IMMOBILIZATION OF THIOBACILLUS-FERROOXIDANS USING VARIOUS POLYMERS ASMATRIX

The cells of acidophilic iron-oxidizing bacteria (Thiobacillus ferroox idans) were immobilized using five kinds of polymers (photo-crosslinka ble resin, agar, calcium alginate, kappa-carrageenan, and gelrite) as gel matrix, and the characteristics of cell immobilization were reveal ed. Among these gels, gelrite showed promise for application in iron o xidation under strongly acidic conditions. In continuous cultures of i ron-oxidizing bacteria immobilized in gelrite beads, a steady state of strong iron oxidation was maintained for a month. The thick layer of iron-oxide precipitates was formed around reddish-brown ''activated be ads'' that harbored a large number of iron-oxidizing bacteria and were the sources of cells living in the liquid phase.