It is known that normal functioning of a human or animal body requires a balanced qualitative and quan titative composition of intestinal microbiocenosis [1,2]. The intestinal microflora forms the systemic and tissue immunity, and participates in the fat and pigment metabolism, digestive enzyme production, and endogenous synthesis of vitamins and substances hav ing bactericidal action on pathogenic organisms [3,4]. A considerable stimulating effect on the generation, growth, and functional activity of the microflora is exerted by food biopolymers (prebiotics), which are not digested or uptaken in the upper gastrointestinal tract of the host organism but are efficiently bioutilized by the colonic microflora.The prebiotic oligo and polysaccharides contain ing β glycosidic bonds that are not cleaved in the upper gastrointestinal tract but are readily hydrolyzed in the intestines by microflora enzymes are most effi cient [5,6]. Currently, the natural polysaccharide κ carrageenan (CG), which has a beneficial effect of detoxification, immune, and metabolic systems of the body, is considered as an efficient prebiotic [7,8].A possible way of enhancing the prebiotic activity of CG is to combine it with complexes of macro and micro nutrient elements, in particular, magnesium ammonium phosphate. It is most convenient to make use of the known ability of polysaccharides to incorpo rate inorganic nanoparticles [9][10][11][12].This communication reports the results of using CG for the synthesis of organomineral nanobiocom posites formed by the double salt magnesium ammo nium phosphate with multielement prebiotic activity (the source of carbon, nitrogen, phosphorus, sulfur, and magnesium readily accessible for microorgan isms).The CG macromolecule used for the synthesis of nanobiocomposites is composed of regularly alter nating 3 O substituted β D galactopyranose (with a sulfo group in the 4 position) and 4 O substituted 3,6 anhydro α D galactopyranose residues (Fig. 1) [13].The water soluble organomineral nanocomposites with a 3-16% content of the inorganic phase were synthesized in an aqueous medium in the presence of CG as a stabilizing matrix for the ammonium magne sium phosphate nanocrystals being formed. It was found that Mg 2+ , , and ions react in the presence of CG to give nanoparticles of the ammo nium magnesium phosphate crystal hydrate such as the mineral struvite NH 4 MgPO 4 ⋅ 6H 2 O. The replace ment of ammonium hydroxide, which is usually employed for the synthesis of struvite [14], by ammo nium chloride results in the nanocomposite being formed in a more physiological pH range (5.3-5.7). The process is described by the following equation: 2MgCl 2 + 4NH 4 Cl + 3Na 2 HPO 4 = NH 4 MgPO 4 ↓ + NH 4 H 2 PO 4 + 6NaCl + 2NH 4 Cl + MgHPO 4 . NH 4 − HPO 2 4 − CHEMISTRY
