title: The characteristics and two-step reaction model of p-nitroacetophenone biodegradation mediated by Shewanella decolorationis S12 and electron shuttle in the presence/absence of goethite.
abstract: The current study mainly focused on the biodegradation process of p-nitroacetophenone (NP) in the presence and absence of goethite mediated by iron-reducing microbe (Shewanella decolorationis S12) and electron shuttle. The results showed that introduction of electron shuttle could obviously lead to an accumulation of biodegradation intermediate, especially in reaction systems containing high content of electron shuttle in the absence of goethite. Goethite could enhance the degree and rate of NP biodegradation. The microbial reductively generated Fe(II) played an active role in the biodegradation process. The relationship between the concentrations of biodegradation end product and the reaction times could be fitted by a consecutive reaction model with correlation coefficients (adjusted R(2)) in the range from 0.9241 to 0.9831 during the biodegradation stage from the beginning to about 250 h of incubation. However, during the subsequent biodegradation stages, in the presence and absence of goethite, transitions from the consecutive reaction model to zero-order reaction model and from the consecutive reaction model to exponential growth reaction model were observed, respectively. The newly proposed two-step reaction model will help understand the mechanism of the biodegradation process of nitroaromatic compounds and related pollutants.
authors.affiliation: a Key Laboratory of Northwest Water Resources, Environment and Ecology, Ministry of Education , Xi'an University of Architecture and Technology , Xi'an 710055 , People's Republic of China.
authors.forename: Weihuang
authors.initials: W
authors.lastname: Zhu
authors.forename: Ruihua
authors.initials: R
authors.lastname: Wang
authors.forename: Tinglin
authors.initials: T
authors.lastname: Huang
authors.forename: Fengchang
authors.initials: F
authors.lastname: Wu
mesh_terms: D000098:Acetophenones / Q000378:metabolism*; D001673:Biodegradation, Environmental; D004583:Electrons; D007501:Iron / Q000378:metabolism; D058085:Iron Compounds / Q000378:metabolism*; D008903:Minerals / Q000378:metabolism*; D008962:Models, Theoretical; D020592:Shewanella / Q000378:metabolism*
chemical_list: D000098:Acetophenones; D058085:Iron Compounds; D008903:Minerals; C001972:4-nitroacetophenone; C094886:goethite; D007501:Iron
keywords: biodegradation; kinetic characteristics; two-step reaction model