ANALYSIS OF GROWTH MODELS FOR BATCH KEFIR GRAIN BIOMASS PRODUCTION IN RC1 REACTION SYSTEM

Abstract

ABSTRACT This work describes the statistical analysis of three mathematical models, modified for describing the kefir grain biomass growth curve. Experimental data of time‐dependent kefir grain mass increase were used. The propagation was performed in RC1 batch reaction system under optimal bioprocess parameters (temperature, rotational frequency of stirrer, glucose mass concentration) using traditional cultivation in fresh, high‐temperature, pasteurized whole fat cow's milk. We compared values of biological parameters obtained by applying the nonlinear regression of experimental data in logistic, Gompertz and Richards models. The most statistically appropriate model was determined using the seven statistical indicators. We established that the kefir grain biomass growth curve during batch propagation under optimal bioprocess conditions can be most successfully described using the Gompertz growth model. PRACTICAL APPLICATIONSKefir grains can be used not only for traditional, large‐scale kefir fermentation but also for bread, ethanol and volatile aroma compound production. When they are produced commercially, it is critically important for optimization, monitoring and controlling of their batch production to develop mathematical models that provide an accurate description of the kefir grain biomass growth curve. Furthermore, these models represent an important tool in any predictive kefir grain biomass growth curve modeling. Their incorporation into the early laboratory development stage can significantly reduce costs associated with the design of industrial kefir grain biomass production plants.Presented results cannot be specified as general for all kinds of batch kefir grain biomass propagations. In spite of all that, the experimental and statistical procedure given in this article can be used to find the statistically best growth model for describing the batch kefir grain biomass growth curve under different experimental and propagation setups.