Examinando por Autor "Araya, Matías"

Mostrando 1 - 4 de 4
  • Miniatura
    Ítem
    Controlled cultivation of different stages of Pyropia orbicularis (Rhodophyta; Bangiales) from the South Pacific coast
    (Elsevier B.V., 2023-06) Piña, Florentina; Núñez, Alejandra; Araya, Matías; Rivas, Jorge; Hernández, Constanza; Bulboa, Cristian; Contreras-Porcia, Loretto
    The species of the genus Pyropia have a diplohaplontic life cycle, in which there is a gametophytic phase (n) or blade, and a microscopic sporophytic phase (2n), known as conchocelis, as well as intermediate stages of development. Pyropia species, together with Porphyra species, belong to the group of the most commercialized and produced macroalgae worldwide, mainly due to their high nutritional value and high content of bioactive compounds with antioxidant and anti-inflammatory activity. The interest in cultivating and exploiting this marine resource has increased in recent years; nevertheless, despite the development of cultivation techniques and technologies for these species, there are still difficulties involved in their successful cultivation, mainly related to the great interspecific and intraspecific variability in the required culture conditions. In this work, we study the life cycle development of Pyropia orbicularis, a species endemic to the South Pacific, to determine the effect of abiotic culture parameters, such as the temperature and photoperiod, on the formation and development of early and late life cycle stages, such as conchocelis formation, cochoesporangial filaments, conchospore release and blade growth. Our results demonstrate that the conchocelis phase grew rapidly under 8:16 h (L:D) photo period conditions at both 15 ◦C and 20 ◦C. The lower temperatures favored the formation of conchosporangia and conchospores; the rate of their development was increased at 15 ◦C. The development of the blades in the suspended culture system was constant during the experimental period, generating blades of the same color and shape as those from natural populations. Our results reflect the adaptation of P. orbicularis to the seasonal environmental conditions it is exposed to and the importance of maintaining optimal abiotic parameters for the success of its culture. This work is the first to describe the full life cycle development of P. orbicularis under controlled conditions, which has important implications for commercial production.
  • Miniatura
    Ítem
    Effect of pyrolysis temperature on copper aqueous removal capability of biochar derived from the kelp macrocystis pyrifera
    (MDPI, 2021-10) Araya, Matías; Rivas, Jorge; Sepúlveda, Graciela; Espinoza-González, Camila; Lira, Sebastián; Meynard, Andrés; Blanco, Elodie; Escalona, Néstor; Ginocchio, Rosanna; Garrido-Ramírez, Elizabeth; Contreras-Porcia, Loretto
    Seaweed biochar is an efficient alternative bioadsorbent for Cu2+ removal due to its low cost and heavy metal removal capacity. Using the slow pyrolysis process, we produced biochars from Macrocystis pyrifera at 300 (BC300), 450 (BC450), and 600◦C (BC600). The physicochemical and structural properties of the biochar samples improved with increasing pyrolysis temperature from 300 to 450◦C, whereas no significant differences were observed with further increases in temperature to 600◦C. The yield ranged between 49% and 62% and had a high ash content (57.5–71.1%). BC450 and BC600 presented the highest surface areas and higher porosities. The FTIR spectra indicated that an increase of temperature decreased the acidic functional groups due to depolymerization and the dehydration processes, increasing the aromatic structures and the presence of calcium carbonate. The fittings of the kinetic models were different for the BCs: for the BC450 and BC600 samples, the Cu2+ adsorption was well-represented by a pseudo-first-order model; for BC300, a better fit was obtained with the pseudo-second-order model. The rate-limiting step of Cu2+ adsorption on BCs was represented by both models, liquid film diffusion and intraparticle diffusion, with surface diffusion being more important in BC300 and BC600, and intraparticle diffusion in BC450, in agreement with the pore size of the biochar samples. The adsorption isotherms of all BCs showed Langmuir behavior, representative of a chemisorption process, which was corroborated by the energy adsorption values determined by the D–R model. The maximum monolayer Cu2+ adsorption capacities were 93.55 and 58.0 mg g−1 for BC600 and BC450, respectively, whereas BC450 presented the highest affinity. Other mechanisms involved in controlling heavy metal removal from aqueous suspensions using these seaweed biochars remain to be explored. We conclude that BC450 and BC600 from M. pyrifera are the most efficient adsorbents for Cu2+ aqueous removal and are thus an appropriate alternative for bioremediation. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
  • Miniatura
    Ítem
    Heavy Metal Depuration Steps for Gracilaria chilensis in Outdoor Culture Systems
    (MDPI, 2022-10) Rivas, Jorge; Piña, Florentina; Araya, Matías; Latorre-Padilla, Nicolás; Pinilla-Rojas, Benjamín; Caroca, Sofía; Bronfman, Francisca C.; Contreras-Porcia, Loretto
    Seaweed aquaculture is affected by natural and anthropogenic stressors, which put the biomass productivity of the cultures at risk. Seaweed biomass for commercial purposes, principally in pharmaceutical and/or nutraceutical applications, needs to be free of pollutants; therefore, controlled cultures have relevance in regulating the quality of biomass. The aim of this work was to demonstrate the successful utilization of controlled outdoor cultures to remove excess heavy metal accumulation in Gracilaria chilensis, an important commercial seaweed farming model. Specifically, we designed a simple and operational heavy metal depuration protocol, utilizing seawater and tap water removal, which permitted the concentration reduction of 10 heavy metals, including As, Cu, and Cd but not Zn, from the biomass at 7 days of culture. The percentage of depuration of the heavy metals ranged from 32 to 92% at 7 days, which was maintained throughout 21 days of culture. During the culture period, the monitored physicochemical parameters (temperature, salinity, and dissolved oxygen, among others) remained stable, with an increase in the daily growth rate (DGR% d−1) of the biomass recorded after 14 days of culture. Consequently, the experimental setup was successful for heavy metal depuration, which highlights the importance of controlled outdoor cultures as important tools of sustainability. © 2022 by the authors.
  • Miniatura
    Ítem
    Indoor and Outdoor Cultures of Gracilaria chilensis: Determination of Biomass Growth and Molecular Markers for Biomass Quality Evaluation
    (MDPI, 2023-03) Caroca-Valencia, Sofía; Rivas, Jorge; Araya, Matías; Núñez, Alejandra; Piña, Florentina; Toro-Mellado, Fernanda; Contreras-Porcia, Loretto
    Taking into consideration climate change scenarios, marine contamination, and a constantly expanding world population, seaweed aquaculture has become an important option for the large-scale production of high-quality biomass. Due to existing biological knowledge of Gracilaria chilensis, several cultivation strategies have been established for obtaining diverse biomolecules (lipids, fatty acids, pigments, among others) with nutraceutical properties. In this research, indoor and outdoor cultivation methodologies were applied to generate high biomass of G. chilensis with positive quality for productive purposes, where the quality was determined according to the concentrations of lipoperoxides and phenolic compounds and the total antioxidant capacity (TAC). The results showed that G. chilensis cultures, which were fertilized for three weeks with Basfoliar® Aktiv (BF) at concentrations of 0.05–1% v/v, obtained high biomass (1–1.3 kg m–2) and DGR (0.35–4.66% d–1), low lipoperoxides (0.5–2.8 µmol g–1 DT), and high phenolic compounds (0.4–0.92 µ eq. GA g–1 FT) and TAC (5–7.5 nmol eq. TROLOX g–1 FT) as compared with other culture media. Lower stress was determined under indoor cultures, due to the operative control of diverse physicochemical stressor parameters (T°, light intensity, photoperiod, among others). Therefore, the cultures developed allow scaling the biomass in productive terms and are suitable for obtaining compounds of interest. © 2023 by the authors.