Biotechnological application of homo- and heterotrinuclear iron(III) furoates for cultivation of iron-enriched Spirulina

Abstract

New trinuclear iron(III) furoates with the general formula [Fe 3O(α-fur) 6(R–OH) 3] X, where α-fur C 4H 3OCOO, R = CH 3 ( 1), C 2H 5 ( 2), n-C 3H 7 ( 3), n-C 4H 9 ( 4), X = NO 3 − ( 1– 4); [Fe 3O(α-Fur) 6(DMF)(CH 3OH) 2]NO 3 ( 5); [Fe 3O(α-Fur) 6(H 2O)(CH 3OH) 2]Cl ( 6); [Fe 2MO(α-Fur) 6(L)(H 2O) 2], where L = THF ( 7– 9), DMF ( 10– 12), M = Mn 2+ ( 7, 10), Co 2+ ( 8, 11), Ni 2+ ( 9, 12) and [Fe 2MO(α-Fur) 6(3Cl-Py) 3], where M = Mn 2+ ( 13), Co 2+ ( 14), Ni 2+ ( 15); have been prepared and investigated by Mössbauer and IR spectroscopy. The X-ray crystal structure for the 1·2CH 3OH complex indicates that it crystallizes in the monoclinic crystal system ( P2 1/ n) and has a structure typical of μ 3-O-bridged trinuclear iron(III) compounds. Coordination compounds 1, 4, 7, 8 can be used as regulators of the biochemical composition of cyanobacterium Spirulina platensis biomass. The supplementation of these compounds, in concentrations exceeding 5–10 mg/l, increases the content of iron, amino acids, peptides and carbohydrates in Spirulina.