Effect of humic acids on a naphthalene degrading microorganism isolated from a petroleum contaminated soil

摘要

Because of environmental problems created by spills of petroleum and derivative products, there has been interest in the development of waste treatment processes for these. Studies were conducted with the bacteria Pseudomonas fluorescens, isolated from petroleum contaminated soils, to find the effect of humic acids on the biodegradation potential of one strain of the bacteria identified as degrading naphthalene. Humic acids, the main component of humic substances, were employed at concentrations between 0.02 to 0.08%. With the exception of the experiments at 0.02%, where degradation was observed only at 48 hours, all concentrations were inhibitory to the organism and no degradation was observed during the 48 hour experimental period. The optimum main growth parameters for P.fluorescens, namely temperature, medium pH, and agitation speed, were determined by applying response surface methodology (RSM).