Effect of alginate encapsulation and selected disinfectants on survival of and phenanthrene mineralization by Pseudomonas sp UG14Lr in creosote-contaminated soil
1996
Weir, S.C. | Providenti, M.A. | Trevors, J.T.
The survival and phenanthrene-mineralizing ability of free and alginate-encapsulated Pseudomonas sp UG14Lr cells were examined in a creosote-contaminated soil. Alginate encapsulation adversely affected both survival and phenanthrene mineralization. This was postulated to be due to concentration of water-soluble toxic compounds in the alginate beads. Toxicity studies showed that the concentrated water-soluble fraction of the creosote-contaminated soil may be toxic to Pseudomonas sp UG14Lr in soil with a low moisture content. Survival of alginate-encapsulated cells improved with increasing soil moisture content. Free cells survived well at a steady population of 10(8) CFU g-1 dry soil for 28 days in the creosote-contaminated soil. However, phenanthrene mineralization was not improved compared to the uninoculated control. This was attributed to the existence of indigenous phenanthrene-mineralizing microorganisms already present in this contaminated soil. The effect of calcium hypochlorite and Germiphene on survival of and phenanthrene mineralization by free and alginate-encapsulated Pseudomonas sp UG14Lr cells creosote-contaminated soil was also studied. Addition of 0.1% (w/w dry soil) calcium hypochlorite reduced the introduced free cells to below detection limits (10 CFU g-1 dry soil) within 14 days, while Germiphene had no effect on cell numbers. Phenanthrene mineralization by free cells was not adversely affected by treatment with calcium hypochlorite or Germiphene. Survival of alginate-encapsulated cells after treatment with disinfectants was as poor as that without disinfection. The results show that alginate encapsulation may not be a suitable formulation introduction of Pseudomonas sp UG14Lr into creosote-contaminated soils.
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