Isolation of Diverse Members of the Aquificales from Isolation of Diverse Members of the Aquificales from Geothermal Springs in Tengchong, China Geothermal Springs in Tengchong, China
Four strains isolated from diverse springs in the Rehai Geothermal Field had variable capacity for chemolithotrophic oxidation of hydrogen and sulfur compounds and nitrate reduction; however, they had variable capacity for chemolithotrophic oxidation of hydrogen and sulfur compounds and nitrate reduction.
Genome analysis identified genetic features potentially associated with stress adaptation and iron/tryptophan metabolism, providing additional ecological context for this plant-associated isolate.
Xue Li, Yu Tao, Ming Li et al.· Archives of Microbiology· 0 citations
Various isolates exhibited cellulase, xylanase, and esterase activities on untreated rice and wheat straw, demonstrating the capacity to deconstruct lignocellulosic biomass without prior pretreatment, and Enzymatic activities and fermentation profiles varied substantially among strains.
Sai Suresh Hivarkar, P. Dhakephalkar, S. Dagar· World Journal of Microbiolog...· 0 citations
Abstract Two alphaproteobacterial strains, designated EGI L300112T and EGI L300120, were isolated from sediment collected from Chaiwopu Lake in Xinjiang, China. The taxonomic position of the two strains was determined using polyphasic taxonomic analysis and phylogenomic analysis. Based on 16S rRNA gene sequence similarities, strain EGI L300112T and EGI L300120 were both closely related to Pelagerythrobacter rhizovicinus AY-3RT and shared the highest sequence identities of 96.2% and 96.3%, respectively. However, phylogenetic analysis based on the 16S rRNA gene and genomes clearly demonstrated that the two strains formed a distinct clade with validly published species of the genus Altererythrobacter. Furthermore, the two strains exhibited distinct phenotypic, physiological and genotypic characteristics that differentiate them from other related type species of the genus Altererythrobacter and related species in the family Erythrobacteraceae. Cells of the two strains were aerobic, Gram-stain negative, non-motile and rod-shaped. Optimal growth conditions for EGI L300112T and EGI L300120 occurred on marine agar 2216 at pH 7 at 30 °C. The major respiratory quinone was Q-10. The detected polar lipids of two strains included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylmethylethanolamine, phosphatidylcholine and unidentified phospholipids. The major fatty acids (>10%) were identified as summed feature 3 (C16 : 1ω7 c/C16 : 1ω6 c) and summed feature 8 (C18 : 1ω7 c). The G+C content of strain EGI L300112T and EGI L300120 was 61.2% and 61.4%, respectively. Based on differential phenotypic and genotypic characteristics of the two strains and related species in the genus Altererythrobacter, the two strains should be classified as representing a new species of this genus, for which the name Altererythrobacter chaiwopuensis sp. nov. is proposed. The type strain is EGI L300112T (=MCCC 1K09432T=KCTC 8712T).
Xin-Yao Li, Yi-Fei Yang, Yiyu Liang et al.· International Journal of Sys...· 0 citations
Till to date, there is no report on isolation of microorganisms from the Mahiwal hot water spring in Balochistan, Pakistan. In the current manuscript, we report on isolation and morphological, biochemical and molecular characterization of a thermophilic microorganism from this hot water spring. The isolated bacterial strain, MAS2, is rod shaped with 1 µm width and 5 µm length. It forms cream-colored slimy colonies. The strain has the ability to grow in the presence of air between 40 and 75 °C with an optimum growth temperature and pH of 65 °C and 6.5, respectively. It can utilize various sugars, hydrocarbons and carboxylic acids as sole carbon source. No additional salt is required for its growth, though relatively higher yield was achieved with the addition of 0.5% NaCl. The strain MAS2 is capable of producing several important extracellular enzymes of industrial use including an amylase, a lipase, an oxidase and a protease. The 16S rRNA gene sequence of strain MAS2 exhibited high homology with various species belonging to genus Geobacillus. The highest homology of 98.66% was observed with Geobacillus kaustophilus. However, the biochemical characteristics of the strain were more similar to Geobacillus thermopakistaniensis and Geobacillus uzenensis. These results indicate that strain MAS2 represents an unidentified species belonging to genus Geobacillus.
Keywords: Thermophiles; 16S rRNA sequence: Geobacillus sp. MAS2; biochemical characterization; extracellular enzymes.
N. Taj, M. A. Siddiqui, Osama Ahmed Siddiqui et al.· The Journal of Animal and Pl...· 0 citations
Hypersaline soils are poly-extreme terrestrial habitats characterized by high salinity, in some cases heavy-metal contamination, temperature fluctuations, and nutrient limitation. These conditions impose strong selective pressures, and many prokaryotic inhabitants still remain uncultured. Here, we conducted an extensive culturomics study of 549 isolates from the hypersaline soils of the Odiel Saltmarshes Natural Area (Southwest Spain) and compared the results with previously generated shotgun metagenomic datasets from the same environment in order to evaluate taxonomic composition, functional potential, and ecological representativeness. Cultivation across media containing 7.5%, 15%, and 25% (w/v) total salts yielded microorganisms belonging to three major phyla: Pseudomonadota, Bacillota (Bacteria) and Halobacteriota (Archaea). At the genus level, bacterial isolates were dominated by Marinobacter, Halomonas, and Aquibacillus at 7.5% (w/v) salinity, whereas extremely halophilic archaea, including Halorubrum, Halogeometricum, and Haloarcula, were predominantly recovered from media containing 25% (w/v) salts. Among the isolates, 57 strains displayed identity values < 98.65% for 16S rRNA gene sequence comparison, suggesting their putative status as new taxa. Comparison with metagenomic datasets showed that culture-dependent approaches successfully recovered the dominant haloarchaeal groups but missed some abundant bacterial phyla, such as Gemmatimonadota. Conversely, culturomics enabled the isolation of unknown species from the rare biosphere, including representatives of the novel genus Terrihalobacillus, which are typically detected at low abundance in metagenomic datasets. Together, these results demonstrate the complementarity of culturomics and metagenomics and provide an insight into the microbial communities inhabiting the hypersaline soils of the Odiel Saltmarshes.
ABSTRACT Polyethylene terephthalate (PET) waste represents a major environmental challenge due to limited recycling solutions. Thermophilic bacteria from geothermal environments harbor diverse enzymatic machinery adapted to extreme conditions, offering promising biocatalysts for plastic degradation; however, biological resources from Peru and other South American countries remain scarce. We characterized four bacterial strains isolated from two geothermal sites in Cajamarca, Peru, screened for PET hydrolysis at 50°C. Whole‐genome sequencing using hybrid assembly achieved near‐complete circular genomes. GTDB‐Tk classification identified three species: Neobacillus thermocopriae (strain 19A), Bacillus licheniformis (strains 16P and BI2), and Brevibacillus agri (strain BI8). Quantitative assays revealed that strain 16P achieved the highest mass loss (0.598%), followed by strain BI8 (0.449%). ATR‐FTIR analysis of the incubated sheets showed a significant reduction of the ester carbonyl index in strains 16P, 19A, and BI8 relative to both non‐incubated PET and an abiotic control, whereas strain BI2 did not differ from the controls, indicating preferential modification of ester bonds at the sheet surface. Genome mining and structure‐based homology searches identified multiple candidate enzymes similar to validated PETases and carboxylesterases, including PETase46‐like homologs in strains BI8 and 16P and a terephthalate‐active carboxylesterase homolog in strain 16P. Molecular docking supported the conservation of catalytic geometry and substrate‐binding sites in these candidates. This work represents one of the first systematic genomic and structural characterizations of putative PET‐hydrolases in Peruvian geothermal bacteria, expanding knowledge of extremophile diversity and advancing thermostable enzymes for sustainable plastic waste management.
Marco A Rivera-Jacinto, Claudia Rodríguez-Ulloa, Sara R Briones-Ramírez et al.· MicrobiologyOpen· 0 citations
