Butamax Advanced Biofuels LLC announced March 6 it has been granted a patent from the U.S. Patent and Trademark Office for engineered ketol-acid reductoisomerase (KARI) enzymes that will be used to optimize the company’s biobutanol production process. According to Butamax, the microorganisms are engineered using an isobutanol biosynthetic pathway invented by the company. The KARI enzymes perform the second of a five-step pathway used to convert sugars to isobutanol.

Butamax CEO Paul Beckwith said the newly patented enzyme step will allow more cost effective production of biobutanol. “With these new KARI enzymes, we have achieved a significant improvement in performance, which is necessary for low-cost commercial production of biobutanol,” he said in a statement.

Butamax has tested various feedstocks throughout the past several years, but Pam Schools, public relations and corporate communications manager at Butamax, said corn currently tops the company’s feedstock agenda. “For now we are focused on commercializing first in the U.S. using existing corn ethanol facilities,” she said. Butamax is scheduled to begin its first retrofit of a corn ethanol plant next year and is actively recruiting other ethanol producers to convert to butanol production. Butamax executives said the latest patent approval makes Butamax’s retrofit plan more cost-effective for existing corn ethanol producers, which they hope will inspire more ethanol plants to make the switch. “This is very exciting for the ethanol producer who’s ready to move on to the next step in the biofuels arena,” Schools said. “Isobutanol is a very exciting place to be with this kind of technology behind it.”