Aerobic biotransformation of linear alkylbenzene sulphonates under laboratory conditions

Sulphophenyl carboxylates (SPC) derived from the biodegradation of commercial blends of linear alkylbenzene sulphonates (LAS), were recorded during OECD-301E screening tests under aerobic conditions. Both HPLC-FL and GC-MS were employed to determine biotransformation products. Two well defined groups of detectable SPC were generated: transient compounds, i.e. SPC which degrade very quickly, and compounds more persistent than the parent LAS which required an acclimatization period before their mineralization could take place. The biodegradation of a C10-C13 LAS commercial mixture and of two individual homologs (C11-LAS and C12-LAS) led to the identification of the most persistent SPC which were C6-SPC, C7-SPC and C8-SPC. The C6-SPC turned out to be the homolog which biodegrades most slowly, this suggests that odd LAS homologs are more easily biodegradable.