An algal facilitated bacterial oxidation of manganese (Mn 2 +), which overcomes slow of bacteria-only manganese oxidation, was used to produced high yields of oxides using 1.6 g/L Mn 2+ at neutral pH. Metals such as Cu, Zn, Co and Ni can be immobilised in stable co-precipitated manganese oxides. This effect was achieved either by the direct addition of metals during oxidation or by pretreating algal cells with metals prior to oxidation.