José Raí de Jesus Coelho

This study aimed to conduct an integrated analysis (systematic and exploratory bibliometric) on Cocos nucifera L. residues as a source of bioactive compounds, using the Scopus and Web of Science databases and VOSviewer and bibliometrix software. A total of 27 documents were identified between 2008 and 2024, reflecting research interest in this scope. The highest number of publications occurred in 2023 (5 articles), reflecting the strengthening of the circular bioeconomy and the valorization of residues, associated with the use of more sustainable extractive technologies and experimental optimization strategies. The term "Cocos nucifera" was central to the network, integrating studies on chemical characterization, bioactivities, and potential applications of residues from the species. The results presented in the Sankey Diagram reinforce the interdisciplinary nature of the topic and indicate connections between authors, institutions, and journals in different application fronts. However, as it is a reduced corpus, these patterns should be interpreted only as an internal organization of the analyzed literature. Residues have evolved from environmental liabilities to valuable bioactive matrices. Underutilized parts of Cocos nucifera L., such as husk, mesocarp, testa, haustorium, and roots, have been investigated as potential sources of phenolic compounds, flavonoids, and other metabolites of interest. The analyzed studies also indicate advances in the use of more sustainable extraction methods, such as ultrasound and supercritical CO₂, as well as modeling and optimization tools to improve process efficiency. The available evidence suggests antioxidant, antimicrobial, anti-inflammatory, antidiabetic, and hepatoprotective activities, although, for the most part, these are still associated with in vitro assays, experimental models, or laboratory applications. In this context, the extracts show potential for future applications in cosmeceuticals, functional foods, post-harvest conservation, and technological valorization of plant biomass, provided that additional studies on standardization, stability, safety, scaling, and validation in real systems are carried out.

Microalgae are present in the aquatic environment and produce bioproducts of great added value (e.g. carbohydrates, lipids, fatty acids, pigments, protein) through the conversion of solar energy into chemical energy by fixing atmospheric CO2. Therefore, microalgae biomass has many potential applications in several industries, for example, cosmetics, pharmaceuticals, agricultural biopesticides, biofuel production, and food supplements. However, microalgae harvesting involves energy consumption and high operating costs (about 30 % of the total production cost). Thus, this paper aims to review the main achievements of microalgae harvesting processes, their efficiencies, and the main advantages and disadvantages of each harvesting method. Coagulant dosage, mixing time, and velocity gradient are parameters that affect the efficiency of microalgae harvesting. Therefore, the optimal conditions of these variables will be presented in this review article. On the other hand, coagulation, followed by flotation, is influenced by attraction-repulsion forces between cells and the coagulant agent. Factors such as cell size, viability, density, possible cell damage, strain properties, sedimentation rate, the salt concentration of each algae species of microalgae, energy demand, final product, and the reuse of culture medium determine if will be necessary one or methods combined for harvesting the microalgae biomass. However, coagulation and flocculation are still relevant for the harvesting of algae cells.

The use of microalgae and natural coagulants in biological water treatment has been explored, as the use of chemical products can generate contaminants harmful to human health. Chlorella vulgaris primarily uses nitrogen and phosphorus as nutrients, managing to develop in various media where these and other compounds are present, removing them. In coagulation processes, Moringa oleifera is able to remediate effluents and raw water in a biodegradable manner, being an effective substitute for aluminum and iron-based coagulants and avoiding problems caused by them. Experiments with Chlorella vulgaris and Moringa oleifera were carried out in order to, firstly, analyze the growth of the microalga in the water of the Poxim River and verify its efficiency in removing chemical substances, followed by the evaluation of the capacity of Moringa oleifera in removing the microalga. The results showed that Chlorella vulgaris completely removed chlorite and glyphosate and reduced the concentration of other compounds, including nitrate, phosphorus, and iron. This study has proven that microalgae can be used to remove contaminants from raw water and that Moringa oleifera helps the microalgae to settle more quickly.