Experimental Research and Mathematical Modeling of Cultivation Processes of Halophilic Communities of Algae and Bacteria

The aim of the research is to study the kinetics of growth and cultivation of halophilic microalgae and bacteria communities, develop a mathematical model and implement a software module for calculating the growth process of this community. In laboratory conditions, a controlled metabolically coupled (closed) system based on the components (microorganisms) of extremely halophilic communities has been created. The resulting system allows to co-cultivate with minimal aseptic requirements (sterility) and subsequently can be used on an industrial scale to obtain useful and unique biologically active compounds: carotenoids, osmoprotectors, thermostable enzymes. The results of experimental studies on the cultivation of extremely halophilic microalgae Dunaliella salina and bacteria Salicola marasensis are presented. Using Monod equation, microalgae growth rates were obtained for various growth-limiting components contents. The optimal value of its concentration was following: for phosphates—0.2 g/l, nitrates—2 g/l. The value of the nitrogen saturation constant was obtained by the Cornish-Bowden method. Based on the predator–prey model, a mathematical model was developed for the growth of halophilic microalgae and bacteria communities. The model is a system of differential equations solved by the difference method. An algorithm for solving equations of a mathematical model and a software module based on it are developed. To implement the algorithm the Python programming language was selected. The values of the model parameters are determined. The results of calculations by a mathematical model correspond to experimental data.