Myo-inositol hexakisphosphate degradation by Bifidobacterium infantis ATCC 15697

The ability of five strains of different bifidobacterial species (Bifidobacterium animalis, B. bifidum, B. infantis, B. longum, B. pseudolongum) isolated from human and animal gut to degrade myo-inositol hexaphosphate or phytic acid (InSP6) has been evaluated. The disappearance of phytate and the generation of lower myo-inositol phosphates were determined in a complex medium in which phytic acid was the only source of phosphorus. Bifidohacterium infantis ATCC 15697 showed the highest level of phytate-degrading activity. This strain displayed optimal activity at slight acid pH (6.0-6.5) and 50 degrees C, but also retained high activity levels at neutral pH and 37 degrees C. B. infantis ATCC 15697 produced maximum activity during the stationary phase of growth and when 1% lactose was used as carbon source. In contrast, the presence of inorganic phosphate in the growth medium inhibited phytase activity. The ability of B. infantis ATCC 15697 to generate lower nqo-inositol phosphates and, particularly, accumulate myo-inositol tri-phosphates (InsP(3)) from partial hydrolysis of InSP6 could contribute to the reduction of the anti-nutritional properties of InSP6 and the generation of intermediate compounds with beneficial properties during food processing and gastrointestinal transit. (c) 2007 Elsevier B.V. All rights reserved.