Aguas Calientes (AC) is an isolated geothermal spring located deep into the Amazon rainforest (7°21′12″ S, 75°00′54″ W) of Peru. This geothermal spring is slightly acidic (pH 5.0–7.0) in nature, with temperatures varying from 45 to 90 °C and continually fed by plant litter, resulting in a relatively high degree of total organic content (TOC). Pooled water sample was analyzed at 16S rRNA V3–V4 hypervariable region by amplicon metagenome sequencing on Illumina HiSeq platform. A total of 2,976,534 paired ends reads were generated which were assigned into 5434 numbers of OTUs. All the resulting 16S rRNA fragments were then classified into 58 bacterial phyla and 2 archaeal phyla. Proteobacteria (88.06%) was found to be the highest represented phyla followed by Thermi (6.43%), Firmicutes (3.41%) and Aquificae (1.10%), respectively. Crenarchaeota and Euryarchaeota were the only 2 archaeal phyla detected in this study with low abundance. Metagenomic sequences were deposited to SRA database which is available at NCBI with accession number SRX1809286. Functional categorization of the assigned OTUs was performed using PICRUSt tool. In COG analysis “Amino acid transport and metabolism” (8.5%) was found to be the highest represented category whereas among predicted KEGG pathways “Metabolism” (50.6%) was the most abundant. This is the first report of a high resolution microbial phylogenetic profile of an Amazonian hot spring.

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Aim: Aguas Calientes (AC) is an isolated geothermal spring located deep into the Peruvian Amazon rainforest. The principal aim of this study was to isolate and characterize thermophilic lignocellulolytic bacterial strains from AC. Study Design: Bacterial strains were cultured in laboratory and screened for cellulase activity. Superior lignocellulolytic strains were characterized by 16S rRNA sequences. Place and Duration of Study: Samples were collected from Aguas Calientes (7°21'12'' S, 75°00'54'' W). The duration of the study was 2013-20 16. Methodology: Primary isolation of lignocelluloytic bacterial strains was carried out by direct plating, filtration and water enrichment analysis techniques. Secondary screening was performed by semi quantitative plate clearing assay. In both primary and secondary screening assay the growth media contained carboxymethylcellulose (CMC). CMC hydrolysis by bacterial colonies was evaluated by Congo red solution. Selected strains with higher cellulase activity were characterized by 16s rRNA gene sequencing. Original Research Article-1) throughout different alkaline pH levels. In CS, the highest cellulase activity (5.2 U ml -1 ) was showed by strain LMB-SC4 at pH 7.4. Sequence homology analysis of selected bacterial 16S RNA revealed that most of our strains are similar with different reported strains of Geobacillus, more precisely with Geobacillus thermoleovorans and Geobacillus kaustophilus. Conclusion: For the first time several thermophilic lignocellulolytic bacterial strains were isolated from a remote Amazonian geothermal spring and some of them were found very promising.