Comparative Biodegradation of 2, 4-Dichlorophenoxyacetic Acid by Cupriavidus canpinensis and Achromobacter xylosoxidans Isolated from Rice Cultivated Soils in Kura, Kano State, Nigeria.

Abstract

This study presents a comparative evaluation of two indigenous bacterial strains, Cupriavidus campinensis and Achromobacter xylosoxidans, isolated from rice cultivated soils in Kura Local Government Area, Kano State, Nigeria, for their ability to degrade 2,4-dichlorophenoxyacetic acid (2,4-D). Both isolates were previously identified and characterized using morphological, biochemical, and molecular techniques. Their biodegradation efficiency was assessed under varying environmental conditions including pH, temperature, substrate concentration, inoculum size, and incubation time. Results revealed that both isolates effectively utilized 2,4-D as a sole carbon and energy source. Achromobacter xylosoxidans exhibited slightly higher degradation efficiency (95.38%) compared to Cupriavidus campinensis (94.69%) under optimal conditions. While both organisms showed optimal degradation at pH 7–7.5 and temperature of 40°C respectively, variations were observed in inoculum size and incubation time requirements. The findings demonstrate that both bacterial strains possess strong bioremediation potential, with Achromobacter xylosoxidans showing marginally superior performance. This comparative study highlights the importance of selecting efficient indigenous microorganisms for sustainable remediation of herbicide-contaminated environments.