Elemental composition and bioaccessibility of farmed oysters (Crassostrea gigas) fed different ratios of dietary seaweed and microalgae during broodstock conditioning

Tropical Seaweeds as a Sustainable Resource Towards Circular Bioeconomy: Insights and Way Forward

Seaweeds are photosynthetic marine macroalgae known for their rapid biomass growth and their significant contributions to global food and feed production. Seaweeds play a crucial role in mitigating various environmental issues, including greenhouse gases, ocean acidification, hypoxia, and eutrophication. Tropical seaweeds are typically found in tropical and subtropical coastal zones with warmer water temperatures and abundant sunlight. These tropical seaweeds are rich sources of proteins, vitamins, minerals, fibers, polysaccharides, and bioactive compounds, contributing to their health-promoting properties and their diverse applications across a range of industries. The productivity, cultivability, nutritional quality, and edibility of tropical seaweeds have been well-documented. This review article begins with an introduction to the growth conditions of selected tropical seaweeds. Subsequently, the multifunctional properties of tropical seaweeds including antioxidant and anti-inflammatory, anti-coagulant, anti-carcinogenic and anti-proliferative, anti-viral, therapeutic and preventive properties were comprehensively evaluated. The potential application of tropical seaweeds as functional foods and feeds, as well as their contributions to sustainable cosmetics, bioenergy, and biofertilizer production were also highlighted. This review serves as a valuable resource for researchers involved in seaweed farming as it provides current knowledge and insights into the cultivation and utilization of seaweeds.

Seaweed for climate mitigation, wastewater treatment, bioenergy, bioplastic, biochar, food, pharmaceuticals, and cosmetics: a review

The development and recycling of biomass production can partly solve issues of energy, climate change, population growth, food and feed shortages, and environmental pollution. For instance, the use of seaweeds as feedstocks can reduce our reliance on fossil fuel resources, ensure the synthesis of cost-effective and eco-friendly products and biofuels, and develop sustainable biorefinery processes. Nonetheless, seaweeds use in several biorefineries is still in the infancy stage compared to terrestrial plants-based lignocellulosic biomass. Therefore, here we review seaweed biorefineries with focus on seaweed production, economical benefits, and seaweed use as feedstock for anaerobic digestion, biochar, bioplastics, crop health, food, livestock feed, pharmaceuticals and cosmetics. Globally, seaweeds could sequester between 61 and 268 megatonnes of carbon per year, with an average of 173 megatonnes. Nearly 90% of carbon is sequestered by exporting biomass to deep water, while the remaining 10% is buried in coastal sediments. 500 gigatonnes of seaweeds could replace nearly 40% of the current soy protein production. Seaweeds contain valuable bioactive molecules that could be applied as antimicrobial, antioxidant, antiviral, antifungal, anticancer, contraceptive, anti-inflammatory, anti-coagulants, and in other cosmetics and skincare products.

Microalgal biosorption of heavy metals: A comprehensive bibliometric review

Heavy metals in the effluents released from industrial establishments pose risks to the environment and society. Prevalent organisms such as microalgae in industrial wastes can thrive in this harmful environment. The connection of the metal-binding proteins of the microalgal cell wall to the metal ions of the heavy metals enables microalgae as an ideal medium for biosorption. The current literature lacks the review of various microalgae used as biosorption of heavy metals from industrial effluents. This work aims to comprehensively review the literature on the use of microalgae as a biosorption for heavy metals. The study summarizes the application of different microalgae for heavy metals removal by identifying the various factors affecting the biosorption performance. Approaches to quantifying the heavy metals concentration are outlined. The methods of microalgae to generate biocompounds to enable biosorption of heavy metals are itemized. The study also aims to identify the materials produced by microalgae to facilitate biosorption. The industrial sectors with the potential benefit from the adoption of microalgal biosorption of heavy metals are recognized. Moreover, the current challenges and future perspectives of microalgal biosorption are discussed.

Sustainable Fishing and Aquaculture Activities in the Atlantic Coast of the Portuguese North Region: Multi-Stakeholder Views as a Tool for Maritime Spatial Planning

The experienced view of stakeholders is a very valuable tool to build inclusive and reliable maritime spatial planning (MSP). Within this context, the present work assesses the potential and limitations for a further sustainable development of fishing and aquaculture activities, considering the Portuguese North Region as case study. The official strategies and legal framework drafted by Portugal in MSP issues were initially reviewed, with the corresponding management objectives identified. Official statistical data were used to show the current situation of regional fishery and aquaculture, while the perceptions of involved groups were collected by a methodology based in a multi-stakeholder survey and subsequent workshop. Taking into account the regional circumstances defined by a decreased fishing production (decline of 45.9% during the period of 2012–2019) and scarce aquaculture weight (≤1% in terms of national production in 2018), the stakeholders brought to light great difficulties on the part of public administration to implement official management objectives. The stakeholders also considered that conflicts between maritime activities are almost inexistent at present, even though they predicted future disagreements when new players intend to use maritime space. A positive response about a successful future for aquaculture was obtained from every group surveyed, although the specialized stakeholders pointed out severe limitations for a further development of both off-shore and extensive coastal aquaculture modalities. In conclusion, it seems evident there is the need for a fluent collaboration with the regional fishing stakeholder, particularly promoting synergies involving small scale fleets, in order to avoid future potential conflicts. Against the challenges and limitations posed by the aquaculture industry, promoting the intensive cultivation of high commercial value fish and new interest local species, when conducted under sustainable practices that add value to the harvested product, would be an interesting strategy to implement in our case study.

Seaweed Potential in the Animal Feed: A Review

Seaweed (known as marine algae) has a tradition of being part of the animal feed in the coastal areas, from ancient times. Seaweeds, are mixed with animal feed, because when consumed alone can have negative impact on animals. Thus, seaweeds are very rich in useful metabolites (pigments, carotenoids, phlorotannins, polyunsaturated fatty acids, agar, alginate and carrageenan) and minerals (iodine, zinc, sodium, calcium, manganese, iron, selenium), being considered as a natural source of additives that can substitute the antibiotic usage in various animals. In this review, we describe the nutritional values of seaweeds and the seaweed effects in the seaweed-based animal feed/supplements.