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Cultivation-dependent assessment, diversity, and ecology of haloalkaliphilic bacteria in arid saline systems of southern Tunisia.

El Hidri D, Guesmi A, Najjari A, Cherif H, Ettoumi B, Hamdi C, Boudabous A, Cherif A - Biomed Res Int (2013)

Bottom Line: Three gram-positive isolates showing between 95 and 96% of 16S rRNA sequence homology with Bacillus saliphilus could represent new species or genus.Activity tests showed that gram-positive bacteria were mostly active, particularly for protease, lipase, DNase, and amylase production.Our overall results demonstrate the huge phenotypic and phylogenetic diversity of haloalkaliphiles in saline systems of southern Tunisia which represent a valuable source of new lineages and metabolites.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Microorganisms and Active Biomolecules, Faculty of Sciences of Tunis, University of Tunis El Manar, 2092 Tunis, Tunisia ; LR Biotechnology and Bio-Geo Resources Valorization, Higher Institute for Biotechnology, Biotechpole Sidi Thabet, University of Manouba, 2020 Ariana, Tunisia.

ABSTRACT
Haloalkaliphiles are polyextremophiles adapted to grow at high salt concentrations and alkaline pH values. In this work, we isolated 122 haloalkaliphilic bacteria upon enrichments of 23 samples from 5 distinct saline systems of southern Tunisia, growing optimally in media with 10% salt and at pH 10. The collection was classified into 44 groups based on the amplification of the 16S-23S rRNA internal transcribed spacers (ITS-PCR). Phylogenetic analysis and sequencing of the 16S rRNA genes allowed the identification of 13 genera and 20 distinct species. Three gram-positive isolates showing between 95 and 96% of 16S rRNA sequence homology with Bacillus saliphilus could represent new species or genus. Beside the difference in bacterial diversity between the studied sites, several species ecological niches correlations were demonstrated such as Oceanobacillus in salt crust, Nesterenkonia in sand, and Salinicoccus in the rhizosphere of the desert plant Salicornia. The collection was further evaluated for the production of extracellular enzymes. Activity tests showed that gram-positive bacteria were mostly active, particularly for protease, lipase, DNase, and amylase production. Our overall results demonstrate the huge phenotypic and phylogenetic diversity of haloalkaliphiles in saline systems of southern Tunisia which represent a valuable source of new lineages and metabolites.

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Related in: MedlinePlus

Location of the sampled sites: BDV1 and BDV2 (Oasis Ksar Ghilane), BDV4 (Sabkhet Ennaouel), BDV6 (Chott el Douz), BDV17, BDV18, BDV19, BDV20 (Chott el Djerid), and BDIII-11 (Sabkhet El Melah).
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fig1: Location of the sampled sites: BDV1 and BDV2 (Oasis Ksar Ghilane), BDV4 (Sabkhet Ennaouel), BDV6 (Chott el Douz), BDV17, BDV18, BDV19, BDV20 (Chott el Djerid), and BDIII-11 (Sabkhet El Melah).

Mentions: All enrichments and strains described here were isolated from twenty-three samples collected from arid saline systems in southern Tunisia during February 2008 and 2010: salt crust, hypersaline water, thermomineral water, sand, sediment (with or without salt), bulk soil, algal biofilm, and the rhizosphere of the desert plant Salicornia when present. The sampling sites include three continental ephemeral salt lakes: Chott el Djerid (9 samples from 4 sites: BDV17, N 33°59′558′′, E 08°39′212′′; BDV18, N 33°58′736′′, E 08°20′632′′; BDV19, N 33°57′252′′, E 08°24′507′′; BDV20, N 33°57′252′′, E 08°24′508′′), Chott el Douz (3 samples from site BDV6: N 33°28′204′′, E 08°56′733′′), and Sabkhet Ennaouel (2 samples from BDV4: N 34°26′951′′, E 09°54′102′′); one coastal salt lake, Sabkhet El Melah (4 samples from BDIII-11: N 33°25′119′′, E 11°00′523′′), and one nonsaline system; Ksar Ghilane Oasis (5 samples from 2 sites: BDV1, N 32°59′012′′, E 09°38′072′′; BDV2, N 32°59′293′′, E 09°38′374′′) (Figure 1). Samples were collected into sterile flasks and kept aseptically at 4°C until analyzed.


Cultivation-dependent assessment, diversity, and ecology of haloalkaliphilic bacteria in arid saline systems of southern Tunisia.

El Hidri D, Guesmi A, Najjari A, Cherif H, Ettoumi B, Hamdi C, Boudabous A, Cherif A - Biomed Res Int (2013)

Location of the sampled sites: BDV1 and BDV2 (Oasis Ksar Ghilane), BDV4 (Sabkhet Ennaouel), BDV6 (Chott el Douz), BDV17, BDV18, BDV19, BDV20 (Chott el Djerid), and BDIII-11 (Sabkhet El Melah).
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3842069&req=5

fig1: Location of the sampled sites: BDV1 and BDV2 (Oasis Ksar Ghilane), BDV4 (Sabkhet Ennaouel), BDV6 (Chott el Douz), BDV17, BDV18, BDV19, BDV20 (Chott el Djerid), and BDIII-11 (Sabkhet El Melah).
Mentions: All enrichments and strains described here were isolated from twenty-three samples collected from arid saline systems in southern Tunisia during February 2008 and 2010: salt crust, hypersaline water, thermomineral water, sand, sediment (with or without salt), bulk soil, algal biofilm, and the rhizosphere of the desert plant Salicornia when present. The sampling sites include three continental ephemeral salt lakes: Chott el Djerid (9 samples from 4 sites: BDV17, N 33°59′558′′, E 08°39′212′′; BDV18, N 33°58′736′′, E 08°20′632′′; BDV19, N 33°57′252′′, E 08°24′507′′; BDV20, N 33°57′252′′, E 08°24′508′′), Chott el Douz (3 samples from site BDV6: N 33°28′204′′, E 08°56′733′′), and Sabkhet Ennaouel (2 samples from BDV4: N 34°26′951′′, E 09°54′102′′); one coastal salt lake, Sabkhet El Melah (4 samples from BDIII-11: N 33°25′119′′, E 11°00′523′′), and one nonsaline system; Ksar Ghilane Oasis (5 samples from 2 sites: BDV1, N 32°59′012′′, E 09°38′072′′; BDV2, N 32°59′293′′, E 09°38′374′′) (Figure 1). Samples were collected into sterile flasks and kept aseptically at 4°C until analyzed.

Bottom Line: Three gram-positive isolates showing between 95 and 96% of 16S rRNA sequence homology with Bacillus saliphilus could represent new species or genus.Activity tests showed that gram-positive bacteria were mostly active, particularly for protease, lipase, DNase, and amylase production.Our overall results demonstrate the huge phenotypic and phylogenetic diversity of haloalkaliphiles in saline systems of southern Tunisia which represent a valuable source of new lineages and metabolites.

View Article: PubMed Central - PubMed

Affiliation: Laboratory of Microorganisms and Active Biomolecules, Faculty of Sciences of Tunis, University of Tunis El Manar, 2092 Tunis, Tunisia ; LR Biotechnology and Bio-Geo Resources Valorization, Higher Institute for Biotechnology, Biotechpole Sidi Thabet, University of Manouba, 2020 Ariana, Tunisia.

ABSTRACT
Haloalkaliphiles are polyextremophiles adapted to grow at high salt concentrations and alkaline pH values. In this work, we isolated 122 haloalkaliphilic bacteria upon enrichments of 23 samples from 5 distinct saline systems of southern Tunisia, growing optimally in media with 10% salt and at pH 10. The collection was classified into 44 groups based on the amplification of the 16S-23S rRNA internal transcribed spacers (ITS-PCR). Phylogenetic analysis and sequencing of the 16S rRNA genes allowed the identification of 13 genera and 20 distinct species. Three gram-positive isolates showing between 95 and 96% of 16S rRNA sequence homology with Bacillus saliphilus could represent new species or genus. Beside the difference in bacterial diversity between the studied sites, several species ecological niches correlations were demonstrated such as Oceanobacillus in salt crust, Nesterenkonia in sand, and Salinicoccus in the rhizosphere of the desert plant Salicornia. The collection was further evaluated for the production of extracellular enzymes. Activity tests showed that gram-positive bacteria were mostly active, particularly for protease, lipase, DNase, and amylase production. Our overall results demonstrate the huge phenotypic and phylogenetic diversity of haloalkaliphiles in saline systems of southern Tunisia which represent a valuable source of new lineages and metabolites.

Show MeSH
Related in: MedlinePlus