The effect of growth conditions on the biodegradation of tributyl phosphate and potential for the remediation of acid mine drainage waters by a naturally-occurring mixed microbial culture.
The biodegradation of tributyl phosphate (Bu3-P, TBP), releasing phosphate at a high enough concentration locally to precipitate uranium from solution, was demonstrated by a mixed culture consisting primarily of pseudomonads. The effect of various parameters on Bu3-P biodegradation by growing cells is described. Growth at the expense of Bu3-P as the carbon and phosphorus source occurred over a pH range from 6.5 to 8, and optimally at pH 7. Bu3-P biodegradation was optimal at 30 degrees C, reduced at 20 degrees C and negligible at 4 degrees C and 37 degrees C. Incorporation of Cu or Cd inhibited, and Ni, Co and Mn reduced its degradation. Inorganic phosphate (above 10 mM) and kerosene (up to 1 g/l) reduced Bu3-P biodegradation significantly, but nitrate had no effect. Sulphate (10-100 mM) was inhibitory. When pregrown biomass was used the fastest rates of tributyl and dibutyl phosphate biodegradation were 25 mumol h-1 mg protein-1 and 37 mumol h-1 mg protein-1 respectively. Microcarrier-immobilised biomass decontaminated uranium-bearing acid mine waste water by uranium phosphate precipitation at the expense of Bu3-P hydrolysis in the presence of 35 mM SO(4)2-. At pH 4.5, 79% of the UO2(2)+ was removed at a flow rate of 1.4 ml/h on a 7-ml.test column.
Thomas
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School of Biological Sciences, University of Birmingham, UK.
Macaskie
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LE
D000838:Anions / Q000494:pharmacology; D001419:Bacteria / Q000254:growth & development / Q000378:metabolism*; D001673:Biodegradation, Environmental; D018533:Biomass; D018914:Cells, Immobilized; D011232:Chemical Precipitation; D003470:Culture Media; D005618:Fresh Water / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D007648:Kerosene; D008670:Metals / Q000494:pharmacology; D008906:Mining; D010755:Organophosphates / Q000378:metabolism*; D011850:Radioactive Waste; D013696:Temperature; D014501:Uranium / Q000032:analysis*; D014875:Water Pollutants, Radioactive / Q000032:analysis*
D000838:Anions; D003470:Culture Media; D007648:Kerosene; D008670:Metals; D010755:Organophosphates; D011850:Radioactive Waste; D014875:Water Pollutants, Radioactive; D014501:Uranium; C009524:tributyl phosphate