Biodegradation of Glyphosate by Bacteria Isolated from Agricultural Fields

Abstract

The most commonly used herbicide around the world is glyphosate, mostly sold as “Roundup”. Due to its intensive use both in agricultural and non-agricultural purposes which has led to its accumulation in the soil, it has become a matter of environmental concern and the best option to ease its effects is through bioremediation. Four bacterial strains (Exiguobacterium alkaliphiluim, Alcaligenes faecalis, Sinorhizobuim fredi and Acinetobacter nosocomialis.) were isolated from three different agricultural fields polluted with glyphosate. The ability of the four strains to degrade glyphosate as a sole source of carbon, singly and as a consortium was evaluated in this study. Their degradation abilities were evaluated by checking the residual glyphosate after 14 days’ incubation, using Gas Chromatography – Mass Spectrophotometer (GC-MS). Their glyphosate degradation capability in mineral salt medium with the addition of glucose and ammonium sulphate was analyzed separately and as a consortium. At the end of the 14-day incubation period the residual glyphosate was far lower when pesticide was used as a sole source of carbon than when glucose or ammonium sulphate or both were added to the MSM. It was observed that the consortium had a better degradation ability of glyphosate. Based on these results the four bacterial strains do not require bio stimulation to mineralize glyphosate, thus these bacteria can be used for remediation of glyphosate contaminated soil.