Optimization of Low-Cost Culture Media for the Production of Biomass and Bacteriocin by a Urogenital Lactobacillus salivarius Strain

Abstract

The aim of this work was to formulate a culture medium of lower cost than conventional laboratory media, in order to simultaneously
obtain high amounts of both biomass and bacteriocin of vaginal Lactobacillus salivarius CRL 1328. The growth assays under different culture conditions were performed by using a 28−2 central composite experimental design, with a central point and sixteen additional points. The factors taken into consideration
were glucose, lactose, yeast extract, tryptone, ammonium citrate, sodium acetate, MgSO4 and MnSO4. The simultaneous presence of a carbon source (mainly glucose), a nitrogen source (mainly yeast extract) and salts (mainly
MnSO4, MgSO4 and sodium acetate) allowed the highest cell biomass and bacteriocin levels to be reached in the experimental design. Through
the application of the desirability function, several optimal medium compositions to achieve efficient production of biomass
and bacteriocin were predicted. The optimized growth media allow a cost reduction of around 25 to 40% compared with conventional
broths. The results obtained represent an advance in the search of the most suitable strategies for the production of bioactive
compounds for pharmaceutical products to prevent or treat female urogenital infections.

KeywordsUrogenital probiotics-Bacteriocin-Culture medium optimization-Desirability function