Nitrogen removal and metabolic profiling of a cold-adaptive and biofilm producing paddy soil bacterium Cupriavidus sp. PDN31

ABSTRACT

To assess the physiology and low temperature adaptability of the key players of nitrification and denitrification, denitrifying bacteria were isolated and characterized from the selected paddy fields. Bacterial strains belonging to Cupriavidus and Ochrobactrum sp. were explored through the selective screening of heterotrophic nitrifying and aerobic denitrifying bacteria. The direct implication of nitrate removal in the natural sample was estimated by taking the nitrate supplemented soil as well as the enriched culture. A more prominent cold-adaptive bacterium was identified as Cupriavidus sp. PDN31. The utilization of ammonium, nitrate, and nitrite and the presence of nitrous oxide reductase (nosZ) gene, catalyses the first step of the denitrification conferred its heterotrophic nitrification and aerobic denitrification ability. The ammonium, nitrate, and nitrite removal efficiency of PDN31 was found to be 92.1%, 93.5%, and 99.8%, respectively. The functional traits, evaluated from metabolizing various nitrogen substrates (Biolog) suggested its ability to utilize some sources as L-arginine, L-asparagine, L-cysteine, L-glutamic Acid, L-glutamine, L-histidine, L-citrulline and N-acetyl-L glutamic acid. The adaptive behaviour of PDN31 with its ability to remove nitrogen and induced biofilm production under low temperature regime makes it a suitable candidate among the plethora of microorganism resided in any agriculture environment.

KEYWORDS:

• Nitrification
• denitrification
• phylogeny
• biolog
• RT-PCR

Acknowledgments

This study has been supported by Council of Scientific and Industrial Research, New Delhi, India [38(1316)/12/EMR-II]. One of us (MS) is also thankful to UGC, New Delhi for providing financial assistance in the form of fellowship (JRF and SRF). The Head, Department of Botany, BHU, Varanasi, India is gratefully acknowledged for providing laboratory facilities.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Council for Scientific and Industrial Research [38(1316)/12/EMR-II].