Screening and Characterization of an Efficient Phthalate-Ester-Degrading Strain

Abstract:

With dibutyl phthalate (DBP) as the sole carbon source, we isolated a DBPdegrading strain; by its morphology as well as 16S rDNA sequencing and phylogenetic analysis, the strain was identified as Stenotrophomonas sp., designated as strain B3. Degradation of Phthalate esters (PAEs) by Stenotrophomonas was reported for the first time. The degradation efficiency of 0.05 g?L-1 DBP is 93.4%;B3 could efficiently degrade DBP up to 50 g?L-1,and under the conditions of pH 8, 35 ℃, the degradation efficiency of 10 g?L-1 DBP by B3 reached 95.8%. Kinetic studies showed that DBP degradation by B3 followed first-order kinetics, and the initial degradation rate of 50 g?L-1 DBP can reach 1.25 g?L-1?h-1. The degradation efficiencies of four other common PAEs（di-2-ethylhexylPhthalate、dimethyl phthalate、benzyl butyl phthalate、diethyl phthalate）as well as aniline, toluene and phthalic acid by B3 were 50% or higher, suggesting that B3 had a broad substrate spectrum. The ability of B3 to degrade various PAEs at high concentrations indicates that B3 is promising in bioremediation of PAEs.

Key words:Stenotrophomonas; phthalate esters; dibutyl phthalate; biodegradation; kinetics