Optimization study of 2-hydroxyquinoxaline (2-HQ) biodegradation by Ochrobactrum sp. HQ1.
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 physico-chemical 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.
Department of Microbiology, Sri Krishnadevaraya University, Anantapuramu-, 515003, Andhra Pradesh, India. visitsubbu@gmail.com.|Department of Agriculture and Animal Health, University of South Africa, Private Bag X6, Florida, 1710, Johannesburg, South Africa. visitsubbu@gmail.com.
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Subba Reddy
Department of Biotechnology, Sri Krishnadevaraya University, Anantapuramu-, 515003, Andhra Pradesh, India.
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Rafi
Department of Pharmaceutical Analysis, JNTUA-Oil Technological Research Institute, Anantapuramu-, 515001, Andhra Pradesh, India.
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Rubesh Kumar
Department of Agriculture and Animal Health, University of South Africa, Private Bag X6, Florida, 1710, Johannesburg, South Africa.
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Khayalethu
Department of Biotechnology, Sri Krishnadevaraya University, Anantapuramu-, 515003, Andhra Pradesh, India.
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Muralidhara Rao
Department of Life Sciences, Universidad de las Fuerzas Armadas-ESPE, Sangolquí, Quito, Ecuador, South America.
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Manjunatha
Department of Biotechnology, Sri Krishnadevaraya University, Anantapuramu-, 515003, Andhra Pradesh, India.
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Philip
Department of Microbiology, Sri Krishnadevaraya University, Anantapuramu-, 515003, Andhra Pradesh, India.
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Reddy
16S rRNA sequence analysis; 2-Hydroxyquinoxaline; HPLC and GC–MS analysis; Ochrobactrum sp. HQ1