SURVIVAL AND ACTIVITY OF LUX-MARKED PHENANTHRENE-DEGRADING&

Viable cell concentration and luminescence activity of P. stutzeri P16 luxAB4 was measured by plate counting and luminometery in sterile and non-sterile soil adjusted to matric potential of -1500, -750 and -30 kPa. Results showed that matric potential had a significant effect on survival and activity of P. stutzeri P16 luxAB4 in soil. P. stutzeri P16 luxAB4 could survive better in Hutner’s minimal medium supplemented with 1mg l-1 phenanthrene than 1 mg ml-1. However changes in viable cell concentration and luminescence activity of lux-marked and wild type strains of P. stutzeri P16 were significantly different in Hutner’s medium, amended with high and low concentrations of phenanthrene. Inoculation of soil with high concentrations of phenanthrene caused an initial decline in the viable cell concentration of P. stutzeri P16 luxAB4 that took a longer time than liquid medium. Changes in viable cell concentration were similar to changes in luminescence indicating the advantage of Bioluminescence-marker systems for monitoring the survival and activity of biodegradative genetically engineered microorganisms (GEMs) in polluted environments. Our results also showed the importance of influence of environmental factors such as matric potential and pollutant concentration on the fate of GEMs.