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.
Cellulose nanocrystals (CNCs) were successfully isolated from marine biomass of brown, red, and green seaweeds by a four step process of de-polymerization, bleaching, acid hydrolysis, and mechanical ...dispersion. Chemical composition, yield, and density were determined for each seaweed group and compared to other cellulose sources. Morphological analysis was performed by transmission electronic microscopy (TEM) and showed that CNCs from seaweed showed rod shape particles 21–248 nm length and 4.8–41 nm width. The obtained aspect ratio was varied from 2.5 to 15. Fourier transform infrared spectroscopy (FTIR) analysis was performed to investigate chemical structure of CNCs from seaweeds, which revealed obtained crystalline cellulosic from the extraction process. X-ray diffraction (XRD) data showed the main crystalline structure of CNCs was cellulose I in all cases. The crystalline index increased about 21.5% going from cellulose to CNCs. The thermal properties of untreated seaweeds, extracted cellulose, and CNCs were compared by thermogravimetric analysis (TGA). The onset thermal decomposition (Ton) increased in all cases and weight loss changes significantly decreased during the extraction process except Sargassum fluitans, indicating the thermal stability of CNCs.
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•Cellulose nanocrystals were isolated from brown, red, and green seaweeds.•De-polymerization, bleaching, acid hydrolysis, and mechanical dispersion was used.•Morphological properties were investigated through transmission electron microscopy.•Amorphous rons were effectively removed through the isolating process.•Cellulose nanocrystals showed high crystallinity and thermal stability.
The seaweed hydrocolloid industry, comprising agar, alginate, and carrageenan extracts, continues to grow in the order of 2–3% per year with the Asia-Pacific region increasingly dominating the raw ...material and manufacturing aspects of the industry. Geographic overviews, also in a historical perspective, of seaweed raw material availability including prices and consumption, manufacturing capacities, and utilizations and sales of extracts is presented. Some current and future industry dynamics, requirements, and changing structures, e.g., Indonesia’s increasingly dominant role within farming of agar and carrageenan-bearing seaweed species, randomly imposing of seaweed harvest restrictions or ban on exports, creation of a global certification standard for seaweed, and supply-demand dynamics for seaweed versus future global population are presented. The industry is increasingly being commoditized and China has become an important and, in many cases, dominant factor within all types of seaweed hydrocolloids and some explanations to this and strategic response by the rest of the industry is also touched upon. Also presented are some areas where the seaweed industry needs help from the scientific community. The main challenge is the ongoing general seaweed deterioration experienced in cultivated species—how are the strains to be improved and revitalized and can cultivation techniques be improved further? There is a general trend towards sustainability and, although seaweed cultivation and harvest can be sustainable, there is interest in the development of greener processes.
Seaweeds are well-known for their exceptional capacity to accumulate essential minerals and trace elements needed for human nutrition, although their levels are commonly very variable depending on ...their morphological features, environmental conditions, and geographic location. Despite this variability, accumulation of Mg, and especially Fe, seems to be prevalent in Chlorophyta, while Rhodophyta and Phaeophyta accumulate higher concentrations of Mn and I, respectively. Both red and brown seaweeds also tend to accumulate higher concentrations of Na, K, and Zn than green seaweeds. Their valuable mineral content grants them great potential for application in the food industry as new ingredients for the development of numerous functional food products. Indeed, many studies have already shown that seaweeds can be used as NaCl replacers in common foods while increasing their content in elements that are oftentimes deficient in European population. In turn, high concentrations of some elements, such as I, need to be carefully addressed when evaluating seaweed consumption, since excessive intake of this element was proven to have negative impacts on health. In this regard, studies point out that although very bioaccessible, I bioavailability seems to be low, contrarily to other elements, such as Na, K, and Fe. Another weakness of seaweed consumption is their capacity to accumulate several toxic metals, which can pose some health risks. Therefore, considering the current great expansion of seaweed consumption by the Western population, specific regulations on this subject should be laid down. This review presents an overview of the mineral content of prevalent edible European macroalgae, highlighting the main factors interfering in their accumulation. Furthermore, the impact of using these marine vegetables as functional ingredients or NaCl replacers in foods will be discussed. Finally, the relationship between macroalgae's toxic metals content and the lack of European legislation to regulate them will be addressed.
The harvesting of wild seaweeds continues to play an important cultural and socioeconomic role for many coastal communities on Ireland’s Atlantic seaboard. Although Irish waters contain a diverse and ...substantial benthic seaweed flora, only a few species are exploited commercially. Historically in Ireland, seaweed was commercially used as a raw material in the production of high-volume, low-value commodities such as animal feed and raw material for alginate production. Recently, with increasing acceptance of seaweed as a sea vegetable and its ever-increasing role as a raw material in the cosmetic and pharmaceutical industries, there has been a renewed vigour in the Irish seaweed industry particularly with new entrants into the human nutrition and cosmetic markets producing high-quality, high-value products. Although many of Ireland’s native seaweed species can be sustainably exploited if well managed, the fucoid
Ascophyllum nodosum
maintained its prominent role in the Irish seaweed industry. The traditional harvesting of
A. nodosum
in Ireland continues, although the recent introduction of new harvesting techniques, along with the expected expansion of the Irish seaweed cultivation sector, undoubtedly marks a shift in the Irish seaweed seascape. We focus here on the seaweed resources in Irish waters and how the industry has changed in the last 20 years.
Seaweeds are an integral part of coastal ecosystems and offer invaluable ecosystem services supporting the life of many marine forms. The economic value of seaweeds significantly contributes to the ...sustainable development of rural coastal regions. Seaweeds are consumed as food in some Asian countries, but their utilization for production of phycocolloids is widespread across the globe, with an estimated value of more than one billion US$. In India, seaweeds have been utilized exclusively for the production of phycocolloids but recently they are used for the production of plant growth stimulants for agricultural applications. The domestic agar and alginate industry totally depends on the supplies from natural seaweed beds with some occasional imports. The recent success achieved in both upstream and downstream technologies in production and processing of seaweeds has boosted the prospects for commercialization of seaweed resources in the country. The present article briefly appraises the current status of Indian seaweed resources and their utilization, as well as developments in seaweed farming technologies, the status of seaweed industry and recent efforts to transform seaweed farming into a social enterprise. It also highlights the challenges encountered for mainstreaming these resources so as to evolve into a marine industry.
The use of seaweeds as human food in eastern Asian countries has a long history, stretching back over a thousand years. However, it was not until the late 1940s that cultivation of seaweeds in ...near-shore coastal areas began. Due to their location, the Korean peninsula, the Japanese islands and the Chinese coasts share a similar seaweed flora in their coastal waters, and it is not surprising that seaweed species chosen for cultivation, methods of farming and post-harvest processing in these countries have a lot in common. In 2016, the total seaweed production in these three countries reached 16,218,406 t, approximately 53.8% of global seaweed production (FAO). In the course of seaweed farming development in eastern Asia, the development and use of seaweed cultivars have contributed significantly to the seaweed farming industry in terms of improving both the biomass yield and the quality of the food products produced. In this article, the recent development of cultivar-related research and applications practised in Korea, Japan and China are reviewed with particular reference to the key commercial species: Saccharina japonica, Pyropia spp., Undaria spp., Cladosiphon okamurarus, and Nemacystus decipiens. In the past 21 years, 47 certified seaweed cultivars have been used in commercial cultivation in these countries. While much of the development effort has focused on increasing yields, a current emphasis in cultivar breeding programs is to increase the quality of farmed seaweed products. More recently, molecular analyses have been integrated into these programs and have become indispensable tools in the breeding process.
Metabolites exuded by primary producers comprise a significant fraction of marine dissolved organic matter, a poorly characterized, heterogenous mixture that dictates microbial metabolism and ...biogeochemical cycling. We present a foundational untargeted molecular analysis of exudates released by coral reef primary producers using liquid chromatography-tandem mass spectrometry to examine compounds produced by two coral species and three types of algae (macroalgae, turfing microalgae, and crustose coralline algae CCA) from Mo'orea, French Polynesia. Of 10,568 distinct ion features recovered from reef and mesocosm waters, 1,667 were exuded by producers; the majority (86%) were organism specific, reflecting a clear divide between coral and algal exometabolomes. These data allowed us to examine two tenets of coral reef ecology at the molecular level. First, stoichiometric analyses show a significantly reduced nominal carbon oxidation state of algal exometabolites than coral exometabolites, illustrating one ecological mechanism by which algal phase shifts engender fundamental changes in the biogeochemistry of reef biomes. Second, coral and algal exometabolomes were differentially enriched in organic macronutrients, revealing a mechanism for reef nutrient-recycling. Coral exometabolomes were enriched in diverse sources of nitrogen and phosphorus, including tyrosine derivatives, oleoyl-taurines, and acyl carnitines. Exometabolites of CCA and turf algae were significantly enriched in nitrogen with distinct signals from polyketide macrolactams and alkaloids, respectively. Macroalgal exometabolomes were dominated by nonnitrogenous compounds, including diverse prenol lipids and steroids. This study provides molecular-level insights into biogeochemical cycling on coral reefs and illustrates how changing benthic cover on reefs influences reef water chemistry with implications for microbial metabolism.
Seaweeds have attracted high interest in recent years due to their chemical and bioactive properties to find new molecules with valuable applications for humankind. Phenolic compounds are the group ...of metabolites with the most structural variation and the highest content in seaweeds. The most researched seaweed polyphenol class is the phlorotannins, which are specifically synthesized by brown seaweeds, but there are other polyphenolic compounds, such as bromophenols, flavonoids, phenolic terpenoids, and mycosporine-like amino acids. The compounds already discovered and characterized demonstrate a full range of bioactivities and potential future applications in various industrial sectors. This review focuses on the extraction, purification, and future applications of seaweed phenolic compounds based on the bioactive properties described in the literature. It also intends to provide a comprehensive insight into the phenolic compounds in seaweed.
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