Hyperthermophile diversity microbes in the Calientes geothermal field, Tacna, Peru

Abstract

Hyperthermophile microorganisms have been discovered worldwide, and several studies regarding biodiversity and the potential biotechnological applications have been reported. In this work, we describe for the first time the diversity of hyperthermophile communities in the Calientes Geothermal Field (CGF) located 4400 m above sea level in Tacna Region, Perú. Three hot springs were monitored and showed a temperature around 84 to 88 °C, for the microbiome analyzed was taken by sampling of sediment and water (pH 7.3-7.6). The hyperthermophile diversity was determined by PCR, DGGE, and DNA sequencing. The sediments analyzed showed a greater diversity than water samples. Sediments showed a more abundant population of bacteria than archaea, with the presence of at least 9 and 5 phylotypes, respectively. Most interestingly, in some taxa of bacteria (Bacillus) and archaea (Haloarcula and Halalkalicoccus), any of operational taxonomic units (OTUs) have not been observed before in hyperthermophile environments. Our results provide insight in the hyperthermophile diversity and reveal the possibility to develop new biotechnological applications based on the kind of environments.

Keywords: Archaea; Bacteria; DGGE; Geothermal field; Hyperthermophiles.

Fig. 1

The Calientes Geothermal Field (CGF) geographical characteristics. a Geographical world location of CGF and comparison with other GF. b Location of the CGF in Peru, South America. c The arrows indicate the location where water and sediment samples were taken (Source: INGEMMET-Peru). Panoramic view of hot springs in the CGF. Biofilms are visible in pool G5; calciferous borders are visible in pool G1. The bar approximates 1 m. d Sampling locations in the CGF. (A) Hot spring 1 (G1), arrows indicate where water sample (G1 (W)) was collected; (B) G1, arrow indicates where sediment sample (G1 (S)) was collected; (C) G2, arrows indicate where water samples (G2 (W) and G2S (W)) were obtained; (D) G3, arrow indicates the calciferous sediment. Scale bars represents 1 m of length

Fig. 2

DGGE diversity profiles. A PCR-DGGE analysis of the predominant bacterial/archaeal communities of water and sediment samples obtained from the CGF. Total DNA was extracted from samples, and the 16 S rRNA gene was amplified by nested PCR using primers specific for bacteria (A) or archaea (B). Each labeled well represents a separate sample with a denaturing linear gradient from 30 to 60% for bacteria and 20 to 70% for archaea. The bands had been sequenced and compared in the NCBI database, the best results are shown in Table 4. B Numbered bands were submitted for sequencing. UPGMA (unweighted pair-group method using arithmetic averages) dendrogram generated from bacterial denaturing gradient gel electrophoresis (DGGE) profiles. Samples are from water (W), sediment (S), C bacteria, and D archea. G1, G2, and G3 are the hot springs used for sample collection. (W), water sample collected at 1 m of depth; (s) (W), water sample collected at the surface; (S), sediment sample collected at less than 10 cm of depth; (t) (S), sediment sample collected at more than 10 cm of depth

Fig. 3

Phylogenetic tree of bacterial diversity in the CGF based on partial 16 S rRNA gene sequences. The brightest bands obtained from the DGGE were cut, re-amplified, and sequenced. Sequences were compared with BLASTN to the NCBI database. Sequences from this study are in red, indicating the corresponding DGGE band number. Reference sequences were chosen to represent the greatest diversity of bacteria. Scale bar at the bottom left represents 0.2 (20%) nucleotide sequence difference

Fig. 4

Phylogenetic tree of archaeal diversity in the CGF based on partial 16 S rRNA gene sequences. Sequences were compared with BLASTN to the NCBI database. Sequences from this study are in red, indicating the corresponding DGGE band number. Reference sequences were chosen to represent the greatest diversity of archaea. Scale bar at the bottom left represents 0.2 (20%) nucleotide sequence difference