Dibutyl phthalate degradation by Enterobacter sp. T5 isolated from municipal solid waste in landfill bioreactor

Abstract

A bacterial strain capable of utilizing dibutyl phthalate (DBP) as its sole source of carbon and energy was isolated from municipal solid waste in a landfill bioreactor. Based on its morphology, physiochemical characteristics, and 16S rDNA sequence, the strain was identified as Enterobacter sp. T5. Microbial degradation of DBP was studied for several environmental factors. The optimal pH and temperature for its biodegradation activities were 7.0 and 35 °C, respectively. The effect of initial DBP concentrations on the degradation was investigated between 100 and 1500 mg l −1. The results showed that the degradation fit a first-order kinetic model, and the degradation half-life was about 20.9 h when the concentration of DBP was lower than 1000 mg l −1. The major DBP degradation products by Enterobacter sp. T5 were preliminarily identified as PA and MBP. Enterobacter sp. T5 also grew with dimethyl phthalate, diethyl phthalate or dioctyl phthalate solution as the sole source of carbon and energy, which suggested its ability to resist phthalic acid diester (PAE) toxicities. These results suggested that Enterobacter sp. T5 could be used as a candidate for remediating PAE-containing wastes.