Tim Eggeman* and Dan Verser

ZeaChem Inc.

2319 S. Ellis Ct.

Lakewood, CO 80228

Phone: (303) 358-6390

Fax: (303) 988-9545

E-mail: time@zeachem.com

Rising concerns over the use of fossil fuel resources has generated renewed interest in the production of commodity chemicals via fermentation. Organic acids are a particularly attractive target since their functionality enables downstream catalytic upgrading to a variety of compounds including alcohols, aldehydes, ketones, esters and olefins. This flexibility enables process concepts where organic acids are used merely as intermediates in chemicals production via combined fermentation and chemical synthesis schemes.

Unfortunately, the recovery of organic acids is technically challenging. The broths are often at near neutral pH, so the acid is present in the form of a dissociated ion rather than a protonated species. The dilute nature of the broth also places a special premium on energy efficiency. This paper will survey how these and other common issues are addressed in the commercial recovery schemes for several organic acids.

Recent results from our laboratory on a new energy efficient method for the recovery of acetate will also be highlighted. Our reactive separation scheme utilizes carbon dioxide, an amine and an esterifying alcohol to produce acetate esters in high yield. Furthermore, our method avoids the production of a waste salt coproduct, a critical advantage for large scale commodity chemical production.