THEORETICAL PRINCIPLES AND PRACTICAL RECOMMENDATIONS IN CHOOSING ENZYMES FOR AEROBIC CULTIVATION OF BIOLOGICAL AGENTS
Authors:   National Technical University of Ukraine ", Povodzynskyi Vadym ,   Ihor Sikorskyi Kyiv Polytechnic Institute",   , Ukraine
Published: May 2023

This part of the collective monograph is devoted to the discussion of the main object of biotechnology, namely, the effectiveness of the cultivation of biological agents. Based on this position, the subject of this scientific research is the analysis of the situation, about how the physiological and biochemical properties of biological agents determine the choice of equipment for the cultivation of biological agents in aerobic conditions. The methodology for the implementation of this subject of scientific research is that for the implementation of mass transfer processes and the analysis of technical features of fermenters at the cultivation stage, an analysis of hydrodynamics in the fermenter is required due to the design characteristics of the devices. The work provides an analysis of specific phenotypic features of biological agents and defined conditions for effective realization of their genetic potential during cultivation. Modern biotechnology at the stage of cultivation of biological agents focuses on the use of fermenters of various designs, but there are no scientific and practical recommendations, so the purposeof this work was to create a classification of fermenters depending on the methods of energy input, taking into account the features of the technology. For aerobic biological agents, the influencing factors at the cultivation stage are the mass transfer efficiency of the limiting substrates and the uniformity of the phase distribution in the volume of the fermenter. In the known designs of industrial fermenters, various systems of energy input into the culture liquid are used for effective mass transfer of limiting substrates and homogenization of interacting phases. This part of the monograph provides an analysis and rationale for the classification of typical industrial designs of fermenters by energy input methods, which makes it possible to select equipment for effective cultivation, taking into account the specifics of biological agents. Classification according to general characteristics is a guarantee of the correctness of calculations of hydrodynamic, mass exchange and heat exchange characteristics. The overview of fermenter designs presented in the monograph revealed that this type of device design is the simplest and most reliable due to the absence of moving parts of the design and the simplicity of the body elements. The conclusion of the presented work is that the choice of devices of this type can be proposed for microbial protein biotechnologies when using yeast as biological agents that are resistant to contamination. This part of the monograph makes it possible to identify biotechnologies for which it is appropriate to use devices of this type using the above classification based on the efficiency of the mass transfer processes of the limiting substrate – oxygen and on the structural features of the fermenter. Such biotechnologies include the production of feed microbial protein in non-aseptic cultivation conditions with a high rate of oxygen consumption. In the given review of specific physiological and biochemical features and specifics of the culture fluid, the possibility of using these devices for technologies with difficult-to-dissolve substrates is determined. A significant limitation of the use of devices of this type is the presence of significant shear forces during aeration of the culture liquid, which does not allow the cultivation of biological agents that are affected by shear forces.