Biocides are widely used in medicine and various industries to protect against a number of harmful microorganisms. Organic quaternary ammonium and guanidine-containing compounds, the biological action of which is based on membrane-toxic properties, are used as bactericidal preparations. The aim of this work was to study the bactericidal and fungicidal activities of the synthesized oligomeric alkylsubstituted guanidinium bromides with different radicals -C3H7, -C7H15, -C10H21, against different isolates of heterotrophic bacteria and microscopic fungi. Methods. The synthesis of alkyl-substituted guanidiniumcontaining oligomers was performed in two stages. In the first stage, alkyl-substituted guanidine was obtained by the reaction of guanidine, previously converted by alkali from the salt form to the base form by the base and alkyl bromides (Alk=-C3H7 (propyl), -C7H15 (heptyl), -C10H21 (decyl)) in methanol at a temperature of 50°C and a molar ratio of 1:1. The second carried out the reaction between aromatic oligoepoxide DER-331 and alkyl-substituted guanidine in methanol at a temperature of 50°C for 2–3 hours and a molar ratio of 1:2. Bacteria were grown on meat-peptone agar for 48 hours at a temperature of 28±2°С. Test cultures of micromycetes were cultured on agar beer wort (6°B), incubated for 14 days in a thermostat at a temperature of 28±2°C. Antimicrobial activity of newly synthesized alkyl-substituted guanidinium-containing oligomers was determined by standard disco-diffusion method (method of disks on agar) and fungicidal activity was determined by the method of holes in agar. Results. Oligomeric alkylsubstituted guanidinium bromides with different radicals composed -C3H7, -C7H15, -C10H21- synthesized by the reaction of guanidine alkyl bromides with aromatic oligoepoxydes. It was found that alkyl-substituted guanidinium-containing oligomers at a concentration of 1–3% inhibited the growth of Escherichia coli 475, Pseudomonas aeruginosa 465, Klebsiella pneumonia 479, Pseudomonas pseudoalcaligenes 109, Staphylococcus aureus 451, E. faecalis 422, Rhodococcus erythropolis 102, Bacillus subtilis 138 and most of the studied micromycetes – Aureobasidium pullulans F-41430, Paecilomyces variotii F-41432, Penicillium funiculosum F-41435, Penicillium ochrochloron F-41431, Scopulariopsis brevicaulis F-41434, Trichoderma viride F-41437, Candida albicans F-41441, Aspergillus flavus F-41442, Aspergillus niger F-41448, Penicillium sp. F-41447. Conclusions. Antimicrobial and fungicidal properties significantly depend on the length of the alkyl radical, with increasing of its length the diameter of the zone of bacterial and micromycetes growth retardation increases.10.15407/microbiolj82.06.054

There is information in the literature about the salts of polyhexamethylene guanidine (PGMG), which are effective biocidal and sterilizing drugs and disinfectants due to the wide range of their antimicrobial activity against gram-positive and gram-negative bacteria (including Mycobacterium tuberculosis), viruses, and fungi. The aim of this work is to study the bactericidal and fungicidal activity of the synthesized polyetherguanidinium chloride against a number of bacteria and microscopic fungi. Methods. Cultivation of microorganisms. Bacteria were grown on meat-peptone agar for 48 hours at a temperature of 28±2°C. Test cultures of micromycetes were cultured on beer wort agar (6°B), incubated for 14 days in a thermostat at a temperature of 28±2°C. Antimicrobial activity of newly synthesized polyetherguanidinium chloride was determined by standard disco-diffusion method, and fungicidal activity was determined by agar diffusion method. Results. The synthesis of polyetherguanidinium chloride was carried out in two stages. The first stage was the synthesis of a guanidinium-containing oligoether with terminal guanidine moieties by the reaction between an aromatic oligoepoxide and guanidine. The second stage was the synthesis of polyetherguanidinium chloride by the reaction between a guanidinium-containing oligoether with terminal guanidine moieties and oligooxyethylenediamine. The bactericidal and fungicidal activity of polyetherguanidinium chloride against various heterotrophic bacteria and microscopic fungi has been shown. It was found that polyetherguanidinium chloride at concentrations of 1–3% inhibited the growth of gram-negative (Escherichia coli 475, Klebsiella pneumonia 479) and gram-positive (Staphylococcus aureus 451) bacteria. The proposed 1% solution of polyetherguanidinium chloride shows a 1.5 times higher antimicrobial activity than the polymeric disinfectant polyhexamethyleneguanidinium chloride for E. coli 475 and K. pneumoniae 479 bacteria and lower antimicrobial activity for S. aureus 451 bacteria. According to the obtained data, it was noted that polyetherguanidinium chloride at a concentration of 1% had a high fungicidal activity against almost all investigated isolates: Aspergillus versicolor F-41250, Acremoneum humicola F-41252, Acremoneum roseum F-41251, Cladosporium sphaerospermum F-41255, Paecilomyces lilacinus F-41256 and Scopulariopsis candida F-41257. Conclusions. Received polyetherguanidinium chloride at a concentration of 1% showed bactericidal activity against S. aureus 451, E. coli 475, K. pneumoniae 479 and fungicidal effect to all fungi studied by us, and so can be used as a disinfectant for building materials.

Polymer materials are an integral part of our lives, but their use is a global environmental problem. Despite this, the development of modern approaches to the utilization of used polymer and rubber materials is currently relevant, including the using of anaerobic microbial destruction of polymers by sulfatereducing bacteria. The aim of the work. To study the ability of sulfate-reducing bacteria to utilize rubber and polymer materials such as solid rubber, ethylene vinyl acetate and foamed polyethylene. Methods. Microbiological (cultivation of sulfate-reducing bacteria, method of serial dilutions), biochemical (Lowry method, measurement of enzymatic activity), physical and chemical (gravimetry, iodometry, potentiometry, gas chromatography-mass spectrometry). Results. It was shown that in the presence of the studied materials as the sole sources of carbon, the amount of sulfate-reducing bacteria increased by 2–3 orders compared to the control without adding the materials. On the 90th day of the experiment the destruction coefficients of the studied materials were low and reached KD=0.21–2.88%. In the cultivation medium with the introduced studied materials, the metabolic and enzymatic activity of sulfate-reducing bacteria are changed, in particular, the production of hydrogen sulfide in the presence of ethylene vinyl acetate and foamed polyethylene increased by 0.8–3 times, and rubber – decreased by 1.2–3.5 times. The catalase activity of the studied bacterial cultures was decreased by 1.4–3.4 times compared to the control without adding of materials. During the exposure period with adding the materials, the lipase activity of bacterial cultures decreased and in some cases almost disappeared. The introduction of materials led to increasing of the short-chain fatty acids synthesis by Desulfovibrio desulfuricans DSM642 and D. vulgaris DSM644 strains, while, on the contrary, Desulfovibrio sp. 10 strain showed the decreasing in acid production. The introduction of rubber only in D. vulgaris DSM644 culture leads to the increasing of acetic and propanoic acids synthesis by 59% and 49.5%, respectively, compared to the control without the introduction of the studied materials. The synthesis of acetic acid in the presence of foamed polyethylene and ethylene vinyl acetate in the cultural liquid of sulfate-reducing bacteria increased by 46.2–419.5% and 69.8–92.6%, and propane – by 23.1–46.2% and 71.9–159.0%, respectively. Conclusions. The presence in cultivation media of rubber, foamed polyethylene and ethylene vinyl acetate as a sole carbon sources led to the changes in enzymatic activity (catalase and lipase), the intensification of hydrogen sulfide synthesis by bacteria was observed as well as acetic, propanoic and butanoic acids synthesis increased. This indicates the potential of sulfate-reducing bacteria to utilize the studied materials via acid formation.