Abstract:
A novel aerobic gram-negative bacterial strain
capable of utilizing 2-hydroxyquinoxaline (2-HQ) as sole
source of carbon and energy was isolated from Indian
agricultural soil and named as HQ1. Strain HQ1 was
identified as Ochrobactrum sp. on the basis of morphology,
physico-biochemical characteristics and 16S rRNA
sequence analysis. The generation time of Ochrobactrum
sp. HQ1 on 2-HQ at log phase is 0.71 h or 42.6 min. The
degradation of 2-HQ by HQ1 under various physicochemical
parameters was analysed by HPLC and observed
to be optimum with a high inoculum density (1.0 OD) at
pH 7–8, temperatures 37–40 C and a high concentration of
2-HQ (500 ppm). Degradation of 2-HQ was also improved
when additional nitrogen sources were used and this was
attributed to the enhanced growth of the bacterium on the
readily available nitrogen sources. Analysis of 2-HQ
degradation by GC–MS resulted in elucidation of the
degradation pathway for HQ1, a novel observation for
aerobic Gram-negative bacteria. These findings are a possible
indication of the application of HQ1 in the bioremediation
of pesticide/metabolite contamination.
