Growth of ‘Knallgas’ Bacteria (Hydrogenomonas) using Direct Electrolysis of the Culture Medium

Abstract

IN view of the recent discussion pertaining to the use of the ‘knallgas’ bacteria for the regeneration of exhaled air^1–3, we should like to point out that it is possible to produce the oxygen–hydrogen mixture directly in the culture vessel by electrolysis of the mineral medium, Since the ‘knallgas’ bacteria of the Pseudomonas type (Hydrogenomonas strains H 16 and H 20) grow in chloridefree medium, oxygen and hydrogen can be produced in such a medium without interfering with side-effects using platinum electrodes with a relatively large surface area. Carbon dioxide is led directly into the culture vessel and removes excess oxygen. By using currents between 0.1 and 1.2 amp and at voltages not exceeding 5.3–5.5 V, good growth is achieved^1,4. At low current-levels, growth is proportional to, and limited by, the hydrogen produced.