Carbon Dioxide Fixation and Phosphoenolpyruvate Carboxylase in Ferrobacillus Ferrooxidans

Abstract

Carbon dioxide fixation was studied in intact cells and cell-free extracts of Ferrobacillus ferrooxidans. The major pathways of fixation were found to be the carboxydismutase system and the phosphoenolpyruvate (PEP) carboxylase system. PEP carboxylase activity was shown to be under metabolic regulation, similar to the regulation established in heterotrophic microorganisms.Acetyl-CoA stimulated PEP carboxylase activity, while aspartate was inhibitory. The F. ferrooxidans enzyme appeared to have a neutral or acidic pH optimum, in contrast to the same enzyme isolated from heterotrophs.

Energy-Coupling Mechanisms in Chemolithotrophic Bacteria

“…It was found to be similar to the pattern obtained with photosynthetic orga nisms and compatible with the operation of the ribulose diphosphate path way. Similar results have been reported with whole cells of T. thiooxidans (179 ), H. facilis (180,181 ), Nitrobacter (21,182), Nitrosomonas europaea (183), Ferrobacillus ferrooxidans (184,185), Micrococcus denitrificans (128), and Pseudomonas oxalaticus (160).…”

“…Similar results have been ob tained with H ydrogenomonas (187,191 ). Although the sum of these results conclusively establish the ribulose diphosphate pathway as the major path way of carbon dioxide fixation in chemolithotrophic bacteria, other lesser pathways may contribute significantly to carbon dioxide fixation (184,193,194) and its regulation.…”

“…More re cently, crude extracts of this organism have been prepared in which the specifi c activity of the enzyme approaches that found in green plants (188). Carboxydismutase has now been demonstrated in all groups of chemolithotrophic autotrophs (21,128,160,183,184,189,190). By making use of the unique properties of the facultative autotrophs, T. novellus and Hydrogeno monas, it has been possible to demonstrate the autotrophic nature of the ri bulose diphosphate pathway by comparing the levels of carboxydismutase in heterotrophically and autotrophically grown cells.…”

The effect of carbon dioxide and particle surface area on the microbiological leaching of a zinc sulfide concentrate

“…ferrooxidans. This hypothesis has been supported subsequently by the investigations of Gale and Beckz4 and by Din et al 25 I n studying the effect of carbon dioxide on bacterial activity, Bryner et aL2 found a gradual decrease in the rate of oxidation of pyrite by T . ferrooxidans as carbon dioxide was removed from the aerating air.…”

The role of Thiobacillus ferrooxidans in hydrometallurgical processes

“…Therefore, this process would thermodynamically be impossible without the simultaneous assimilation of metabolic energy [218]. The Calvin cycle has been suggested [98,219,220] as a possible way for the carbon dioxide fixation by T. ferrooxidans. By studying the effect of carbon dioxide on bacterial activity, it has been observed [221 ] that the rate of pyrite oxidation by T. ferrooxidans gradually decreased upon removing the carbon dioxide from air used for aeration.…”