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The application of seaweed extract-based biostimulants is a promising approach for achieving sustainable agriculture, with an enormous potential of improving crop yield and mitigating climate change effects. Abiotic stressors, such as drought, are major factors resulting in tomato (Solanum lycopersicum L.) yield losses and seaweed-based biostimulants have been proposed as an eco-friendly strategy to counteract this negative impact. Chondrus crispus is a common red seaweed widely used as source of carrageenans, not yet explored as a plant biostimulant. In this study, a protein hydrolysate-rich C. crispus extract, by-products of the carrageenan extraction, was tested on tomato plants under well-watered condition and water shortage. The foliar application of the protein-rich C. crispus extract conferred drought tolerance to tomato plants resulting in less noticeable visual stress symptoms. Treated plants showed higher shoot height and biomass under both well-watered and water deficit conditions, evidencing the double effect exerted by this new biostimulant, as plant growth promoter and drought stress protector. The treatment with the biostimulant had an effect on levels of abscisic acid and proline, and triggered the expression of Solyc02g084840, a drought marker gene. Finally, a label-free mass spectrometric approach allowed us to identify phycoerythrins and phycocyanins as major bioactive proteins contained in the extract. Altogether, these results indicate that the foliar application of protein hydrolysate-rich extracts from C. crispus improved tomato plant growth and tolerance to drought stress, suggesting a new opportunity for further applications in the agriculture and horticultural sectors. Xunta de Galicia | Ref. ED431F 2020/01 COST | Ref. CA18224 Ministerio de Ciencia, Innovación y Universidades | Ref. RTI2018-096376-B-I00 Ministerio de Ciencia, Innovación y Universidades | Ref. PRE2019-090567 Ministerio de Ciencia, Innovación y Universidades | Ref. RYC2018-024454-I

The composition of seaweeds is complex, with vitamins, phenolic compounds, minerals, and polysaccharides being some of the factions comprising their structure. The main polysaccharide in brown seaweeds is fucoidan, and several biological activities have been associated with its structure. Chitosan is another marine biopolymer that is very popular in the biomedical field, owing to its suitable features for formulating drug delivery systems and, particularly, particulate systems. In this work, the ability of fucoidan to produce nanoparticles was evaluated, testing different amounts of a polymer and using chitosan as a counterion. Nanoparticles of 200–300 nm were obtained when fucoidan prevailed in the formulation, which also resulted in negatively charged nanoparticles. Adjusting the pH of the reaction media to 4 did not affect the physicochemical characteristics of the nanoparticles. The IC50 of fucoidan was determined, in both HCT−116 and A549 cells, to be around 160 µg/mL, whereas it raised to 675–100 µg/mL when nanoparticles (fucoidan/chitosan = 2/1, w/w) were tested. These marine materials (fucoidan and chitosan) provided features suitable to formulate polymeric nanoparticles to use in biomedical applications. Fundação para a Ciência e a Tecnologia | Ref. UIDB/04326/2020 Fundação para a Ciência e a Tecnologia | Ref. UIDP/04326/2020 Fundação para a Ciência e a Tecnologia | Ref. LA/P/0101/2020 PHC Pessoa Programme between ANR and Fundação para a Ciência e Tecnologia | Ref. 42306YB FCT project | Ref. UID/Multi/04326/2020 Xunta de Galicia | Ref. ED431C 2022/08 Xunta de Galicia | Ref. ED431F 2020/01 Xunta de Galicia | Ref. ED431G 2019/06

The development of greener processes for the sustainable utilization of raw materials is increasingly demanded for environmental and economic reasons. A rapid and chemical-free technique was proposed for the extraction of hybrid kappa/iota (6/4) carrageenan from Sarcopeltis (ex Gigartina) skottsbergii. After separation, carrageenans were analyzed by Fourier transform infrared attenuated total reflectance, high-performance size-exclusion chromatography, and rheology. Maximum carrageenan extraction yields up to 63–64% were obtained operating at 110 or at 160 °C, for 5–7 min considering the sum of the heating and cooling periods, but the extraction of the phenolic fraction was favored at 220 °C. The recovered carrageenan showed apparent viscous values around 103 mPa at the lowest tested shear rates (0.1 1/s) and could be suitable to formulate films. Furthermore, those carrageenans obtained under 140 °C showed gel characteristics without previous separation from the liquid extract, avoiding ethanolic precipitation and energy consumption. The antiradical properties correlated with the phenolic content in the liquid phase, but no influence of temperature on the reducing properties was observed. The microwave-assisted hydrothermal treatment could be an efficient tool without needing chemicals for the extraction of carrageenans, which showed adequate rheological properties for commercial uses. Ministerio de Ciencia, Innovación y Universidades | Ref. RTI2018-096376- BI00 Xunta de Galicia | Ref. ED431C 2018/54 GRC Xunta de Galicia | Ref. ED431G2019/06 Ministerio de Ciencia, Innovación y Universidades | Ref. PRE2019-090567 Ministerio de Ciencia, Innovación y Universidades | Ref. RYC2018-024454-I Xunta de Galicia | Ref. ED431F 2020/01

This study focusses on the valorization of the red seaweed Mastocarpus stellatus, collected in the Northern coast of Portugal, as a natural source of high value compounds due to its beneficial properties. An annual monitoring of the seaweed was performed by determining its lipids, ash, carbohydrates, phycobiliproteins, total phenolic compounds, antioxidant capacity and carrageenan from three different rocky shores located in the north of Portugal. The results showed a seasonal and spatial variability of the studied compounds between October 2018 and September 2019 depending on the climatic variables of temperature, precipitation, and solar radiation. The most productive season coincided with the warmest months, except for carbohydrates and phycobiliproteins, which were promoted in the colder season. The spatial variation also could be explained by the proximity to water channel discharges at the sampling sites. Complementary studies on the carrageenan fraction were conducted in one of the shores due to the high biopolymer content, to determine their carrageenan proportion between the summer and winter period and establish their rheological capabilities for the formulation of gelling matrices. The extracted biopolymers exhibited typical structural and viscoelastic characteristics of kappa/iota-hybrid carrageenans, suggesting notably differences depending on the harvest season, which is critically relevant to define future applications. Agencia Estatal de Investigación | Ref. RYC2018-024454-I Xunta de Galicia | Ref. ED431F 2020/01 Fundação para a Ciência e a Tecnologia | Ref. UIDP/04423/2020 Fundação para a Ciência e a Tecnologia | Ref. UIDB/04423/2020 Universidade de Vigo/CISUG

Novel personal care products are necessary to cope with the growing market demand for sustainable green products. In this context, this work deals with the formulation and fundamental physicochemical and rheological characterization of different natural personal care products using bioactive fractions from Chondrus crispus red macroalgae extracted under optimized green conditions. Body milks, body oils and shampoos were supplemented with soluble extracts with antioxidant features recovered after hydrothermal (200 °C) and microwave (170 °C)- and ultrasound (80 °C)-assisted extraction of the red macroalgae used as raw material. Formulated products were also compared with those prepared using (±)-α-tocopherol and butylhydroxytoluene standards. Body scrubs were formulated with the remaining solids (

Volatile organic compounds (VOCs) include a broad range of compounds. Their production influences a large number of processes, having direct and secondary effects on different fields, such as climate change, economy and ecology. Although our planet is primarily covered with water (~70% of the globe surface), the information on aquatic VOCs, compared to the data available for the terrestrial environments, is still limited. Regardless of the difficulty in collecting and analysing data, because of their extreme complexity, diversification and important spatial-temporal emission variation, it was demonstrated that aquatic organisms are able to produce a variety of bioactive compounds. This production happens in response to abiotic and biotic stresses, evidencing the fundamental role of these metabolites, both in terms of composition and amount, in providing important ecological information and possible non-invasive tools to monitor different biological systems. The study of these compounds is an important and productive task with possible and interesting impacts in future practical applications in different fields. This review aims to summarize the knowledge on the aquatic VOCs, the recent advances in understanding their diverse roles and ecological impacts, the generally used methodology for their sampling and analysis, and their enormous potential as non-invasive, non-destructive and financeable affordable real-time biomonitoring tool, both in natural habitats and in controlled industrial situations. Finally, the possible future technical applications, highlighting their economic and social potential, such as the possibility to use VOCs as valuable alternative source of chemicals and as biocontrol and bioregulation agents, are emphasized. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

The recovery of biopolymers from natural resources using eco-friendly extraction technologies that enhance their mechanical properties has gained attention in recent years. In this context, this work deals with the isolation of hybrid carrageenans from Mastocarpus stellatus red seaweed using subcritical water extraction operating in a wide range of thermal conditions (70–190 °C). The extracted biopolymers were analyzed by means of either Fourier-Transform infrared, nuclear magnetic resonance, rheological or cell viability assays. In parallel, the fundamental chemical composition of the seaweed used as raw material, as well as the main phytochemical properties of the soluble liquid extracts, were also studied. Results indicated that thermal extraction conditions significantly affected the rheological behavior of the recovered hybrid carrageenans. The hybrid carrageenan extraction yields varied, with results between 10.2 and 30.2% being the highest values obtained at hydrothermal treatment of 130 °C. A wide palette of viscous features was identified for recovered hybrid carrageenans, with the strongest rheology properties observed at the same temperature. It should be remarked that the maximum inhibitory effect was also obtained at 130 °C for both the ovarian carcinoma cell line (A2780) (65%, IC50: 0.31 mg/mL) and lung carcinoma cell line (A549) (59%, IC50: 0.41 mg/mL). Ministerio de Ciencia, Innovación y Universidades | Ref. RTI2018-096376-B-I00 Ministerio de Ciencia, Innovación y Universidades | Ref. RYC2018-024454-I Xunta de Galicia | Ref. ED481B 2018/071 Xunta de Galicia | Ref. ED431F 2020/01

The interest in seaweeds for cosmetic, cosmeceutics, and nutricosmetics is increasing based on the demand for natural ingredients. Seaweeds offer advantages in relation to their renewable character, wide distribution, and the richness and versatility of their valuable bioactive compounds, which can be used as ingredients, as additives, and as active agents in the formulation of skin care products. Bioactive compounds, such as polyphenols, polysaccharides, proteins, peptides, amino acids, lipids, vitamins, and minerals, are responsible for the biological properties associated with seaweeds. Seaweed fractions can also offer technical features, such as thickening, gelling, emulsifying, texturizing, or moistening to develop cohesive matrices. Furthermore, the possibility of valorizing industrial waste streams and algal blooms makes them an attractive, low cost, raw and renewable material. This review presents an updated summary of the activities of different seaweed compounds and fractions based on scientific and patent literature. Ministerio de Ciencia y Tecnología | Ref. RTI2018-096376-B-I00 Xunta de Galicia | Ref. ED431G2019/06

Due to the possible depletion of fossil fuels in the near future and the necessity of finding new food sources for a growing world population, marine microalgae constitutes a very promising alternative resource, which can also contribute to carbon dioxide fixation. Thus, seven species (Chaetoceros calcitrans, Chaetoceros gracilis, Isochrysis galbana, Nannochloropsis gaditana, Dunaliella salina, Tetraselmis suecica, and Tetraselmis chuii) were grown in five serial batch cultures at a bench scale under continuous illumination. The batch cultures were inoculated with an aliquot that was extracted from a larger-scale culture in order to obtain growth data valid for the entire growth cycle with guaranteed reproducibility. Thus, measurements of optical density at several wavelengths and cell counting with a haemocytometer (Neubauer chamber) were performed every one or two days for 22 days in the five batch cultures of each specie. Modeling of cell growth, the relationship between optical density (OD) and cell concentration and the effect of wavelength on OD was performed. The results of this study showed the highest and lowest growth rate for N. gaditana and T. suecica, respectively. Furthermore, a simple and accurate discrimination method by performing direct single OD measurements of microalgae culture aliquots was developed and is already available for free on internet. PRUCV2017-162-001 grant from the Universidad Católica de Valencia San Vicente Mártir PRUCV2018-231-001 grant from the Universidad Católica de Valencia San Vicente Mártir PRUCV2017-231-001 grant from the Universidad Católica de Valencia San Vicente Mártir PRUCV2018-162-001 grant from the Universidad Católica de Valencia San Vicente Mártir Ciencias del Mar