Prokaryotic diversity and biogeochemical characteristics of field living and laboratory cultured stromatolites from the hypersaline Laguna Interna, Salar de Atacama (Chile).

Stromatolites are organo-sedimentary structures found principally in seas and saline lakes that contain sheets of sediments and minerals formed by layers of microbial communities, which trap sediments and induce the precipitation of minerals.A living stromatolite from the alkaline Laguna Interna in the Salar de Atacama was collected and one of the fragments was deposited in an experimental aquarium for 18 months. We used Illumina sequencing of PCR-amplified V4 regions of 16S rRNA genes from total extracted DNA to identify the microbial populations. The chemical structure was studied using X-Ray Diffraction (XRD) and bench chemical methods. We found that members belonging to the Proteobacteria, Planctomycetes, Chloroflexi and Bacteroidetes phyla dominated the bacterial communities of the living and aquarium cultured samples. The potential metabolic functionality of the prokaryotic community reveals that sulfur, nitrogen, methane and carbon fixation metabolism functions are present in the samples. This study is the first to provide new insights into the prokaryotic community composition from this unusual aquatic desert site. Further studies will be helpful to obtain a better understanding of the biotic and abiotic mechanisms residing in stromatolites from Laguna Interna, as well as to have better knowledge about the formation of these biosignatures.

Enhancing complex bioprocess learning through simulation technology and hybrid teaching: A case study in university education.

The utilization of computer simulators in university education is progressively being embraced to offer students a practical exposure to industrial bioprocesses. Bioreactor computer simulators hold various advantages over conventional laboratory experiments, such as cost-effectiveness and enhanced safety. The research objective is to assess the effectiveness of integrating bioreactor computer simulators into hybrid teaching to promote active and collaborative learning experiences and evaluate their impact on student participation and understanding. A hybrid strategy combining synchronous, face-to-face, and online teaching has been implemented to enhance the teaching-learning processes in the Industrial Bioprocesses course for Biochemistry students. The simulation software BIOSTAT®T Yeast was used. This software models the production of ethanol with Saccharomyces cerevisiae through batch cultivation and the determination of the kLa value of a bioreactor. In the first simulation activity, students analyzed the software response based on parameter values input by the instructor, while in the second simulation activity, students autonomously used the computer simulator under the primary oversight of the instructor. The survey results indicate that the pedagogical innovation was positively received and significantly motivating for the students. Comparing student satisfaction surveys between the two simulation activities suggests that fostering student autonomy and engagement through simulation technology can improve satisfaction and learning outcomes in bioprocess education.

Development and assessment of a virtual escape-room game for teaching industrial bioprocesses.

This article presents a study on the implementation of a virtual escape-room game as a novel teaching methodology in biochemistry education. The game aimed to engage students in producing monoclonal antibodies against SARS-CoV-2 while reinforcing theoretical concepts and fostering teamwork. Three versions of the game were tested, incorporating modifications to address student feedback on and improve the overall experience. The study employed a satisfaction survey to gather insights from students regarding their perception of the game. Results showed that the implementation of answer flexibility using RegEx had a significant positive impact on student satisfaction and motivation. The introduction of RegEx allowed for a more realistic and immersive gaming experience, as students could provide varied answers while still being evaluated correctly. Overall, the findings highlight the effectiveness of the game's design, the suitability of the Google Forms platform for distance learning, and the importance of incorporating answer flexibility through RegEx. These results provide valuable guidance for educators seeking to enhance student engagement and satisfaction through the use of escape-room games in biochemistry education.

Key energy metabolisms in modern living microbialites from hypersaline Andean lagoons of the Salar de Atacama, Chile.

Microbialites are organosedimentary structures formed mainly due to the precipitation of carbonate minerals, although they can also incorporate siliceous, phosphate, ferric, and sulfate minerals. The minerals' precipitation occurs because of local chemical changes triggered by changes in pH and redox transformations catalyzed by the microbial energy metabolisms. Here, geochemistry, metagenomics, and bioinformatics tools reveal the key energy metabolisms of microbial mats, stromatolites and an endoevaporite distributed across four hypersaline lagoons from the Salar de Atacama. Chemoautotrophic and chemoheterotrophic microorganisms seem to coexist and influence microbialite formation. The microbialite types of each lagoon host unique microbial communities and metabolisms that influence their geochemistry. Among them, photosynthetic, carbon- and nitrogen- fixing and sulfate-reducing microorganisms appear to control the main biogeochemical cycles. Genes associated with non-conventional energy pathways identified in MAGs, such as hydrogen production/consumption, arsenic oxidation/reduction, manganese oxidation and selenium reduction, also contribute to support life in microbialites. The presence of genes encoding for enzymes associated with ureolytic processes in the Cyanobacteria phylum and Gammaproteobacteria class might induce carbonate precipitation in hypersaline environments, contributing to the microbialites formation. To the best of our knowledge, this is the first study characterizing metagenomically microbialites enriched in manganese and identifying metabolic pathways associated with manganese oxidation, selenium reduction, and ureolysis in this ecosystem, which suggests that the geochemistry and bioavailability of energy sources (As, Mn and Se) shapes the microbial metabolisms in the microbialites.