The paper considers proliferation of filamentous fungi in electroless nickel plating baths. We determined that it leads to decomposition of processing media and decreased coating deposition rates. We developed a mathematical model for suppressing filamentous fungi growth in electroless nickel plating solutions in the presence of various inhibitors. The model allows us to predict microorganism proliferation rate under the conditions specified. We used experimental data and mathematical simulation as the basis for investigating processing media biodegradation in electroless nickel plating. Our mathematical simulation showed that it is possible to use the Verhulst model to describe the growth kinetics of filamentous fungi colonies. It also allowed us to determine the parameters of the process kinetics, to predict bath electrolyte stability and select efficient inhibitors. We validate our selection of inhibitor substances (copper sulphate, sodium tetraborate, lactic acid, sodium propionate, chloroform) that have a fungistatic or fungicidal effect on biological object proliferation. We developed a mathematical model for the process of inhibiting processing media biodegradation in electroless nickel plating by means of various substances. We substantiate the ambiguity of selecting the initial condition for stating the Cauchy problem in the mathematical description of the process. We present and analyse the results of mathematically simulating the process under consideration. We found sodium tetraborate to be the most efficient biological object proliferation inhibitor, since, as its concentration increases to 50 mmol/l, there is no deterioration in the coating quality; at the same time, the coating deposition rate increases and the necessary fungicidal effect

The publications on the kinetics of lactic acid biosynthesis were analyzed. The review mainly considers foreign publications. The equations formed using the unstructured approach were given. Special emphasis was laid on the equations that received the best experimental rationale. The equations include substrate and product inhibition. The effect of medium acidity on the kinetic constants was evaluated. A nearly neutral medium was shown to be most acceptable for the synthesis of lactic acid. The kinetic equations including the specific product formation and substrate utilization rates in addition to the specific biomass formation rate were presented. The values of kinetic constants were given.

The scientific work is devoted to mathematical modeling of heterotrophic microalgae cultivation in a fed-batch bioreactor with aeration and mechanical mixing. The multiphase mathematical model, taking into account processes in a cell and on the cell-nutrient medium bound, was developed. By means of analyses of the experiment results it was shown that growth characteristic change takes place after glucose addition in the fed-batch bioreactor. Regularities of these changes were revealed.

A mathematical model of microbial cultivation is developed that describes the emergence of biomass oscillations under continuous conditions with a period shorter than the culture generation time. The model constants at which the calculation results are in the best agreement with experimental data are found. The phase portrait of the system in the oscillation mode is analyzed. The possibility of using the model for describing the behavior of different cultures in different modes is demonstrated.