Phytate-degrading activity of probiotic bacteria exposed to simulated gastrointestinal fluids

• Probiotic strains exhibited sodium phytate-degrading activity in strain-dependent manner.
• Lactobacillus strains had higher phytate-degrading activity than Bifidobacterium strains.
• Better phytate-degrading activity was observed under acidic gastric conditions.
• Bacteria exposed to simulated GI conditions exhibited phytate-degrading activity.

Phytate is considered an anti-nutrient, because it is not digestible for humans given our lack of phytase activity (PhyA). It has been hypothesized that Lactobacilli may act as carriers of phytate-degrading activity in the gastrointestinal tract. Therefore, the aim of this work was to assess the PhyA of nineteen probiotic bacteria exposed to simulated gastrointestinal fluids. Each culture was inoculated to three different growth media (MRS, MRS-MOPS and MRS-MOPS + AA). Cell-free extracts were used to test for PhyA assay. The highest PhyA (P < 0.05) was observed in MRS-MOPS, which was higher than MRS (control). A decrease in PhyA was observed in crude enzyme extracts (CEE) after exposure to gastrointestinal fluids. However, PhyA was higher at low gastric pH values. PhyA was greater in CEE obtained from bacteria that were previously exposed to simulated gastrointestinal conditions, than in those that were not exposed. CEE from Lc-L9 and Lc-12A strains showed the highest activities under intestinal conditions; while Lc-7R1 and Ls-B1917 were the highest under gastric conditions. The ability of specific probiotic bacteria to degrade phytate after exposure to simulated gastrointestinal conditions was demonstrated, which suggests that these bacteria may contribute to improve phytate degradation in humans during digestion.