Fecha de publicación: 21/10/2024 Fuente: Microorganisms - Revista científica (MDPI) Microorganisms, Vol. 12, Pages 2100: A Novel Cold-Adapted Nitronate Monooxygenase from Psychrobacter sp. ANT206: Identification, Characterization and Degradation of 2-Nitropropane at Low Temperature
Microorganisms doi: 10.3390/microorganisms12102100
Authors:
Yatong Wang
Shumiao Hou
Qi Zhang
Yanhua Hou
Quanfu Wang

Aliphatic nitro compounds cause environmental pollution by being discharged into water with industrial waste. Biodegradation needs to be further explored as a green and pollution-free method of environmental remediation. In this study, we successfully cloned a novel nitronate monooxygenase gene (psnmo) from the genomic DNA library of Psychrobacter sp. ANT206 and investigated its ability to degrade 2-nitropropane (2-NP). Homology modeling demonstrated that PsNMO had a typical I nitronate monooxygenase catalytic site and cold-adapted structural features, such as few hydrogen bonds. The specific activity of purified recombinant PsNMO (rPsNMO) was 97.34 U/mg, rPsNMO exhibited thermal instability and reached maximum catalytic activity at 30 °C. Moreover, rPsNMO was most active in 1.5 M NaCl and remained at 104% of its full activity in 4.0 M NaCl, demonstrating its significant salt tolerance. Based on this finding, a novel bacterial cold-adapted enzyme was obtained in this work. Furthermore, rPsNMO protected E. coli BL21 (DE3)/pET28a(+) from the toxic effects of 2-NP at 30 °C because the 2-NP degradation rate reached 96.1% at 3 h and the final product was acetone. These results provide a reliable theoretical basis for the low-temperature degradation of 2-NP by NMO.