Chicago, Ill.-based TetraVitae Bioscience successful completed the demonstration of its process to produce biobased n-butanol (normal butanol) in a corn dry-mill pilot plant. For the demonstration, TetraVitae retrofitted an integrated corn dry-mill pilot facility at the National Corn-to-Ethanol Research Center on campus of Southern Illinois University Edwardsville.

During the demonstration at NCERC, TetraVitae worked with the Separations Research Program at the University of Texas in Austin to refine production purification. To achieve this, the company took the raw chemical products produced at NCERC and manufactured purified n-butanol and acetone in a continuous distillation.

According to TetraVitae President and CEO Jay Kouba, the demonstration at NCERC further validated the company’s technology, and that it could be deployed in existing corn dry-mill ethanol plants to efficiently produce n-butanol on a commercial scale.

“Though our process is very similar to the ethanol production process, we use a different organism during fermentation, and then we isolate the product,” Kouba said, adding that TetraVitae is actively exploring partnership opportunities to deploy its technology within existing North American ethanol plants. Kouba noted that the company is interested in potentially using sugarcane feedstock to produce n-butanol in Brazil.

“Our intent is to partner with asset owners and to share in equity,” Kouba said.

As a result of this successful demonstration, TetraVitae also validated its low-capital profile as a potential partner with ethanol plants. Kouba estimates TetraVitae has the capability of producing approximately 27 MMgy of n-butanol within a 40 MMgy corn dry-mill ethanol facility with a retrofit cost of about $6 million.

“It derates the plant so it doesn’t make much material, but it does prove out the technology for a very low cost,” Kouba said. “The second step of that is that we would make a more significant investment that actually brings the plant back up to its full production capability.”

Like ethanol, n-butanol is an alcohol, but is comprised of four straight-chained carbon molecules as opposed to ethanol’s two-carbon structure. Isobutanol is another form of butanol, but isobutanol’s four-carbon molecules are branched, which make it more suitable as a fuel due to its high octane rating and low vapor pressure properties.

Both n-butanol and acetone are widely used as solvents, and as precursors to monomers used in paint resins such as butyl acrylate, butyl methacrylate, methyl methacrylate and methacrylic acid. TetraVitae is developing a route to 2-ethyl hexanol, which is also used extensively in coatings. The company is also developing n-butanol as a source for 1-butene, a co-monomer in linear low density polyethylene, the most commonly used material for plastic bags. Acetone and isopropanol are frequently used as solvents in a variety of personal care products.

Kouba told Biorefining that TetraVitae intends to initially market its n-butanol and acetone to be used for paint and coating formulations. “We’re also developing technology to use cellulosic feedstock where we can expand potential chemical applications from that.”