Thermophilic bacterial communities inhabiting the microbial mats of “indifferent” and chalybeate (iron‐rich) thermal springs: Diversity and biotechnological analysis

Abstract

Microbial mats are occasionally reported in thermal springs and information on such mats is very scarce. In this study, microbial mats were collected from two hot springs (Brandvlei (BV) and Calitzdorp (CA)), South Africa and subjected to scanning electron microscopy (SEM) and targeted 16S rRNA gene amplicon analysis using Next Generation Sequencing (NGS). Spring water temperature was 55°C for Brandvlei and 58°C for Calitzdorp while the pH of both springs was slightly acidic, with an almost identical pH range (6.2–6.3). NGS analysis resulted in a total of 4943 reads, 517 and 736 OTUs for BV and CA at, respectively, a combined total of 14 different phyla in both samples, 88 genera in CA compared to 45 in BV and 37.64% unclassified sequences in CA compared to 27.32% recorded in BV. Dominant bacterial genera in CA microbial mat were Proteobacteria (29.19%), Bacteroidetes (9.41%), Firmicutes (9.01%), Cyanobacteria (6.89%), Actinobacteria (2.65%), Deinococcus‐Thermus (2.57%), and Planctomycetes (1.94%) while the BV microbial mat was dominated by Bacteroidetes (47.3%), Deinococcus‐Thermus (12.35%), Proteobacteria (7.98%), and Planctomycetes (2.97%). Scanning electron microscopy results showed the presence of microbial filaments possibly resembling cyanobacteria, coccids, rod‐shaped bacteria and diatoms in both microbial mats. Dominant genera that were detected in this study have been linked to different biotechnological applications including hydrocarbon degradation, glycerol fermentation, anoxic‐fermentation, dehalogenation, and biomining processes. Overall, the results of this study exhibited thermophilic bacterial community structures with high diversity in microbial mats, which have a potential for biotechnological exploitation.

Metagenomics revealing molecular profiling of community structure and metabolic pathways in natural hot springs of the Sikkim Himalaya

“…Beta-proteobacteria ( Massilia , Thiomonas , and Janthinobacteria ), detected only in Reshi hot spring, represent the peculiar mesophilic type of environment. These genera have also been reported from other hot water sites [ 30 – 32 ]. However, it cannot be ruled out that these mesophilic microorganisms could be from the soil.…”

Unraveling the bacterial diversity of Cangar Hot Spring, Indonesia by Next Generation Sequencing of 16S rRNA gene

“…Family Flavobacteriaceae and its member, genus Cloacibacterium, were the most dominant family and genus in Cangar Hot Spring. The high abundance of Flavobacteriaceae family members was also reported in Brandvlei hot spring, South Africa (55°C, pH 6.2), and three hot springs in India, i.e., Yumthang (39°C, pH 8.0), Chhoti Anhoni (52.1°C, pH 7.8), and Polok (76.3°C, pH 7.5), India (Najar et al 2018, Panda et al 2016, Saxena et al 2017, Selvarajan et al 2018. The presence of Flavobacteriaceae family members was also reported from other hot springs in Indonesia, i.e., Domas hot spring (90°C, pH 2) (Baker et al 2001).…”

Molecular evolution of Thermophilic Geobacillus species isolated from Tattapani Hotspring (India) and the Worldwide Distribution

“…More recently, Sharma et al [49] identifified thermophilic Flavobacterium and Anoxybacillus from Unexplored Tatapani Hot spring situated of North Western Himalayas. In a different study, thermophile diversity and ecology of microbial mat samples collected from the iron rich hot springs of Brandvlei and Calitzdorp was studied for the first time [50]. In conclusion, the newly isolated Geobacillus spp.…”