Production and initial characterization of bionites: materials formed on a bacterial backbone

See allHide authors and affiliations

Science  04 Dec 1992:
Vol. 258, Issue 5088, pp. 1633-1636
DOI: 10.1126/science.1455245


The addition of soluble metal salts of calcium, iron, or copper to cultures of Bacillus subtilis grown in web form nucleated precipitation at the surface of the bacterial cell walls. The mineralized cell filaments can be drawn into a fiber that when dried consists of a bacterial thread backbone carrying an inorganic solid. The ratios of organic to inorganic components (by weight) in the stiff brittle materials, called bionites, were: 1.08 for fe(2)bactonite, 1.8 for calbactonite, 2.3 for fe(3)bactonite, and 5 for cu(2)bactonite. X-ray photoelectron spectra suggest that the fe(3)bactonite contains Fe2O3, that calbactonite contains calcium carbonate, and that cu(2)bactonite contains CuCl (Cu I). Acid-base reactions of the bionites are compatible with these identifications. Burning out the organic phase of the febactonites yields a black magnetic material, presumably magnetite. The burnt cubactonite appears to yield elemental Cu(s). Calbactonite upon hydration was able to retain a genetically engineered enzymatic activity.