Planococcus sp. S5, a Gram-positive bacterium isolated from the activated sludge is known to degrade naproxen in the presence of an additional carbon source. Due to the possible toxicity of naproxen and intermediates of its degradation, the whole cells of S5 strain were immobilized onto loofah sponge. The immobilized cells degraded 6, 9, 12 or 15 mg/L of naproxen faster than the free cells. Planococcus sp. cells immobilized onto the loofah sponge were able to degrade naproxen efficiently for 55 days without significant damage and disintegration of the carrier. Analysis of the activity of enzymes involved in naproxen degradation showed that stabilization of S5 cells in exopolysaccharide (EPS) resulted in a significant increase of their activity. Changes in the structure of biofilm formed on the loofah sponge cubes during degradation of naproxen were observed. Developed biocatalyst system showed high resistance to naproxen and its intermediates and degraded higher concentrations of the drug in comparison to the free cells.

We have investigated the dielectric response in the terahertz (THz) spectral range of a series of Bi-layered ferroelectrics with Aurivillius structure involving ferroelectric compounds $({\mathrm{Bi}}_4{\mathrm{Ti}}_3{\mathrm{O}}_{12},\mathrm{Sr}{\mathrm{Bi}}_2{\mathrm{Ta}}_2{\mathrm{O}}_9,\mathrm{Sr}{\mathrm{Bi}}_2{\mathrm{Nb}}_2{\mathrm{O}}_9)$, a relaxor ferroelectric $\left(\mathrm{Ba}{\mathrm{Bi}}_2{\mathrm{Nb}}_2{\mathrm{O}}_9\right)$, and intermediate-type compound $\left({\mathrm{Sr}}_{0.5}{\mathrm{Ba}}_{0.5}{\mathrm{Bi}}_2{\mathrm{Ta}}_2{\mathrm{O}}_9\right)$. The lowest-frequency polar phonons were studied by means of the time-domain THz transmission spectroscopy in the frequency range $0.1–2\mathrm{THz}$ at temperatures $10–950\mathrm{K}$. Although previous structural studies suggested a displacive character of the structural phase transitions, no soft-mode anomalies were observed in our THz spectra near $T_c$ in any of the investigated compounds. A gradual and only partial softening of the lowest frequency polar phonon was revealed during heating. Dielectric anomalies near $T_c$ in all the compounds should be caused by slowing down of relaxations, directly observed in some cases below the polar phonon range. The ferroelectric transitions are therefore not classically displacive. In analogy to other relaxor ferroelectrics, existence of dynamic polar clusters is suggested to be in origin of such relaxations. Ferroelectric transitions in such cases are connected with an abrupt freezing and rise of these clusters into domains and the classical division of phase transitions into displacive and order-disorder is no more sufficient.

The naproxen-degrading bacterium Bacillus thuringiensis B1(2015b) was immobilised onto loofah sponge and introduced into lab-scale trickling filters. The trickling filters constructed for this study additionally contained stabilised microflora from a functioning wastewater treatment plant to assess the behavior of introduced immobilized biocatalyst in a fully functioning bioremediation system. The immobilised cells degraded naproxen (1 mg/L) faster in the presence of autochthonous microflora than in a monoculture trickling filter. There was also abundant colonization of the loofah sponges by the microorganisms from the system. Analysis of the influence of an acute, short-term naproxen exposure on the indigenous community revealed a significant drop in its diversity and qualitative composition. Bioaugmentation was also not neutral to the microflora. Introducing a new microorganism and increasing the removal of the pollutant caused changes in the microbial community structure and species composition. The incorporation of the immobilised B1(2015b) was successful and the introduced strain colonized the basic carrier in the trickling filter after the complete biodegradation of the naproxen. As a result, the bioremediation system could potentially be used to biodegrade naproxen in the future.