He has been researching the byproducts from the ethanol-making process, and believes the fermentation residue may be more valuable than the ethanol.
Weimer and his team determined that organisms used to convert biomass stick to cellulose fibers with a glue-like substance called glycocalyx. "Because the glue couldn't be removed from the fibers without destroying the glue, we took the entire mixture - the glue, bacteria, and the rest of the cellulosic biomass - and used it as an adhesive," says Weimer. Specifically, they used it as wood glue.
To explore glue's potential as a commercial product, the team tested it with the help of researchers at the USDA Forest Products Lab. Their primary concern is durability in wet conditions.
Although glycocalyx does fall apart once wet, Weimer's team found that when mixed with another petroleum-based resin it works well. In some tests, researchers have successfully used a mix with up to 73% of the resin replaced with the bio-based adhesive. Researchers still have to see if the process can be scaled up for commercial production.
"The PF the fermentation process would partially replace sells for considerably more than ethanol, and the fermentation would still generate ethanol," says Weimer. But economic incentive is not the only draw to the biomass glue, it also keeps alfalfa, with all it's environmental benefits, on the landscape.
University of Wisconsin-Madison