Influence of nutrient mixtures on p-nitrophenol degradation by Stenotrophomonas sp. isolated from groundwater.

We isolated strain CERAR5, a Stenotrophomonas sp., from an aquifer contaminated with chlorinated hydrocarbons that utilizes up to 1.0 mM PNP within 62 h in M9 medium as a source of carbon and nitrogen. To assess the potential of this strain for use in bioremediation, we investigated the influence of external sources of carbon and nitrogen on bacterial degradation of PNP following a full factorial design analysis. Glucose, sodium acetate, phenol, sodium nitrate and ammonium chloride were the factors chosen, while per cent removal of PNP, growth of the bacterial strain, and change in pH of the medium were the responses measured. Glucose and acetate had significant positive influence on the removal PNP. In particular, acetate exhibited a significant positive effect on all the three responses measured, clearly suggesting that the addition of acetate greatly contributes to an efficient bioremediation of habitats contaminated with PNP by Stenotrophomonas sp. CERAR5.