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 l^-1 d^-1 with the addition of 200 mg l^-1 of salicylate, 3.5 times higher than that (5.6 mg l^-1 d^-1) without the addition of salicylate. The degradation rate was decreased at higher concentrations of salicylate (above 500 mg l^-1), and cell growth was significantly inhibited. The pheranthrene degradation was not affected by increasing glucose up to 2 g l^-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 l^-1 of salicylate, approximately 60% of the initial phenanthrene (50 mg l^-1) was degraded after 96 h. However, with extra addition of 200 mg l^-1 of glucose, the phenanthrene degradation rate decreased, and only 18.5% of the initial phenanthrene was degraded.