Enzymological aspects of bioconversion of m-dinitrobenzene.

Three main enzymes, responsible for bioconversion of 1,3 dinitrobenzene (m-DNB) by Micrococcus colpogenes MCM B 410, were isolated from the sonicated cell mass, grown in presence of m-DNB in a synthetic medium, for 7 days. The soluble proteins were separated by differential precipitation and also separated by native PAGE. Each fraction obtained from both the protocols, was tested for nitro aryl reductase, aryl mono oxygenase and resorcinol 2,3 dioxygenase. The apparent molecular weight of the proteins were nitro aryl reductase (30 kDa), aryl mono oxygenase (110 kDa) and resorcinol 2,3 di oxygenase (65 kDa).

Bioconversion of 1,3 dinitrobenzene by Micrococcus colpogenes strain MCM B410: quantitation and characterization of the intermediates.

Micrococcus colpogenes MCM B 410, indigenous to soil, collected from nitro aromatic contaminated site, could transform 1,3 dinitrobenzene (m-DNB) initially to m-nitroaniline, m-nitrophenol, m-aminophenol and resorcinol at 30 degrees C under shake culture condition. Carbon mineralization studies with unlabelled and radio labelled 1,3 (U14 C) dinitrobenzene subtrates indicated that the above metabolities appeared within 4 days. After 7 days incubation a significant traction of the source compound was degraded to C Q through aliphatic acids. Presence of nitro aryl reductase, aryl monooxygenase and resorcinol 1,3 di oxygenase was also noted in the sonicated cell mass.