Incorporation of 1‐chlorooctadecane into FA and β‐hydroxy acids of Marinobacter hydrocarbonoclasticus

The lipids of the gram‐negative marine bacterium Marinobacter hydrocarbonoclasticus , cultivated in synthetic seawater supplemented with 1‐chlorooctadecane as sole source of carbon, were isolated, purified, and their structures determined. Three pools of lipids were isolated according to the sequential procedure used: unbound lipids extracted by organic solvents, ester‐bound lipids released under alkaline conditions, and amide‐bound lipids released by acid hydrolysis. FA isolated from the unbound lipids included ω‐chlorinated (21%, w/w, of this fraction; C 16 predominant) and nonchlorinated compounds (22%; w/w, C 18 predominant). These acids were accompanied by a high proportion of ω‐chloro‐C 18 alcohols (43%, w/w) and a lower amount of ω‐chloro‐β‐hydroxy‐C 18 ,‐C 16 , and‐C 14 acids (5%, w/w). These data, together with the isolation from the culture medium of γ‐butyrolactone, suggested a metabolism of 1‐chlorooctadecane through oxidation into ω‐chloro acid and then the classic β‐oxidation pathway. The analysis of the ester‐bound and amide‐bound lipids revealed that significant amounts of ω‐chloro‐β‐hydroxy C 10 –C 12 acids were incorporated into the lipopolysaccharides of the bacterium. Incorporation of these ω‐chloro‐β‐hydroxy acids into the lipopolysaccharides represents a novel route for chloroalkane assimilation in hydrocarbonoclastic gram‐negative bacteria. The formation of chlorinated hydroxy acids, like the ω‐chloro FA in the cellular lipids, could account for an incomplete mineralization of chloroparaffins in the environment.