(12a) Development of a Sustainable Bioprocess Platform Technology for Biomass Improvement of Biotherapeutic Strain Lactobacillus Reuteri

The recent market research report has predicted the global probiotic market would be worth USD 32.b billion by 2021, with the Europe and Asia accounting for nearly 42 and 30% of the total revenues, respectively. The Food and Agriculture Organization (FAO) and International Scientific Association of Probiotics and Prebiotics had defined ‘probiotics’ as live microorganisms which will confer a health benefits on the host when administered in adequate amounts. The emergence of probiotic therapeutics had driven major challenges for the probiotic industries. First, selection of a most promising probiotic strain as the industries are looking for multi-potential probiotic bacterial strains. Among numerous species of Lactobacillus are widely used, heterofermentative Lactobacillus reuteri could be most suitable candidate as probiotic industrial workhorse as this bacterium identified to have multiple beneficial effects on host health including prevention and/or amelioration of diverse disorders. In addition, their ‘heterolactic’ fermentation and co-metabolism over wide range of carbon sources has induced synthesis of various organic acids and other valuable bio-active compounds. Yet, scaling up microbial fermentation process is being another challenge for probiotic industries. The selected strains need to be improved to achieve a cost-effective scale up process with several fold improvement in titers. Thus, in this present work, bioprocess strategy was applied to achieve higher cell biomass production of this probiotic bacterium in the semi-industrial scale platform. The strategy involved medium optimization, batch cultivation, optimization of physical parameters and feeding of limiting nutrients. Medium optimization was performed using combinations conventional and statistical methods involving RSM platform. Batch cultivation was performed in 6L stirred tank bioreactor to optimize physical parameters including types of aeration, agitation and controlled or uncontrolled pH cultivations. Further, a fed-batch operation was employed to achieve high cell density with continuous feeding of limiting of nutrients. The key findings were: (i) maximal biomass of 3.56 g L^-1 was produced in the optimized medium compared to 1.67 g L^-1 biomass in the unoptimized MRS medium; (ii) highest biomass obtained under microaerophilic condition; (iii) highest biomass of 6.78 g L^-1 was obtained with further optimization in fed batch cultivation. These results support the industrial use as an alternative to produce probiotics low-cost ingredients to obtain high biomass concentrations in bioreactors.