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A comparative study of chemical and enzymatic methods of aniline polymerization was carried out. Fungal laccase from Trametes hirsuta was used in the synthesis of polyaniline nanoparticles made with poly(2acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS). Template polymerization of aniline was carried out in aqueous buffer. It was shown that the laccase had high long-term and operating stabilities under acidic condition favorable for synthesis of conducting polyaniline. UV-vis, FTIR spectroscopy, and cyclic voltammetry analysis are used for the characterization of the polyelectrolyte complexes of polyaniline and PAMPS. The incorporation of the polymeric acid in polyaniline has been demonstrated by atomic force microscopy. The size and morphology of the nanoparticles of the polyaniline-PAMPS complexes depended on the method of the synthesis. A comparison of some physical and chemical properties of water dispersible conducting polyaniline-PAMPS was performed under production by enzymatic and chemical methods. It was found a difference in structures and some physicochemical properties of polyaniline colloids prepared by chemical and laccase-catalyzed methods.

A new procedure for isolation of cytochrome c nitrite reductase from the haloalkaliphilic bacterium Thioalkalivibrio nitratireducens increasing significantly the yield of the purified enzyme is presented. The enzyme is isolated from the soluble fraction of the cell extract as a hexamer, as shown by gel filtration chromatography and small angle X-ray scattering analysis. Thermostability of the hexameric form of the nitrite reductase is characterized in terms of thermoinactivation and thermodenaturation.

A range of species of four mixed bacterial cultures was studied by molecular systematics methods with the use of 16S rRNA genes. The cultures had been developed for application in minireactors, to degrade volatile organic compounds (VOCs): ethyl benzene, m -xylene, styrene, and o -xylene. A sample of 30 plasmid rDNA clones was obtained for each of the mixed cultures. The clones were analyzed by RFLP according to two restriction sites. Major variants of the 16S-rDNA sequences, corresponding to the most abundant species, were determined for each association. Sequencing of four clones of predominant 16S-rDNAs showed that the culture consuming ethyl benzene was dominated by Pseudomonas fluorescens ; o -xylene, by Achromobacter xylosoxydans ; styrene, by Pseudomonas veronii ; and m -xylene, by Delftia acidovorans . Minor components of all four cultures were generally similar. They included species of the genera Sphingobacter , Rhizobium , Mesorhizobium , Pedobacter , and Paenibacillus . Sampling sequencing of genes for 16S rRNA cloned from total genomic DNA allowed quantitative determination of the composition of actual bacterial associations consuming VOCs in minireactors.

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