Roberto Orellana

Playa Ancha University of Educational Sciences · Departamento Disciplinario de Biología

Some sulfate-reducing bacteria (SRB), mainly belonging to the Desulfovibrionaceae family, have evolved the capability to conserve energy through microbial extracellular electron transfer (EET), suggesting that this process may be more widespread than previously believed. While previous evidence has shown that mobile genetic elements drive the plast...

Parque Nacional La Campana (PNLC) is recognized worldwide for its flora and fauna, rather than for its microbial richness. Our goal was to characterize the structure and composition of microbial communities (bacteria, archaea and fungi) and their relationship with the plant communities typical of PNLC, such as sclerophyllous forest, xerophytic shru...

Coastal zones are ecosystems that are sensitive to climate change and anthropogenic pollution, resulting in a potential loss of biodiversity and ecosystem services through eutrophication and nutrient imbalances, among others. The coastal El Sauce catchment area, Central Chile, is under multiple anthropogenic pressures including wastewater treatment...

Coastal wetlands are ecosystems associated with intense carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) recycling, modulated by salinity and other environmental factors that influence the microbial community involved in greenhouse gases production and consumption. In this study, we evaluated the influence of environmental factors on GHG...

Technical advances have converted bioremediation into a large-scale ecosystem service suitable for the treatment of polluted soils worldwide; however, its application in Chile is scarce. The main hurdles that must be addressed include the capacities of such approaches for the treatment of polluted soils, the lack of knowledge about key factors affe...

Citation: Orellana, R.; Arancibia, A.; Badilla, L.; Acosta, J.; Arancibia, G.; Escar, R.; Ferrada, G.; Seeger, M. Ecophysiological Features Shape the Distribution of Prophages and CRISPR in Sulfate Reducing Prokaryotes. Microorganisms 2021, 9, 931. https://doi.org/10.3390/ microorganisms9050931 Academic Editor: Hanna M. Oksanen

Lignin is the second most abundant carbon polymer on earth and despite having more fuel value than cellulose, it currently is considered a waste byproduct in many industrial lignocellulose applications. Valorization of lignin relies on effective and green methods of de-lignification, with a growing interest in the use of microbes. Here we investiga...

Extremophiles are organisms capable of adjust, survive or thrive in hostile habitats that were previously thought to be adverse or lethal for life. Chile gathers a wide range of extreme environments: salars, geothermal springs, and geysers located at Altiplano and Atacama Desert, salars and cold mountains in Central Chile, and ice fields, cold lake...

Previous studies of acetate-promoted bioremediation of uranium-contaminated aquifers focused on Geobacter because no other microorganisms that can couple the oxidation of acetate with U(VI) reduction had been detected in situ. Monitoring the levels of methyl CoM reductase subunit A (mcrA) transcripts during an acetate-injection field experiment dem...

Some hyperthermophilic heterotrophs in the genus Thermococcus produce H2 in the absence of S° and have up to seven hydrogenases, but their combined physiological roles are unclear. Here, we show which hydrogenases in Thermococcus paralvinellae are affected by added H2 during growth without S°. Growth rates and steady-state cell concentrations decre...

The production of lignocellulosic-derived biofuels is a highly promising source of alternative energy, but it has been constrained by the lack of a microbial platform capable to efficiently degrade this recalcitrant material and cope with by-products that can be toxic to cells. Species that naturally grow in environments where carbon is mainly avai...

Previous studies of in situ bioremediation of uranium-contaminated groundwater with acetate injections have focused on the role of Geobacter species in U(VI) reduction because of a lack of other abundant known U(VI)-reducing microorganisms. Monitoring the levels of methyl CoM reductase subunit A (mcrA) transcripts during an acetate-injection field...

Geobacter species often play an important role in the in situ bioremediation of uranium-contaminated groundwater, but little is known about how these microbes avoid uranium toxicity. To evaluate this further, the proteome of G. sulfurreducens exposed to 100 µM U(VI) acetate was compared with control cells not exposed to U(VI). Of the 1363 proteins...

Previous studies have suggested that protozoa prey on Fe(III)- and sulfate-reducing bacteria that are enriched when acetate is added to uranium contaminated subsurface sediments to stimulate U(VI) reduction. In order to determine whether protozoa continue to impact subsurface biogeochemistry after these acetate amendments have stopped, 18S rRNA and...

Early studies with Geobacter sulfurreducens suggested that outer-surface c-type cytochromes might play a role in U(VI) reduction, but it has recently been suggested that there is substantial U(VI) reduction at the surface of the electrically conductive pili known as microbial nanowires. This phenomenon was further investigated. A strain of G. sulfu...

The possibility of arsenic release and the potential role of Geobacter in arsenic biogeochemistry during in situ uranium bioremediation was investigated because increased availability of organic matter has been associated with substantial releases of arsenic in other subsurface environments. In a field experiment conducted at the Rifle, CO study si...

Geobacter species specialize in making electrical contacts with extracellular electron acceptors and other organisms. This permits Geobacter species to fill important niches in a diversity of anaerobic environments. Geobacter species appear to be the primary agents for coupling the oxidation of organic compounds to the reduction of insoluble Fe(III...

The maturity of compost can be determined using sensitive species to phytotoxic metabolites by germination bioassays. In order to obtain a stabilized and non-phytotoxic product, the phytotoxic compounds must be biodegraded or immobilized during the maturity phase of composting. In this study the sensitivity of lettuce (Lactuca sativa, var. Four Sea...

Con el objeto de establecer la fitotoxicidad de diversos residuos orgánicos, se evaluó el índice de germinación (IG) de las especies de rabanito (cv. Cherry Bell) y pepino (cv. Marketer). Utilizando los residuos de: semilleros de hinojo (H), semilleros de puerro (Pu), semilleros de zapallo (Z), semilleros de lechuga (L), cáscara de almendra (Ca), c...