The transformation mechanism of nitrobenzene in the present of a species of cyanobacteria Microcystis aeruginosa

- M. aeruginosa can adsorb a small portion of NB.
- NB is reduced by M. aeruginosa with NB reductase.
- M. aeruginosa prevents the volatilization process and causes the accumulation of AN.

The transformation mechanism of nitrobenzene (NB) with Microcystis aeruginosa was investigated by a series of laboratory-scale experiments. The result showed only a small fraction of NB can be adsorbed by M. aeruginosa. The adsorption was responsible to the transformation of NB in M. aeruginosa solution but was not the primary cause. The variation of cell activity and illumination could affect the transformation of NB with M. aeruginosa, which indicated that M. aeruginosa have the ability to biodegrade NB. Metabolic intermediate products analysis indicated that M. aeruginosa can reduce NB to aniline (AN), and NB reductase, induced by NB, was the key enzyme during the reduction process. M. aeruginosa cannot further degrade AN and may prevent the volatilization of AN, causing the accumulation of AN in the solution for up to 3 days. Only a small proportion of AN (less than 5%) can be degraded to acetaldehyde and acetone by photolysis in 48 h. The total concentration of nitrogen aromatic compounds is invariant at first, and then decreases after 72 h incubation via a complex process including adsorption, biodegradation, volatilization and photolysis processes.

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