Optimization of biomass production by probiotic bacterium Lactobacillus rhamnonsus at pilot-plant scale

 Probiotics play a very important role in improving the normal intestinal flora and inhibit the growth of harmful bacteria in the gastrointestinal tract and are also important for therapeutic purposes. This study aimed to optimize biomass production by Lactobacillus rhamnosus ATCC53103 (GG) using the experimental design process.

 In this study, the probiotic bacterium Lactobacillus rhamnosus was used. Plackett-Burman design method was used for the optimization. Fermentations in basal and optimized cultures were performed in 1300 liter Parspad Company's fermenters.

 The results showed that beet molasses, glucose, and casein have the greatest effect on biomass production by Lactobacillus rhamnosus. Glucose with casein and beet molasses have a synergistic effect and increasing the concentration of glucose with increasing the concentration of two other factors increases the production of the biomass. Based on the results obtained, after optimization, the optimal culture medium for biomass production by Lactobacillus rhamnosus has the following compounds g/L-1: glucose 112.50, beet molasses 56.25, casein 18.75, yeast extract 18.75, K2HPO4 13.13, Tween 80 1.88, MgSO4. 7H2O 0.3750, MnSO4. 4H2O 0.0750, CaCl2. 2H2O  0.1875 and Simethicone1.25. The biomass production in optimized conditions was increased more than 2-folds higher than the basal medium.

 Biomass production by Lactobacillus rhamnosus on a semi-industrial scale was carried out in 1300 liters fermentors. Therefore, the results of this study can be used in the industrial production of Lactobacillus rhamnosus biomass. Also, commercial production under fed-batch and continuous culture conditions is recommended.