Biodegradation tests of mercaptocarboxylic acids, their esters, related divalent sulfur compounds and mercaptans

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Mercaptocarboxylic acids and their esters, a class of difunctional compounds bearing both a mercapto and a carboxylic acid or ester functional group, are industrial chemicals of potential environmental concern. Biodegradation of such compounds was systematically investigated here, both by literature search and by experiments (Closed Bottle Test OECD 301D and Manometric Respirometry Test OECD 301F). These compounds were found either readily biodegradable or at least biodegradable to a significant extent. Some related compounds of divalent sulfur were tested for comparison (mercaptans, sulfides, disulfides). For the two relevant monofunctional compound classes, carboxylic acids/esters and mercaptans, literature data were compiled, and by comparison with structurally similar compounds without these functional groups, the influence of COOH/COOR’ and SH groups on biodegradability was evaluated. Thereby, an existing rule of thumb for biodegradation of carboxylic acids/esters was supported by experimental data, and a rule of thumb could be formulated for mercaptans. Concurrent to biodegradation, abiotic processes were observed in the experiments, rapid oxidative formation of disulfides (dimerisation of monomercaptans and cyclisation of dimercaptans) and hydrolysis of esters. Some problems that compromise the reproducibility of biodegradation test results were discussed.

Original languageEnglish
JournalEnvironmental Science and Pollution Research
Issue number19
Pages (from-to)18393-18411
Number of pages19
Publication statusPublished - 01.07.2018

Bibliographical note

Funding Information:
Funding information This study was funded by the European Regional Development Fund, grant agreement no. CCI No 2007DE161PR001 in the Lüneburg Innovation Incubator.

Publisher Copyright:
© 2018, The Author(s).

    Research areas

  • Biodegradation rules of thumb, Closed Bottle Test, Difunctional compounds, Manometric Respirometry Test, Mercaptans, Mercaptocarboxylic acid esters, Mercaptocarboxylic acids, Ready biodegradability tests
  • Chemistry