Development of biomaterial composite hydrogel as a passive sampler with potential application in wastewater-based surveillance.

Nowadays, the need to track fast-spreading infectious diseases has raised due to the recent COVID-19 disease pandemic. As a response, Wastewater-based Surveillance (WBS) has emerged as an early detection and disease tracking method for large populations that enables a comprehensive overview of public health allowing for a faster response from public health sector to prevent large outbreaks. The process to achieve WBS requires a highly intensive sampling strategy with either expensive equipment or trained personnel to continuously sample. The sampling problem can be addressed by passive sampler development. Chitosan-based hydrogels are recognized for their capability to sample and remove various contaminants from wastewater, including metals, dyes, pharmaceuticals, among others. However, chitosan-based hydrogels unique characteristics, can be exploited to develop passive samplers of genetic material that can be a very valuable tool for WBS. This study aimed to develop a novel chitosan hydrogel formulation with enhanced characteristics suitable for use as a passive sampler of genetic material and its application to detect disease-causing pathogens present in wastewater. The study evaluates the effect of the concentration of different components on the formulation of a Chitosan composite hydrogel (Chitosan, Glutaraldehyde, Microcrystalline cellulose (MCC), and Polyethylene glycol (PEG)) on the hydrogel properties using a Box Hunter & Hunter experimental matrix. Hydrogels' weight, thickness, swelling ratio, microscopic morphology (SEM), FTIR assay, and zeta potential were characterized. The resulting hydrogel formulations were shown to be highly porous, positively charged (Zeta potential up to 35.80 ± 1.44 mV at pH 3) and with high water swelling capacity (up to 703.89 ± 15.00 %). Based on the results, a formulation from experimental design was selected and then evaluated its capacity to adsorb genetic material from a control spiked water with Influenza A virus synthetic vector. The adsorption capacity of the selected formulation was 4157.04 ± 64.74 Gene Copies/mL of Influenza A virus synthetic vector. The developed hydrogel showed potential to be used as passive sampler for pathogen detection in wastewater. However, deeper research can be conducted to improve adsorption, desorption and extraction techniques of genetic material from chitosan-hydrogel matrices.

Inter-institutional laboratory standardization for SARS-CoV-2 surveillance through wastewater-based epidemiology applied to Mexico City.

Objectives: Wastewater-based surveillance applied to SARS-CoV-2 viral load quantification for COVID-19 has become one of the most relevant complementary tools in epidemiologic prevention programs worldwide. However, this valuable decision-making tool still requires fine-tuning to produce comparable results between laboratories, especially when applied to the surveillance of megacities. Methods: Six laboratories across Mexico and one from the United States executed an interlaboratory study to set up a singular standardized protocol considering method cost, installed infrastructure, materials available, and supply availability for SARS-CoV-2 quantification from five Mexico City sampling sites across this megacity. Results: Comparable data from processing outcomes in the Mexican laboratories and in the external international laboratory serve as a validating data source. The Bland-Altman comparison showed consistency, with cycle threshold values within ±1.96 SD of SARS-CoV-2 genetic copies for the standard curve quantification, with a mismatch of two laboratories. In addition, MS2 bacteriophage recovery rates varied between 35% and 67% among all participating laboratories. Finally, the efficiency of viral genetic material recovered from all participating laboratories varied between 65% and 93% for the participating laboratories. Conclusion: This work lays the foundation for extensive and continuous wastewater-based surveillance application across independent Mexican laboratories in a time- and resource-effective manner.

The Immobilization of a Cyclodipeptide Synthase Enables Biocatalysis for Cyclodipeptide Production.

Cyclodipeptide synthases (CDPSs) are enzymes that use aminoacylated tRNAs as substrates to produce cyclic dipeptide natural products acting as anticancer and neuroprotective compounds. Many CDPSs, however, suffer from instability and poor recyclability, while enzyme immobilization can enhance catalyst efficiency and reuse. Here, the CDPS enzyme from Parcubacteria bacterium RAAC4_OD1_1 was immobilized using three different supports: biochar from waste materials, calcium-alginate beads, and chitosan beads. Immobilization of active PbCDPS was successful, and production of the cyclodipeptide cyclo (His-Glu) (cHE) was confirmed by HPLC-MS. Biochar from spent coffee activated with glutaraldehyde, alginate beads, and chitosan beads activated with glutaraldehyde led to a 5-fold improvement in cHE production, with the immobilized enzyme remaining active for seven consecutive cycles. Furthermore, we co-immobilized three enzymes participating in the cascade reaction yielding cHE (PbCDPS, histidyl-tRNA synthetase, and glutamyl-tRNA synthetase). The enzymatic cascade successfully produced the cyclic dipeptide, underscoring the potential of immobilizing various enzymes within a single support. Importantly, we demonstrated that tRNAs remained free in solution and were not adsorbed by the beads. We paved the way for the immobilization of enzymes that utilize tRNAs and other complex substrates, thereby expanding the range of reactions that can be exploited by using this technology.

Valorization of fishery industry waste: Chitosan extraction and its application in the industry.

Waste from the fishing industry is disposed of in soils and oceans, causing environmental damage. However, it is also a source of valuable compounds such as chitin. Although chitin is the second most abundant polymer in nature, its use in industry is limited due to the lack of standardized and scalable extraction methods and its poor solubility. The deacetylation process increases its potential applications by enabling the recovery of chitosan, which is soluble in dilute acidic solutions. Chitosan is a polymer of great importance due to its biocompatible and bioactive properties, which include antimicrobial and antioxidant capabilities. Chitin extraction and its deacetylation to obtain chitosan are typically performed using chemical processes that involve large amounts of strongly acidic and alkaline solutions. To reduce the environmental impact of this process, extraction methods based on biotechnological tools, such as fermentation and chitin deacetylase, as well as emerging technologies, have been proposed. These extraction methods have demonstrated the potential to reduce or even avoid using strong solvents and shorten extraction time, thereby reducing costs. Nevertheless, it is important to address existing gaps in this area, such as the requirements for large-scale implementation and the determination of the stoichiometric ratios for each process. This review highlights the use of biotechnological tools and emerging technologies for chitin extraction and chitosan production. These approaches truly minimize environmental impact, reduce the use of strong solvents, and shorten extraction time. They are a reliable alternative to fishery waste valorization, lowering costs; however, addressing the critical gaps for their large-scale implementation remains challenging.

Enhancing the production of PHA in Scenedesmus sp. by the addition of green synthesized nitrogen, phosphorus, and nitrogen-phosphorus-doped carbon dots.

Plastic consumption has increased globally, and environmental issues associated with it have only gotten more severe; as a result, the search for environmentally friendly alternatives has intensified. Polyhydroxyalkanoates (PHA), as biopolymers produced by microalgae, might be an excellent option; however, large-scale production is a relevant barrier that hinders their application. Recently, innovative materials such as carbon dots (CDs) have been explored to enhance PHA production sustainably. This study added green synthesized multi-doped CDs to Scenedesmus sp. microalgae cultures to improve PHA production. Prickly pear was selected as the carbon precursor for the hydrothermally synthesized CDs doped with nitrogen, phosphorous, and nitrogen-phosphorous elements. CDs were characterized by different techniques, such as FTIR, SEM, ζ potential, UV-Vis, and XRD. They exhibited a semi-crystalline structure with high concentrations of carboxylic groups on their surface and other elements, such as copper and phosphorus. A medium without nitrogen and phosphorous was used as a control to compare CDs-enriched mediums. Cultures regarding biomass growth, carbohydrates, lipids, proteins, and PHA content were analyzed. The obtained results demonstrated that CDs-enriched cultures produced higher content of biomass and PHA; CDs-enriched cultures presented an increase of 26.9% in PHA concentration and an increase of 32% in terms of cell growth compared to the standard cultures.

Enhancing pectin extraction from orange peel through citric acid-assisted optimization based on a dual response.

Pectin is widely used in several products in the industry. Conventionally, strong and harmful acids are used for its extraction. This study optimized the extraction of orange peel's pectin using citric acid, considering yield and degree of esterification (DE) as response variables. Proximal analyses were performed, and the samples were subjected to a Box-Behnken design on three central points, considering as variables the temperature, time, and pH. The results of proximate analyses of the orange peels revealed 11.76 % moisture content, 87.26 % volatiles, 0.09 % ash, 50.45 % soluble carbohydrates, 70.60 % total carbohydrates, 0.89 % fixed carbon, 5.35 % lipids, and 36.75 mg GAE/g of phenolic compounds. The resulting second-order polynomial model described the relation of the input and output variables related to each other. The best performance to obtain a higher yield (18.18 %) of high methoxyl pectin (DE 50 %) was set at 100 °C/30 min/pH 2.48. Pectin showed antioxidant properties by ABTS and DPPH assays and similar thermal properties to the commercial polymer. Its equivalent weight was 1219.51 mol/g, and the methoxyl and anhydrouronic acid were 2.23 and 67.10 %, respectively. Hence, pectin extraction with citric acid results in a high-quality polymer and could be used as a gelling agent, stabilizer, or texturizer in food products.

Urine biomarkers for Alzheimer's disease: A new opportunity for wastewater-based epidemiology?

While Alzheimer's disease (AD) diagnosis, management, and care have become priorities for healthcare providers and researcher's worldwide due to rapid population aging, epidemiologic surveillance efforts are currently limited by costly, invasive diagnostic procedures, particularly in low to middle income countries (LMIC). In recent years, wastewater-based epidemiology (WBE) has emerged as a promising tool for public health assessment through detection and quantification of specific biomarkers in wastewater, but applications for non-infectious diseases such as AD remain limited. This early review seeks to summarize AD-related biomarkers and urine and other peripheral biofluids and discuss their potential integration to WBE platforms to guide the first prospective efforts in the field. Promising results have been reported in clinical settings, indicating the potential of amyloid ß, tau, neural thread protein, long non-coding RNAs, oxidative stress markers and other dysregulated metabolites for AD diagnosis, but questions regarding their concentration and stability in wastewater and the correlation between clinical levels and sewage circulation must be addressed in future studies before comprehensive WBE systems can be developed.

Biotransformation of 2,4,6-Trinitrotoluene by a cocktail of native laccases from Pycnoporus sanguineus CS43 under oxygenic and non-oxygenic atmospheres.

2,4,6-Trinitrotoluene (TNT) is a highly toxic nitroaromatic explosive known for its environmental consequences, contaminating soil and groundwater throughout its life cycle, from production to disposal. Therefore, the urgency of developing innovative and ecological strategies to remedy the affected areas is recognized. This study reports, for the first time, the enzymatic biotransformation of TNT by a cocktail of native laccases from Pycnoporus sanguineus CS43. The laccases displayed efficient TNT conversion under both oxygenic and non-oxygenic conditions, achieving biotransformation rates of 80% and 87% within 48 h at a temperature of 60 °C and pH 7. Preliminary kinetic constants were calculated with the laccase cocktail, being a Vmax of 1.133 µM min-1 and 0.2984 µM min-1, and the Km values were 1586 µM and 458 µM, in an oxygenic and non-oxygenic atmosphere, respectively. High-performance liquid chromatography-mass spectrometry (HPLC/MS) confirmed the formation of amino dinitrotoluene isomers and hydroxylamine isomers as biotransformation products. In summary, this study suggests the potential application of laccases for the direct biotransformation of recalcitrant compounds like TNT, offering an environmentally friendly approach to address contamination issues.

Metal-organic frameworks for enzyme immobilization and nanozymes: A laccase-focused review.

Laccases are natural catalysts with remarkable catalytic activity. However, their application is limited by their lack of stability. Metal-organic frameworks (MOFs) have emerged as a promising alternative for enzyme immobilization. Enzymes can be immobilized in MOFs via two approaches: postsynthetic immobilization and in situ immobilization. In postsynthetic immobilization, an enzyme is embedded after MOF formation by covalent interactions or adsorption. In contrast, in in situ immobilization, a MOF is formed in the presence of an enzyme. Additionally, MOFs have exhibited intrinsic enzyme-like activity. These materials, known as nanozymes when they have the ability to replace enzymes in certain catalytic processes, have multiple key advantages, such as low cost, easy preparation, and large surface areas. This review presents a general overview of the most recent advances in both enzyme@MOF biocatalysts and MOF-based nanozymes in different applications, with a focus on laccase, which is one of the most widely investigated enzymes with excellent industrial potential.

Omicron and Delta variant prevalence detection and identification during the fourth COVID-19 wave in Mexico using wastewater-based epidemiology.

Objectives: To identify the SARS-CoV-2 variants Delta and Omicron during the fourth wave of the COVID-19 pandemic in Mexico using samples taken from 19 locations in 18 out of the 32 states. Methods: The genetic material concentration was done with PEG/NaCl precipitation, SARS-CoV-2 presence was confirmed by reverse transcriptase-quantitative polymerase chain reaction assay, the variant detection was carried out using a commercial mutation detection panel kit, and variant/mutation confirmation was done by amplicon sequencing of receptor-binding domain target region. The study used 41 samples. Results: The Delta variant was confirmed in two samples during August 2021 (Querétaro and CDMX) and in three samples during November 2021 (Aguascalientes, Ciudad Juárez campuses, and Nuevo Leon). In December 2021, another sample with the Delta variant was confirmed in Nuevo Leon. Between January to March 2022 only the presence of Omicron was confirmed, (variant BA.1). Additionally, in this period six samples were identified with the status "Variant Not Determined". Conclusion: To our knowledge, this study is one of the first to identify Omicron and Delta variants with polymerase chain reaction in Mexico and Latin America and its distribution across the country with 56% Mexican states making it a viable alternative for variant detection without conducting a large quantity of sequencing of clinical tests.

Assessing environmental health impacts of coal mining exploitation in Iran: A Rapid Impact Assessment Matrix (RIAM) approach for environmental protection.

Environmental Impact Assessment is the process of evaluating the effects caused by a project on the environment. The outcomes generated by this assessment can lead to a reduction of the negative effects and an increase in the positive effects caused by mine projects. The present study was conducted to evaluate the environmental impact assessment of the Goliran Coal Mine in northern Iran. In the descriptive-analytical study, to achieve the objectives, observatory surveys were conducted around the coal mine using a checklist, which was about the positive and negative effects of a coal mine. Then the data were entered into the RIAM and the positive and negative effects were ranked and the most important effects were determined. In RIAM, one point is assigned to each component. 17 important activities for environmental impacts were identified using a checklist. Among the activities carried out at the coal mine site, the major ones included tunnel excavation, construction of the rail line collection and disposal of coal mine effluent, coal transportation, collection and disposal of mine tailings, and technical defects and leakage. The scores of each environmental factor were based on the four environmental components: physical/chemical, biological/ecological, social/cultural, and economic/operational. The results of the present study showed that the most negatively affected environmental components are the physical/chemical components derived from three activities; the construction of the underground tunnel; the construction of a coal transport rail line; and the actual transportation of coal extracts. The scores of each environmental factor based on the four components at the Goliran coal mine in northern Iran indicate that the highest negative score was -64, corresponding to the physical/chemical component, and was assigned to air pollution. On the other hand, the highest positive score corresponds to the economic/operational component with +54, assigned to the income that employees earn from the mine. Overall results showed that the coal mine in northern Iran had negative effects on the environment but the effects were not severe. It is suggested that for future research, corrective measures should be taken in the form of an environmental management plan to reduce the negative effects caused by coal mining, and then prospective research should be done to check the extent of reducing the negative effects.

Emerging Applications of Nanobiosensors in Pathogen Detection in Water and Food.

Food and waterborne illnesses are still a major concern in health and food safety areas. Every year, almost 0.42 million and 2.2 million deaths related to food and waterborne illness are reported worldwide, respectively. In foodborne pathogens, bacteria such as Salmonella, Shiga-toxin producer Escherichia coli, Campylobacter, and Listeria monocytogenes are considered to be high-concern pathogens. High-concern waterborne pathogens are Vibrio cholerae, leptospirosis, Schistosoma mansoni, and Schistosima japonicum, among others. Despite the major efforts of food and water quality control to monitor the presence of these pathogens of concern in these kinds of sources, foodborne and waterborne illness occurrence is still high globally. For these reasons, the development of novel and faster pathogen-detection methods applicable to real-time surveillance strategies are required. Methods based on biosensor devices have emerged as novel tools for faster detection of food and water pathogens, in contrast to traditional methods that are usually time-consuming and are unsuitable for large-scale monitoring. Biosensor devices can be summarized as devices that use biochemical reactions with a biorecognition section (isolated enzymes, antibodies, tissues, genetic materials, or aptamers) to detect pathogens. In most cases, biosensors are based on the correlation of electrical, thermal, or optical signals in the presence of pathogen biomarkers. The application of nano and molecular technologies allows the identification of pathogens in a faster and high-sensibility manner, at extremely low-pathogen concentrations. In fact, the integration of gold, silver, iron, and magnetic nanoparticles (NP) in biosensors has demonstrated an improvement in their detection functionality. The present review summarizes the principal application of nanomaterials and biosensor-based devices for the detection of pathogens in food and water samples. Additionally, it highlights the improvement of biosensor devices through nanomaterials. Nanomaterials offer unique advantages for pathogen detection. The nanoscale and high specific surface area allows for more effective interaction with pathogenic agents, enhancing the sensitivity and selectivity of the biosensors. Finally, biosensors' capability to functionalize with specific molecules such as antibodies or nucleic acids facilitates the specific detection of the target pathogens.

Emergent Molecular Techniques Applied to the Detection of Porcine Viruses.

Molecular diagnostic tests have evolved very rapidly in the field of human health, especially with the arrival of the recent pandemic caused by the SARS-CoV-2 virus. However, the animal sector is constantly neglected, even though accurate detection by molecular tools could represent economic advantages by preventing the spread of viruses. In this regard, the swine industry is of great interest. The main viruses that affect the swine industry are described in this review, including African swine fever virus (ASFV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine epidemic diarrhea virus (PEDV), and porcine circovirus (PCV), which have been effectively detected by different molecular tools in recent times. Here, we describe the rationale of molecular techniques such as multiplex PCR, isothermal methods (LAMP, NASBA, RPA, and PSR) and novel methods such as CRISPR-Cas and microfluidics platforms. Successful molecular diagnostic developments are presented by highlighting their most important findings. Finally, we describe the barriers that hinder the large-scale development of affordable, accessible, rapid, and easy-to-use molecular diagnostic tests. The evolution of diagnostic techniques is critical to prevent the spread of viruses and the development of viral reservoirs in the swine industry that impact the possible development of future pandemics and the world economy.

New Perspective for Macroalgae-Based Animal Feeding in the Context of Challenging Sustainable Food Production.

Food production is facing challenging times due to the pandemic, and climate change. With production expected to double by 2050, there is a need for a new paradigm in sustainable animal feed supply. Seaweeds offer a highly valuable opportunity in this regard. Seaweeds are classified into three categories: brown (Phaeophyceae), red (Rhodophyceae), and green (Chlorophyceae). While they have traditionally been used in aquafeed, their demand in the feed market is growing, parallelly increasing according to the food demand. Additionally, seaweeds are being promoted for their nutritional benefits, which contribute to the health, growth, and performance of animals intended for human consumption. Moreover, seaweeds contain biologically active compounds such as polyunsaturated fatty acids, antioxidants (polyphenols), and pigments (chlorophylls and carotenoids), which possess beneficial properties, including antibacterial, antifungal, antiviral, antioxidant, and anti-inflammatory effects and act as prebiotics. This review offers a new perspective on the valorization of macroalgae biomass due to their nutritional profile and bioactive components, which have the potential to play a crucial role in animal growth and making possible new sources of healthy food ingredients.

Pharmaceutical pollution fingerprinting and waterbodies remediation using waste-derived carbon dots as sustainable advanced nanomaterials.

The conversion of biomass waste into high-value nanomaterials such as carbon dots might represent a great advancement towards a circular economy system. Biomass wastes are an excellent choice as carbon precursors because of their wide availability, abundance, chemical composition, and eco-friendly nature. Moreover, their use as a raw material might decrease the total cost of the synthesis processes and reduce the environmental impacts. In addition, the complex composition of biomass leads to carbon dots with abundant functional groups, which in turn enhances water dispersibility and photoluminescence properties. In this manner, the effective transformation of biomass wastes into carbon dots reduces environmental pollution through the inadequate management of waste while producing carbon dots with enhanced performances. Therefore, this review describes biomass wastes as potential candidates for the synthesis of carbon dots through different synthesis methods. In addition, we have analyzed the great potential of biomass-derived carbon dots (CDs) for the degradation and detection of emerging pharmaceutical pollutants by promoting a circular economy approach. Finally, we identified current challenges to propose possible research directions for the large-scale and sustainable synthesis of high-quality biomass-derived CDs.

Nano and Technological Frontiers as a Sustainable Platform for Postharvest Preservation of Berry Fruits.

Berries are highly perishable and susceptible to spoilage, resulting in significant food and economic losses. The use of chemicals in traditional postharvest protection techniques can harm both human health and the environment. Consequently, there is an increasing interest in creating environmentally friendly solutions for postharvest protection. This article discusses various approaches, including the use of "green" chemical compounds such as ozone and peracetic acid, biocontrol agents, physical treatments, and modern technologies such as the use of nanostructures and molecular tools. The potential of these alternatives is evaluated in terms of their effect on microbial growth, nutritional value, and physicochemical and sensorial properties of the berries. Moreover, the development of nanotechnology, molecular biology, and artificial intelligence offers a wide range of opportunities to develop formulations using nanostructures, improving the functionality of the coatings by enhancing their physicochemical and antimicrobial properties and providing protection to bioactive compounds. Some challenges remain for their implementation into the food industry such as scale-up and regulatory policies. However, the use of sustainable postharvest protection methods can help to reduce the negative impacts of chemical treatments and improve the availability of safe and quality berries.

Passive Sampler Technology for Viral Detection in Wastewater-Based Surveillance: Current State and Nanomaterial Opportunities.

Although wastewater-based surveillance (WBS) is an efficient community-wide surveillance tool, its implementation for pathogen surveillance remains limited by ineffective sample treatment procedures, as the complex composition of wastewater often interferes with biomarker recovery. Moreover, current sampling protocols based on grab samples are susceptible to fluctuant biomarker concentrations and may increase operative costs, often rendering such systems inaccessible to communities in low-to-middle-income countries (LMICs). As a response, passive samplers have emerged as a way to make wastewater sampling more efficient and obtain more reliable, consistent data. Therefore, this study aims to review recent developments in passive sampling technologies to provide researchers with the tools to develop novel passive sampling strategies. Although promising advances in the development of nanostructured passive samplers have been reported, optimization remains a significant area of opportunity for researchers in the area, as methods for flexible, robust adsorption and recovery of viral genetic materials would greatly improve the efficacy of WBS systems while making them more accessible for communities worldwide.

Growth Behavior, Biomass Composition and Fatty Acid Methyl Esters (FAMEs) Production Potential of Chlamydomonas reinhardtii, and Chlorella vulgaris Cultures.

The production of biomolecules by microalgae has a wide range of applications in the development of various materials and products, such as biodiesel, food supplements, and cosmetics. Microalgae biomass can be produced using waste and in a smaller space than other types of crops (e.g., soja, corn), which shows microalgae's great potential as a source of biomass. Among the produced biomolecules of greatest interest are carbohydrates, proteins, lipids, and fatty acids. In this study, the production of these biomolecules was determined in two strains of microalgae (Chlamydomonas reinhardtii and Chlorella vulgaris) when exposed to different concentrations of nitrogen, phosphorus, and sulfur. Results show a significant microalgal growth (3.69 g L-1) and carbohydrates (163 mg g-1) increase in C. reinhardtii under low nitrogen concentration. Also, higher lipids content was produced under low sulfur concentration (246 mg g-1). It was observed that sulfur variation could affect in a negative way proteins production in C. reinhardtii culture. In the case of C. vulgaris, a higher biomass production was obtained in the standard culture medium (1.37 g L-1), and under a low-phosphorus condition, C. vulgaris produced a higher lipids concentration (248 mg g-1). It was observed that a low concentration of nitrogen had a better effect on the accumulation of fatty acid methyl esters (FAMEs) (C16-C18) in both microalgae. These results lead us to visualize the effects that the variation in macronutrients can have on the growth of microalgae and their possible utility for the production of microalgae-based subproducts.

Polysaccharides from the Sargassum and Brown Algae Genus: Extraction, Purification, and Their Potential Therapeutic Applications.

Brown macroalgae represent one of the most proliferative groups of living organisms in aquatic environments. Due to their abundance, they often cause problems in aquatic and terrestrial ecosystems, resulting in health problems in humans and the death of various aquatic species. To resolve this, the application of Sargassum has been sought in different research areas, such as food, pharmaceuticals, and cosmetics, since Sargassum is an easy target for study and simple to obtain. In addition, its high content of biocompounds, such as polysaccharides, phenols, and amino acids, among others, has attracted attention. One of the valuable components of brown macroalgae is their polysaccharides, which present interesting bioactivities, such as antiviral, antimicrobial, and antitumoral, among others. There is a wide variety of methods of extraction currently used to obtain these polysaccharides, such as supercritical fluid extraction (SFE), pressurized liquid extraction (PLE), subcritical water extraction (SCWE), ultrasound-assisted extraction (UAE), enzyme-assisted extraction (EAE), and microwave-assisted extraction (MAE). Therefore, this work covers the most current information on the methods of extraction, as well as the purification used to obtain a polysaccharide from Sargassum that is able to be utilized as alginates, fucoidans, and laminarins. In addition, a compilation of bioactivities involving brown algae polysaccharides in in vivo and in vitro studies is also presented, along with challenges in the research and marketing of Sargassum-based products that are commercially available.

Microencapsulation of Gallic Acid Based on a Polymeric and pH-Sensitive Matrix of Pectin/Alginate.

The encapsulation of gallic acid (GA) through several methods has enhanced its shelf life and facilitated industrial applications. Polymeric matrices made of alginate and pectin were evaluated to encapsulate GA via spray drying. The pH-responsive release mechanism was monitored to validate the matrices' performances as wall materials and extend the bioactive compound stability. The microcapsules produced were characterized via scanning electron microscopy (SEM), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), and cyclic voltammetry (CV). The retention and encapsulation efficiency ranges were 45-82% and 79-90%, respectively. The higher values were reached at 3 and 0.75% (w/v) pectin and sodium alginate, respectively. The scanning electron microscopy showed smooth spherical capsules and the average particle size ranged from 1327 to 1591 nm. Their performance and stability were evaluated with optimal results at a pH value of 7 throughout the investigation period. Therefore, this work demonstrated the suitability of gallic acid encapsulation via spray drying using pectin and alginate, which are biopolymers that can be obtained from circular economy processes starting from agro-industrial biomass. The developed formulations provide an alternative to protecting and controlling the release of GA, promoting its application in the food, pharmaceutical, and cosmetic industries and allowing for the release of compounds with high bioactive potential.