Modeling and cultivation of some microorganisms on waste substrate hydrolysates

The aim of Diploma thesis was the cultivation of microorganisms Lactobacillus plantarum CCM 7039 and Bacillus coagulans CCM 2658 on hydrolysed spent coffee grounds, production of lactid acid and modelling of these processes to find out more detailed characteristics. First, both microorganisms were cultivated in Erlenmeyer flasks on spent coffee grounds hydrolysate containing lipids and processed by extraction of lipids, e.g. lipid-free. The effect of nitrogen source and inoculation medium were monitored in the course of cultivation. The optimal conditions found were used for subsequent fermentation in bioreactors. Further, microorganisms were cultivated in the Erlenmeyer flasks in the media with individual carbohydrates typical for hydrolysed spent coffee grounds to determine its ability to utilize these carbohydrates. By fermentation in the bioreactors, the yield of lactic acid from carbohydrates was 97 % in Lactobacillus plantarum and 99 % in Bacillus coagulans, respectively. Models for growth and productivity of microorganisms were processed in MATLAB using logistic, generalized logistic and Monod functions. In general, the best data fit was achieved using a logistic function