A Coarse Techno-Economic Model of a Combined Fermentation-Catalysis Route to Sorbic Acid

The conversion of biomass into bulk chemicals provides the potential for multiple environmental and economic benefits. While current research in industrial biotechnology focuses primarily on biocatalysts, a significant opportunity exists when combining biological and chemical catalysis into one process train. This hybrid process approach will potentially produce a wide array of economically viable molecules. One test-case of this hybrid approach is the production of sorbic acid via biocatalytic conversion of glucose to 4-Hydroxy-6-methyl-2-pyrone (HMP), followed by catalytic conversion of HMP to sorbic acid. Current collaborative research has developed this process to the stage where gram-quantities of biologically-produced HMP have been delivered to catalysis to produce butyl sorbate (a hydrolysis step can then take this to sorbic acid). Although the final process details needed for a detailed technoeconomic analyses are several years away, it is desirable to understand a coarse structure of the economics of such a process. Such an understanding can provide insight into opportunities for process improvement, as well as into fundamental technoeconomic limitations of the approach. To this end, we have developed a spreadsheet-based model of this hybrid process and have estimated the sorbic acid production cost from the process, which are then compared to current wholesale prices. We also report results of a comprehensive sensitivity analysis to demonstrate potential process improvements.