Kazuaki Miura

Biodegradation of 2-sulfonatofatty acid methyl ester (α-SFMe)

The biodegradation pathways of α-SFMe were determined based on changes in the chemical structure of C 14 -α-SFMe by IR, NMR and HPLC analyses in the MITI test. Microbial attack on the surfactant structure was initiated by ω-oxidation to form a carboxyl group and continued with β-oxidation, causing the removal of two carbons at a time, to form a temporary intermediate, monomethyl α-sulfosuccinate. Degradation subsequently occurred by desulfonation

Kinetic study on the biodegradation of linear alkylbenzenesulfonates (LAS) in well-water

Abstract Linear alkylbenzenesulfonate (LAS) was added five times to well-water at weekly intervals and the number of LAS acclimated bacteria and the residual LAS concentration were measured to examine the kinetics of acclimation in well-water and the biodegradation of LAS by the acclimated bacteria. LAS acclimated bacteria in well-water multiplied rapidly after the first addition of LAS and was maintained in steady state after the further addition of LAS. The biodegradation of LAS began after the time lag of about one day after the first addition, while LAS was biodegraded immediately after the addition of LAS in further additions. Residual concentrations of all homologues and isomers of LAS decreased according to zero-order kinetics. The zero-order rate constants were determined. The composition of residual LAS at 96 hours after LAS addition was approximately consistent with a zero-order rate constant.

Biodegradation of 2-sulfonato fatty acid methyl ester (α-SFMe) : identification of microorganisms isolated from activated sludge and their capability for degrading α-SFMe

Three bacterial strains, A, B and C, were isolated from activated sludge as 2-sulfonato-fatty-acid-methyl-ester (α-SFMe)-degrading microorganisms. From the results of morphological, physiological and biochemical studies, and analyses of 16S rRNA gene sequences, isolate A was identified as Agrobacterium tumefaciens while B and C were Pseudomonas putida, respectively. To demonstrate their capability for the ultimate biodegradation of α-SFMe, the degradation kinetics have been investigated using C14-α-SFMe and 2-14C-labeled C16-α-SFMe. The biodegradation was determined by measuring dissolved organic carbon (DOC) and released SO42−, in the shake-culture test, and evolved 14CO2 in the modified Organisation for Economic Co-operation and Development (OECD) test. In the shake culture test with C14-α-SFMe, DOC removal was progressive throughout the test. Liberation of inorganic sulfate started after DOC removal and then rapidly increased. During the 14CO2 evolution tests, the mineralization of radiolabeled carbon started quickly and reached about 80% of the initially added radioactivity at the end of the tests. The results obtained indicated that all of the isolates had the capability for ultimately degrading α-SFMe through the oxidation of the alkyl carbons and desulfonation (cleavage of the C-S linkage).