PILOT-PLANT SCALE BIOMASS PRODUCTION BY LACTOBACILLUS RHAMNOSUS GG ATCC 53103: A COMPARISON BETWEEN BATCH AND FED-BATCH FERMENTATION

Abstract

Probiotics such as Lactobacilli are important in improving normal intestinal flora and hindering the growth of harmful bacteria in the digestive system. Given the above reasons, the industrial production of probiotics and the use of high-yield strains is of great importance. The present study compares the biomass production by Lactobacillus rhamnosus GG ATCC 53103 in batch and fed-batch cultures conditions at a pilot plant scale. An optimized medium containing the following compounds (g/L): glucose 112.50, sugar 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 Simethicone 1.25 was used for biomass production. During the fermentation process, culture conditions such as pH, temperature, and oxygen concentration were monitored using process analytical technology (PAT). Based on the obtained results, the maximum biomass production in the batch condition in the first 20 hours of culture in the optimized medium was about 68.14 g/L. After three stages of fed-batch culture, the biomass production by L. rhamnosus GG ATCC 53103 reached 93.5 g/L at 37°C with agitation and aeration rates of 100 rev/min and 300 VV-1min-1, respectively. Therefore, biomass production increased about 2.67-fold more than the basal medium.