Browsing by Autor "C. Hoepfner"

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Caldisphaera lagunensis
(CAB International Publishing, 2025) D.W. Minter; C. Hoepfner; V. Foronda; David Sánchez-Migallón Guzman
Abstract
Cyanobacterial mats and their associated microbiomes in saline and freshwater lakes from the Bolivian Altiplano
(Frontiers Media, 2025) Guilherme Scotta Hentschke; Miguel Semedo; Jimmy Ciancas; C. Hoepfner; Daniel Guzmán; Daniela S. Rivera; Vı́tor Vasconcelos
The Bolivian Altiplano presents extreme environmental conditions, including high altitude, intense UV radiation, low precipitation, freezing temperatures, and saline to alkaline waters. Despite these harsh settings, cyanobacteria thrive in microbial mats, although their diversity remains poorly characterized. This study aimed to explore the morphological and molecular diversity of cyanobacterial mats and their associated microbiomes in saline and freshwater ecosystems of the Bolivian Altiplano. Morphological analyses revealed seven distinct cyanobacterial morphotypes affiliated with Nostocaceae, Coleofasciculaceae, Rivulariaceae, and Microcoleaceae. Amplicon-based analysis of the 16S rRNA gene identified 4.113 ASV for the bacterial community. Of these, 310 were identified as Cyanobacteria, with 134 classified as Cyanophyceae assigned to 32 genera. Phylogenetic reconstruction and sequence identity comparisons resolved 42 cyanobacterial genera across nine orders. Moreover, 30 ASVs grouped into 16 clades unrelated to any known genus, suggesting the presence of potentially novel cyanobacterial lineages. The microbiome associated with these mats was dominated by Alphaproteobacteria, Bacteroidia, Gammaproteobacteria, Clostridia, Cyanophyceae, and Campylobacteria. Functional predictions based on 16S rRNA gene profiles indicated a predominance of phototrophic and chemoheterotrophic metabolisms, along with sulfur respiration, nitrogen fixation, nitrate and nitrite reduction, and fermentation pathways. Notably, nitrogen-fixing cyanobacteria and bacterial groups with bioremediation potential were prevalent, highlighting the ecological importance and possible biotechnological applications of these microbial consortia. This is the first comprehensive metabarcoding analysis of cyanobacterial mats from Bolivia, including their associated microbiomes. Many new bacterial and cyanobacterial taxa remain to be described in these ecosystems. Based on the functional genomic analysis, this work also highlights the great unexplored biotechnological potential of Bolivia's extreme environments and the functional roles of microbial mats in biogeochemical cycling under polyextreme conditions.
Functional stratification and enzymatic arrangement in microbial communities across a hypersaline depth gradient
(Frontiers Media, 2025) C. Hoepfner; Daniel Guzmán; Boris Vidal‐Veuthey; V. Foronda; Antonia Beggs; Juan Pablo Cárdenas; Virginia A. Vargas; Fernando D. Alfaro
Extreme environments comprise a significant portion of Earth's terrestrial surface, posing challenges, such as extreme temperatures, pressure, pH extremes, oxygen and nutrient scarcity, and high salinity. Hypersaline ecosystems, such as those in the Andean Cold Deserts, exemplify extreme environments where microbial life has evolved specialized survival mechanisms. The Central Andean Mountains host extensive salt flats exposed to extreme temperature fluctuations, intense ultraviolet radiation, and high soil salinity. While most studies focus on surface layers, the impact of soil depth on functional diversity remains poorly understood. This study utilized shotgun metagenomics and functional annotation to explore enzymatic diversity across a 8-meter depth gradient in the Uyuni Salt Flat aiming to understand microbial adaptations to depth and abiotic stress. Our findings revealed a complex, stratified microbial ecosystem. Surface layers showed high abundance of amylases, enzymes that degrade accessible carbohydrates, likely derived from photosynthetic communities or surface-imported organic matter. These patterns suggest a dominance of strategies for rapid carbon decomposition. Intermediate depths exhibited elevated lipase and peroxidase activity, reflecting the presence of complex lipids and oxidative stress management, essential for survival in oxygen-limited, high-salinity zones. Lipase support lipid utilization as a carbon source, while peroxidase activity points to redox adaptations for microbial resilience under fluctuating oxidative conditions. Deeper sediment layers showed a shift toward protease and peptidase activity, indicating organic nitrogen recycling in nutrient-deprived environments and suggesting an efficient protein degradation system among halophilic archaea. Peroxidases remained abundant even at these depths, supporting sustained redox regulation and biogeochemical cycling thus enabling microbes to manage redox imbalances in high-salinity, low-oxygen settings. The enzymatic diversity across the depth gradient demonstrates functional stratification and remarkable microbial adaptability to hypersaline conditions. This functional resilience underpins nutrient cycling and organic matter decomposition deep in the salt flats. Notably, the identified halophilic enzymes, stable and active under high-salinity conditions, hold significant potential for biotechnological applications. This study contributes to our understanding of microbial life's complexity in hypersaline environments, enhancing our ability to harness extremophilic enzymes for biotechnological applications while underscoring the ecological value of these unique habitats.
Halodesulfurarchaeum formicicum
(CAB International Publishing, 2025) D.W. Minter; C. Hoepfner; V. Foronda; David Sánchez-Migallón Guzman
Abstract
Halopiger xanaduensis
(CAB International Publishing, 2025) D.W. Minter; C. Hoepfner; V. Foronda; David Sánchez-Migallón Guzman
Abstract
Haloplanus rubicundus
(CAB International Publishing, 2025) D.W. Minter; C. Hoepfner; V. Foronda; David Sánchez-Migallón Guzman
Abstract
Halorhabdus tiamatea
(CAB International Publishing, 2025) D.W. Minter; C. Hoepfner; V. Foronda; David Sánchez-Migallón Guzman
Abstract
Candidatus nanohalobium constans
(CAB International Publishing, 2025) Debbie Minter; C. Hoepfner; V. Foronda; David Sánchez-Migallón Guzman
Abstract
Candidatus nitrosocosmicus hydrocola
(CAB International Publishing, 2025) Deborah Minter; C. Hoepfner; V. Foronda; David Sánchez-Migallón Guzman
Abstract
Candidatus nitrosomarinus catalina
(CAB International Publishing, 2025) D.W. Minter; C. Hoepfner; V. Foronda; David Sánchez-Migallón Guzman
Abstract
Candidatus promethearchaeum syntrophicum
(CAB International Publishing, 2025) Deborah Minter; C. Hoepfner; V. Foronda; David Sánchez-Migallón Guzman
Abstract
Lipase production from Bacillus safensis VC-6 isolated from the volcanic region of Copahue: optimization and functional genomic insights
(Frontiers Media, 2025) V. Foronda; Valeria Castellanos; C. Hoepfner; Daniel Guzmán; Héctor Guzmán; Jerry L. Solis
Extremophilic microorganisms produce highly stable and industrial-grade enzymes with enhanced performance. Thermostable enzymes, such as lipases that catalyze the hydrolysis and esterification of lipids, are of great industrial interest due to their stability and efficacy under harsh conditions, making them ideal for applications in biotechnology, pharmaceuticals, and cosmetics. Lipase production from various microorganisms is well-studied. However, optimization studies remain limited for lipases sourced from halotolerant bacteria, such as Bacillus safensis strain VC-6, known to grow above 10% (w/v) NaCl and 50°C. The limited research on optimizing these enzymes prevents their widespread adoption in industries requiring high thermostability and solvent tolerance. This study optimized the production of thermostable and halotolerant lipases using the extremophilic strain VC-6, isolated from samples from the Copahue Volcano, Chile. Strain VC-6 was selected from five candidate strains due to its stable growth within simple culture media and positive results in qualitative lipase activity assays. In the initial phases, VC-6 demonstrated superior potential for lipase production. Growth conditions were optimized using a heterotrophic medium supplemented with 2% (w/v) NaCl, 2% (v/v) glycerol, and pH 6 at 37°C. Lipase production was maximized based in the previous medium supplemented with 1% (w/v) yeast extract, 0.5% (w/v) KCl, 3% (v/v) sunflower oil, 2% (v/v) glycerol, and pH 8 at 37°C. Extracellular lipase activity was assessed, and enzyme recovery was facilitated through precipitation methods. Lipase activity was quantified in a batch bioreactor under controlled conditions achieving a maximum enzymatic activity of 12.83 U mL-1 at 16 h of cultivation, correlated with the exponential growth phase of the bacteria. Genetic identification (16S rRNA gene) confirmed that strain VC-6 belongs to the Bacillus genus, sharing 99.93% similarity with Bacillus safensis. Genomic analysis revealed the presence of key genes related to lipase production, including YtpA (phospholipase), LipC (germination lipase), and a thermostable monoacylglycerol lipase. These genes likely explain the observed peaks of enzymatic activity during the fermentation process, with distinct activity observed at different time points. This study highlights the potential of Bacillus safensis strain VC-6 as a promising source of thermostable and halotolerant lipases. The integration of optimized bioprocess conditions and genomic-based understanding establishes a solid groundwork for the future industrial exploitation of these biocatalysts under extreme environmental conditions. The optimization of growth conditions and the identification of critical genes related to lipase production further enhance the potential for scaling up production processes in biotechnological applications.
Methanofollis liminatans
(CAB International Publishing, 2025) D.W. Minter; C. Hoepfner; V. Foronda; David Sánchez-Migallón Guzman
Abstract
Nutritional modulation of host physiology, behavior, and gut microbiome in the captive rodent Octodon degus
(Nature Portfolio, 2025) Daniela S. Rivera; Valentina Beltrán; C. Hoepfner; María del Pilar Fernández; Carolina A. Oliva; María Jesús Vera; Camila Farías; Rodrigo Valenzuela; Isaac José Pérez López; Loreto A. Correa
The Description of the Extremophile Reticulonema bolivianum gen. et sp. nov. (Microcoleaceae, Cyanobacteria) and the Review of the Phylogenetic Status of the Genus Capilliphycus Based on the 16S rRNA Gene
(Multidisciplinary Digital Publishing Institute, 2025) Guilherme Scotta Hentschke; C. Hoepfner; Daniel Guzmán; Vı́tor Vasconcelos
This article describes a new genus and species of cyanobacteria isolated from Laguna Pastos Grandes in the Bolivian Altiplano. This discovery marks the first described species of this phylum from this extreme environment. Additionally, the phylogenetic status of the genus Capilliphycus is reassessed. The analyses are based on 16S rRNA gene maximum likelihood and Bayesian phylogenies, identity (p-distance), morphology and habitat comparisons. The new genus is a Lyngbya-like type from a mat at the margin of a brackish-alkaline lake with borax. It is phylogenetically close to Dapis, Tenebriella and Okeania, but compared to these genera, the maximum 16S rRNA gene identity values reached only 90.9%, 91.1% and 92.5%, respectively. The genus Capilliphycus was found to be polyphyletic. The type species Capilliphycus salinus is clustered with C. guerandensis. However, "C. tropicalis" and "C. flaviceps" form a distinct clade, distant from the Capilliphycus type species. Between the two "Capilliphycus" clades, Sirenicapillaria and Limnoraphis are found.
The extremophile Eurychoronema bolivianum gen. et sp. nov. (Nodosilineales, Cyanobacteria) and Leptolyngbya aquatica comb. nov
(Taylor & Francis, 2024) Guilherme Scotta Hentschke; Juan A. Jiménez; C. Hoepfner; Daniel Guzmán; M. Mesquita; Vı́tor Vasconcelos
The microbiome of a polluted urban lake harbors pathogens with diverse antimicrobial resistance and virulence genes
(Elsevier BV, 2021) Jorge Quillaguamán; Daniel Guzmán; Melina Campero; C. Hoepfner; Laura Relos; Daniela Mendieta; Shawn M. Higdon; Daniel Eid Rodríguez; Carla E. Fernández