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.
Emerging Infections: Shewanella – A Series of Five Cases
