title: Effects of Fe(III) on biofilm and its extracellular polymeric substances (EPS) in fixed bed biofilm reactors.
abstract: The effects of Fe(III) on the biofilm mass and activity, the biofilm micromorphology as well as the composition and functional groups characteristics of extracellular polymeric substances (EPS) in biofilm were investigated in laboratory-scale fixed bed biofilm reactors. The results showed that 2 mg/L of Fe(III) promoted the biofilm mass and improved the biofilm activity, but 16 mg/L of Fe(III) adversely affected biofilm development. Scanning electron microscopy (SEM) study indicated a high concentration (16 mg/L) of Fe(III) led to signiﬁcant reduction of the ﬁlaments, great promotion of the EPS secretion in biofilm. The result of the EPS composition suggested 2 mg/L of Fe(III) increased soluble EPS and loosely bound EPS which contributed to the microbial aggregation, while 16 mg/L of Fe(III) promoted tightly bound EPS production unfavourable for substrate mass transfer. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis demonstrated that Fe(III) exerted a significant influence on the -CONH- groups of proteins and the C-O groups of polysaccharides in EPS. This study reveals that Fe(III) influences biofilm development and activity not only by directly impacting the microbial physiology but by indirectly affecting the EPS constituents, and it helps to provide theoretical guidance for iron ion containing wastewater treatment.
authors.affiliation: Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, China E-mail: huxuewei.env@gmail.com.
authors.forename: Xuewei
authors.initials: X
authors.lastname: Hu
authors.affiliation: Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, China E-mail: huxuewei.env@gmail.com.
authors.forename: Kai
authors.initials: K
authors.lastname: Chen
authors.affiliation: Faculty of Environmental Science and Engineering, Kunming University of Science and Technology, Kunming 650500, Yunnan, China E-mail: huxuewei.env@gmail.com.
authors.forename: Xinke
authors.initials: X
authors.lastname: Lai
authors.affiliation: School of Chemistry and Environment, Yunnan University of Nationalities, Kunming 650500, Yunnan, China.
authors.forename: Siping
authors.initials: S
authors.lastname: Ji
authors.affiliation: Institute for Applied Material Flow Management, University of Applied Sciences Trier, PO Box 1380, D-55761 Birkenfeld, Germany.
authors.forename: Kevin
authors.initials: K
authors.lastname: Kaiser
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D018407:Bacterial Physiological Phenomena; D018441:Biofilms / Q000254:growth & development*; D019149:Bioreactors; D005290:Ferric Compounds / Q000494:pharmacology*; D007501:Iron / Q000737:chemistry; D008970:Molecular Weight; D056951:Photoelectron Spectroscopy; D011108:Polymers / Q000737:chemistry; D011134:Polysaccharides; D011506:Proteins; D017550:Spectroscopy, Fourier Transform Infrared; D014865:Waste Disposal, Fluid; D062065:Wastewater
chemical_list: D005290:Ferric Compounds; D007501:Iron; D011108:Polymers; D011134:Polysaccharides; D011506:Proteins; D062065:Wastewater