Absolute configuration of 3‐hydroxy acids formed by Stenotrophomonas maltophilia: Application of multidimensional gas chromatography and circular dichroism spectroscopy

Abstract

The soil bacterium Stenotrophomonas maltophilia was found to transform various long-chain fatty acids selectively into 3-hydroxy fatty acids of shorter chain length. Their chiral evaluation was performed by multidimensional gas chromatography (MDGC) on modified cyclodextrin phase comparing the enantiodistribution of 1,3-diol formed without loss of stereochemical information from a representative microbial product with those of synthetic (3RS)- and (3S)-1,3-diols. Enantiomeric excesses of 84-98% (R) were determined for the microbially produced 3-hydroxy acids. In addition, the CD exciton chirality method was applied to determine their absolute configuration. Derivatization with 9-anthryldiazomethane and 2-naphthoylimidazole led to the required bichromophoric structures. Their CD spectra displayed a positive first Cotton effect around 254 nm and a negative second Cotton effect around 237 nm, which confirmed the (R)-configuration of the bacterial products.

Non-volatile floral oils of Diascia spp. (Scrophulariaceae)

“…Experiments to determine the absolute configuration of the target compounds proved that the hydroxyl at C-3 shows (R)-configuration. Results are based on GC-comparison between the (2S)-phenylpropionyl derivative of a chiral standard and the samples (Hammarströ m, 1975;Weil et al, 2002).…”

“…The floral oils play an important role in larval provision and have also been suggested to be used in nest construction (Cane et al, 1983;Buchmann, 1987). Some hydroxylated fatty acids are reported to possess antibiotic properties (Valcavi et al, 1989;Weil et al, 2002). The prevalence of such chemical species in the Diascia flower oils instead of simple fatty acid oils -may be necessary to keep the larval food free of microbial decomposition, or for the nest cell lining.…”

Impact of free hydroxylated and methyl-branched fatty acids on the organization of lipid membranes

“…2-HFAs were detected as (R)-enantiomers in wool wax whereas (S)-enantiomers dominate in lipopolysaccharides from various bacterial groups (Rietschel, 1976;Tokamolthom et al, 2002). Frequently, both enantiomers of 2-HFAs were detected while bacteria predominantly contained the (R)-form of 3-HFAs (Rietschel, 1976;Weil et al, 2002).…”

Enantioselective Analysis of 2- and 3-Hydroxy Fatty Acids in Food Samples

“…For instance, 2-OH-FAs in sphingolipids as well as ester-linked 2-OH-FAs in wool wax and plants were reported to be present enantiopure in the ( R )-form − , whereas ( S )-enantiomers dominated in LPS of bacteria , , . Microbial 3-OH-FAs were shown to occur predominantly in ( R )-configuration , , − . On the other hand, 3-OH-FAs resulting from β-oxidation were predicted to share the ( S )-configuration, but these metabolites were found to be almost racemic .…”