Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 2, 2007
Publication Date: July 15, 2007
Citation: Kuo, T., Isbell, T., Rooney, A.P., Levinson, W.E., Frykman, H.B. 2007. Production of 14-oxo-cis-11-eicosenoic acid from lesquerolic acid by Sphingobacterium multivorum NRRL B-23212. Journal of the American Oil Chemists' Society. 84(7):639-643. Interpretive Summary: Surplus vegetable oils represent attractive renewable resources for the production of useful chemicals. Biodiesel is a viable alternative fuel produced from vegetable oils and effective utilization of the by-product glycerol will enhance the long-term self-sufficiency of the biodiesel industry. We are investigating new microbial systems for effectively converting the plant lipids and glycerol to produce value-added products. In our laboratories, we previously found that microbial isolates selected from compost manure could convert oleic acid and ricinoleic acid into new compounds potentially useful as lubricants and antifungal agents, respectively. In this study, we applied these compost isolates to modify lesquerolic acid, the dominant fatty acid component of the new crop lesquerella oil. The results showed that a compost isolate was able to convert the fatty acid to produce a unique, new compound in good yields. In addition, glycerol could be used in the culture medium to replace glucose for the effective bioconversion reaction. The impact of this study provides new information and technology for scientists to develop bioprocesses for producing similar types of new compounds from low cost vegetable oils.
Technical Abstract: The objective of this study was to explore the extent of microbial conversion of lesquerolic acid (LQA) by whole cell catalysis and to identify the newly converted products. Among compost isolates including NRRL strains B-23212 (Sphingobacterium multivorum), B-23213 (Acinetobacter sp.), B-23257 (Enterobacter cloacae B), B-23259 (Escherichia sp.) and B-23260 (Pseudomonas aeruginosa) examined in small shake flask experiments, the S. multivorum strain was the only microorganism that possessed biological activity for the conversion of LQA to a major new product with a 47.4% yield. Other NRRL strains B-23260 and B-23259 were either fully active or inactive toward LQA, and B-23213 as well as B-23257 exhibited limited extent of LQA degradation for use as energy source during fermentation but failed to convert LQA to major new products. Bioconversion of LQA was performed in Fernbach flasks using 18-h-old NRRL B-23212 cultures and a reaction medium that also contained EDTA and used glycerol in lieu of glucose as carbon source to produce 6.88 g of the new product (a yield of more than 62% in 72 h). The new compound showed a GC retention time closely resembling LQA, and it was determined to be 14-oxo-cis-11-eicosenoic acid by GC-MS and NMR analyses. Therefore, S. multivorum NRRL B-23212 carried out a stereospecific dehydrogenation reaction for converting LQA to produce 14-oxo-cis-11-eicosenoic acid, and this is the first report that demonstrates the functional modification of LQA by whole cell biocatalysis.