ZeaChem’s process combines the outputs of two traditional ethanol production pathways (fermentation of sugars and gasification of biomass) into a third catalytically-driven step—hydrogenation—to produce ethanol. (Earlier post.) 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 bio-based chemicals. The next step will be to concentrate and purify the ZeaChem produced acetic acid into a salable product, using an energy efficient, non-distillation based process.

In our experience, these 10,000 times scale-up results verify the ability to scale to commercial fermentation.

—Geoff Stephenson, P.E., Principal Process Engineer at Burns & McDonnell Engineering Company, Inc.

The positive scaling results are a direct outcome of ZeaChem’s collaboration with Hazen Research, Inc., an industrial research and development firm in Golden, Colorado. 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 November 18, 2009 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. 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.

—Jim Imbler, president and CEO of ZeaChem

Naturally-occurring acetogens are highly robust and, unlike yeast, produce no carbon dioxide 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 more than 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.

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, Oregon. The core technology of the facility will begin to come online in 2010.