Fiber-Hungry Bacteria Could Form Natural "Bond" With Wood Industry

The tiny, gut-dwelling bacteria that help cows and other herbivores break down the tough fiber in their diets could someday find their way into various wood products and furniture.

An Agricultural Research Service scientist has found that these microbes' ability to secrete a sticky outer coating provides the ideal basis for a biologically based wood "glue." Brought about through fermentation, this adhesive residue is strong enough to create wood products like plywood and particleboard.

ARS microbiologist Paul Weimer and U.S. Forest Service collaborators have discovered a way to combine strains of Ruminococcus bacteria and scrap plant material--crop residue, wood chips and even recycled newspapers--to form a sticky fermentation residue that boasts powerful adhesive properties.

The all-natural residue could replace a portion of the petroleum-based, phenol-formaldehyde (PF) resin currently used to bond multiple layers of wood together. The researchers' invention could lead to a safer and more environmentally friendly adhesive.

Weimer, who works at the ARS U.S. Dairy Forage Research Center in Madison, Wis., studies bacteria that reside in dairy cows' digestive tracts. He stumbled upon the idea for a wood adhesive when observing how tightly certain cellulose-digesting bacteria like Ruminococcus and Clostridium bind to plant material while metabolizing.

These bacteria have an outer glycocalyx, or slime layer, that allows them to cling to a surface, similar to how cavity-causing bacteria adhere to teeth.

Weimer teamed up with Linda Lorenz, Charles Frihart and now-retired Anthony Conner of the Forest Service's Forest Products Laboratory in Madison, Wis., for their expertise on conventional wood adhesives.

The bacterially based residues can replace up to 45 percent of the amount of traditional adhesive, like PF resin, used in many wood products--and even withstand moisture. Generated at minimal cost as a co-product of fuel ethanol, the residues could also bring an economic boost to the development of processes that convert plant materials into fuels.

Weimer and his colleagues have filed for a patent on their research, so the technology is now available for licensing.

ARS is the U.S. Department of Agriculture's chief scientific research agency.