degradation

A review of the literature on the phenomenon of aging (a significant drop in viscosity over time) of acidic chitosan solutions is given. A study was made on acetic acid (2%) solutions of chitosan of two viscosity-average molecular weights (200 and 46 kDa) by ion probing (addition of a KI solution). It has been indirectly confirmed that the motion of the probing ions in an electric field disturbs part (about a quarter) of the average macromolecule rather than the whole one.

Lignin peroxidase is one of the main enzymes of fungi decomposers of wood, that is capable to many non-specific oxidation of aromatic and polycyclic compounds. By the beginning of our research there were virtually no data of the bacteria’s ability to produce the lignin peroxidase. Rather recently lignin peroxidase activity was detected by us in the washouts from the surface of the bacterial cells and in intracellular extracts of bacteria from genus Azospirillum.

For 40 years the soil microflora of the Landscape Reserve «Osinsk Forest Summer House» (Perm region, Russia) was exposed to high concentrations of DDT. Soil from the blocks 11 and 32 were selected and used in the process of artificial selection of aerobic bacterial communities capable of degrading DDT. Selection was carried out in the laboratory in four stages. As a result, successional changes were recorded, accompanied by reduction in the number and diversity of morphological types of bacterial strains in microbial communities.

Synthetic dyes are the largest class of chemicals that have found their commercial use in various industries. The most used are azo and anthraquinone dyes. However, most of them are not only toxic, carcinogenic, and mutagenic, but also resistant to biological destruction. The aim of the work was the screening of azospirillum strains according to their ability to biodegrade azo dyes and anthraquinone dyes. 

Soil-inhabiting ligninolytic basidiomycetes, such as Stropharia rugosoannulata, play an important role in the transformation of soil organic matter, including the degradation of pollutants. Information on the mechanisms of degradation of xenobiotics by these fungi and their ligninolytic enzymes is still limited. The degradative activity of the soil-inhabiting basidiomycete S. rugosoannulata towards four-rings PAHs was revealed. Fluorene and 2-carboxybenzaldehyde have been identified as products of degradation of fluoranthene and pyrene. The laccase of S.

Composite films were obtained from a mixture of starch, polyvinyl alcohol, and a plasticizing additive based on aspartic acid. The surface morphology, structural features of the composites, and their behavior in a polythermic mode were studied by scanning electron microscopy, X-ray diffractometry, IR spectroscopy, differential thermal and thermogravimetric analysis. Only carbon dioxide was detected in the gaseous products of thermal decomposition of the samples. The sorption and physico-mechanical properties of our composite films were analyzed.