Three freshwater microalgae (Spirogyra sp., Cosmarium sp., and Cosmarium blytii) collected from several locations in Gran Canaria have been studied to explore their potential as a novel source of bioactive compounds for biotechnological applications. Soluble carbohydrates were quantified after extraction with 3 M HCl at 100 °C, ranging from 35.8 to 43.3 %, and with water at room temperature, ranging from 19 to 22.8 %. Amino acids glutamic acid, proline and aspartic acid were quantified by RP‐HPLC. Glutamic acid was the most abundant, ranging from 12.2 to 3.63 mg g⁻¹ of dry biomass. Cosmarium blytii was the richest sample in amino acids (24.02 mg g⁻¹ of dry weight). In addition, Cosmarium blytii and Spyrogira sp. exhibited higher radical scavenging activity (RSA) against 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) than that of the synthetic antioxidant butylhydroxytoluene (BHT), commonly used as food additive. These results show a great potential of these microalgae for exploitation in the food, feed and pharmaceutical industries.

Microbial β-(1→3)-glucans are polysaccharides of biological and technological in-terest whose production depends strongly on strain and culture conditions. This study characterized the temporal relationship between bacterial growth and aniline-blue re-activity in Alcaligenes faecalis A12C under growth and fermentation conditions. Growth, viability, and β-(1→3)-glucan-associated signals were monitored over 96 h using spec-trophotometric, microbiological, and microscopic approaches. In growth culture me-dium (GCM), OD600 increased after 24–30 h and reached approximately 2.4 at 72 h, coinciding with the highest viable count (2.49 × 10²¹ CFU/mL). Aniline-blue coloration became clearly detectable after approximately 30 h and persisted through 96 h, when microscopy showed blue staining associated with bacterial cells. In fermentation culture medium (FCM), OD600 increased progressively to approximately 2.8 at 96 h, whereas viable counts followed a distinct temporal profile. Aniline-blue reactivity increased during early fermentation and remained stable at an A610 of approximately 1.0 from 24 h onward. The divergence among OD600, viable counts, and aniline-blue reactivity in-dicates that bacterial proliferation and development of the aniline-blue-reactive signal followed distinct temporal patterns. These findings characterize this temporal rela-tionship in A12C cultures, although chemical and structural characterization is required to determine whether the detected polymer corresponds to curdlan.

Este estudio compara diferentes estrategias de enseñanza-aprendizaje en prácticas de laboratorio de química: (1) aula invertida; (2) aprendizaje basado en resolución de problemas. Para ello, se tienen en cuenta los resultados académicos de los participantes que coinciden en dos asignaturas de química impartidas en el primer curso del Grado en Ciencias del Mar en la Universidad de Las Palmas de Gran Canaria. Estos resultados mejoran con la estrategia (2) en la asignatura Química General (de segundo semestre), con un 78,8% de participantes que alcanza una calificación ≥9 sobre 10, mientras que un 6,1% supera el 9 en la asignatura Fundamentos de Química (de primer semestre). Los estudiantes se muestran satisfechos con las prácticas, con lo aprendido y con el trabajo que han realizado, calificando estos aspectos con puntuaciones entre 4,28 y 4,57 en una escala Likert de 5 puntos. Los resultados de este trabajo pueden ayudar a reconsiderar los procesos de enseñanza y aprendizaje en las prácticas de laboratorio de las asignaturas de química básica.

Microbial exopolysaccharides (EPSs) are functional biopolymers of growing scientific and industrial interest because of their structural diversity, biocompatibility, and rheological properties. Microbial β-(1→3)-glucans are of particular biological and technological interest, and their production depends strongly on strain characteristics, medium composition, and culture conditions. This study characterized the temporal relationship among bacterial growth, viability, and aniline-blue reactivity in Alcaligenes faecalis A12C under batch growth and fermentation conditions. Growth turbidity, viable bacterial concentration, and β-(1→3)-glucan-associated signals were monitored over 96 h using spectrophotometric, microbiological, and microscopic approaches. In growth culture medium (GCM), OD600 increased after 24–30 h and reached approximately 2.4 at 72 h, coinciding with the highest viable count (2.44 × 10²¹ CFU/mL). Aniline-blue coloration became clearly detectable after 30 h and persisted through 96 h, when microscopy showed blue staining associated with bacterial cells. In fermentation culture medium (FCM), OD600 increased progressively to approximately 2.8 at 96 h, whereas viable counts followed a distinct temporal profile. Aniline-blue reactivity changed during the first 24 h and remained close to an A610 of approximately 1.0 thereafter. These findings indicate distinct temporal patterns among culture turbidity, viability, and aniline-blue reactivity and provide a framework for subsequent structural characterization of the detected material.