Biodegradation of Glyphosate by Four Plant Growth Promoting Bacteria (4PGPB)

Glyphosate was a non-specific organophosphate pesticide, which finds widespread application in shielding crops against the weeds. The degradation of glyphosate in soil usually carried out by microbial activity. Soil Pesticide bioremediation is the most economical,  environmentally friendly and successful method available. In this research, four types of bacteria as Bacillus megaterium, Bacillus subtilis, Rhizobium sp., and Azotobacter sp.. The four plant growth promoting Bacteria (4PGPB) were found abundantly in soil. To study the decomposition of the glyphosate pesticide under laboratory conditions and at different concentrations starting  from 5ppm, 10ppm, 15ppm, to 20ppm. These bacteria were grown on mineral salt media in 60 days incubation for the experimental condition in the presence of different concentrations of glyphosate. The removal efficiency of the Glyphosate  depending on the starting concentration were obtained about (0, 60, 80.5 and 99.98%) for 5ppm, (0, 60.98, 79.80, and 96.80%) for 10 ppm, (0, 51.80, 71.80, and 88.95%) for 15 ppm , and (0, 47.94, 63.94, 87.28%), for 20 ppm respectively, via using the Bacillus megaterium bacterial, while the removal efficiency  with values of (0, 59.70, 83.99 and 99.00%) for 5 ppm, (0, 49.87, 82.87, and 93.19%) for 10 ppm, (0, 52.45, 77.45, and 84.99%) 15ppm, and (0, 51.48, 71.48, 75.12%) for 20 ppm, respectively, for the Bacillus subtilisat bacterial. Besides, the removal efficiency for the Glyphosate with values of (0, 96, 86 and 92%) for 5ppm, (0, 57, 80, and 86 %) for 10ppm , (0, 47, 74, and 85 %)for 15ppm , (0, 47, 72, and 84 %), and (0, 45, 67, 80 %) for 20 ppm via using the Azotobacter sp.bactira, respectively. The biodegradation using Rhizobium sp. at 60 day incubation with   the same experimental conditions which was (0, 96, 86 and 92%) for 5 ppm , (0, 57, 80, and 86%) 10 ppm, (0, 47, 74, and 85%), (0, 47, 72, and 84%) for 15 ppm , and (0, 45, 67, 80%) for 20ppm from the Glyphosate concentration.  The removal efficiency increased with increasing incubation time and with the decreasing of Glyphosate concentrations when used it as a source of phosphorus and carbon for the three plant growth promoting Bacteria (4PGPB). The biodegradation of Glyphosate in soil may be effectively utilized for bioremediation or biodegradation for duration of 30 to 60 days.