In this study, we performed the qualitative analysis of exoproteins during granule formation in the pres- ence or in the absence of cations. The staining of thin granule cryosections showed that nucleic acids, proteins, polysaccharides and calcium cations were the dominant components of the granules. Proteins are the structural components associated with calcium ions. We determined changes in the proteomic profile and tightly bound extracellular polymeric substances (EPS) of the slime. The exopolymeric matrix containing the proteins was extracted using the Dowex resin method. Proteomic profile was analysed by SDS-PAGE method (sodium dodecyl sulphate polyacrylamide gel electrophoresis) using Coomassie blue staining in the samples of the aerobic granule matrix formed in the presence of multivalent cations and compared with that of the aerobic granules cultivated without cations. The results indicate that the granule matrix is predominantly composed of large and complex proteins that are tightly bound within the granular structure. The tightly bound extracellular polymeric substances (TB-EPS) may play a role in improved mechanical stability of aerobic granules. In the supernatant fraction of the sludge, only a small amount of free proteins in the medium molecular mass range was detected. The protein with high molecular mass ( 116 kDa) produced in the reactors with added Ca2+. Ca2+ had a considerable regulatory influence on production of extracellular proteins during aerobic granulation.

This study investigated the quantity and distribution of extracellular polymeric substances (EPS) in aerobic granules. Results showed that EPS play an important role in the formation and stabilisation of granules. The content of EPS significantly increases during the first weeks of biogranulation. An analysis of EPS in the granules revealed that the protein level was 5 times higher than in polysaccharides. The increase of protein content correlated with the growth of cell hydrophobicity (r2 = 0.95). EPS and hydrophobicity are important factors in cell adhesion and formation of granules.

The aim of this work was also to determine the distribution of EPS in the granule structure. In situ EPS staining showed that EPS are located mostly in the center of granules and in the subsurface layer. The major components of the EPE matrix are proteins, nucleic acids and β-polysaccharides. These observations confirm the chemical extraction data and indicate that granule formation and stability are dependent on protein content.

The main aim of the study was to assess the feasibility of using biopolymers of different viscosities (high, medium and low viscosity) as immobilization carriers for laccase in synthetic dye removal. The following dye solutions were decolorized: indigo carmine (IC, anionic dye), methylene blue (MB, cationic dye), and their mixture in a molar mass ratio MB/IC=0.69, using biopolymers of different viscosities as laccase immobilization carriers. Toxicity tests were also carried out to assess the toxicity of the post-decolorization samples. Decolorization tests showed that the main decolorization mechanism depends on the dye class. The removal of IC (max. total removal efficiency 72.15%) was mainly by biocatalysis. The mechanism of the MB decolorization process was mainly by sorption on alginate beads, and the efficiency of enzymatic removal was low. However, the highest efficiency of MB decolorization (45.80%) was obtained for beads prepared using the high viscosity alginate when decolorization occurred by both sorption and biocatalysis. The results of mixture decolorization tests differ from the results obtained for single dyes.The results showed differences in the efficiency of the dye sorption process depending on the alginate used for immobilization. Moreover, the varying mechanisms of dye removal from the dye mixture were confirmed by toxicity tests. The occurrence of both biocatalysis and sorption promotes reduced toxicity

The aim of the study was to assess the feasibility of utilizing sodium alginate biopolymer as animmobilization carrier for laccase in the removal of indigo carmine (IC), an anionic dye. The main goal of this work was to optimize the decolourization process by selecting the appropriate immobilized enzyme dose per 1 mg of dye, as well as the process temperature. The effective immobilization of laccase using sodium alginate as a carrier was confirmed by Raman spectroscopy. An analysis of the size and geometric parameters of the alginate beads was also carried out. Tests of IC decolourization using alginate-laccase beads were conducted. Applying the most effective dose of the enzyme (320 mg of enzyme/1 mg of IC) made it possible to remove 92.5% of the dye over 40 days. The optimal temperature for the IC decolourization process, using laccase immobilized on sodium alginate, was established at 30-40ºC. The obtained results indicate that laccase from Trametes versicolor immobilized on sodium alginate was capable of decolourizing the tested dye primarily based on mechanism of biocatalysis.