Total counts, culturable and viable, and non‐culturable microflora of a French mineral water: a case study

Defives, C.; Guyard, S.; Oularé, M. M.; Mary, P.; Hornez, Jean‐Christophe

doi:10.1046/j.1365-2672.1999.00794.x

Cited by 42 publications

(32 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The culturability of bacteria in bioWlms formed in the presence and absence of HSs was 94 and 77%, respectively, obtained in the last week of the experiment. Similar high percentages of bacterial culturability are described in studies carried out with the R2A medium for mineral water (65%, [28]) and sediment bacteria (82%, [29]). This result might be explained by the fact that a nutrient poor media (R2A agar) was used for bacteria cultivation in combination with a low incubation temperature (20°C) and an extended incubation time (7 days) [30].…”

Section: Dynamics Of Biowlm and Suspended Biomass Developmentmentioning

confidence: 58%

Characterization of biofilm formation on a humic material

Rodrigues¹,

Brito²,

Janknecht³

et al. 2008

J Ind Microbiol Biotechnol

View full text Add to dashboard Cite

Biofilms are major sites of carbon cycling in streams. Therefore, it is crucial to improve knowledge about biofilms' structure and microbial composition to understand their contribution in the self-purification of surface water. The present work intends to study biofilm formation in the presence of humic substances (HSs) as a carbon source. Two biofilm flowcells were operated in parallel; one with synthetic stream water, displaying a background carbon concentration of 1.26+/-0.84 mg L(-1), the other with added HSs and an overall carbon concentration of 9.68+/-1.00 mg L(-1). From the biofilms' results of culturable and total countable cells, it can be concluded that the presence of HSs did not significantly enhance the biofilm cell density. However, the biofilm formed in the presence of HSs presented slightly higher values of volatile suspended solids (VSS) and protein. One possible explanation for this result is that HSs adsorbed to the polymeric matrix of the biofilm and were included in the quantification of VSS and protein. The microbial composition of the biofilm with addition of HSs was characterized by the presence of bacteria belonging to beta-Proteobacteria, Cupriavidus metallidurans and several species of the genus Ralstonia were identified, and gamma-Proteobacteria, represented by Escherichia coli. In the biofilm formed without HSs addition beta-Proteobacteria, represented by the species Variovorax paradoxus, and bacteria belonging to the group Bacteroidetes were detected. In conclusion, the presence of HSs did not significantly enhance biofilm cell density but influenced the bacterial diversity in the biofilm.

show abstract

Section: Dynamics Of Biowlm and Suspended Biomass Developmentmentioning

confidence: 58%

Characterization of biofilm formation on a humic material

Rodrigues¹,

Brito²,

Janknecht³

et al. 2008

J Ind Microbiol Biotechnol

View full text Add to dashboard Cite

show abstract

“…Other Sphingomonas spp. has been isolated from oligotrophic environments such as river water and seawater (38,41), bottled mineral water (8), and aquifer sediments (1,12). This suggests that adaptation to oligotrophic conditions is a characteristic feature of several members of the genus Sphingomonas.…”

Section: Discussionmentioning

confidence: 99%

Isolation from Agricultural Soil and Characterization of a Sphingomonas sp. Able To Mineralize the Phenylurea Herbicide Isoproturon

Sørensen

Ronen

Aamand

2001

Appl Environ Microbiol

134

141

View full text Add to dashboard Cite

A soil bacterium (designated strain SRS2) able to metabolize the phenylurea herbicide isoproturon, 3-(4-isopropylphenyl)-1,1-dimethylurea (IPU), was isolated from a previously IPU-treated agricultural soil. Based on a partial analysis of the 16S rRNA gene and the cellular fatty acids, the strain was identified as a Sphingomonas sp. within the ␣-subdivision of the proteobacteria. Strain SRS2 was able to mineralize IPU when provided as a source of carbon, nitrogen, and energy. Supplementing the medium with a mixture of amino acids considerably enhanced IPU mineralization. Mineralization of IPU was accompanied by transient accumulation of the metabolites 3-(4-isopropylphenyl)-1-methylurea, 3-(4-isopropylphenyl)-urea, and 4-isopropyl-aniline identified by high-performance liquid chromatography analysis, thus indicating a metabolic pathway initiated by two successive N-demethylations, followed by cleavage of the urea side chain and finally by mineralization of the phenyl structure. Strain SRS2 also transformed the dimethylurea-substituted herbicides diuron and chlorotoluron, giving rise to as-yet-unidentified products. In addition, no degradation of the methoxy-methylurea-substituted herbicide linuron was observed. This report is the first characterization of a pure bacterial culture able to mineralize IPU.The phenylurea herbicide isoproturon, 3-(4-isopropylphenyl)-1,1-dimethylurea (IPU), which is used for pre-and postemergence control of annual grasses and broad-leaved weeds in wheat, rye, and barley crops, is among the most extensively used pesticides in conventional agriculture in Europe (34). Ecotoxicological data suggest that IPU and some of its metabolites are harmful to aquatic invertebrates (20), freshwater algae (25), and microbial activity (28). IPU is also suspected of being carcinogenic (2, 14). As a result of its widespread and repeated use, IPU is frequently detected in groundwater and surface waters in Europe in levels exceeding the European Commission drinking water limit of 0.1 g l Ϫ1 (23,33,34). Degradation of IPU in agricultural soils occurs predominantly by microbiological processes (6,22). Several studies have demonstrated a slow natural attenuation rate in various soils and subsurface environments with respect to mineralization of the phenyl structure (4,15,17,18,26,35). The detection of IPU as an environmental pollutant and its apparently low mineralization potential has stimulated research aimed at isolating and characterizing microbial cultures able to mineralize IPU. Enrichment culture techniques have been used with varied success in attempts to isolate IPU-degrading microorganisms. In previous studies, slurries of mineral media and soils from different agricultural fields failed to degrade IPU (4,19,35). Enrichment on the IPU metabolite 3-(4-isopropylphenyl)-1-methylurea (MDIPU) as the sole source of carbon and energy recently yielded a mixed bacterial culture able to perform growth-linked mineralization of MDIPU and 4-isopropylaniline (4IA) but with no degradation activity toward IPU (35)....

show abstract

“…The bacterial samples were diluted 1:10 and 5 mL was placed on a microscope slide and overlaid with a coverslip (22 mm Â 22 mm). A five-point cell count (viable and nonviable cells) was conducted following the method of Defives et al (19) using a microscope with a fluorescent light source (Olympus, Watford, UK). The mean of the five-point cell count was used as a representation of the mean total number of cells on each membrane filter.…”

Section: Disruption Assaymentioning

confidence: 99%