1994 Volume 40 Issue 4 Pages 349-358
The cells of acidophilic iron-oxidizing bacteria (Thiobacillus ferrooxidans) were immobilized using five kinds of polymers (photo-crosslinkable resin, agar, calcium alginate, k-carrageenan, and gelrite) as gel matrix, and the characteristics of cell immobilization were revealed. Among these gels, gelrite showed promise for application in iron oxidation under strongly acidic conditions. In continuous cultures of iron-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 beads" that harbored a large number of iron-oxidizing bacteria and were the sources of cells living in the liquid phase.