste, as its unique trait; it didn't occur to her to think about the importance of its ethanol-generating prowess. Then, in 2005, she conducted an experiment, feeding Q more plant material to see if ethanol production would jump. While Leschine had discovered other bugs that consumed sugar and made trace amounts of ethanol, there was never a 1:1 ratio of increased food intake and increased ethanol production. In fact, with other bugs, the ethanol production had hardly budged at all. But with Q, the more sugar she fed it, the more ethanol it put out. "That was the moment that the light bulb went on."

Leschine loved being a professor, and had never dreamed of starting a company. Yet as UMass faculty, she had a contract with the state requiring her to divulge any discovery made in her lab that might have commercial application. "In the end, I felt obligated to disclose what I had found," she says. "I thought, ‘Wow, this could actually be really useful to humans.' As opposed to much of microbiology."