Biosorption of diethyl phthalate ester by living and nonliving Burkholderia cepacia and the role of its cell surface components.
In this study, the dibutyl phthalate (DBP) binding properties of a DBP-tolerant bacterium (B. cepacia) were characterized in terms of adsorption kinetics and isotherm. Living and nonliving cells both exhibited rapid removal of DBP, achieving more than 80% of maximum sorption within 30 min of contact and reached the equilibrium after 3 h. The adsorption isotherms were well fitted with the Sips model and the nonliving cells have greater biosorption capacity and affinity for DBP than the living cells. Furthermore, the absence of an active mechanism dependent on metabolism implied that the DBP bioaccumulation by living cells was mainly attribute to passive surface binding. The optimum pH for DBP adsorption by living and nonliving cells were both observed to be 6.0. The biosorptive mechanism of DBP binding by B. cepacia was further confirmed by FTIR analysis and various chemical treatments. FTIR results indicated that the phosphate and CH2groups on B. cepacia were the main bounding sites for DBP. Furthermore, 2.28, 2.15, 1.93 and 0.87 g of pretreated cells were obtained from 2.40 g of native cells via extracellular polymeric substances (EPS), superficial layer-capsule, lipids components and cell membrane removal treatments, respectively. Total binding amount of DBP on the native cells, EPS-removed cells, capsule-removed cells, lipids-extracted cells and membrane-removed cells were 26.69, 24.84, 24.93, 16.11 and 10.80 mg, respectively, suggesting that the cell wall lipids, proteins or peptidoglycan might play important roles in the sorption of DBP by B. cepacia. The information could be applied in understanding on the mobility, transport and ultimate fate of PAEs in soil and related environment.
College of Resources and Environment, Hunan Agricultural University, Changsha 410128, PR China.
Si
S
Luo
College of Resources and Environment, Hunan Agricultural University, Changsha 410128, PR China.
Langlang
L
Li
College of Resources and Environment, Hunan Agricultural University, Changsha 410128, PR China.
Anwei
A
Chen
College of Resources and Environment, Hunan Agricultural University, Changsha 410128, PR China.
Qingru
Q
Zeng
College of Resources and Environment, Hunan Agricultural University, Changsha 410128, PR China.
Hao
H
Xia
College of Resources and Environment, Hunan Agricultural University, Changsha 410128, PR China; Laboratory of Environmental Microbiology and Toxicology, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong Special Administrative Region, PR China. Electronic address: jdgu@hkcc.hku.hk.
Ji-Dong
JD
Gu
D000327:Adsorption; D001665:Binding Sites; D016956:Burkholderia cepacia / Q000737:chemistry*; D002462:Cell Membrane / Q000378:metabolism; D052918:Environmental Restoration and Remediation / Q000379:methods; D007700:Kinetics; D010795:Phthalic Acids / Q000737:chemistry*; D012987:Soil; D017550:Spectroscopy, Fourier Transform Infrared
D010795:Phthalic Acids; D012987:Soil; C007379:diethyl phthalate
Bacteria; Bioaccumulation; Biosorption; Cell walls components; Diethyl phthalate ester