Identification of aerobic-denitrifying Psychrobacter cryohalolentis strain F5-6 and its nitrate removal at low temperature

• Published in: International biodeterioration & biodegradation 2022-08, Vol.172, p.105426, Article 105426
• Main Authors: Hou, Yue, Zhang, Duoying, Cao, Haoran, Zhang, Yanlong, Zhao, Dandan, Zeng, Weimin, Lei, Hong, Bai, Ye
• Format: Article
• Language: English
• Subjects: Acetic acid; Carbon sources; Cold adaptation; Denitrification; Fatty acids; Kinetics; Low temperature; Metabolism; Nitrate; Nitrate removal; Nitrates; Nitrogen removal; Nutrient removal; Psychrobacter; Psychrobacter cryohalolentis; Psychrophilic bacteria; Shaking
• ISSN: 0964-8305; 1879-0208
• DOI: 10.1016/j.ibiod.2022.105426

Biological denitrification is suppressed when temperature is lower than 10 °C. In this study, Psychrobacter cryohalolentis F5-6 was isolated from Harbin region and showed high aerobic-denitrifying rate at low temperature. It contained high percentage of unsaturated fatty acids (87.32%) and short chain saturated acid (3.4% C10:0 and 4.0% C12:0 3-OH). Acetate was the best carbon source for the strain F5-6 performing denitrification. Aerobic denitrification (napA gene) and nitrate assimilation (nasA gene) were the nitrate metabolism processes for the strain F5-6. Its biological nitrate removal (BNR) rate at 10 °C showed fit with Monod equation (R2 = 0.9808). The maximum BNR rate was 23.71 mg NO3−-N g−1DW h−1 and KS was 116.96 mg L−1. The optimal denitrifying condition was pH 7.5, 15 °C with shaking speed of 180 rpm and C/N of 2. Results of this study supplied a bacterial resource for improving nitrate removal from low C/N water at low temperature. [Display omitted] •The strain F5-6 was classified in species of Psychrobacter cryohalolentis.•The strain F5-6 had high aerobic denitrifying rate at low temperature.•The strain F5-6 adapt low and wide range of temperature because of specific fatty acid of membrane.•The strain F5-6 had applying perspective in low C/N ratio water treatment at low temperature.