STUDIES ON THE CHEMOAUTOTROPHIC IRON BACTERIUM FERROBACILLUS FERROOXIDANS II

Publisher Website
Google Scholar
Abstract
Some of the physiological properties of this obligate chemoautotrophic Fe-oxidizing bacterium were studied manometrically using intact cells. Fe was oxidized at an unusually rapid rate (Q02 (N) of from 2027 to 5131). O2 uptake was over 92% of the theoretical amount required by the reaction: 4FeSO4 + O2 + 2H2SO4[forward arrow]2Fe2(SO4)3 + 2H2O The optimal pH and temperature for the Fe-oxidizing system were 3.0 to 3.6 and 37[degree]C, respectively, although no growth occurred at 37[degree]C. There was no evidence of Fe toxicity to the intact cells at concentrations as high as 500 [mu]M Fe++ per Warburg vessel. During the oxidation of 50 [mu]M of Fe, F. ferrooxidans assimilated an average of 0.97 [plus or minus] 0.20 [mu]M CO2 with an average efficiency of 20.5 [plus or minus] 4.3%. Phosphate moderately inhibited Fe oxidation; citrate was strongly inhibitory. Resting cells were unable to oxidize ammonium, thiosulfate, di- and tetravalent Mn, Co, or Ni. However, a slow but significant oxidation of elemental S was observed.