Biodegradation of 2-Sulfonatofatty Acid Methyl Ester (α-SFMe). III

Ultimate Biodegradation of α-SF Me by Activated Sludge

Abstract

For elucidation of the mechanism for the ultimate biodegradation of 2-sulfonatofatty acid methyl ester (α-SFMe), the degradation of sulfosuccinic acid (an analogue to the biodegradation intermediate of α-SFMe, monomethyl α-sulfosuccinate), C₁₄-α-SFMe and 2-¹⁴ C-labeled C₁₆-α-SFMe, was carried out. The biodegradation was done by measuring BOD, dissolved organic carbon (DOC) and released SO₄^2- using the Japanese MITI test and shake culture method. ¹⁴CO₂ evolved from radiolabeled α-SFMe was measured by the modified OECD test (¹⁴CO₂ evolution test).
In the MITI test, sulfosuccinic acid was degraded by activated sludge previously acclimatized to-α-SFMe but no degradation occurred using unacclimatized sludge.DOC removal continued throughout the shake culture test with C₁₄-α-SFMe, and inorganic sulfate was liberated during the early stage of the test. In the ¹⁴CO₂ evolution test, radiolabeled α-SFMe showed 77 % degradation of the initially added radioactivity after 2 weeks.
The present results clearly indicate α-SFMe to be ultimately biodegraded through ω-and β-oxidation, desulfonation (cleavage of C-S linkage) and the oxidation of carbonaceous residues.