Synchronous fluorescence as a selective method for monitoring pyrene in biodegradation studies

A simple and effective method based on synchronous fluorescence spectroscopy for quantifying pyrene and its metabolites in a biodegradation study using Mycobacterium frederiksbergense is reported in this work. An optimum excitation-emission wavelength offset of 39 nm and a corresponding excitation wavelength of 335 nm was found to be suitable for the determination of pyrene. Interference due to naphthalene and anthracene in the analysis were found to be 11 and 4.7%, respectively. Batch biodegradation experiments in a 3L fermentor revealed a high pyrene degradation rate of 10.22 mg L(-1) d(-1) by the mycobacterium in presence of the surfactant tween 20. Tween 20 was, however, found preferentially utilized over pyrene, which resulted in a lag of 120 h in pyrene degradation by the culture. In the absence of the surfactant, pyrene degradation rate was found to be only 6.1 mg L(-1) d-(1), but without any lag in its degradation.