FIG. 3.

Mass spectra of the methyl esters of the 15:0 fatty acid recovered from cultures of strain Hxd3 grown on hexadecane with unlabeled bicarbonate (a) or [¹³C]bicarbonate (b). Chemical structures represented by the mass spectra are shown as insets. Key diagnostic ion peaks are annotated in bold type with their m/z values, and the structural compositions of the represented ion fragments are delineated. Intersection with a dotted line indicates a point of bond cleavage, and the ion fragment formed subsequently contains only the part of the molecule to the left of the dotted line.