ZeaChem hits industrial-level fermentation goals

Posted February 2, 2010, at 1:52 p.m. CST

ZeaChem Inc., a developer of biorefineries for the conversion of renewable biomass into fuels and chemicals, announced Feb. 2 the first fermentation results of acetic acid, an intermediate in the ZeaChem process. The results demonstrated successful process scaling to a level that is 10,000 times greater than standard lab scale. Fermentation units were scaled from 0.5 liter to 5,000 liters.

The positive results are a direct outcome of ZeaChem's collaboration with Hazen Research Inc., an industrial research and development firm in Golden, Colo. Hazen has constructed and is hosting the initial front-end process unit and providing infrastructure and operations support. Start of construction at Hazen was announced on Nov. 18 and the first fermentation runs exceeded commercially acceptable acetic acid concentration levels. The fermentation process also exceeded ZeaChem's time goals for achieving the concentration level. The results demonstrated successful fermentation of greater than 50 grams of acetic acid per liter in less than 100 hours. These results have been repeated and verified.

"ZeaChem has met and exceeded its concentration and rate fermentation targets," said Jim Imbler, president and CEO of ZeaChem. "We now have sufficient evidence, based on mixed sugars, to indicate that our results are scalable to industrial production levels. Our process, using naturally-occurring acetogen bacteria and existing processes, exceeds the commercially viable threshold for fermentation. ZeaChem is meeting its milestones and continuing to move forward in deploying cellulosic biorefinery technology."

Acetogens have been shown to be powerful organisms in other industries such as wastewater treatment before ZeaChem began utilizing them for biobased chemicals and fuels production. Naturally occurring acetogens are highly robust and, unlike yeast, produce no carbon dioxide (CO2) during the fermentation process, allowing ZeaChem to realize a significant efficiency and yield advantage. ZeaChem has successfully used acetogens to produce acetic acid at the lab scale in over 1,000 fermentation trials using mixed sugars as well as hydrolyzate derived from cellulosic biomass. ZeaChem is now seeking hydrolyzate supply to replicate these scale-up results.

"In our experience, these 10,000 times scale-up results verify the ability to scale to commercial fermentation," said Geoff Stephenson, P.E., principal process engineer at Burns & McDonnell Engineering Co. Inc.

Acetic acid, the product of ZeaChem's front-end fermentation unit, is the first step in the hybrid biochemical and thermochemical process for creating cellulosic ethanol and biobased chemicals. The next step will be to concentrate and purify the ZeaChem produced acetic acid into a salable product, using an energy efficient, nondistillation based process.

ZeaChem intends to scale to a commercial biorefinery upon successful operations at the 250,000 gallon-per-year facility, which is proposed to be built in Boardman, Ore. The core technology of the facility will begin to come on line in 2010.