Modelling complex growth profiles of Bacteroides fragilis and Escherichia coli on various carbohydrates in an anaerobic environment

Previously published models for microbial growth focus only on either death or growth and are unable to account for differently shaped growth curves. Currently, there is no model capable of incorporating combinations of microbial growth trends. This study creates a bacterial growth model that incorporates growth, death, lag, and tail phases as well as applies this model to the growth trends of Bacteroides fragilis and Escherichia coli on 13 different carbohydrate substances. Growth trends were collected by measuring the optical densities over 72 hours for either B. fragilis or E. coli in a chemically defined media supplemented by a mono- or disaccharide. The Digital Environment to Enable Data-driven Science (DEEDS) platform was utilized to parse data and apply the developed model to obtain parameter values. E. coli was found to grow on the chemically defined media alone while B. fragilis was unable to grow on it alone. E. coli growth was led by 10 mM concentration of substrates while B. fragilis growth was substrate dependent. Bacterial death only occurred for B. fragilis but was found to be dependent on concentration for the two most significant substrates. A singular model was developed that does not require prior knowledge of metabolomics and is capable of incorporating a combination of growth and death trends.