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: μm = 0.1188 h−1, KS = 5.984 mg l−1, and Ki = 156.6 mg l−1. The yield coefficient mean value 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 md = 0.0165 h−1 and the maximum yield coefficient value . Chemostat experiments confirmed the high value of yield coefficient 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.

Four Gram-negative strains, E3_2001, EC1_2004, EC3_3502 and EC2_3502, previously isolated from soil samples, were subjected to comparative studies in order to select the best vinyl acetate degrader for waste gas treatment. Comparison of biochemical and physiological tests as well as the results of fatty acids analyses were comparable with the results of 16S rRNA gene sequence analyses. The isolated strains were identified as Pseudomonas putida EC3_2001, Pseudomonas putida EC1_2004, Achromobacter xylosoxidans EC3_3502 and Agrobacterium sp. EC2_3502 strains. Two additional strains, Pseudomonas fluorescens PCM 2123 and Stenotrophomonas malthophilia KB2, were used as controls. All described strains were able to use vinyl acetate as the only source of carbon and energy under aerobic as well as oxygen deficiency conditions. Esterase, alcohol dehydrogenase and aldehyde dehydrogenase were involved in vinyl acetate decomposition under aerobic conditions. Shorter degradation times of vinyl acetate were associated with accumulation of acetic acid, acetaldehyde and ethanol as intermediates in the culture fluids of EC3_2001 and KB2 strains. Complete aerobic degradation of vinyl acetate combined with a low increase in biomass was observed for EC3_2001 and EC1_2004 strains. In conclusion, P. putida EC1_2004 is proposed as the best vinyl acetate degrader for future waste gas treatment in trickle-bed bioreactors.

BACKGROUND Studies on the removal of styrene from airstreams carried out in pilot‐scale biotrickling filters (BTF) are still scarce thus making its industrial application difficult. Moreover, it seems necessary to develop a comprehensive description of the phenomena occurring in the bioreactor that could be used as a tool for BTF design and performance prediction. RESULTS The removal of styrene from airstreams in a pilot‐scale biotrickling filter (BTF) inoculated with Pseudomonas sp. E‐93486 bacteria was investigated (operational parameters: Vg*= 100–150 m3 h−1, VL*= 8 m3 h−1, Cs0= 0.2–1 g−3, EBRTs = 41–62 s, T = 303 K). The experiments performed during a period of more than 120 days confirmed high effectiveness of the examined process; RE = 78–94.2% was obtained for all the sets of operational parameters. The experimental database was exploited to validate the three mathematical models of the process. All the tested models approximate very well the experimental data; the mean percentage error of the RE value prediction did not exceed 3%. CONCLUSION The formulated approximate simple one‐substrate model (SOSM) described the investigated process with excellent accuracy (eY = 2.72%) and was numerically relatively simple. Therefore, this model was recommended as a useful tool for modelling the biodegradation processes of moderately hydrophobic compounds carried out in a BTF. © 2018 Society of Chemical Industry