Influence mechanism of C/N ratio on heterotrophic nitrification- aerobic denitrification process

• Published in: Bioresource technology 2022-01, Vol.343, p.126116-126116, Article 126116
• Main Authors: Gu, Xin, Leng, Juntong, Zhu, Jitao, Zhang, Kai, Zhao, Jianqiang, Wu, Pei, Xing, Qingyi, Tang, Kejing, Li, Xiaoling, Hu, Bo
• Format: Article
• Language: English
• Subjects: ATP content; Enzyme activity; ETSA; Heterotrophic nitrification- aerobic denitrification; NADH/NAD+ ratio
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2021.126116

•Acinetobacter junii ZHG-1 which can conduct HNAD process was isolated.•The optimal growth conditions for Acinetobacter junii ZHG-1 were identified.•A high C/N ratio can enhance the electron transport of Acinetobacter junii ZHG-1.•When the C/N ratio was 30, the activities of the relating enzymes in HNAD process reached the maximum.•The activities of the enzymes cannot increase continuously with the increasing of C/N ratio. A heterotrophic nitrification- aerobic denitrification (HNAD) bacterium, Acinetobacter junii ZHG-1, was isolated, meanwhile, the optimal conditions for the strain were evaluated, moreover, the influence mechanism of the C/N ratio on the HNAD process was investigated from the perspective of electron transport and energy level. The increasing of C/N ratio enhanced the reduced/oxidized nicotinamide adenine dinucleotide (NADH/NAD+) ratio, NADH concentration, electron transport system activity (ETSA), ATP content, as well as enzymes activities, consequently, the HNAD performance of the strain can be improved, however, when the C/N ratio was higher than 30, the activities of enzymes relating to the HNAD process and the ETSA had reached the maximum, which might limit the further improvement of the nitrogen removal with the increasing of C/N ratio. As the interaction between different biochemical reactions in HNAD process, more efforts should be devoted to the influent mechanism of different environmental factors on the HNAD process.