TY - JOUR
T1 - Influence of lepidocrocite (γ-FeOOH) on Escherichia coli cultivability in drinking water
AU - Grandjean, D.
AU - Jorand, F.
AU - Yañez, C.
AU - Appenzeller, B. M.R.
AU - Block, J. C.
N1 - Funding Information:
This work was carried out as part of a larger research program entitled "Biofilm" and coordinated by the Centre International de l'Eau de Nancy (NanCIE, France). It was funded by Compagnie Générale des Eaux (CGE, France), Agence de l'Eau Seine-Normandie (AESN, France), Anjou-Recherche (VEOLIA, France), Syndicat des Eaux d'Ile de France (SEDIF, France) and the Communauté Urbaine du Grand Nancy (CUGN, France).
PY - 2005/2
Y1 - 2005/2
N2 - A washed suspension of the bacteria Escherichia coli, pre-grown on a complex culture medium, was stored in sterilized drinking water for 21 days at 25° C in glass flasks in order to assess the effect of iron corrosion products on the persistenceof the bacteria in drinking water. Four conditions were tested: aerobic with 50 mM lepidocrocite (γ-FeOOH, an insoluble iron corrosion product), anaerobic with 50 mM lepidocrocite, aerobic without lepidocrocite and anaerobic without lepidocrocite. The survival of E. coli was monitored by their cultivability and their membrane integrity (propidium iodide staining). When the samples were not supplemented with the iron oxide, the cultivability and cell integrity of the bacteria were dramatically altered: from the 107 initially added, only 10 CFU ml-1 remained after 21 days; 90% of the cells exhibited membrane alteration after 2 weeks of storage. In contrast, bacteria with lepidocrocite preserved their cultivability and integrity over the 21 days of storage. In the presence of di-oxygen and without iron oxide, the alteration of cell cultivability was more pronounced than that in anaerobic conditions, suggesting that oxidative stress was part of the phenomenon. When the cells were pre-grown in a growth medium supplemented by a large excess of an easily available form of iron (ferric-citrate), the cells stored a higher amount of iron and persisted one week longer in the iron-free drinking water than cells pre-grown in the standard growth medium. Therefore, in an oligotrophic environment like drinking water, E. coli cells can find the ability to survive a long time through the presence of iron corrosion products. The necessity of controlling the corrosiveness of drinking water for sanitary reasons is therefore emphasized by this study.
AB - A washed suspension of the bacteria Escherichia coli, pre-grown on a complex culture medium, was stored in sterilized drinking water for 21 days at 25° C in glass flasks in order to assess the effect of iron corrosion products on the persistenceof the bacteria in drinking water. Four conditions were tested: aerobic with 50 mM lepidocrocite (γ-FeOOH, an insoluble iron corrosion product), anaerobic with 50 mM lepidocrocite, aerobic without lepidocrocite and anaerobic without lepidocrocite. The survival of E. coli was monitored by their cultivability and their membrane integrity (propidium iodide staining). When the samples were not supplemented with the iron oxide, the cultivability and cell integrity of the bacteria were dramatically altered: from the 107 initially added, only 10 CFU ml-1 remained after 21 days; 90% of the cells exhibited membrane alteration after 2 weeks of storage. In contrast, bacteria with lepidocrocite preserved their cultivability and integrity over the 21 days of storage. In the presence of di-oxygen and without iron oxide, the alteration of cell cultivability was more pronounced than that in anaerobic conditions, suggesting that oxidative stress was part of the phenomenon. When the cells were pre-grown in a growth medium supplemented by a large excess of an easily available form of iron (ferric-citrate), the cells stored a higher amount of iron and persisted one week longer in the iron-free drinking water than cells pre-grown in the standard growth medium. Therefore, in an oligotrophic environment like drinking water, E. coli cells can find the ability to survive a long time through the presence of iron corrosion products. The necessity of controlling the corrosiveness of drinking water for sanitary reasons is therefore emphasized by this study.
KW - Corrosion
KW - Cultivability
KW - Drinking water
KW - Escherichia coli
KW - Iron
UR - http://www.scopus.com/inward/record.url?scp=16344381711&partnerID=8YFLogxK
U2 - 10.1080/09593332608618577
DO - 10.1080/09593332608618577
M3 - Article
C2 - 15791802
AN - SCOPUS:16344381711
SN - 0959-3330
VL - 26
SP - 211
EP - 218
JO - Environmental Technology (United Kingdom)
JF - Environmental Technology (United Kingdom)
IS - 2
ER -