Isolation and characterization of two n-butyl benzyl phthalate degrading bacteria

nButyl benzyl phthalate (BBP) is a phthalic acid ester (PAE) used extensively in the manufacturing of plastics that contributes to the environmental pollution. It easily released to the environment and resistant to degradation. Bioremediation has been proposed for removal of PAEs from contaminated sites. Studies showed that the biodegradation of PAEs was slow if the lateral chain was longer and more complex. Two BBP degrading bacterial strains, HS-B1, HS-B2, were isolated from contaminated sludge in the river of Jingzhou in Hubei province. The two bacteria were identified as Acinetobacter sp. and Arthrobacter sp. by morphology and 16S rDNA sequence analysis. BBP at 500 mg L-1 in the culture medium was tested and after 24 h of culture, chloroform was used to extract the BBP in the culture medium. The initial and the final concentrations of BBP were assessed by UV-visible spectrophotometer. The results showed that the bacterium could grow well on BBP as the sole source of carbon and energy. The degradation of 500 mg L-1 BBP by strains HS-B1 and HS-B2 was 28% and 59% after 24 h, respectively. The rate of degradation increased to 40%, 75% respectively with addition of 0.1% LB in 24 h, suggesting that additional sources of growth factors enhanced biodegradation. This study is helpful to the development of microbial resources for bioremediation. (C) 2012 Elsevier Ltd. All rights reserved.