(655f) Bioprocess Development for High Cell Mass and Bioactive Antimicrobial Metabolites Production of Lactobacillus Reuteri

Nowadays, it has been well understood that the gastrointestinal (GI) microbiota play vital role in human health beyond digestion and production of vitamins and bioactive metabolites. In addition, they contribute in prevention in many diseases by inhibiting pathogens, regulate body metabolism, and enhance immune system. This has driven the growth of global probiotic market and increased the need to develop new processes for probiotics cultivation. However, selecting the most promising probiotic strain being one of the current challenges as the probiotic industries. Among numerous species of Lactobacillus widely used, the heterofermentative Lactobacillus reuteri exhibits multiple beneficial effects on host health including prevention and/or amelioration of diverse disorders. L. reuteri is characterized by high consumption rate of carbon sources and accumulate organic acids and other antimicrobial metabolites such as reuterin which inhibit the colonization pathogenic microbes naturally. In 1960s, it was reported that L. reuteri forms 30 – 40 percent of the human total GI microbiota. However, recent studies revealed that population of L. reuteri in the GI environment has decreased to below 20 percent, in major world population. Notably, dysbiosis in the population of L. reuteri from human GI in the past decades has correlated with numerous inflammatory diseases reported over the same time periods. Direct supplementation and prebiotic modulation to enhance L. reuteri could be a promising therapeutic avenue. In the present work, studies have been carried out to enhance higher cell growth kinetics to improve cell mass production of this probiotic bacterium in semi-industrial scale. Different formulations were optimized by conventional and statistical methods to increase cell mass and synthesis of reuterin “an important bioactive metabolites against Helicobacter pylori”. A maximal biomass of 3.56 g L^-1 was produced in the conventionally optimized medium compared to 1.67 g L^-1 biomass in the MRS medium. Further developed in high biomass and reuterin production was achieved by optimizing bioprocess engineering parameters in semi-industrial scale bioreactors using different batch and fed-batch cultivation strategies.