Statistical medium optimization for enhancing high biomass production of Lactobacillus reuteri using response surface methodology

Abstract

The high cell mass production of probiotic lactic acid bacteria using low-cost substrate is critical for successful large-scale production. Lactobacillus reuteri DSM20016T is a heterofermentative lactic acid bacterium that is well recognized for its probiotic properties. Defining an optimal cultivation medium could enhance the yield and reduce the production cost as well. In this paper, seven media reported in the literature were reviewed and assessed for their capability to be used as a growth medium of L. reuteri. The most appropriate cultivation medium for L. reuteri, which has reached the best cell mass yield, annotated M5, was selected. The selected medium from the screening stage was optimized using response surface methodology (RSM). The optimized medium composition was (gL-1): sucrose (55), yeast extract (44), sodium acetate (2.6), tri-ammonium citrate (0.2), KH2PO4 (0.2), Mg SO4 (0.2), Mn SO4 (0.05), and NaCl (0.01). The comparative study showed 28% increase was achieved in the optimized medium with the yield of 3.31 gL-1 compared to the cell mass production in the unoptimized medium that was 2.59 gL-1. A significant cell mass growth rate accompanied the achieved increment. Finally, an optimum medium was proposed for enhanced cell mass production.