Submitted to: World Journal of Microbiology and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/25/2002
Publication Date: 2/1/2003
Citation: FREER, S.N., DIEN, B.S., MATSUDA, S. PRODUCTION OF ACETIC ACID BY DEKKERA/BRETTANOMYCES YEASTS UNDER CONDITIONS OF CONSTANT PH. WORLD JOURNAL OF MICROBIOLOGY AND BIOTECHNOLOGY. 2003. V. 19. P. 101-105.
Interpretive Summary: More than 10 million tons of rock salt are poured onto North American highways each year to provide safer driving conditions during the winter months. This heavy use of de-icing chemical destroys roadside vegetation, damages aquatic ecosystems, pollutes groundwater and domestic potable water supplies, and damages the highway infrastructure. Calcium magnesium acetate (CMA) has been identified as a potentially acceptable, non-corrosive, environmentally benign alternative to road salt. CMA is a mixture of calcium acetate and magnesium acetate and is manufactured by reacting glacial acetic acid with dolomitic lime (CaO-MgO) or limestone (Ca/MgCO3). Currently, the commercial production of glacial acetic acid is exclusively by petrochemical routes and amounted to an annual domestic production of about 4.68 billion pounds in 1995. Recently, 60 yeast strains belonging to these and several other genera were screened for their rability to produce acetic acid from either glucose or ethanol in batch culture. Seven of the cultures that produced the most acetic acid were further tested under conditions of constant pH in bioreactors. The most promising yeast, D. intermedia NRRL YB-4553 produced 42.8 g/l acetic acid from 100 g/l glucose and 65 g/l acetic acid from 150 g/l glucose in 64 to 122 h. This compares quite favorably to the results others have obtained using the bacterial system Clostridium thermoaceticum, which generally produces less than 30 g/l acetic acid at a much slower rate. This yeast will be evaluated for the potential production of acetic acid from renewable substrates (starch and/or biomass), thus, potentially mitigating the USA's dependence upon petroleum.
Technical Abstract: Sixty yeast strains were previously screened for their ability to produce acetic acid, in batch culture, from either glucose or ethanol. Seven of the strains belonging to the Brettanomyces and Dekkera genera, from the ARS Culture Collection, Peoria, IL, were further evaluated for acetic acid production in bioreactors at 28 deg C, constant aeration (.75 v/v/m), and pH (6.5) in medium containing either 100 g glucose/l or 35 g ethanol/l. D. intermedia NRRL YB-4553 produced 42.8 g acetic acid/l and 14.9 g acetic acid/l from the two carbon sources, respectively, after 64.5 hr. The optimal pH was determined to be 5.5. When the initial glucose concentration was 150 g/l or 200 g/l, the yeast produced 62.2 g acetic acid and 65.1 g acetic acid/l, respectively.