Enhancement of the denitrification in low C/N condition and its mechanism by a novel isolated Comamonas sp. YSF15

• Published in: Environmental pollution (1987) Vol. 256; p. 113294
• Main Authors: Su, Jun feng, Yang, Shu, Huang, Ting lin, Li, Min, Liu, Jia ran, Yao, Yi xin
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2020
• Subjects: Aerobiosis; Biodegradation, Environmental; Carbon - analysis; Comamonas - growth & development; Comamonas - isolation & purification; Comamonas - metabolism; Denitrification; Extracellular polymeric substance (EPS); Extracellular Polymeric Substance Matrix - metabolism; Low C/N; Metabolic characteristics; Nitrates - analysis; Nitrites - analysis; Nitrogen - analysis; Nitrogen balance; Waste Water - chemistry; Waste Water - microbiology; Denitrification; Low C/N; Extracellular polymeric substance (EPS); Nitrogen balance; Metabolic characteristics
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2019.113294

A novel denitrifying bacterium YSF15 was isolated from the Lijiahe Reservoir in Xi’an and identified as Comamonas sp. It exhibited excellent nitrogen removal ability under low C/N conditions (C/N = 2.5) and 94.01% of nitrate was removed in 18 h, with no accumulation of nitrite. PCR amplification and nitrogen balance experiments were carried out, showing that 68.92% of initial nitrogen was removed as gas products and the nitrogen removal path was determined to be NO3−-N→NO2−-N→NO→N2O→N2. Scanning electron microscopy and three-dimensional fluorescence spectroscopy were used to track extracellular polymeric substances (EPS). The results show that complete-denitrification under low C/N conditions is associated with EPS, which may provide a reserve carbon source in extreme environments. These findings reveal that Comamonas sp. YSF15 can provide novel basic materials and a theoretical basis for wastewater bioremediation under low C/N conditions. [Display omitted] •Strain YSF15 adapted to low C/N conditions was isolated from reservoir.•Strain YSF15 can achieve complete-denitrification in low C/N condition (C/N = 2.5).•YSF15 can use its EPS products as a reserve carbon source to promote denitrification.•Nitrogen removal path was determined using nitrogen balance experiments and PCR. This study isolated a novel denitrifying strain which can use its EPS products as a reserve carbon source to promote denitrification at low C/N condition (C/N = 2.5).