Biodegradation of catechol by free and immobilized cells of Achromobacter xylosoxidans strain 15DKVB isolated from paper and pulp industrial effluents

Abstract

Abstract The aim of the current study was to isolate and characterize a strain which could utilize catechol as sole source of carbon and energy. The strain Achromobacter xylosoxidans 15DKVB was isolated from paper and pulp industrial effluent contaminated site of Harihar. In the present study 38 bacterial strains isolated were investigated for their ability to degrade catechol in MBM at different concentrations ranging from 100 mg/L to 2000 mg/L. The taxonomic position of strain 15DKVB was studied by sequencing of 16SrRNA gene with a GenBank accession number HQ448950. The maximum-likelihood algorithm showed that, strain 15DKVB formed a coherent cluster with the clade that comprised type strains of Achromobacter genus. The optimal temperature and pH for biodegradation of catechol by strain 15DKVB were 37 °C and pH 7.5 respectively. Among the carbon and nitrogen sources tested, glucose (83.4%) and yeast extract (99.6%) showed highest catechol degradation. Interestingly the strain 15DKVB was able to degrade catechol completely up to 1600 mg/L within 198 h. Immobilization experiment demonstrated that freely suspended cells could degrade 500 mg/L catechol within 60 h of incubation, whereas, the same cell population in alginate-immobilized flask, amended with 500 mg/L catechol was degraded in 42 h. Our results evidently depict that physicochemical parameters of Harihar industrial effluents does not comply with national standards set by ISI to discharge the effluents into irrigation waters. The isolated strain 15DKVB could be a good alternative for the bioremediation of catechol contaminated paper and pulp industrial effluent water and soil. These findings may open new bioremediation applications for the degradation of catechol.