Characteristics of the heterotrophic bacterial populations in hypersaline environments of different salt concentrations (original) (raw)
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Microbial Ecology, 1985
A multi-pond saltern that creates a gradient of salt concentrations has been studied with respect to some characteristics of the resulting environments and their microbial populations. The increase in salt concentration was correlated with increase in diurnal temperature and biomass present and with decrease in oxygen concentrations. Many types of organisms below 15% (w/v) total salts, were found, many of them normal inhabitants of seawater and even freshwater. Most organisms over 15% salts were halophilic. The salt concentrations comprised two ranges, each characterized by different microbial populations. First, between 15 and 30% salts, the populations of Dunaliella increased, reaching large numbers; moderately halophilic eubacteria and some fast-growing halobacteria predominated as heterotrophic microorganisms and, among the first, the Pseudornonas-Alteromonas-Alcaligenes group and Vibrio were the more abundant taxonomic groups; and gram-positive cocci appeared mainly over 25% salts. Phototrophic bacteria, both oxygenic and anoxygenic, were also found in this range, and among the anoxygenic type, Chromatium species and Rodospirillum salexigens were probably predominant. Second, over 30% salts the diversity decreased greatly, all organisms found at the lower salt concentrations disappeared, and instead large populations of halobacteria developed. Over 50% salts, only three species of halobacteria were found.
Application of halophilic bacteria in traditional solar salt pond: a preliminary study
IOP Conference Series: Earth and Environmental Science
Microbial community in salt ponds have an important role in salt quality production. One of important microorganisms is halophilic bacteria and archaea which has been reported to positively correlated with salt quality. This manuscript reported a preliminary study on application of the halophylic bacteria consortia on to traditional salt pond in Pati. An amount of 0.5% (v/v) of the halophilic bacterial consortia was applied in 20 Baume (Be) salt pond sizing 20 m 3. After the saltwater reached 25 Be, the halophilic-treated saltwater was moved to the crystallization pond. Salt has been harvested by scrubbing cristal salt manually after 3-5 days, the time used by salt farmers in Pati. Yield, NaCl content, salt impurities, crystal whiteness, and compactness were parameters studied in this trial. Salt produced from pond interfered with halophilic bacteria consortia had higher NaCl content by 2%, lower content of impurities (Mg and Ca) and higher whiteness degree. SEM analysis showed that crystal salt produced from halophilic pond showed more compact, cubical form compared to the crystal salt from untreated pond which was more fragile. However, the yield of salt produced was not different between treated and untreated pond.
Behaviour of mixed populations of halophilic bacteria in continuous cultures
Canadian Journal of Microbiology, 1980
Two main physiological groups of bacteria are known which are adapted to high saline environments, moderate and extreme halophiles. In order to clarify some aspects of the competition between these two groups in their natural habitats, continuous cultures were used to provide a changing spectrum of conditions of salt concentration, temperature, and nutrient concentration (dilution rate). The effects of these parameters on natural solar saltern populations were studied. Complex media were used to increase the range of competing microorganisms. Nineteen strains of halophilic bacteria were isolated and studied with respect to their growth response at different salt concentrations. The temperature seemed to be the decisive factor within the range of salt concentrations studied (20-30%, w/v), the moderate halophiles being favored by low temperatures. Within this group, motile, gram-negative rods, and spiral forms were the predominant morphological types. In general, microorganisms that showed high growth rates in batch cultures predominated in continuous cultures with high dilution rates (high nutrient concentrations); those that grew slowly in batch cultures predominated in cultures with low dilution rates.
Extremely Halophilic Bacteria in Crystallizer Ponds from Solar Salterns
Applied and Environmental Microbiology, 2000
It is generally assumed that hypersaline environments with sodium chloride concentrations close to saturation are dominated by halophilic members of the domain Archaea, while Bacteria are not considered to be relevant in this kind of environment. Here, we report the high abundance and growth of a new group of hitherto-uncultured Bacteria in crystallizer ponds (salinity, from 30 to 37%) from multipond solar salterns. In the present study, these Bacteria constituted from 5 to 25% of the total prokaryotic community and were affiliated with the Cytophaga-Flavobacterium-Bacteroides phylum. Growth was demonstrated in saturated NaCl. A provisional classification of this new bacterial group as "Candidatus Salinibacter gen. nov." is proposed. The perception that Archaea are the only ecologically relevant prokaryotes in hypersaline aquatic environments should be revised.
2018
In the present study four halophytic bacteria strains were identified and were characterized on the basis of the cell morphology and 16S rRNA gene sequencing. These strains were identified as Halomonas elongatastrain ECTC/RF, Cobetia marinastrain New Alix5, Virgibacillus species strain Rr Alix3 and Staphylococcus saprophyticus strain S Alix1. The strains ECTC/RF, New Alix5 and Rr Alix3 accumulate Ectoine under high salinity condition. The genes involved in ectoine biosynthesis (ectA, ectB, and ectC), were isolated and characterized from strains ECTC/RF and New Alix5 and can be used as a source of microbial salt tolerant enzymes. The ectoine genes expression (ectA, ectB, and ectC) of the strain ECTC/RF was determined relative to the control (without adding NaCl) by using Real time PCR analysis. The transcription levels of ectA, ectB, and ectC, have different response to the different concentration of NaCl. The three Ectoine genes showed an increase in there expression in 20% salt concentration. These results proves that the accumulation of Ectoine is one of the main compatible solute responsible for growth and survival of these halophiles strains under salinity stress condition.
5. Ecology of Hypersaline Microorganisms
2005
The oceans are the largest bodies of saline water with average salinities ranging from 32-35 psu. Hypersaline environments, with salinities far more than the normal seawater salinities, generally originate as a result of evaporation of seawater. Such environments are inhabited by halophiles, the salt loving organisms. Halophiles are distributed in hypersaline environments all over the world, mainly in natural hypersaline brines in arid, coastal and deep sea locations as well as in artificial salterns. Halophiles include prokaryotes and eukaryotes which are adapted to these hypersaline environments at the highest salt concentrations at or close to the solubility limit of NaCl.
The contribution of halophilic Bacteria to the red coloration of saltern crystallizer ponds1
FEMS Microbiology Ecology, 2000
Analysis of the pigments extracted from solar saltern crystallizer ponds in Santa Pola near Alicante and on the Balearic island of Mallorca, Spain, showed that 5^7.5% of the total prokaryotic pigment absorbance could be attributed to a novel carotenoid or carotenoidlike compound. This unidentified pigment was identical to the sole pigment present in Salinibacter ruber, the only described member of a newly discovered genus of red halophilic Bacteria related to the Cytophaga-Flavobacterium-Bacteroides group. On the basis of fluorescence in situ hybridization experiments it has been shown that Salinibacter is an important component of the microbial community of Spanish saltern ponds. The red color of saltern crystallizer ponds may thus not only be due to red halophilic Archaea and to L-carotene-rich Dunaliella cells as previously assumed, but may contain a bacterial contribution as well. The Salinibacter pigment was not detected in samples collected from crystallizer ponds of the salterns of Eilat, Israel, and only traces of it may have been present in the Newark, CA, USA, salterns. The community structure of the prokaryote community inhabiting saltern crystallizers thus shows significant geographic variations. Polar lipid analyses of the biomass collected from the Santa Pola salterns showed that the total contribution of Salinibacter and other Bacteria to the total biomass was minor, the most important component of the community being halophilic Archaea. ß 1 Non-standard abbreviations : The names of genera of the family Halobacteriaceae were abbreviated using three-letter abbreviations as recommended in Int.
Hydrobiologia, 2007
Salinibacter is a genus of red, extremely halophilic Bacteria. Thus far the genus is represented by a single species, Salinibacter ruber, strains of which have been isolated from saltern crystallizer ponds in Spain and on the Balearic Islands. Both with respect to its growth conditions and its physiology, Salinibacter resembles the halophilic Archaea of the order Halobacteriales. We have designed selective enrichment and isolation techniques to obtain Salinibacter and related red extremely halophilic Bacteria from different hypersaline environments, based on their resistance to anisomycin and bacitracin, two antibiotics that are potent inhibitors of the halophilic Archaea. Using direct plating on media containing bacitracin, we found Salinibacter-like organisms in numbers between 1.4×103 and 1.4×106ml−1 in brines collected from the crystallizer ponds of the salterns in Eilat, Israel, being equivalent to 1.8–18% of the total colony counts obtained on identical media without bacitracin. A number of strains from Eilat were subjected to a preliminary characterization, and they proved similar to the type strain of S. ruber. We also report here the isolation and molecular detection of Salinibacter-like organisms from an evaporite crust on the bottom of salt pools at the Badwater site in Death Valley, CA. These isolates and environmental 16S rRNA gene sequences differ in a number of properties from S. ruber, and they may represent a new species of Salinibacter or a new related genus.