Bacterial Diversity in a Nonsaline Alkaline Environment: Heterotrophic Aerobic Populations

Abstract

Heterotrophic populations were isolated and characterized from an alkaline groundwater environment generated by active serpentinization, which results in a Ca(OH) 2 -enriched, extremely diluted groundwater with pH 11.4. One hundred eighty-five strains were isolated in different media at different pH values during two sampling periods. To assess the degree of diversity present in the environment and to select representative strains for further characterization of the populations, we screened the isolates by using random amplified polymorphic DNA-PCR profiles and grouped them based on similarities determined by fatty acid methyl ester analysis. Phenotypic characterization, determinations of G؉C content, phylogenetic analyses by direct sequencing of 16S rRNA genes, and determinations of pH tolerance were performed with the selected isolates. Although 38 different populations were identified and characterized, the vast majority of the isolates were gram positive with high G؉C contents and were affiliated with three distinct groups, namely, strains closely related to the species Dietzia natrolimnae (32% of the isolates), to Frigoribacterium/Clavibacter lineages (29% of the isolates), and to the type strain of Microbacterium kitamiense (20% of the isolates). Other isolates were phylogenetically related to strains of the genera Agrococcus, Leifsonia, Kytococcus, Janibacter, Kocuria, Rothia, Nesterenkonia, Citrococcus, Micrococcus, Actinomyces, Rhodococcus, Bacillus, and Staphylococcus. Only five isolates were gram negative: one was related to the Sphingobacteria lineage and the other four were related to the ␣-Proteobacteria lineage. Despite the pH of the environment, the vast majority of the populations were alkali tolerant, and only two strains were able to grow at pH 11.

Bacillus foraminis sp. nov., isolated from a non-saline alkaline groundwater

“…The majority of the populations recovered during this survey comprised high-G+C-content Gram-positive bacteria (Tiago et al, 2004). However, several low-G+C-content Gram-positive bacteria were also isolated; one strain, designated CV53 T , was of particular interest and was found to be phylogenetically related to the lineage containing the type strain of the species Bacillus jeotgali of the family Bacillaceae.…”

“…The ophiolite-like geological background of this aquifer and its chemical characteristics strongly suggest serpentinization. This groundwater, which has an outflow at a temperature of 20?5 uC, has a high level of alkalinity (pH 11?4) associated with an extremely low ionic concentration, with Ca 2+ and OH 2 as the major chemical constituents (Tiago et al, 2004).The majority of the populations recovered during this survey comprised high-G+C-content Gram-positive bacteria (Tiago et al, 2004). However, several low-G+C-content Gram-positive bacteria were also isolated; one strain, designated CV53 T , was of particular interest and was found to be phylogenetically related to the lineage containing the type strain of the species Bacillus jeotgali of the family Bacillaceae.…”

“…In this study, we describe the morphological, physiological, chemotaxonomic and phylogenetic characteristics of strain CV53 T . On the basis of our results we propose that strain CV53 T represents a novel species of the genus Bacillus.Strain CV53 T was isolated from a non-saline alkaline groundwater environment by using alkaline buffered medium 2 (ABM2), adjusted to pH 8?5, at 37 u C, as described previously (Tiago et al, 2004). The isolate was routinely cultured under the same conditions and maintained at 270 u C in the same medium supplemented with 15 % glycerol.…”

Diversity of culturable aerobic bacteria colonizing four petroleum by-products storage reservoirs

“…The isolates SS25, S212 and SSS13 were related to Bacillus pumilus (GQ152134.1 and EF173329.1) strains isolated from soil contaminated with chlorinated hydrocarbon, and characterised as alkaliphiles. The six strains belonging to the genus of Staphylococcus, showed 99% similarity to the heterotrophic aerobic Staphylococcus strains, isolated from nonsaline alkaline environment (Tiago et al, 2004). The strains of the genus of Enterobacter showed homology with isolates characterized as chlorophenol and lignin degrading aerobic bacteria and 1,3-propanediol fermenting bacteria (GU193983.1 DQ185604.1).…”

Salinicoccus salsiraiae sp. nov.: a new moderately halophilic gram-positive bacterium isolated from salted skate

“…Growth of the strains was examined by measuring the turbidity of cultures incubated at 37°C as described previously (Moreira et al 2000). Degryse 162 medium basal salts and ABM2 basal medium (Tiago et al 2004) were also used to assess the assimilation of single carbon sources. API 50 CH test strips (Analytab Products Inc., BioMe´rieux) were also used to examine the assimilation of carbohydrates and to examine the production of acid using a defined medium (Ventosa et al 1982) containing the following components per litre: NaCl, 40.0 g (for strains RH1 T and RH4) or 80.0 g (for S. roseus and S. hispanicus); MgSO 4 AE7H 2 O, 2.0 g; CaCl 2 AE2H 2 O, 0.5 g; FeCl 3 AE6H 2 O, traces; KH 2 PO 4 , 0.5 g; proteose-peptone no.…”