Phylogenetic Diversity of Microorganisms from the Abakan Arzhan Thermal Spring: Potential Producers of Microbial Energy

Abstract

Microbial energy is a promising area of innovative development in bio- and nanotechnology. Recent studies have revealed that microbial communities of thermal springs have excellent implementation prospects in this area. The present article introduces the microbial diversity of the Abakan Arzhan thermal spring and their isolates that are potentially applicable in microbial electricity synthesis. The research featured microbial isolates obtained from a microbiota analysis of water and slit samples from the Abakan Arzhan thermal spring. The study involved a metagenomic analysis of the microbial community, as well as such molecular biology methods as nucleic acid extraction, PCR, sequencing, phylogenetic, and bioinformatic analysis. The Silva library was used to compare 16S RNA sequences Firmicutes, Bacteroides, and Proteobacteria proved to be the dominant phylotypes for water samples, while Firmicutes, Thermomonas, Gammaproteobacteria, and Proteobacteria were the dominant phylotypes for slit samples. The analysis of minor phylotypes confirmed the presence of Geobacter and Shewanella in the samples. The total number of obtained enrichment cultures was nine. Two types of resistant colonies were discovered during the isolation of extremophilic iron-reducing isolates. The samples were grown on a medium containing iron (III) acetate and iron (III) nitrate, and the isolates appeared to be in the process of Fe(III) reduction. The isolates showed an intense iron recovery of 409 and 407 µg/mL after 72 h of cultivation. The study confirmed the ability of the acquired isolates to reduce iron, making them a priority for future microbial energy research. The isolates belonged to the Shewanella algae and Geobacter sulfurreducens species, as determined by 16S RNA morphology and phylogenetic analyses.