Kinetics of styrene biodegradation by Pseudomonas sp. E-93486

Abstract

The research into kinetics of styrene biodegradation by bacterial strain Pseudomonas sp. E-93486 coming from VTT Culture Collection (Finland) was presented in this work. Microbial growth tests in the presence of styrene as the sole carbon and energy source were performed both in batch and continuous cultures. Batch experiments were conducted for initial concentration of styrene in the liquid phase changed in the range of 5–90 g m−3. The Haldane model was found to be the best to fit the kinetic data, and the estimated constants of the equation were: μ m = 0.1188 h−1, K S = 5.984 mg l−1, and K i = 156.6 mg l−1. The yield coefficient mean value Y_{text{xs}}^{text{app}} for the batch culture was 0.72 gdry cells weight (gsubstrate)−1. The experiments conducted in a chemostat at various dilution rates (D = 0.035–0.1 h−1) made it possible to determine the value of the coefficient for maintenance metabolism m d = 0.0165 h−1 and the maximum yield coefficient value Y_{text{xs}}^{text{M}} = 0.913 . Chemostat experiments confirmed the high value of yield coefficient Y_{text{xs}}^{text{app}} observed in the batch culture. The conducted experiments showed high activity of the examined strain in the styrene biodegradation process and a relatively low sensitivity to inhibition of its growth at higher concentrations of styrene in the solution. Such exceptional features of Pseudomonas sp. E-93486 make this bacterial strain the perfect candidate for technical applications.