Improvement of biomass production by Lactobacillus reuteri using double-carbon source cultivation strategy

Gastric ulcer is caused by Helicobacter pylori which also can cause peptic ulcer and gastric cancer. The rise in the global prevalence of antibiotic resistance leads to a continuous decrease in the eradication rate of H. pylori infection. Recently, probiotic treatment, especially Lactobacillus reuteri supplementation has proven to show inhibitory effects on H. pylori and able to reduce antibiotic-associated side effects. Yet, the efficacy of probiotic treatment is hampered by the lower cell mass production, mainly due to the low efficiency of the fermentation process. In this study, the cultivation medium was optimized by combining two different carbon-sources to enhance cell multiplication. Cultivation media components were optimized by conventional and statistical methods to increase cell mass. In statistical optimization, Plackett-Burman design was used to screen significantly contributing factors in which their composition was then optimized by using response surface methodology. The optimized cultivation medium contained (in g L-1): lactose, 30.0; glucose, 45.15; yeast extract, 33.0; K2HPO4, 2.0; CH3COONa, 3.0; C6H17N3O7, 2.0; MgSO4, 0.5 and MnSO4, 0.05. After culturing in this optimized medium, the cell biomass of L. reuteri produced was 4.12 g L−1 compared to 1.27 g L−1 in sole carbon-source MRS medium. In addition, the highly efficient production process of L. reuteri was also developed by batch cultivation using bioreactor system. The optimized double-carbon source cultivation medium had improved biomass production of L. reuteri fermentation.