BIOGENIC IRON OXIDES FROM LABORATORY CULTIVATED LEPTOTHRIX SP. FOR APPLICATION IN THE BIONANOTECHNOLOGY
RALITSA ANGELOVA1,2*, LYUBOMIR SLAVOV2, MICHAIL ILIEV1, MILENA MITOVA1, BLAGOY BLAGOEV3, IVAN NEDKOV2, VENETA GROUDEVA1
1 – Department of General and Industrial Microbiology, Faculty of Biology, Sofia University “St. Kliment Ohridski”, Sofia, Bulgaria
2 – Laboratory Microwave Magnetics, Institute of Electronics, Bulgarian Academy of Sciences, Sofia, Bulgaria
3 – Laboratory Superconductivity and Cryoelectronics, Institute of Electronics, Bulgarian Academy of Sciences, Sofia, Bulgaria
*Corresponding author: raly_angelova@abv.bg
Keywords: Leptothrix sp., biogenic iron oxides/(oxy)hydroxides, sheaths, bionano-technology
Abstract: The bacteria from the genus Leptothrix have the ability to oxidize Fe2+ at neutral pH. As a result, insoluble iron oxides/(oxy)hydroxides are formed on the bacterial surface called sheath. Such structures and oxides are of great interest for application in nanotechnology.
The goal of this study is to obtain iron oxides/(oxy)hydroxides and sheaths after cultivation of the bacteria under laboratory conditions. The pure cultures of the bacteria isolated from natural habitats and identified by the methods of classical and molecular taxonomy as strains of the genus Leptothrix are used. Few elective media as well as different conditions of cultivation are used. Four media are found to be the most appropriate for bacterial growth and obtaining of the iron oxides/(oxy)hydroxides. The sheaths are formed only on SIGP medium. They are about 7 μm in length, and up to 1 μm in width. The average size of the biogenic nanoparticles is up to 30 nm.
The characterization of the oxides/(oxy)hydroxides and the sheaths formed is performed by different physical methods.
The composition of the growth media as well as the cultivation procedure have strongly influenced the type of ferric oxides formed.