Efficient bacterial isolate from roots of cactus degrading Reactive Black 5

The current study aimed at azo dye degradation using a facultative anaerobe. A bacterial strain capable of decolorization and degradation of RB5 under static conditions was isolated from root nodules of Cactus. The strain efficiently degraded Reactive Black 5 (RB5) with metabolites detected by GC–MS. The strain was identified as Proteus mirabilis and placed in phylogenetic position through 16S rRNA gene analysis. The degradation increased with time to achieve up to 90 % after 72 h incubation at 37 oC and pH value of 7. Variations of C source did not affect the process while yeast extract was effective. The effective degradation was achieved at 100 ppm of dye. The GC–MS detected metabolites included; acetaldoxime, oxirane trimethyl, acetic acid-2-propenyl ester, acetaldehyde semi carbazone, 2-pentanone, 4-hydroxy-4-methyl, hydrazine, 1-5-hexenyl-1-methyl and enanthamide Protox and phytotoxicity results showed fewer toxic ranges of these metabolites as compared to products of benzene and amines. The isolated strain can be useful in the bioremediation of azo dyes contaminated environments.