Process for the production of esters
Methods for producing an ester from a gas comprising carbon monoxide. More specifically the invention provides for methods for producing one or more products by the anaerobic fermentation of a gaseous substrate comprising CO and the subsequent conversion of the one or more products to an ester in a down-stream reaction. The invention further provides methods for improving the efficiency of the production of esters from gaseous substrates.
1. A method for the production of ethyl acetate, the method comprising:
a. passing a gaseous substrate comprising CO to a bioreactor comprising a culture of a Clostridium autoethanogenum bacterium strain deposited at the German Collection of Microorganisms and Cell Cultures (DSMZ) under the accession number DSM 23693;
b. anaerobically fermenting the substrate comprising CO to produce a fermentation broth comprising ethanol;
c. passing the fermentation broth to an extraction module, wherein the ethanol is separated from the fermentation broth to provide a purified ethanol stream and a waste broth stream;
d. passing the waste broth stream back to the bioreactor;
e. passing the purified ethanol stream to a reaction vessel; and
f. converting the purified ethanol to ethyl acetate in the reaction vessel by a process selected from esterification or dehydrogenation.
2. The method of claim 1 further comprising continuously removing water produced as a by-product of the esterification reaction from the reaction vessel by reactive distillation.
3. The method of claim 1 wherein hydrogen is produced as a by-product of the dehydrogenation reaction in the reaction vessel and the hydrogen is recovered.
4. The method of claim 3 wherein the recovered hydrogen is recycled back to the bioreactor for use as a co-substrate in the fermentation reaction.
5. The method of claim 1 wherein the gaseous substrate comprising CO is derived from a process selected from the group consisting of steam reforming, water gas shift, ferrous metal products manufacturing, non-ferrous products manufacturing, petroleum refining processes, gasification of coal, electric power production, carbon black production, ammonia production, methanol production, gasification of coal and coke manufacturing.