Substrate characteristic bacterial fatty acid production based on amino acid assimilation and transformation in marine surface sediments from the Wadden Sea, Germany

However, PLFA patterns derive from multiple species and may be influenced by substrate types. Here, we investigated such dependencies by monitoring the transformation of position-specifically 13C-labeled amino acids (AAs) in coastal marine sediments dominated by heterotrophic bacteria.

Alanine was assimilated into straight-chain FAs, while valine and leucine incorporation led to the characteristic production of even- and odd-numbered iso-series FAs. This suggests that identical microbial communities adjust lipid biosynthesis according to substrate availability. Transformation into precursor molecules for FA biosynthesis was manifested in increased 13C recoveries of the corresponding volatiles acetate, isobutyrate and isovalerate of up to 39.1%, much higher than for PLFAs (<0.9%).