Authors: Susanne Machill Lydia Köhler Susanne Ueberlein René Hedrich Marco Kunaschk Silvia Paasch Renate Schulze Eike Brunner
Publish Date: 2012/12/25
Volume: 26, Issue: 1, Pages: 141-150
Abstract
The eukaryotic diatoms are unicellular algae They are well known for their filigree micro and nanostructured cell walls which mainly consist of amorphous silica as well as various organic compounds However diatoms are also known to incorporate certain amounts of aluminium into their cell walls Unexpectedly enhanced Al concentrations in the Southern Yellow Sea were found to be correlated with a diatom spring bloom Therefore we have analyzed the influence of strongly enhanced Al concentrations in the culture medium upon the growth behaviour of the diatom Stephanopyxis turris S turris The uptake and incorporation of Al into the cell walls was monitored It turned out that S turris survives aluminium concentrations up to 1055 μM 285 mg/l in the culture medium Under the applied conditions this corresponds to an Al/Si ratio of 11 These large amounts of Al had to be offered in the form of bis–trischelates in order to prevent uncontrolled precipitation Under these conditions the Al/Si ratio in the cell walls could be increased up to about 115 as determined by ICPOES the highest amount of aluminium found in diatom cell walls yet Structural characterization of the biosilica by ATRFTIR and solidstate 27Al NMR spectroscopy revealed that an amorphous aluminosilicate phase is formed where the aluminium exists as four and sixfoldcoordinated species
Keywords: