Sticky bacteria may soon be cleaning up your drinking water.

Research by R. Kramer Campen (graduate-geosciences) has found the forces behind bacterial adhesion may be molecular. In the past, researchers have generally believed bacterial adhesion was due to large-scale factors.

"The problem with those measures is they don't tell what is actually happening," Campen said.

Bacterial adhesion is an important part of cleaning contaminated water sources. The organisms can be used to clean up oil spills or industrial wastewater. However, cleaning groundwater for drinking is a more complex issue.

The overall goal of the research project is to understand the molecular-level mechanism by which bacteria adhere to soil. Eventually, Campen hopes his findings will lead to methods where bacteria can easily clean groundwater.

"You would have to find a way to change the water chemistry or, eventually, genetically engineer the bacteria to move along the subsurface," Campen said. Right now, polluted groundwater is treated with nutrients that spur the activity of bacteria already present in the water. Companies that are large producers of pollution may run their waste through reactors with these organisms.

In particular, Campen is looking at gram-negative bacteria. The cell walls of these organisms are covered with proteins called lipopolysaccharides. These proteins anchor into the membrane and create an atomic-scale "hair." These "hairs," along with positive and negative charges, create the stickiness of a bacterium.

"The main goal is to explain why these bacteria stick to sand but do not stick to iron oxide," Campen said. "We want to do this by exploring the surface properties."

Bacteria can use the charge of the "hairs," or polymers as they are technically known, as a way to control their degree of stickiness. If a bacterium is completely negative, it will have a long and floppy shape and "can lie like a zipper," Campen said. These floppy bacteria are the stickiest. Less sticky are the tightly coiled bacteria. Alternating positive and negative charges give this bacterium their shape.

Campen's adviser, James Kubicki, assistant professor of geosciences, encourages caution when considering the findings. "I'm a little reluctant because it's very preliminary," he said.

Despite his findings, Campen acknowledges that more research needs to be done.

"Any applications are somewhat distant," he said. "We're looking at a decade to a multi-decade scale."

Campen's adviser, James Kubicki, assistant professor of geosciences, also encourages caution when considering the findings.

"I'm a little reluctant because it's very preliminary," he said.