This study provides a deep modern insight into the phylogenetic diversity among bacterial consortia found in working and nonworking high‐methane natural gas pipelines located in Poland. The working pipeline was characterized by lower biodiversity (140–154 bacterial genera from 22 to 23 classes, depending on the source of the debris) in comparison to the off‐gas pipeline (169 bacterial genera from 23 classes). The sediment recovered from the working pipeline contained mostly DNA identified as belonging to the phylum Firmicutes (66.4%–45.9% operational taxonomic units [OTUs]), predominantly Bacillus (41.4%–31.1% OTUs) followed by Lysinibacillus (2.6%–1.5% OTUs) and Clostridium (2.4%–1.8% OTUs). In the nonworking pipeline, Proteobacteria (46.8% OTUs) and Cyanobacteria (27.8% OTUs) were dominant. Over 30% of the Proteobacteria sequences showed homologies to Gammaproteobacteria, with Pseudomonas (7.1%), Enhydrobacter (2.1%), Stenotrophomonas (0.5%), and Haempohilus (0.4%) among the others. Differences were noted in terms of the chemical compositions of deposits originating from the working and nonworking gas pipelines. The deposits from the nonworking gas pipeline contained iron, as well as carbon (42.58%), sulphur (15.27%), and oxygen (15.32%). This composition can be linked to both the quantity and type of the resident microorganisms. The presence of a considerable amount of silicon (17.42%), and of aluminum, potassium, calcium, and magnesium at detectable levels, may likewise affect the metabolic activity of the resident consortia in the working gas pipeline. All the analyzed sediments included both bacteria known for causing and intensifying corrosion (e.g., Pseudomonas, Desulfovibrio, Shewanella, Serratia) and bacteria that can protect the surface of pipelines against deterioration (e.g., Bacillus). Biocorrosion is not related to a single mechanism or one species of microorganism, but results from the multidirectional activity of multiple microbial communities. The analysis presented here of the state of the microbiome in a gas pipeline during the real gas transport is a particularly valuable element of this work.

Wpłynęło w styczniu, zaakceptowano w czerwcu 2017 r. 1. Wprowadzenie. 2. Drobnoustroje w podziemnych magazynach gazu. 3. Mikroorganizmy w gazociągach. 4. Podsumowanie Microbiological contaminations of underground gas storage facilities and natural gas pipelines

This paper presents investigation results of the influence of gas microbes on the biocorrosion rate of the materials used for gas pipelines construction in the Lodz Province. Samples of two types of carbon steel and cast iron were stored in the laboratory pipeline model reflecting the real conditions of working natural gas pipelines were. In the next step the influence of cathodic protection with parameters recommended for protection of underground structures was tested. Analyses of biological corrosion products generated on the test surface were carried out using a scanning electron microscope with an X-ray analyzer. The level of ATP was measured to confirm presence of the adsorbed microorganisms on the observed structures. Corrosion rates were determined by gravimetric methods. In the course of the study it was revealed that the rate of biocorrosion of steel is lower than that for cast iron. Our results also proved that the weight corrosion rate depends on the number of adhered microorganisms. In addition, it has been found that application of the carbon steel cathodic protection decreases its weight corrosion rate. The information obtained will help to increase the knowledge on the rate of biological corrosion causing losses/pits inside gas pipline.

In 2013, the Polish enterprise sector generated 73,5% of GDP, of which small and medium-sized enterprises generated 50,1% of GDP – i.e. every second zloty of this value. Among all groups of enterprises according to their sizes, the largest share in generating GDP had microenterprises – approx. 30,8%. The aim of the study was to analyze the degree of changes and tendencies in the development of newly created enterprises – according to the length of years of operation and size classes – micro, small, medium-sized and large enterprises in Poland. The analysis of enterprises was based on CSO data included in the study entitled “Non-financial enterprises established in the years 2012-2016”. The analysis covered enterprises that were established in the years 2012-2016 and actively performed their business activity until the last examined year. The following conclusions were drawn: In the structure of enterprises in the years 2012-2016, microenterprises were dominant. Together with the increase in the number of years of running business, the number and share of small, medium and large enterprises increased at the expense of microenterprises. The survival rate of enterprises established in the years 2012-2016 is the highest for large, medium-sized and small enterprises. In the analyzed period, the highest number of employees was in microenterprises, but the number of employees was constantly fluctuating over the years. The number of people working in small and medium-sized enterprises has constantly increased along with the length of business activity. The highest remunerations were observed in enterprises (successively) – large, medium-sized, small and micro- enterprises. In microenterprises, there is the largest disparity in the amount of salaries.