Study the catalyzing mechanism of dissolved redox mediators on bio-denitrification by metabolic inhibitors

• Published in: Bioresource technology 2013-07, Vol.140, p.22-27
• Main Authors: Xi, Zhenhua, Guo, Jianbo, Lian, Jing, Li, Haibo, Zhao, Lijun, Liu, Xiaoyu, Zhang, Chenxiao, Yang, Jingliang
• Format: Article
• Language: English
• Subjects: Anthraquinones - pharmacology; AQDS; Biocatalysis - drug effects; Biological and medical sciences; Catalysis; Catalysts; Chains; Denitrification; Denitrification - drug effects; Dicumarol - pharmacology; Dissolution; Electron Transport - drug effects; Fundamental and applied biological sciences. Psychology; Inhibitors; Mechanism; Metabolic inhibitor; Nitrates; Nitrates - metabolism; Nitrites; Nitrites - metabolism; Oxidation-Reduction - drug effects; Paracoccus - drug effects; Paracoccus - metabolism; Rotenone - pharmacology; Sodium Azide - pharmacology; Sodium azides
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2013.04.065

•The role of AQDS on denitrification was first studied by metabolic inhibitors.•The bio-denitrification rates were enhanced by dissolved redox mediators.•AQDS concentration was relatively related to denitrification.•AQDS eased the inhibitions of inhibitors and enhanced nitrate to nitrite. 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 0.17mmolL−1. Denitrification rate was found to be pseudo-zero order with 0–0.32mmolL−1 AQDS (k=19.874CAQDS+10.301 (R2=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.