Heterotrophic Iron‐Precipitating Bacteria

Abstract

In this study, non‐filamentous heterotrophic bacteria with the ability to cause iron precipitation were isolated from water in a ferric ammonium citrate medium. Aerobacter aerogenes was the most common of the organisms found, especially in surface waters. All the bacteria appeared to have two characteristics in common, the ability to utilize citrate as a carbon source and the production of capsular material. Microscopic observations showed a large capsule which appeared to be encrusted with iron. Much of the iron can be removed with the capsule by sonication. In the ferric ammonium citrate medium where the iron is bound with citrate and ammonia, it is hypothesized that this complex material is absorbed into the cell, the carbon from the citrate is utilized, and the remaining iron is absorbed in the capsule. Although different types of organisms were isolated, three cultures were chosen and studied, Aerobacter aerogenes, Serratia indica, and Bacillus pumilus. As in much of the previously reported work, ferric ammonium citrate was used as the organic iron complex. The advantage of this compound is that iron is held in solution under alkaline conditions as high as pH 9.0‐9.5. None of the cultures produced a pH high enough to cause iron precipitation.

Seasonal and Spatial Distribution of Iron Precipitating Heterotrophs in Water and Sediments of Fish Ponds of Differing Farming Managements

“…Kalyani and Naihati are represented in t8he figures as Nos 1 and 2, respectively. The morphonietry, manuring and stocking programmes followed in the three types were described in detail by PATEL (1982), JANA I n the present investigation, iron precipitating heterot,rophs were grown on ferric ammonium citrate agar medium (CLARK et al 1967). Water and surface sediment samples for microbial examination were collected from the ponds twice a month from July 1978 to October 1980, and the two samplings were averaged in order to calculate standard error of the mean.…”

Effet de berge, effet de vase, deux facteurs différents de mobilisation du manganèse : un exemple dans un champ captant de la vallée du Lot (France)

“…Des observations au microscope optique de microorganismes ont été effectuées à partir de cultures réa-lisées sur un milieu pour Leptothrix (Mulder & Van Veen 1972) et sur un milieu, pour bactéries hétéro-trophes, au citrate ferrique (Clark et al 1967). …”

“…La mise en culture d'échantillons d'eau provenant des forages FE2 et FE6 dans le milieu au citrate ferrique pour bactéries hétérotrophes (Clark et al 1967), n'a pas permis d'obtenir un développement bactérien. Par contre, dans le milieu pour Leptothrix des bactéries ont pu être observées au microscope à immersion entre 8 jours de culture.…”

Study and interpretation of the chemical characteristics of natural water

“…Reduction or oxidation of iron may occur incidentally, and iron may play no essential role in the life processes of the bacteria. Some species of bacteria that have been shown to influence the behavior of iron are discussed by Clark, Scott, and Bone (1967). The effect of bacteria may thus be either to increase or to decrease dissolved-iron concentrations in water.…”