The necessity of rational water resource management and reduction of water consumption demandsthat water utilities address water losses during water treatment. Therefore, the backwash water generated during the filtration process is often the focus of research aimed at its reuse within the water treatment system. The studies outlined here were conducted in a large water treatment plant (100,000 m3), focusing on the backwash water produced from sand bed filter flushing. Prior to its reintroduction into the treatment train, the backwash water underwent pre-treatment using ultrafiltration (UF) process with two different modules: a spiral module with a PVFD (200kDa) membrane and a capillary module with a PES (80kDa) membrane. The effectiveness of the process was evaluated based on the degree of retention of organic substances and microorganisms, which pose health risks in backwash water recirculation. The capillary membrane exhibited greater effectiveness in retaining these contaminants, thereby ensuring the complete elimination of pathogenic microorganisms. The study findings indicate that pre-treating backwash water using UF membranes and reintroducing it into the water treatment system before the ozonation process can lead to a reduction of environmental fees. However, this process results in a 1.5% increase in water treatment costs

Extreme cold environments like glaciers, present substantial obstacles to the survival of organisms. Cryoconite, dark sediment covering glacier, provide unique niche for microorganisms. Therefore, we focused on understanding the diversity of fungi in Arctic ecosystems (Hansbreen, Spitsbergen), which is important in the analysis of the structure and of fungi populations. Due to a combination of two incubation temperatures (7°C or 24°C) and two media during isolation (potato dextrose agar, PDA or yeast extract peptone glucose, YPG), and classical/molecular identification approaches, we identified 20 different fungi (17 species and three unassigned species). Most belonged to filamentous fungi within the Ascomycota (19 isolates), with one identified as Basidiomycota-yeast. Regarding growth conditions, both media yielded greater number of fungal cultures at 24°C compared to 7°C. Additionally, PDA was more effective than YPG in isolating fungal cultures. On the other hand, the optimal temperature for achieving the highest CFU (colony–forming unit)/g of sediment was 7°C. The most frequently isolated species was Cladosporium cladosporioides, and to the best of our knowledge, we are the first to detect, the following species in an Arctic environment: Aspergillus jensenii, A. tennesseensis, Peziza varia, and Trichoderma paraviridescens. Additionally, there was a visible increase in the number of fungal propagules but a decrease in their biodiversity towards the upper parts of the glacier. Considering the Arctic amplification there is a need for further research on diversity and function of fungi in glacial ecosystems.

The marine psychrophilic and endemic Antarctic yeast Leucosporidium antarcticum strain 171 synthesizes intracellular b-fructofuranosidase, and intra- and extracellular a-glucosidases. Each enzyme is maximally produced at 5°C , while the strain’s optimum growth temperature is 15°C . Invertase biosynthesis appeared regulated by catabolic repression, and induced by sucrose; the enzyme was extremely unstable ex vivo, and only EDTA, Mn2+, and BSA stabilized it for up to 12 h after yeast cell lysis. Thermal stability of the invertase was also low (30 min at temperatures up to 12°C). The optimum temperature for invertase activity was 30°C , and optimum pH was 4.55 to 4.75. The extracellular a-glucosidase was maximally active at 35°C and pH 6.70–7.50, and stable for 30 min up to 20°C.

Microbes living in the polar regions have some common and unique strategies to respond to thermal stress. Nevertheless, the amount of information available, especially at the molecular level is lacking for some organisms such as Antarctic psychrophilic yeast. For instance, it is not known whether molecular chaperones in Antarctic yeasts play similar roles to those from mesophilic yeasts when they are exposed to heat stress. Therefore, this project aimed to determine the gene expression patterns and roles of molecular chaperones in Antarctic psychrophilic Glaciozyma antarctica PI12 that was exposed to heat stress. G. antarctica PI12 was grown at its optimal growth temperature of 12ºC and later exposed to heat stresses at 16ºC and 20ºC for 6 hours. Transcriptomes of those cells were extracted, sequenced and analyzed. Thirty-three molecular chaperone genes demonstrated differential expression of which 23 were up-regulated while 10 were down-regulated. Functions of up-regulated molecular chaperone genes were related to protein binding, response to a stimulus, chaperone binding, cellular response to stress, oxidation, and reduction, ATP binding, DNA-damage response and regulation for cellular protein metabolic process. On the other hand, functions of down-regulated molecular chaperone genes were related to chaperone-mediated protein complex assembly, transcription, cellular macromolecule metabolic process, regulation of cell growth and ribosome biogenesis. The findings provided information on how molecular chaperones work together in a complex network to protect the cells under heat stress. It also highlights the evolutionary conserved protective role of molecular chaperones in psychrophilic yeast, G. antarctica, and mesophilic yeast, Saccharomyces cerevisiae.

The research covered the determination: of the numbers or hcicrorrophic bacteria: psychrophil ic, psychrctolcrant, mcsophilic and percentage participation or hemolytic bacteria and .ieromonas hydrophila (with acrolysinc and hcmolysine genes) in the waters of the Drwęca River depending on environmental Ilictors and fishery management. The mean quantities 01· hclcrotrophic bacteria (Ht'C) at 4, 14 and 2~°C ranged: O. 78-7.57-101, 1.40-6.65-101 and 1.93-16.23- 103 efuen -3, respectively. The percentage participation 01· hemolytic heterotrophic bacteria (HemPC) and A. hvdrophila among psychrophilic, psychrotolcrant, mcsophilic microorganisms determined at 4, 14, 28°C, ranged: 7.9-10.4, 6.8-12.2, 8.6-22.0 ,111d 1.1-6.4%, respectively. Statistically significant correlation between examined bacteria and temperature values, flows and O2 saturations confirm that the occurrence of those microorganisms depends on the degree of microbiological contamination of that ecosystem, resulting from the fishery management and environmental factors.