The focus of the study was on the dynamics of the variation in the population of copiotrophic and oligotrophic bacteria and actinobacteria as well as the level of acid and alkaline phosphatase activities taking place during pine bark composting, depending on the application of different organic admixtures and the Effective Microorganisms microbiological preparation as well as variation in pH values and temperature. Above all, the trend in the variation in the population of microorganisms under analysis and enzymatic activity depended on the type of admixture applied to the composted pine bark. Apart from that, the course of microbiological activity was also influenced by temperature variation, which resulted from the course of the composting process. The results obtained in the experiment proved that the admixture of PGM (plant green matter) to the composted prisms had stimulating influence on the microbiological indexes under analysis.

Microbiological studies were carried out of atmospheric air sampled on the area and in the surroundings of a mechanical and biological wastewater treatment plant (WTP) treating municipal sewage. The capacity of the wastewater treatment plant, which also received some wastewater from the dairy industry, was ca 3· 103 m3d-1. Counts ofheterotrophic psychrophilic, psychrotrophic and mesophilic bacteria as well as some physiological groups of microorganisms which belong to Enterobacteriaceae family, Staphylococcus and Enterococcus genera, Pseudomonas fluorescens and P. aeruginosa species, hemolysing bacteria and actinomycetes were analyzed. Air samples were collected in summer, autumn, winter and spring seasons simultaneously by the sedimentation and impact methods at 6 sites located on the area of the WTP and at 5 sites situated in its surroundings. The background was established depending on the direction of wind, always on the windward side in relation to the location of the WTP. In addition, temperature and air humidity as well as wind speed and direction at each sampling sites were observed. Statistically significant differences were found in studied groups of microorganisms counts between air samples collected in different seasons of the year (with the exception of psychrophilic bacteria and by the two different methods (with the exception of psychrophilic bacteria) and microorganisms which belong to Enterobacteriaceae family). The highest mean counts of the microorganisms were usually determined in air samples collected by the sedimentation method, especially during the autumn (with the exception of actinomycetes, which are the most numerous in spring), the lowest ones in winter and/or in summer. No statistically significant differences were observed in counts of the analyzed groups of microorganisms in air sampled at particular sites (with the exception of Enterobacteriaceae bacteria isolated on Chromocult medium). However, higher counts of these microorganisms were typically found in the air sampled in the area of the WTP, particularly near the grit chamber, phosphorus removal tank, nitrification and denitrification chambers and secondary settling tank. According to the Polish Standards used for evaluation of atmospheric air pollution, the air sampled in the area of wastewater treatment plant and in its surroundings was classified as only slightly and sporadically strongly polluted. It was mainly in the spring and autumn seasons that the air was strongly polluted with psychrophilic and mesophilic bacteria. No increased emission of the analyzed groups of microorganisms, including faecal bacteria was determined in the air samples collected outside the WT

This work aims at investigating the influence of the initial concentrations of carbon (glucose) and organic nitrogen (yeast extract) sources on Streptomyces rimosus ATCC10970 secondary metabolism in the stirred tank bioreactors. Additionally, glucose utilisation, biomass formation, pH, redox potential and dissolved oxygen levels, and the morphological development of S. rimosus pseudomycelium were studied. Eighteen secondary metabolites were detected by mass spectrometry and identified with the use of the authentic standard, or putatively with the use of literature and database of secondary metabolites. Varied initial yeast extract concentration acted much stronger on the formation of secondary metabolites than glucose did. For example, oxytetracycline was not biosynthesised at high yeast extract concentration while the formation of three other metabolites was enhanced under these conditions. In the case of glucose its increasing initial concentration led to higher secondary metabolite levels with the exception of an unnamed angucycline. High initial yeast extract concentration also drastically changed S. rimosus pseudomycelial morphology from the pelleted to the dispersed one. Ultimately, the cultivation media with the varied initial levels of carbon and nitrogen sources were proved to have the marked effect on S. rimosus secondary metabolism and to be the simplest way to either induce or block the formation of the selected secondary metabolites.