Degradation of phthalic acid and dimethyl phthalate by aerobic microorganisms

Abstract

Microbial degradation of phthalate and dimethyl phthalate esters was investigated using an enrichment culture obtained from sewage sludge. Optimal degradation conditions were determined by an orthogonal test for environmental factors. More than 99% PA at a concentration of 4 000 mg/L was degraded within 5 days under the optimized conditions at an initial pH 6.0, m(C)m(N)m(P)=10051, and NaCl concentration 10 g/L. As the sole source of carbon and energy, dimethyl phthalate (DMP) can be degraded by a culture derived from an acclimated activated-sludge under aerobic conditions and two degradation intermediates were identified as mono-methyl phthalate (MMP) and PA. The addition of PA, one of DMP biodegradation intermediates, resulted in acceleration of DMP degradation rate in the culture. Fig 2, Tab 3, Ref 14