title: Study the catalyzing mechanism of dissolved redox mediators on bio-denitrification by metabolic inhibitors.
abstract: The effect of dissolved redox mediators on denitrification by Paracoccus versutus sp. GW1 were studied with α-AQS, AQS, 1,5-AQDS, AQDS and 2,7-AQDS. AQDS presented the best catalytic effect which increased denitrification rate by 1.5-fold with 0.17 mmol L(-1). Denitrification rate was found to be pseudo-zero order with 0-0.32 mmol L(-1) AQDS (k=19.874C AQDS+10.301 (R(2)=0.9984)). The accelerating mechanism for respiratory chain was also explored by using metabolic inhibitors. Addition of AQDS eased the inhibitions of rotenone, dicumarol, sodium azide on respiratory chain, and enhanced the nitrite accumulation during bio-denitrification process. AQDS exhibited slight catalytic effect on nitrite denitrification. These results allowed us to deduce the accelerating site of AQDS on the denitrification respiratory chain. Increased nitrate denitrification by AQDS might mainly attribute to the accelerated electrons transfer from NADH to nitrate reductase via complex I and ubiquinone/ubiqunol. This study provided further understanding of the mechanism of redox mediators on denitrification.
authors.affiliation: School of Environmental Science and Engineering, Hebei University of Science and Technology, Yuhua East Road 70#, Shijiazhuang City 050018, PR China.
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Xi
authors.forename: Jianbo
authors.initials: J
authors.lastname: Guo
authors.forename: Jing
authors.initials: J
authors.lastname: Lian
authors.forename: Haibo
authors.initials: H
authors.lastname: Li
authors.forename: Lijun
authors.initials: L
authors.lastname: Zhao
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Liu
authors.forename: Chenxiao
authors.initials: C
authors.lastname: Zhang
authors.forename: Jingliang
authors.initials: J
authors.lastname: Yang
mesh_terms: D000880:Anthraquinones / Q000494:pharmacology*; D055162:Biocatalysis / Q000187:drug effects*; D058440:Denitrification / Q000187:drug effects*; D001728:Dicumarol / Q000494:pharmacology*; D004579:Electron Transport / Q000187:drug effects; D009566:Nitrates / Q000378:metabolism; D009573:Nitrites / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D010230:Paracoccus / Q000187:drug effects / Q000378:metabolism*; D012402:Rotenone / Q000494:pharmacology*; D019810:Sodium Azide / Q000494:pharmacology*
chemical_list: D000880:Anthraquinones; D009566:Nitrates; D009573:Nitrites; D012402:Rotenone; C023554:anthraquinone sulfonate; D001728:Dicumarol; D019810:Sodium Azide