Can amino acids be synthesized by H2S in anoxic lakes?

Abstract

The starting point of the current work is the hypothesis that amino acids are being synthesized abiotically in the hydrogen sulphide bearing anoxic Lake Nakanoumi (Kimoto and Fujinaga, 1988, 1990). Kimoto and Fujinaga claimed to have detected amino acids in an experiment modelling the lake. The amino acid analyser (HPLC), however, is considered an inappropriate analytical instrument in this case as it is dedicated primarily to the analyses of amino acids and not to other organic molecules. Analyses by HPLC confirmed the reported data, however gas chromatography and gas chromatography-mass spectrometry analyses, including selected ion monitoring, failed to verify the presence of amino acids. Some of the compounds identified (amines and carbon/sulphur- and carbon/sulphur/nitrogen ring systems) might account for false detection of amino acids by the amino acid analyser and can, unlike amino acids, be obtained from the starting materials by known chemical reactions. A number of the identified compounds are known to occur in sediments from hydrothermal vents, and so the Kimoto and Fujinaga experiment remains of importance to the origin of life debate.