Bioprospecting for new exopolysaccharide-producing microalgae of marine origin / Bioprospección de nuevas microalgas de origen marino productoras de exopolisacáridos

Microalgae are photosynthetic organisms that can produce biomolecules with industrial interest, including exopolysaccharides (EPS). Due to their structural and compositional diversity, microalgae EPS present interesting properties that can be considered in cosmetic and/or therapeutic areas. Seven microalgae strains from three different lineages, namely Dinophyceae (phylum Miozoa), Haptophyta, and Chlorophyta, were investigated as EPS producers. All strains were found to be EPS producers, though the highest EPS yield was obtained for Tisochrysis lutea, followed by Heterocapsa sp. (126.8 and 75.8 mg L−1, respectively). Upon assessment of the polymers’ chemical composition, significant contents of unusual sugars, including fucose, rhamnose, and ribose, were found. Heterocapsa sp. EPS stood out due to its high content of fucose (40.9 mol%), a sugar known to confer biological properties to polysaccharides. The presence of sulfate groups (10.6–33.5 wt%) was also noticed in the EPS produced by all microalgae strains, thus contributing to the possibility that these EPS might have biological activities worth exploring.(AU)

Microalgas: ¿los primeros ingenieros nucleares? / Microalgae: the first nuclear engineers?

Self-sustaining nuclear chain reactions ran spontaneously 1.7 billion years ago at Oklo (Gabon, Africa) are a mystery. It was hypothesized that the microalgae concentrated enough rich-uranium in Oklo as for a natural reactor to start operating. The key to understanding as microalgae could do this is in an extremely U-contaminated pond of Saelices uranium-mine (Spain). Some microalgae colonized this extreme pond due to spontaneous mutations of single-genes. These U-resistant microalgae concentrate 115 mg U/g dried-biomass by bio-adsorption and bioaccumulation and are able to enrich uranium producing isotopic fractionation 235U/238U. Consequently, microalgae could be able to build a nuclear reactor in appropriate circumstances (AU)

Las reacciones nucleares en cadena auto-sostenibles que ocurrieron espontáneamente hace 1.700 millones años en Oklo (Gabón, África) son un misterio. Hipotéticamente las microalgas concentraron suficiente uranio enriquecido para que un reactor nuclear natural comenzara a operar. La clave está en un estanque contaminado por uranio en la mina de Saelices (España). Algunas microalgas colonizaron este estanque extremo debido a mutaciones espontáneas de genes individuales. Estas microalgas Uranio-resistentes concentran 115 mg U / g de biomasa seca mediante bio-absorción y bioacumulación, siendo capaces de enriquecer uranio produciendo fraccionamiento isotópico 235U/238U. Estas microalgas podrían construir un reactor nuclear en circunstancias apropiadas (AU)