Isolation, Identification and Role of Glyphosate-Degrading Bacteria from Soils of Baghdad

Abstract

Glyphosate (N-phosphonomethylglycine) is the most commonly used herbicide worldwide. Due to concern regarding its toxicity for non-targeted species in soil, finding glyphosate-degrading microorganisms in soil is important as these bacteria can grow by utilizing glyphosate as a source of carbon. Two bacteria species were isolated from soils of Baghdad. Morphological characteristic and biochemical reactions indicated these species were identified as Bacillus and Serratia marcescens. These bacterial isolates showed an ability to consume glyphosate as energy and sole carbon source at 20 mM. The growth of bacteria in the media containing glyphosate was determined after two days of incubation at 30 C by measuring turbidity (O.D) at 680 nm. The maximum growth of Bacillus in halogenated compound containing media was found to be (O.D=0.3836) after two days of incubation as compared to control media (O.D=0.0170)  without halogenated compound. In comparison to Bacillus, Serratia marcescens showed less growth activity (O.D=0.06) in halogenated compound containing media after two days of incubation as compared to its growth in control media (O.D= 0.03). The maximum chloride ion released due to dehalogenase enzyme activity was higher for Bacillus (O.D=1.3199) as compared to S. marcescens (O.D= 0.3) with respect to their control media (O.D =0.0491 and 0.04) respectively. This result gives hint regarding the role of dehalogenase present in the bacteria for their affinity to substrate and utilizing it for their growth. For a better understanding of dehalogenase enzyme produced by these two bacterial species, more research has to be explored for their possible use as bioremediation tools in the natural environment.

Keywords

• Glyphosate,Soil bacteria,Bio-degredation

References

1. Abel, E., Ibrahim, N., & Huyop, F. (2012). Identification of Serratia marcescens SE1 and determination of its herbicide 2, 2-dichloropropionate (2, 2-DCP) degradation potential. Malaysian Journal of Microbiology, 8(4), 259-265. Allison, N., Skinner, A. J., & Cooper, R. A. (1983). The dehalogenases of a 2, 2-dichloropropionate-degrading bacterium. Microbiology, 129(5), 1283-1293. Diamand, E., & Barron, H. (2001). Health and environmental impacts of glyphosate. Eker, S., Ozturk, L., Yazici, A., Erenoglu, B., Romheld, V., & Cakmak, I. (2006). Foliar-applied glyphosate substantially reduced uptake and transport of iron and manganese in sunflower (Helianthus annuus L.) plants. Journal of agricultural and food chemistry, 54(26), 10019-10025. Hamada, M., Matar, A., & Bashir, A. (2015). Carbaryl degradation by bacterial isolates from a soil ecosystem of the Gaza Strip. Brazilian Journal of Microbiology, 46(4), 1087-1091. Javaid, M. K., Ashiq, M., & Tahir, M. (2016). Potential of biological agents in decontamination of agricultural soil. Scientifica, 2016. Krzyśko-Łupicka, T., & Orlik, A. (1997). The use of glyphosate as the sole source of phosphorus or carbon for the selection of soil-borne fungal strains capable to degrade this herbicide. Chemosphere, 34(12), 2601-2605. Ortiz-Hernández, M. L., Sánchez-Salinas, E., Dantán-González, E., & Castrejón-Godínez, M. L. (2013). Pesticide biodegradation: mechanisms, genetics and strategies to enhance the process. In Biodegradation-life of science. Intech. Peng, R. H., Tian, Y. S., Xiong, A. S., Zhao, W., Fu, X. Y., Han, H. J., ... & Yao, Q. H. (2012). A novel 5-enolpyruvylshikimate-3-phosphate synthase from Rahnella aquatilis with significantly reduced glyphosate sensitivity. PloS one, 7(8), e3 Talbot, H. W., Johnson, L. M., & Munnecke, D. M. (1984). Glyphosate utilization byPseudomonas sp. andAlcaligenes sp. isolated from environmental sources. Current Microbiology, 10(5), 255-259. Tohge, T., Watanabe, M., Hoefgen, R., & Fernie, A. R. (2013). Shikimate and phenylalanine biosynthesis in the green lineage. Frontiers in plant science, 4, 62. Wang, J., Zhu, L., Wang, Q., Wang, J., & Xie, H. (2014). Isolation and characterization of atrazine mineralizing Bacillus subtilis strain HB-6. PLoS One, 9(9), e107270.