Improving the Energy Efficiency of a Shell-and-Tube Jet-injection Fermenter for Aerobic Cultivation of Microorganisms

The main objective of the study is to improve energy efficiency of a shell-and-tube jet injection fer-menter (SJT) for aerobic cultivation of microorganisms. The relevance of the work is determined by the biotechnology industry’s need to transition to energy-efficient cultivation processes. Using high biomass concentrations increases specific productivity, yet creating such bioreactors requires precise knowledge of thermophysical and mass transfer properties of dense suspensions, which are currently lacking. To achieve the stated goal, the following tasks were solved: a scientific literature review; development of an experimental methodology; selection of research objects (water-suspended Sac-charomyces cerevisiae at 4.81–20.17 wt.% ADY); analysis of rheological behavior and thermal con-stants from 10 to 50°C (283.15-323.15 K) with 10°C steps; and derivation of regression equations. The most important results are experimentally established heat and mass transfer patterns. The ex-istence of limiting concentration, at which the nature of the suspension flow changes fundamental-ly, was discovered. It was revealed that at low shear rate gradients, water-yeast suspension behaves like pseudoplastic fluids, but with an increase in the velocity gradient, their behavior becomes char-acteristic of dilatant fluids. Also, after 30°C thermal conductivity - previously declining- began to rise, likely as yeast cells perished. The significance of the obtained results lies in their further use in laboratory testing of the characteristics of supplied raw materials, in choosing technological modes for culturing microorganisms in production, as well as in heat and mass transfer calculations in the design of modern apparatus designs.