Production of 14-Oxo-cis-11-eicosenoic Acid from Lesquerolic Acid by Sphingobacterium multivorum NRRL B-23212

The objective of this study was to explore the extent of microbial conversion of lesquerolic acid (14-hydroxy-cis-11-eicosenoic 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) the S. multivorum strain was the only microorganism that converted LQA to produce a new product identified as 14-oxo-cis-11-eicosenoic acid by GC-MS and NMR analyses. The conversion yield was 47.4% in 48 h at 200 rpm and 28°C in small shake flask experiments. In comparison, both Acinetobacter and Pseudomonas strains failed to convert LQA to major new products but used LQA apparently as an energy source during fermentation. For structural analysis, 6.88 g of 14-oxo-cis-11-eicosenoic acid was produced from converting 11 g LQA (a 62% yield) in 72 h at 200 rpm and 28 °C in Fernbach flasks using 18-h-old NRRL B-23212 cultures and an improved medium that also contained EDTA and glycerol in lieu of glucose as carbon source. NRRL B-23212 was further identified by 16S rRNA gene sequence analysis as a unique strain of S. multivorum. Therefore, S. multivorum NRRL B-23212 possesses an enzymatic activity presumably a secondary alcohol dehydrogenase for converting LQA to produce 14-oxo-cis-11-eicosenoic acid, a first report that demonstrates the functional modification of LQA by whole cell catalysis.