title: Extracellular polymeric substances enhanced mass transfer of polycyclic aromatic hydrocarbons in the two-liquid-phase system for biodegradation.
abstract: The objective was to elucidate the role of extracellular polymeric substances (EPS) in biodegradation of polycyclic aromatic hydrocarbons in two-liquid-phase system (TLPs). Therefore, biodegradation of phenanthrene (PHE) was conducted in a typical TLPs--silicone oil-water--with PHE-degrading bacteria capable of producing EPS, Sphingobium sp. PHE3 and Micrococcus sp. PHE9. The results showed that the presence of both strains enhanced mass transfer of PHE from silicone oil to water, and that biodegradation of PHE mainly occurred at the interfaces. The ratios of tightly bound (TB) proteins to TB polysaccharides kept almost constant, whereas the ratios of loosely bound (LB) proteins to LB polysaccharides increased during the biodegradation. Furthermore, polysaccharides led to increased PHE solubility in the bulk water, which resulted in an increased PHE mass transfer. Both LB-EPS and TB-EPS (proteins and polysaccharides) correlated with PHE mass transfer in silicone oil, indicating that both proteins and polysaccharides favored bacterial uptake of PHE at the interfaces. It could be concluded that EPS could facilitate microbial degradation of PHE in the TLPs.
authors.affiliation: State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Yinping
authors.initials: Y
authors.lastname: Zhang
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.forename: Xinglun
authors.initials: X
authors.lastname: Yang
authors.forename: Chenggang
authors.initials: C
authors.lastname: Gu
authors.forename: Fredrick Orori
authors.initials: FO
authors.lastname: Kengara
authors.forename: Qing
authors.initials: Q
authors.lastname: Hong
authors.forename: Zhengyong
authors.initials: Z
authors.lastname: Lv
authors.forename: Xin
authors.initials: X
authors.lastname: Jiang
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D001673:Biodegradation, Environmental; D005110:Extracellular Space / Q000378:metabolism*; D008837:Micrococcus / Q000378:metabolism*; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry / Q000378:metabolism*; D011135:Polysaccharides, Bacterial / Q000378:metabolism*; D011485:Protein Binding; D012995:Solubility; D042301:Sphingomonadaceae / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D011084:Polycyclic Aromatic Hydrocarbons; D011135:Polysaccharides, Bacterial