CHAPTER 



BIOSYNTHESIS OF 

 MONOUNSATURATED FATTY 

 ACIDS BY MICROORGANISMS 



1. GROWTH STUDIES 



Since c?j-vaccenic and lactobacillic acids are important 

 constituents of the lipids of many microorganisms, and since 

 these two acids are closely linked metabolically, we explored 

 the biosynthetic routes to c/j-vaccenic acid. As a point of 

 departure, it was assumed (1, 2) that the biosynthesis of un- 

 saturated fatty acids either may take place through desatura- 

 tion of saturated long-chain fatty acids or may involve 

 elongation of the carbon chain of an already unsaturated (or 

 potentially unsaturated) precursor. 



Suspensions of L. arabinosus, L. casei, and L, delbrueckii 

 show no dehydrogenase activity toward stearic, palmitic, 

 lauric, and myristic acids under a variety of experimental 

 conditions (2). Since it was possible that the fatty acids 

 are incapable of entering the cell, a series of experiments 

 were conducted with ruptured cell preparations with simi- 

 larly negative^ results. These observations in conjunction 



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