Light Induction of Biogenic Manganese Oxide Production By Pseudomonas Putida.

Manganese oxides are capable of immobilizing harmful contaminants (such as arsenic and selenium) via oxidation and sorption.  Certain bacteria and fungi have the ability to produce biogenic manganese oxides with greater surface area and higher cation exchange capacity than synthetic manganese oxides.  However, the biological function of manganese oxide production by a manganese oxidizing bacterium, Pseudomonas putida, has not been established.  A laboratory study was conducted to determine if light impacts the production of manganese oxides by P. putida.  Bacteria were grown under different light conditions  for 4 days at 27°C, and the growth medium was assayed for the production of manganese oxides.  Results from this study indicated that light induced biogenic manganese oxide production with significantly more manganese oxides being produced under the ambient and artificial light conditions than in the dark .  This suggests that biogenic manganese oxides may be produced by microorganisms as a protection mechanism against light damage.