Microbial Interactions between Amylolytic and Non-Amylolytic Lactic Acid Bacteria Strains Isolated during the Fermentation of Pozol.

Pozol is a Mexican beverage prepared from fermented nixtamalized maize dough. To contribute to understanding its complex microbial ecology, the effect of inoculating on MRS-starch pure and mixed cultures of amylolytic -25124 and non-amylolytic 17, isolated from pozol, were studied on their interactions and fermentation parameters. These were compared with A6, an amylolytic strain isolated from cassava. Microbial growth, kinetic parameters, amylolytic activity, lactic acid production, and hydrolysis products from starch fermentation were measured. The population dynamics were followed by qPCR. A6 showed higher enzymatic activity, lactic acid, biomass production, and kinetic parameters than pozol LAB in pure cultures. Mixed culture of each pozol LAB with A6 showed a significant decrease in amylolytic activity, lactic acid yield, specific growth rate, and specific rate of amylase production. The interaction between -25124 and 17 increased the global maximum specific growth rate (µ), the lactic acid yield from starch (Y lactic acid yield from biomass (Y), and specific rate of lactic acid production (q) by 15, 30, 30, and 40%, respectively, compared with the pure culture of -25124. Interactions between the two strains are essential for this fermentation.