Biobased Lubricants and Fuels: Integration of Chemical Catalysis with Mixed Culture Fermentation
Principal Investigator: Thomas Schwartz (Chemical and Biological Engineering, UMaine)
Partners: Peter van Walsum (Department of Chemical & Biological Engineering, UMaine), Scott J. Eaton (Maine Maritime Academy)
Abstract: Motivated by a shale-gas-driven shift to lighter (C1-C3) petroleum feedstocks, we propose to demonstrate that biomass is a suitable alternative for the production of high-carbon-number, value-added chemicals. In particular, we will focus on the synthesis of biobased lubricant base stocks. Our primary research goal is to convert local biomass to these base stocks using a combination of chemical and biological processing. Fermentation will be used to produce a mixture of medium-chain-length carboxylic acids that is suitable for further oligomerization using heterogeneous chemical catalysis. The end product will be a mixture of C20-C30 molecules that is analogous to existing synthetic lubricants. To achieve this research goal, the following objectives will be met: 1.Demonstrate mixed culture acidogenic digestion (AcD) of local feedstocks to yield a mixture of carboxylic acids; 2.Demonstrate chain elongation during AcD by enrichment of the broth with ethanol; 3.Demonstrate selective separation of medium-chain-length-acids (e.g., caproic acid) from the fermentation broth; 4.Convert esters of these mixed acids to lubricant base-stocks using bifunctional metal/mixed-oxide catalysts; 5.Elucidate the nature of the active sites that are present on these catalysts; 6.Design an improved catalyst for producing lubricants from esters of mixed carboxylic acids; and 7.Quantify industrially-relevant properties of the product oils.