4 FATTY ACID METABOLISM IN MICROORGANISMS 



saponified, the fatty acids converted into the methyl esters, 

 and the ensuing ester mixture was separated into various 

 components by fractional distillation. Inspection of typical 

 distillation curves (Fig. 1.1), relating boiling point to 

 amount distilled, shows the prominent presence of fatty 

 acids containing 16 and 18 carbon atoms with lower fatty 

 acids being present in small proportions. The presence of 

 esters with boiling points above methyl stearate in the ester 

 mixture derived from L. arahinosuSj I casei, and A. tume- 

 faciens is of particular interest. SapoL fication of this high- 

 est boiling fraction gave a low melting (28-29°) crystalline 

 acid of the composition C19H36O2, which was given the name 



4000 3000 2000 



J \ I 



Wave numbers in cm-i 

 1500 1200 1000 900 



800 



700 



T 

 7 8 9 10 11 

 Wave length in microns 



Fig. 1.2. Infrared absorption spectra of cyclopropane fatty acids. 

 (1) "Phytomonic" acid from A. tumefaciens. (2) Lactobacillic acid 

 from L. casei. 



