Carbon and nitrogen metabolic pathways and interaction of cold-resistant heterotrophic nitrifying bacteria under aerobic and anaerobic conditions. (November 2019)

• Record Type: Journal Article
• Authors: Yang, Mo; Lu, Dongwei; Yang, Jiaxuan; Zhao, Yumeng; Zhao, Qi; Sun, Yan; Liu, Huiling; Ma, Jun
• Is Part Of: Chemosphere. Volume 234(2019)
• Page Start: 162
• Page End: 170
• Publication Date: 2019-11
• Subjects: Heterotrophic nitrifying bacteria -- Carbon metabolic pathway -- Nitrogen metabolic pathway -- Low temperature -- Non-readily biodegradable carbon feed; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2019.06.052
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: In this study, both the carbon and nitrogen metabolisms of two heterotrophic nitrification bacteria were investigated under aerobic and anaerobic conditions at 2 °C. Similar catabolism and anabolism trends were observed for the two bacteria in stable experimental systems under aerobic and anaerobic conditions. Based on the nitrogen and carbon balance analysis and adenosine triphosphate (ATP) calculation, we proposed the following metabolic pathways: i) aerobic: except for microbial assimilation, the carbon and nitrogen sources were removed through respiration and nitrification, which provided energy for cell synthesis; and ii) anaerobic: the nitrification process almost stopped and most of the carbon sources decomposed into inorganic carbon, which dissolved in the medium. Based on our proposed metabolic pathways, we speculated that the nitrifying process almost stopped under anaerobic conditions and the nitrification bacteria would degrade more carbon contaminants to produce energy and maintain the cell growth. Furthermore, these bacteria may decompose the non-readily biodegradable carbon through anaerobic degradation. To verify these hypotheses, experiments with two types of synthetic wastewater were conducted: i) synthetic wastewater rich in carbon and poor in nitrogen, and higher carbon removal efficiencies of strain J and strain P (∼25%) were obtained under anaerobic conditions compared with aerobic conditions (∼19%); and ii) synthetic wastewater with recalcitrant carbon sources, and carbon removal efficiencies under anaerobic conditions were higher than those under aerobic conditions. The results of the synthetic wastewater experiments were consistent with the hypotheses and thus validated the metabolic pathways proposed for carbon and nitrogen. Highlights: Anaerobic performance of heterotrophic nitrifying bacteria was investigated. Aerobic and anaerobic C, N metabolic pathways were proposed and verified. Cold wastewater of high C and poor N was efficiently treated in anaerobic status. C source hardly degraded in aerobic status were degraded in anaerobic status.