Abstract.1 A short overview of the formation methods of the biofilm with high exoelectrogens activity, which includes alternate partial and complete changes of culture medium, was done in the article. The influence of adaptation processes on electric current generation during the exoelectrogens biofilm formation was analyzed. The article also describes the reasons of sharp current variation, which appeared after nutrient medium changes.
Background. Microbial fuel cells are devices in which electricity is generated by microorganisms called exoelectrogens. During the process of anaerobic respiration exoelectrogens emit electrons outside the cell. These electrons can be transferred to the anode of biofuel cell via several different mechanisms. Electricity generation in microbial fuel cells depends primarily on the electrochemical activity of the exoelectrogens present in the anode space. Nowadays, the usage of microorganisms, immobilized as biofilms on the anode, is constantly increasing. Natural sources for exoelectrogens selection such as activated sludge, biofilter biofilms, sediments of seas and rivers have a very diverse microbial composition. Therefore, it is important to immobilize relatively deficient in natural sources exoelectrogens on the anode during the biofilm formation process. The main research areas are the development of a technique for obtaining of electroactive biofilms enriched with exoelectrogens along with reduction of the period of biofilm formation process. Objective. We set a goal to study the process of high exoelectrogenic biofilm formation basing on the combination of different methods of exoelectrogens isolation and immobilization at the anode of a microbial fuel cell. Methods. A three-stage technique was used to obtain a highly exoelectrogenic biofilm which, due to the combination of typical isolation and immobilization techniques of exoelectrogens, allows obtaining the biofilm in which the vast majority of microorganisms are exoelectrogens. In the first stage, a biofilter biofilm was used as a source of exoelectrogens. The biofilm formed in the first stage was used as an inoculum for the second stage of biofilm formation. During the second stage an additional selective factor (applied additional potential in the electrical circuit of the microbial fuel cell) was used. The third stage of biofilm formation was the isolation of exoelectrogens capable of reducing ferum (III) compounds from secondary biofilm with subsequent application of these cells as inoculum.Results. The usage of the proposed method allows obtaining of a biofilm enriched with exoelectrogenic bacteria. The maximum current density generated by the biofilm, obtained during the first stage, reaches 140 μA/cm 2 , during the second -400 μA/cm 2 , during the third -615 μA/cm 2 . The duration of biofilm formation at each stage was 110 h, 40 h, and 60 h, respectively. Conclusions. It has been proven that the duration of biofilm formation is reduced almost twice as a result of a combination of typical methods of isolation and immobilization of exoelectrogens; obtained biofilm has high electrochemical activity and properties similar to biofilm, formed by pure cultures of exoelectrogens.
The article focuses on the issues of physical training (PT) for senior schoolchildren in future, the cadets of Donetsk Law Institute of the Ministry of Internal Affairs of Ukraine. The purpose of the article is to substantiate the feasibility of using the system of exercises «Fitness Boot Camp» to motivate senior schoolchildren to PT classes. It is noted that today, there is an extremely low general physical training of senior schoolchildren, future cadets. That is why, in order to involve senior schoolchildren into PT classes in modern life, it is necessary to choose such types of health and physical activity, to be effective not only for health, but also attractive from the emotional side. The program “Fitness Boot Camp” is built on the principles of American recruits training and includes a mix of sit-ups, push-ups, Burpee and other «sweets» of Army life. The main purpose of «Fitness Boot Camp» is to force a person to exceed their physical capabilities, to "jump above the head". The mentor in «Fitness Boot Camp» gives not commands, but orders, and often even in a raised voice. In a pilot program for schoolchildren «Fitness Boot Camp» in Donetsk Law Institute of the Ministry of Internal Affairs of Ukraine include: combat training; basics of topography; basics of tactics; handling of weapons; special physical training. During such training sessions, much attention is paid to physical exercises of strength and aerobic orientation, especially working and strengthening the muscles of the arms, legs and back. The program «Fitness Boot Camp» for future police officers can be considered as a rational way to improve the physical qualities of senior schoolchildren, the opportunity to join the training program of cadets and demonstrate the benefits of this profession.
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