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Assessing the Susceptibility of Bacillus Subtilis to the Toxic effects of two lower Molecular Weight Phthalate Congeners in Pure Culture

Author Affiliations

  • 1State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan 430074, CHINA
  • 2 School of Civil and Environmental Engineering, and National “International Cooperation Base on Environment and Energy”, University of Science and Technology Beijing, Beijing 100084, P.R. CHINA
  • 3 Chemistry Department, Fourah Bay College, University of Sierra Leone, Freetown, SIERRA LEONE

Int. Res. J. Environment Sci., Volume 2, Issue (9), Pages 45-52, September,22 (2013)


Microbial degradation of phthalate esters has been proffered as one the most effective processes of remediating environmental media polluted by these ubiquitous compounds in the environment. A number of previous studies have shown Bacillus subtilis among a host of other soil bacteria to metabolize phthalates, however, the reported toxicity of phthalates to microbial life especially at certain levels of pollution could be a deterrent to this process. The nature of interaction between a pollutant and a bacterium depends on both the chemical properties of the pollutant and the metabolic characteristics of the bacterium. This work seeks to investigate the susceptibility of B. subtilis as a model soil microbe to the toxic effects of two lower molecular weight phthalate congeners (Dimethyl phthalate, DMP and Diethyl phthalate, DEP) using a combination of methods that examine the metabolic heat response and morphological changes of the bacterial cells in different dose of the phthalates both aqueous media. Microcalorimetry assessment suggests the phthalates stimulated growth and metabolic activities of the bacteria at doses between 50-100g/mL but however produced inhibitory effects at higher doses. The half inhibitory dose index (ID50) obtained from the metabolic heat response shows that DMP is relatively more toxic to the bacterium than DEP which is attributed to the slightly higher solubility of DMP permitting its easier mobility across cell membrane. Scanning electron microscopic images of cells incubated at different doses of the phthalates show that both DMP and DEP impeded the bacterial growth and reproductive process especially at doses 200g/mL. Comparing these results to previous studies, lower molecular weight phthalates show relatively higher toxicity to B. subtilis than their higher molecular weight congeners. These evidences show that within certain low doses, phthalates can serve as carbon or energy sources to microbes by stimulating their metabolic activities but beyond certain limits, can exhibit their toxic effects by inhibiting microbial growth.


  1. Cartwright C.D., Thompson I.P. and Burns R.G., Degradation and impact of phthalate plasticizers on soil microbial communities, Environ. Toxicol. Chem., 19, 1253-1261 (2000b)
  2. Shen O., Du G., Sun H., Wu W., Jiang Y., Song L. and Wang X., Comparison of in vitro hormone activities of selected phthalates using reporter gene assays, Toxicol. Lett.,191(1), 9-14 (2009)
  3. Vamsee-Krishna C. and Phale P. S., Bacterial degradation of phthalate isomers and their esters, Indian J. Microbiol., 48 (1), 19-34 (2008)
  4. Naseem A., Malik N., Firoj H., Singh A.K., Patel D.K., Khan A.R., and Masihur R., Heavy metal assessment of leachates of some plastic toys purchased from different districts of UP, India, Int. Res J.Environ. Sci.,1(4), 32-36 (2012)
  5. Vats S., Singh R.K., Tyagi P., Phthalates-A priority pollutant, Int. J. Adv. Biol. Res., 3(1), 1-8 (2013)
  6. Rael L.T., Bar-Or R., Ambruso D.R., Mains C.W., Slone D.S., Craun M.L. and Bar-Or D., Phthalate esters used as plasticizers in packed red blood cell storage bags may lead to progressive toxin exposure and the release of pro-inflammatory cytokines, Oxid. Med. Cell Longev., 166–171 (2009)
  7. Hu X.Y., Wen B., Shan Q.X., Survey of phthalate pollution in arable soils in China, J. Environ. Monit., 649-653 (2003)
  8. Bauer M.J. and Herrmann R., Estimation of the environmental contamination by phthalic acid esters leaching from house-hood wastes, Sci. Total Environ., 208, 49-57 (1997)
  9. Giam C.S., Atlas E., Powers M.A. and Leonard J.E., Phthalic acid esters. In: Hutzinger, O. (Ed.), The Handbook of Environmental Chemistry, Part C. Springer- Verlag, 66–142 (1982)
  10. Schulz C.O., Assessing human health risks from exposure to di(2-ethylhexyl) phthalate (DEHP) and related phthalates: scientific issues, Drug Metab. Rev., 21, 111–120 (1989)
  11. Nielsen E. and Larsen P.B., Toxicological evaluation and limit values for DEHP and phthalates, other thanDEHP. Environ. Rev. Danish Environmental Protection Agency, Copenhagen, Denmark, (1996)
  12. Staples C.A., Peterson D.R., Parkerton T.F. and Adams W.J., The environmental fate of phthalate esters; a literature review, Chemosphere, 35, 667–749 (1997)
  13. Wu X., Wang Y., Liang R., Dai Q., Jin D., Chao W., Biodegradation of an endocrine-disruptingchemical di-n-butyl phthalate by newly isolated Agrobacterium sp. and the biochemical pathway. Process Biochem.,46, 1090-1094 (2011)
  14. Kleerebezem R., Hulshoff Pol L.W. and Lettinga G., Anaerobic Degradation of Phthalate Isomers by Methanogenic Consortia, Appl. Environ. Microbiol.,65, 1152–1160 (1999)
  15. Yuan S. Y., Liu C., Liao C. S. and Chang B. V., Occurrence and microbial degradation of phthalate esters in Taiwan river sediments, Chemosphere, 49, 1295-1299 (2002)
  16. Copley S.D., Evolution of efficient pathways for degradation of anthropogenic chemicals, Nat. Chem. Biol., 559-566 (2009)
  17. Okamoto Y., Toda C., Ueda K., Hashizume K. and Kojima N. Transesterification in the microbial degradation of phthalate esters, J. Health Sci., 57(3), 293-299 (2011)
  18. Wu M.H., Lu N., Hu G., Ma J., Tang L., Wang L., Fu H.Y., Kinetics and mechanisms studies on dimethyl phthalate degradation in aqueous solutions by pulse radiolysis and electron beam radiolysis, Radiat. Phys.Chem., 80, 420-425 (2011)
  19. GroupE.F. Jr), Environmental fate and aquatic toxicology studies on phthalate esters, Environ. Health Perspect.65, 337–340 (1986)
  20. Liu Y., Guan Y., Yang Z., Cai Z., Mizuno T., Tsuno H., Zhu W. and Zhang X., Toxicity of seven phthalate esters to embryonic development of the abalone Haliotisdiversicolorsupertexta, Ecotoxicol.,18(3), 293-303 (2009)
  21. Jones A.E., Kahn R.H., Groves J.T. and Napier E.A. (Jr), Phthalate Ester Toxicity in Human Cell Cultures, Toxicol. Appl. Pharmacol., 31, 283-289 (1975)
  22. Lyche J.L., Gutleb A.C., Bergman A., Eriksen G.S., Murk A.J., Ropstad E., Saunders M. and Skaare J.U., Reproductive and developmental toxicity of phthalates. J. Toxicol. Environ. Health B Crit. Rev.,, 225-249 (2009)
  23. Navacharoen A., Vangnai A.S. Biodegradation of diethyl phthalate by an organic-solvent-tolerant Bacillus subtilisstrain 3C3 and effect of phthalate ester coexistence. Int. Biodeter. Biodegr., 65, 818-826 (2011)
  24. Patil N.K., Veeranagouda Y., Vijaykumar M.H., AnandNayak S. and Karegoudar T.B., Enhanced and potential degradation of o-phthalate by Bacillus sp. Immobilized in alginate and polyurethane, Int. Biodeter. Biodegr., 57, 82-87 (2006)
  25. Park J., KimM., Yoon J., Kobayashi F., Iwasaka Y., Hong C., Min J. and Kim Y., Biodegradation of diisodecyl phthalate (DIDP) by Bacillus sp. SB-007, J. Basic Microbiol., 49, S31-S35 (2009)
  26. Chen H., Yao J., Wang F., Choi M.M.F., Bramanti E. and Zaray G., Study on the toxic effects of diphenol compounds on soil microbial activity by a combination of methods, J. Hazard. Mater., 167, 846–851 (2009)
  27. Critter S.A.M., Freitas S. S. and Airoldi C.A., Calorimetry versus respirometry for the monitoring of microbial activity in a tropical soil, Appl. Soil Ecol., 18, 217–227 (2001)
  28. Backman P., Bastos M., Briggner L.E., Hägg S., Hallén D., Lönnbro P., Nilsson S.O., Olofsson G., Schön A., Suurkuusk J., Teixeira C. and Wadsö I., A system of microcalorimeters, Pure Appl. Chem., 66, 375–382 (1994)
  29. Prado A.G.S. and Airoldi C., Microcalorimetry of the degradation of the herbicide 2,4-D via the microbial population on a typical Brazilian red Latosol soil, Thermochim. Acta,371, 169–174 (2001)
  30. Critter S.A.M., Freitas S.S. and Airoldi C.A., Comparison between microorganism counting and calorimetric method applied to tropical soils, Thermochim. Acta, 394, 133–144 (2002)
  31. Sandy E.H., YaoJ., ZhengS., Gogra A.B., Chen H., Zheng H., YormahT.B.R., Zaray G., Ceccanti B. and Choi M.M.F., A comparative cytotoxicity study of isomeric alkylphthalates to metabolically variant bacteria, J. Hazard. Mater., 182 (1-3), 631-639(2010)
  32. Bais H.P., Fall R. and Vivanco J.M., Biocontrol of Bacillus subtilis against infection of Arabidopsis roots by Pseudomonas syringae is facilitated by biofilm formation and surfactin production, Plant Physiol., 34, 307-319 (2004)
  33. Gavala H.N., Alastriste-Mondrayon F., Iranpour R. and Ahing B.K., Biodegradation of phthalate esters during the mesophilic anaerobic digestion of sludge, Chemosphere, 4, 673-682 (2003)