Effects of salicylate and glucose on biodegradation of phenanthrene by Burkholderia cepacia PM07

The stimulatory effects of exogenous salicylate as a pathway inducer on phenanthrene biodegradation were investigated using Burkholderia cepacia PM07. The phenanthrene degradation rate was greatly enhanced by increasing the salicylate additions, and the maximum rate was 19.6 mg 1(-1) d(-1) with the addition of 200 mg 1(-1) of salicylate, 3.5 times higher than that (5.6 mg 1(-1) d(-1)) without the addition of salicylate. The degradation rate was decreased at higher concentrations of salicylate (above 500 mg 1(-1)), and cell growth was significantly inhibited. The phenanthrene degradation was not affected by increasing glucose up to 2 g 1(-1), although dramatic microbial growth was obtained. The stimulatory effect of exogenous salicylate decreased in the presence of glucose. After the addition of 200 mg 1(-1) of salicylate, approximately 60% of the initial phenanthrene (50 mg 1(-1)) was degraded after 96 h. However, with extra addition of 200 mg 1(-1) of glucose, the phenanthrene degradation rate decreased, and only 18.5% of the initial phenanthrene was degraded.