title: Microbial metabolism induced chain shortening of polyacrylamide with assistance of bioelectricity generation.
abstract: The water-soluble polyacrylamide (PAM) can accumulate in ecosystems and cause serious environmental pollution. Biological approach achieves poor PAM degradation efficiency, due to the extreme resistance of PAM to the microbial metabolism. In the present work, the potential of bioelectrochemical system (BES) as an effective tool to degrade the PAM is adequately evaluated. The closed-circuit operation of BES obtains COD removal efficiencies of 29.2 and 33.6 % for the PAM and polyacrylic acid (PAA), respectively. In comparison, 4.3 and 2.7 % of COD are removed after the PAM and PAA are treated in the open-circuit BES, and 7.3 and 6.6 % are removed in the aerobic BES. These results suggest the bioelectricity generation is crucial to trigger the activity of bioanode for the effective degradation of PAM. Bioelectricity generation not only favors the decomposition of carbon backbone but also facilitates the hydrolysis of amide group in the side-chain of PAM. Microbial attack on the carbon backbone of PAM is proposed to initiate at the head-to-head linkage, resulting in the formation of ether bond within the shortened carbon chain. The Ignavibacterium sp. and phenotypically uncharacterized bacteria are classified as the dominant species on the anode of PAM-fed BES.
authors.affiliation: Department of Chemical Engineering, Hefei University of Technology, Hefei, 230009, China. sunmin81@mail.ustc.edu.cn.
authors.forename: Min
authors.initials: M
authors.lastname: Sun
authors.affiliation: Department of Chemistry, University of Science and Technology of China, Hefei, 230026, China.
authors.forename: Zhong-Hua
authors.initials: ZH
authors.lastname: Tong
authors.affiliation: Department of Chemical Engineering, Hefei University of Technology, Hefei, 230009, China.
authors.forename: Yu-Zhi
authors.initials: YZ
authors.lastname: Cui
authors.affiliation: Department of Chemical Engineering, Hefei University of Technology, Hefei, 230009, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
mesh_terms: D000180:Acrylic Resins / Q000032:analysis / Q000378:metabolism*; D041963:Bacteroidetes / Q000378:metabolism*; D001673:Biodegradation, Environmental; D001674:Bioelectric Energy Sources; D002244:Carbon / Q000378:metabolism; D055664:Electrochemical Techniques / Q000379:methods*; D004566:Electrodes; D006868:Hydrolysis; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D002244:Carbon; D014874:Water Pollutants, Chemical; D000099166:Polyacrylamides; C006903:carbopol 940
keywords: Bioelectricity; Bioelectrochemical system; Chain shortening; Enhancement; Partial degradation; Polyacylamide