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Biotechnological potential of benthic marine algae collected along the Brazilian coast
Abstract
The use of algal biomass as bioproducts source has been studied; in fact, some species produce a high amount of carbohydrates, proteins, pigments and oils, and such species could be used for the production of several products , even nutraceuticals and biofuels. To evaluate this potential, the biochemical composition of macroalgae collected along the Brazilian coast, including 14 species of Rhodophyta, 4 of Chlorophyta, and 7 of Phaeophyceae, was investigated. Photosynthesis was estimated for species belonging to the most representative orders in order to evaluate its relationship to macromolecule biosynthesis. There was a wide variation in the content of lipids, carbohydrates and proteins, and the highest values were found in the species Dictyota men-strualis (Hoyt) Schnetter, Hörning & Weber-Peukert, Gracilaria mammillaris (Montagne) M.A.Howe, and Aglaothamnion uruguayense (W.R. Taylor) Aponte, D.L. Ballantine & J.N.Norris, respectively. The content of phycobiliproteins was also higher in this last species. Results showed that D. menstrualis to be the best source for biodiesel production based on its high photosynthetic rate, high content of lipids and fatty acids, and high content of monounsaturated fatty acids. Spatoglossum schroederi (C.Agardh) Kützing showed a high content of polyunsaturated fatty acids and ω-3, making it interesting for nutraceutical application. A distinct pattern among the different groups of macroalgae in relation to photosynthesis and biosynthesis of macromolecules was also observed, suggesting that different strategies should be undertaken to divert algae metabolism to the production of the metabolite of interest.
... Light, in addition to activating photosynthesis and distinct metabolic pathways, plays a fundamental role in the vertical zonation of species, which results from variations in the photosynthetic apparatus of the different groups of macroalgae [40]. Martins et al. [64] studied the photosynthesis of different species of the Brazilian coast and verified that the red seaweeds present the lowest values of EQY, Pmax, alpha and Ik. This result may be related to the vertical distribution of these organisms, in which red macroalgae can be found at greater depths and have a pigmentary apparatus that allows them to photosynthesize at low irradiance, presenting shade-plants patterns [40]. ...
... This result may be related to the vertical distribution of these organisms, in which red macroalgae can be found at greater depths and have a pigmentary apparatus that allows them to photosynthesize at low irradiance, presenting shade-plants patterns [40]. On the other hand, the green seaweed Ulva lactuca, a supralittoral species, displayed a high value for all photosynthetic parameters, including saturation irradiance, showing a photosynthetic apparatus capable of resisting to high irradiance [64]. ...
... They found a difference in photosynthetic efficiency and photosynthesis saturation point values as a function of depth, but they did not observe a zonation pattern, which may be related to the ability of macroalgae to acclimate to different light conditions. Weykam et al. [65] studied the photosynthetic characteristics of 36 seaweeds species and had similar results that showed by Martins et al. [64], with lower values of Pmax and Ik in Rhodophyta. However, they observed high photosynthetic efficiency, which confirms the best pigment adaptation present in this group to photosynthesize in low light conditions [67]. ...
Seaweeds play an important role for the environment, since they are photosynthetic organisms, contributing to the cycling of nutrients and to the protection and feeding of several animals. The potential for biotechnological applications of marine macroalgae biomass is enormous, and to attend the demand of the current market, the knowledge of the physiological characteristics of these organisms is essential to ensure a high productivity in cultivation systems. In this review, we contribute to the knowledge about the photosynthetic characteristics of seaweeds, ranging from the basic aspects about marine macroalgae and photosynthesis, to the photosynthetic characteristics of these organisms and their relation with the abiotic factors and the biotechnological use of seaweeds.
... Seaweeds are sources of hydrosoluble and liposoluble vitamins, such as thiamin, riboflavin, β-carotene, and tocopherols. It has been reported that long-chain polyunsaturated fatty acids (PUFAs) of the omega-3 family (LC-PUFAs n-3), such as eicosapentaenoic acid (20:5n-3), which can reduce the risk of heart disease, thrombosis, and atherosclerosis, are predominant in seaweeds (Martins et al. 2018). ...
... In addition, the cultivation of seaweeds by traditional raft or tube net-based onshore methods can be unreliable owing to seasonal changes in seawater composition and temperature that potentially affect their growth and annual turnover (Suthar et al. 2019). There are wide variations in the content of lipids, carbohydrates, and proteins and distinctive patterns among the different groups of seaweed in relation to photosynthesis and biosynthesis of macromolecules (Martins et al. 2018). ...
... In addition, they observed a seasonal stability in the lipid content of seaweed, as in this study. Marinho et al. (2016) and Fernando et al. (2018) stated that carbohydrates and fibers are generally the main components of seaweed, formed primarily from soluble Martins et al. (2018), in general, red algae show higher levels of total soluble carbohydrates and total soluble protein than brown algae. In contrast, the present study determined that the carbohydrate content was higher in the green seaweed (U. fasciata) than in the red; however, it was lower than that of S. vulgare from Buzios, northwest Brazil (67.80 % DW), which is also in the Brazilian tropical region (Marinho et al. 2016). ...
Algae that are found in the coastal regions are an important food source for humans and animals. They are highly susceptible to the influence of environmental parameters on their chemical composition. Thus, the aim of this study was to analyze the influence of seasons (dry and rainy) and species on the biochemical composition of the seaweeds Ulva fasciata, Crassiphycus corneus, and Sargassum vulgare occurring in tropical environment. It was found that crude protein (10.32–22.93%), total lipids (1.74–4.11%), ash (16.51–36.79%), carbohydrates (23.55–42.24%), and neutral detergent fiber (16.50–25.20%) differed significantly among species (p < 0.05). The essential amino acids, histidine, isoleucine, leucine, lysine, methionine + cysteine, phenylalanine + tyrosine, threonine, tryptophan, and valine were identified. Saturated fatty acids, essential fatty acids, and n-6 polyunsaturated fatty acids (PUFAs) were predominant. The lowest protein and PUFA content were found in C. corneus, whereas U. fasciata contained the highest carbohydrate concentrations. Photosynthetic pigments, phenolic, and mineral compounds (such as high concentrations of Sr and As) were found in S. vulgare. However, all seaweed showed significant concentrations of Mn, Zn, K, and Mg indicating that they can be important sources of minerals in animal feed. The three seaweeds showed susceptibility to seasons (rainy and dry), indicated by the synthesis of chemical constituents that consequently affected biomass composition. However, the results demonstrated that because of their biochemical composition, they have biotechnological potential that could be explored in several industrial sectors, including human and animal nutrition.
... The reported total carbohydrate fraction varies between 10.8 and 54.2% of DW (Table 2). Total soluble carbohydrates (fucans, laminarans and monosaccharides) are reported to range from 5.9 to 26.7% in the field (McDermid and Stuercke, 2003;Martins et al., 2018). These can be artificially increased to~50% of DW by addition of nitrogen and CO 2 in a bioreactor setup in D. menstrualis (Martins et al., 2016). ...
... (Tabarsa et al., 2012) PUFAs ω3 % of total fatty acids methyl esters 10.7 10.7 Dictyota sp. (Tabarsa et al., 2012) Fatty acids (dry weight basis) SFAs mg g −1 DW 5.3 35.2 D. bartayresiana, Dictyota sp., D. menstrualis (Gosch et al., 2012;Gosch et al., 2015;Martins et al., 2018) MUFAs mg g −1 DW 4.5 30.8 D. bartayresiana, Dictyota sp., D. menstrualis (Gosch et al., 2012;Gosch et al., 2015;Martins et al., 2018) PUFAs mg g −1 DW 4.3 39.1 D. bartayresiana, Dictyota sp., D. menstrualis (Gosch et al., 2012;Gosch et al., 2015;Martins et al., 2018) PUFAs ω6 mg g −1 DW 1.9 16.7 D. bartayresiana, Dictyota sp., D. menstrualis (Gosch et al., 2012;Gosch et al., 2015;Martins et al., 2018) PUFAs ω3 mg g −1 DW 1.0 22.9 D. bartayresiana, Dictyota sp., D. menstrualis (Gosch et al., 2012;Gosch et al., 2015;Martins et al., 2018) ω6/ω3 0.3 3.9 Dictyota sp., D. ceylanica, D. pinnatifida, D. bartayresiana, D. dichotoma, C. cervicornis, D. ciliolata, D. haukiana, D. menstrualis (Chakraborty and Santra, 2008;Gosch et al., 2012;Tabarsa et al., 2012;Kumari et al., 2013;Gosch et al., 2015;Martins et al., 2018) Vitamins -Bermudez et al., 1981;Chakraborty and Santra, 2008;Deyab et al., 2017;Martins et al., 2018) Chlorophyll c mg g −1 DW 0.6 2.0 Dictyota sp., D. dichotoma, D. ceylanica (Perez-Bermudez et al., 1981;Chakraborty and Santra, 2008;Deyab et al., 2017) Carotenoids mg g −1 DW 0.03 0.03 D. ceylanica (Chakraborty and Santra, 2008) Fucoxanthin mg g −1 DW 0.1 2.3 D. dichotoma, Dictyota sp. (Perez-Bermudez et al., 1981;Deyab et al., 2017) Protein and amino acids As a fast-growing alga, especially in warm temperate to tropical environments, Dictyota may be of interest as a food, feed or protein source. ...
... (Tabarsa et al., 2012) PUFAs ω3 % of total fatty acids methyl esters 10.7 10.7 Dictyota sp. (Tabarsa et al., 2012) Fatty acids (dry weight basis) SFAs mg g −1 DW 5.3 35.2 D. bartayresiana, Dictyota sp., D. menstrualis (Gosch et al., 2012;Gosch et al., 2015;Martins et al., 2018) MUFAs mg g −1 DW 4.5 30.8 D. bartayresiana, Dictyota sp., D. menstrualis (Gosch et al., 2012;Gosch et al., 2015;Martins et al., 2018) PUFAs mg g −1 DW 4.3 39.1 D. bartayresiana, Dictyota sp., D. menstrualis (Gosch et al., 2012;Gosch et al., 2015;Martins et al., 2018) PUFAs ω6 mg g −1 DW 1.9 16.7 D. bartayresiana, Dictyota sp., D. menstrualis (Gosch et al., 2012;Gosch et al., 2015;Martins et al., 2018) PUFAs ω3 mg g −1 DW 1.0 22.9 D. bartayresiana, Dictyota sp., D. menstrualis (Gosch et al., 2012;Gosch et al., 2015;Martins et al., 2018) ω6/ω3 0.3 3.9 Dictyota sp., D. ceylanica, D. pinnatifida, D. bartayresiana, D. dichotoma, C. cervicornis, D. ciliolata, D. haukiana, D. menstrualis (Chakraborty and Santra, 2008;Gosch et al., 2012;Tabarsa et al., 2012;Kumari et al., 2013;Gosch et al., 2015;Martins et al., 2018) Vitamins -Bermudez et al., 1981;Chakraborty and Santra, 2008;Deyab et al., 2017;Martins et al., 2018) Chlorophyll c mg g −1 DW 0.6 2.0 Dictyota sp., D. dichotoma, D. ceylanica (Perez-Bermudez et al., 1981;Chakraborty and Santra, 2008;Deyab et al., 2017) Carotenoids mg g −1 DW 0.03 0.03 D. ceylanica (Chakraborty and Santra, 2008) Fucoxanthin mg g −1 DW 0.1 2.3 D. dichotoma, Dictyota sp. (Perez-Bermudez et al., 1981;Deyab et al., 2017) Protein and amino acids As a fast-growing alga, especially in warm temperate to tropical environments, Dictyota may be of interest as a food, feed or protein source. ...
The genus Dictyota (Dictyotales, Phaeophyceae) comprises parenchymatous algae occurring predominantly in tropical to warm-temperate waters and has gathered attention due to its diverse secondary metabolites with antibiofouling and pharmaceutical potential, its oil content, and its potential as animal feed. This has resulted in an increase in economic potential during the last decade. In this review, we summarise the recent knowledge on the genus and concentrate on the applications and the economic potential of Dictyota. In addition, the review summarises the taxonomy, anatomy, cytology, genetic data, life history, chemical composition, nutritional value and ecological and economic importance of Dictyota species. Currently, around 100 species are recognised together with the morphologically similar and closely related genera Dilophus, Canistrocarpus and Rugulopteryx (tribus Dictyoteae). The thallus is characterised by one or more lens-shaped apical cells that divide into cortical and medullary cell layers. Species typically grow in rocky intertidal pools and subtidal areas. Dictyota is consumed locally in the Caribbean, Malayan-Indonesian and Hawaiian regions. Extracts of Dictyota which contain active compounds, such as diterpenes and phlorotannins, have been attributed antimicrobial, health and wellness promoting effects which render them promising candidates for the design of functional foods, phytomedicinal products, and cosmetics. The high fraction of lipids and fatty acids has propelled emerging applications in the biofuel industry and as a feedstock species.
... 21, 24, 29) were also found, which, like dolabelladienes, predominated in the D. fasciola extract. Being the least polar analytes, six chlorophyll-related compounds, pheophytin derivatives (No. [43][44][45][46][47][48] with the elemental composition C 55 H 74(72) N 4 O 5-9 , were the last to be eluted from the chromatographic column and, accordingly, sharply predominated in the F4 fraction. Pheophorbide A and its hydroxylated derivative (No. 34 and 31, respectively) were also found in small amounts. ...
... Deyab et al. [46] reported that carbohydrates contributed to 30% of dry D. dichotoma biomass, followed by 11.1% of proteins and only 1.3% of total lipids. Additionally, Martins et al. [47] analyzed 24 macroalgae, and carbohydrate content for D. menstrualis was around 250 mg/g DW, 3-fold lower than the results obtained for both D. dichotoma and D. fasciola. The differences between obtained and previously reported results may be attributed to different extraction procedures, location of sample collection, or harvesting season. ...
The marine environment has a significant impact on life on Earth. Organisms residing in it are vital for the ecosystem but also serve as an inexhaustible source of biologically active compounds. Herein, the biodiversity of two brown seaweeds, Dictyota dichotoma and Dictyota fasciola from the Adriatic Sea, was evaluated. The aim of the study was the determination of differences in compound composition while comparing their activities, including antioxidant, antimicrobial, and enzyme inhibition, in connection to human digestion, dermatology, and neurological disorders. Chemical analysis revealed several terpenoids and steroids as dominant molecules, while fucoxanthin was the main identified pigment in both algae. D. dichotoma had higher protein, carbohydrate, and pigment content. Omega-6 and omega-3 fatty acids were identified, with the highest amount of dihomo-γ-linolenic acid and α-linolenic acid in D. dichotoma. Antimicrobial testing revealed a dose-dependent inhibitory activity of methanolic fraction against Escherichia coli and Staphylococcus aureus. Moderate antioxidant activity was observed for both algae fractions, while the dietary potential was high, especially for the D. fasciola dichloromethane fraction, with inhibition percentages of around 92% for α-amylase and 57% for pancreatic lipase at 0.25 mg/mL. These results suggest that Dictyota species might be a potent source of naturally derived agents for obesity and diabetes.
... These diverse biological properties of BPs highlight their great potential for biotechnological applications. Some of these applications in different biotechnological fields may be in the pharmaceutical, cosmetic and food industries [20]. ...
Bromophenols, which belong to the family of phenolic compounds, are halogenated secondary metabolites characterized by the incorporation of bromine atoms into the phenol ring structure, resulting in unique chemical properties. These compounds, synthesized as secondary metabolites by algae, exhibit different isomeric forms due to bromine substitution at different positions within the phenol ring, showing variability among species. Bromine substitution not only confers specific chemical properties but also plays an important role in the ecological functions of bromophenols by inducing increased lipophilicity, which affects solubility and reactivity, an adaptive response to external conditions. Certain genera of red algae, such as Gracilaria and Rhodomela, have been identified as important sources of bromophenols. Research on bromophenols involves extraction , commonly using solvents such as methanol or methanol-dichloromethane, and identification and structural elucidation using advanced analytical techniques such as mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy for the precise determination of structure and configuration. Bromophenols display diverse biological activities, highlighting antimicrobial, antidiabetic, antiviral and antioxidant properties, which are closely related to their specific chemical structure. The importance of understanding the chemical group of bromophenols is underlined by their role in chemical defense mechanisms, contributing to potential biotechnological applications and broader contributions to the marine ecosystem. Therefore, this study is aimed to review the chemical characteristics and biological properties of bromophenols in red algae.
... Ácidos graxos isolados da alga D. dichotoma (28-30) exibiram efeito anti-incrustrante, podendo desempenhar um papel importante na defesa e proteção contra bactérias formadoras de biofilme (BAKAR et al., 2017). Além disso, autores sugerem que o alto teor de ácidos graxos mono e poli-insaturados de algas do gênero Dictyota pode ser aproveitado, no futuro, para produção de biocombustíveis e/ou como fonte nutracêutica (BAKAR et al., 2017;MARTINS et al., 2018). ...
In recent years, research into the marine environment has increased, resulting in a wide variety of compounds with a significant diversity of biological activities. Thus, seaweed is a promising source of molecules with biotechnological and pharmaceutical interest. Brown algae of the Dictyotaceae family contribute an important percentage to the structural diversity of natural products, which have already demonstrated antifungal, antibacterial, antiviral potential, in addition to exercising multiple ecological functions in algae. Most species belong to the genera Dictyota, Lobophora and Padina, being known to produce diterpenes, sterols, fatty acids and polysaccharides. Thus, the objective of this review is to provide an updated overview of the natural products produced by the Dictyotaceae family, highlighting their antioxidant and antifungal activities. This review opens the way for discussion on the use of marine biodiversity for the development and innovation of new bioproducts, promoting a critical approach to bioprospecting, sustainability and conservation of marine brown algae.
... The chromatic adaptation was annotated thru Pmax showed a significant positive correlation to the ω-6/ ω-3 ratio, PUFA, MUFA, SFA, TFA, and Cla. Thus, the correlation implied that sonar radiation affects the biosynthesis of FAs [146,147]. ...
The unexploited red algae Acanthophora is intriguing since some species of which are invasive and pose a threat to their new ecosystem. The algae express potent effects due to possessing a diversity of metabolites. Additionally, their crude extracts were intensively investigated. This review is interested in discussing the effects of the extracts and chemical structures of the isolated bioactive metabolites of the genus Acanthophora. Several classes of metabolites as steroids, alkaloids, and flavonoids, were documented. Polysaccharides, their derivatives, and fatty acids were also discussed. The standard protocols detected broad classes of metabolites. Nevertheless, the description of tannins, saponin, and terpenoids was missing in the further fractionation and structure elucidation. The crude extracts and their fractions showed bioactivities, including anticancer, antimicrobial, antivirus, antioxidant, and anticoagulant. The reported studies were limited to some species of Acanthophora, it is considered an opening the gate to do exploration of the other species.
... Gas chromatography procedures were nearly identical to Martins et al. (2018). Fatty acid methyl esters were analyzed by gas chromatography coupled with mass spectrometry (QP2010, Shimadzu, Japan). ...
Symbiotic octocorals are important reef inhabitants, from shallow to mesophotic depths. However, information regarding their nutritional ecology along the depth gradient, and in particular the changes in the autotro-phic and heterotrophic acquisition of nutrients, is limited, despite the fact that nutrient acquisition is a fundamental process in explaining the distribution of reef organisms. Here, the abundance of three lipid bio-markers, specific for autotrophy and heterotrophy, was investigated in the tissue of four octocoral species and one scleractinian sampled in shallow and upper mesophotic reefs of the oligotrophic Northern Red Sea. Our findings show functional mixotrophy for all dinoflagellate-bearing species, with a significant input of heterotro-phic feeding on herbivorous crustacean zooplankton at both depths. The relatively high level of the heterotro-phic marker in all symbiotic species in shallow conditions does not corroborate the common idea that corals rely mostly on autotrophy in shallow waters. The increase in heterotrophic capacity with depth was however species-specific, likely related to physiological and morphological characteristics. In addition, octocorals maintained similar concentrations of autotrophic markers with increasing depth, while the scleractinian species exhibited a decrease in these markers with depth. These results are in agreement with previous measurements of photosynthetically-fixed carbon acquisition, suggesting that autotrophy remains stable in Red sea soft corals, whereas it decreases in scleractinian corals. This study highlights the importance of heterotrophy across the euphotic-upper mesophotic depth gradient and brings relevant advances on our understanding of the ecological significance of feeding for reef corals.
... Gas chromatography procedures were nearly identical to Martins et al. (2018). Fatty acid methyl esters were analysed by gas chromatography coupled with mass spectrometry (QP2010, Shimadzu, Japan). ...
Octocorals living in symbiosis with photosynthetic dinoflagellates are one of the major benthic groups of tropical coral reefs. They are notably abundant within disturbed ecosystems where environmental changes have led to the decline of reef-building corals. Although nutrition plays a fundamental role in regulating the abundance of a population, the acquisition of nutrients by octocorals has received little attention to date. The aims of this thesis were to characterize the acquisition and assimilation of autotrophic and heterotrophic nutrients by octocoral species from the Red Sea, from the shallow down to the upper mesophotic zone. The results show that the autotrophic carbon fixation in octocorals is lower at shallow depth compared to scleractinians, but equivalent at mesophotic depths. In addition, the assimilation of dissolved nitrogen compounds is lower in octocorals than in scleractinian corals. These results suggest that octocorals strongly depend on heterotrophic food sources to meet their nutritional requirements. Such mixotrophy provides octocorals with a wide trophic plasticity, which may contribute to their higher resistance to cope with already on-going environmental changes.
... The production of 10.7 kg of tilapia spends 96 kg of nitrogen/cycle and releases 10.7 kg of NH 4+ to the environment [3]. Also, it is necessary 1.78 m 2 of agricultural soil [4] and about 50 m 3 of fresh water to produce 1 kg of tilapia [5]. According to Huang et al. [6], there was an increase of 325% (2.54 × 10 4 tons) of annual phosphorus input to aquaculture while farming and feeding livestock increased only 20% (0.64 × 10 4 tons) and 15% (679 tons), respectively. ...
The rapid development of large-scale aquaculture leads to wastewater accumulation, increasing environmental problems. Microalga cultivation is a potential biotechnological alternative to treat aquaculture wastewater. While this microorganism consumes the wastewater nutrients, high added value biomass is produced. The role of Spirulina in aquaculture wastewater treatment is not fully elucidated in the literature. Thus, this study aimed to reuse and treat aquaculture wastewater by Spirulina sp. LEB 18 cultures. The microalga growth parameters, the biochemical composition of the biomass produced, and the Spirulina efficiency to nutrient removal from the aquaculture wastewater were evaluated. The assays were performed in closed photobioreactors (1 L) using 100% aquaculture wastewater (T-0) supplemented with 25 (T-25), 50 (T-50), and 75% (T-75) of the Zarrouk synthetic culture medium. The maximum biomass concentrations showed no statistical difference between the assays T-50 (1.02 g L−1), T-25 (1.10 g L−1), and control (1.05 g L−1). The biomass from the T-25 assay showed the highest concentrations of protein (65.73%), phycocyanin (16.60 mg/mL), polyunsaturated fatty acid (38.20%), and γ-linolênico (23.29%). Besides that, the Spirulina sp. LEB 18 highest removal rate of sulfate (94.01%), phosphate (93.84%), bromine (96.77%), and COD (90.00%) was obtained from the T-25 assay. The biomass from T-25 and T-50 assays showed ideal properties for biodiesel application. The Spirulina sp. LEB 18 cultures using 100% aquaculture wastewater supplemented with 25% of Zarrouk culture medium was the best option for the aquaculture wastewater treatment, producing added value biomass and reducing production cost.
Algae include a diverse group of photosynthetic organisms with extraordinary metabolic profiles that could facilitate their wide-ranging applications in various sectors. They are richly augmented in vitamins, carbohydrates, lipids, minerals, and other high-value nutrients. Because of their nutritional properties, they are often used as dietary supplements for animals and humans. They are emerging as a substitute for traditional food sources because algae are used to upgrade the nutritional value of functional foods, bakery products, beverages, nutraceuticals, snacks, and smoothies. Besides developing functional foods, algae provide an alternative direction toward aquaculture feeds. They play a vital role in improving fish nutrition and sustainable aquaculture practices. This book chapter mainly highlights several algae species with the potential for human and animal food and feed products. Along with several success stories, the futuristic path toward sustainable food and feed industries is also discussed.
Coral reefs worldwide are under severe threat due to their inherent fragility and urgent need for conservation. The escalating tourism in coral reefs significantly impacts the marine ecosystem's biodiversity and conservation. This study analyzed the diversity and conservation status of macrobenthos in the Seixas coral reef, located in northeastern Brazil, and proposed a zoning plan. We employed monitoring protocols adapted from the Reef Check Program, the Rapid Assessment Protocol for Atlantic and Gulf Reefs, and the Protocol for Monitoring Coastal Benthic Habitats. Species identification was carried out by analyzing 25 transects, each divided into 1 m 2 grids, with photos recorded for each grid, totaling 625 photos. Margalef, Shannon-Weaver, Simpson, and Pielou indices were used to analyze species distribution and diversity. The results indicated Dictyotaceae, Sargassaceae, and Corallinaceae as prevalent families. This research offers decision-makers a snapshot of species distribution in the Seixas coral reefs, providing a non-destructive, efficient methodology for assessing environmental impacts on coastal coral reefs.
Ongoing research in the food supplement sector provides insightful information regarding algae as a new-generation nutritional supplement and is also referred to as a superfood. Due to the diverse nutritional components, algae have documented numerous health benefits like fighting microbial diseases, hypertension, obesity, and diabetes. Therefore, algae-derived nutraceuticals account for a rapidly expanding market in the food supplements sector. The concept of algal prebiotics and their role in modulating gut microbiota have also been a chief contributor to this. This review evaluates the use of possible algal species and their specific bioactive compounds for the management of several chronic diseases. Proteins, peptides, polysaccharides, phenolics, and vitamins give an insight into the significance of algae in boosting the immune system and improving the body’s nutritional makeup. In addition, phyco-compounds such as polysaccharides and polyphenols are also receiving a lot more interest in cosmeceutical applications for protecting skin from photodamage. The incorporation of algae in the diet for the management and prevention of chronic diseases like cancer, lung, and heart disease has been discussed in this review along with their action mechanism. This review provides a brief overview of several bioactive compounds present in micro and macroalgae and their therapeutic effect on lifestyle diseases, gastrointestinal diseases as well as neurodegenerative diseases.
The role that seaweeds play as primary producers and ecosystems engineers in marine coastal ecosystems is widely acknowledged. Seaweeds, however, are also important drivers in the development of the blue bioeconomy due to their vast diversity of unique chemicals with a broad range of industrial and biotechnological applications. In tropical regions, seaweed production has been focused on a few species only, because of their hydrocolloids used in the food industry. There is a strong need to identify new applications of red seaweed species in other sectors such as aquaculture. Therefore, to diversify the culture of red seaweeds, more tropical species need to be investigated for their chemical composition and potential application in aquaculture, and then, to develop a method for a sustainable cultivation of new seaweed candidates and enhance their economic potential. Based on this context, we analyze the potential value of the red edible seaweed Acanthophora spp., an under-valued seaweed species which is naturally abundant in tropical countries, and Kappaphycus spp., a commercially valuable seaweed commonly used for polysaccharide extraction. The vast chemical diversity of seaweeds (polysaccharides, phytohormones, amino acids, and pigments) has led to research on a wide range of applications in aquaculture, including pathogen control, immunostimulant, antioxidant, bioremediation, feed, UV protectants, increase in seafood shelf life, animal colorant, and growth regulator for microalga culture. This review hopes to stimulate the interest among seaweed researchers to investigate other local seaweed species and seek greater added value of their biomass and chemical compounds and their applications in the aquaculture sector. Additionally, this information will help stakeholders to benefit from these two red seaweeds by contributing to the diversification of the blue bioeconomy in tropical countries.
This study describes the lithium (I) uptake behavior of Dunaliella salina alga for a potential functional nutritional supplement. For this purpose, cultivation of the isolated D. salina strain in a lithium (I)-free medium was followed by the harvesting and drying of the cells. The characterization studies of the alga revealed that D. salina has a high surface negativity, which has a direct positive effect on its ability to capture lithium (I) ions. Critical parameters such as pH and initial lithium (I) concentration, which directly affect the lithium (I) uptake of the cells, were optimized. The maximum lithium (I) uptake capacity of D. salina was determined as 4.003 mg lithium (I)/g dry biomass (576.7 μmol/g) at an initial lithium (I) concentration of 20.0 mg/L and pH of 9.0. Lithium (I) uptake by the alga rapidly reached equilibrium for all cases examined. Experimental equilibrium data were found to be compatible with both Langmuir and Freundlich models under the experimental conditions studied. It can be said that D. salina with its efficient lithium (I) ion uptake holds great promise in the nutrition, pharmaceutical and seawater feeding industries.
The macroalgae showed varied quantities of biochemical constituents like total carbohydrate, total protein and total lipid. Studies were conducted to evaluate biochemical composition of Spatoglossum asperum. Fatty acid, vitamins and minerals composition were carried out by using gas chromatography method and flame atomic absorption spectrophotometry method respectively. Among biochemical content total protein is present in high amount, 11.03 ± 0.06%, total carbohydrates is 6.55 ± 0.14% and total lipid is 3.14± 0.14%. Among the 7 identified fatty acid, Linoleic acid (29.41± 0.01%) and stearic acid (21.99 ± 0.01%) are found to be the major components. Among vitamins, vitamin C (15.60 ± 0.00 mg/100gm) and Niacin (10.86 ± 0.02 mg/100gm) are present in major quantities. Macro minerals such as Potassium (203.38 ± 0.02 mg/100gm), Sodium (145.50 ± 0.10 mg/100gm) and Calcium (134.51 ± 0.01mg/100gm) were identified in higher amount.
Salinity is an important abiotic factor since it is responsible for the local and/or regional distribution of algae. In coastal regions, salinity changes with prevailing winds, precipitation and tide, and particularly in extreme intertidal conditions. Acanthophora spicifera is a red seaweed that occurs in the supratidal region in which changes in abiotic conditions occur frequently. This study evaluated the effects of salinity on the metabolism and morphology of A. spicifera. Algae were acclimatized under culture conditions with sterilized seawater for seven days. Experiments used different salinities (15 to 50 psu) for seven days, followed by metabolic analyses. This study demonstrates that extreme salinities affect physiological parameters of A. spicifera, such as decrease in growth rate, as well as morphological parameters and concentrations of secondary metabolites. Acanthophora spicifera exhibited high tolerance to 25 to 40 psu, with little change in physiology, which favors the occurrence of this species in diverse environments. However, 15, 20, 45 and 50 psu were the most damaging and led to loss of biomass, depigmentation of apices, and the highest concentrations of antioxidant metabolites. The 50 psu treatment caused the greatest changes in general, greatly reducing a biomass and chlorophyll content, and facilitating the presence of endophytes.
The use of cultivated seaweeds as a feedstock for multiple industrial applications has gained increasing interest in the Western World over the past decades. Norway has an extensive coastline and a well-established aquaculture sector offering suitable preconditions for developing large-scale cultivation of seaweed biomass both in monoculture and in Integrated Multi-Trophic Aquaculture (IMTA) systems. Recent efforts from research, industry and public authorities have been committed to develop a Norwegian bio-economy based on cultivated seaweed, focusing on cultivation and processing of the biomass. This review reports on the status of seaweed aquaculture in Norway, supported by production data collected since the delivery of the first commercial cultivation permits at sea in 2014. Although novel product developments are currently limited, future industrial perspectives based on cultivated biomass are being discussed. Upscaling from experimental cultivation schemes to commercial production requires a thorough assessment of the risks and benefits associated with seaweed aquaculture, as well as the development of a regulative framework adapted to this industry. Issues associated with upscaling the macroalgal production that needs to be addressed includes (i) genetic interactions between cultivated and wild crops, (ii) impacts of seaweed cultivation on surrounding ecosystems, (iii) epiphytes and diseases, (iv) area utilization and (v) threats from climate change. Addressing these issues and adapting production practices will ensure the environmental and economic sustainability of an emerging industry based on cultivated seaweed biomass in Norway.
Spectral light changes evoke different morphogenetic and photosynthetic responses that can vary among different algae species. The aim of this study is to investigate the photosynthetic characteristics of the red macroalgae grown under different spectrum environments. In this study, Pyropia haitanensis were cultured under blue, red, and green LED and fluorescent tubes light. The growth rate, photopigment composition, chlorophyll fluorescence, and antioxidative enzymes activities in different light spectrums were investigated. The results revealed that growth rate was significantly higher in the thalli grown under blue, green, and fluorescent tubes light. Contents of Chl a and phycobiliprotein in red light were lower among all the growth conditions. Furthermore, a striking increase in SOD and CAT activity was observed in red light treatment along with the NPQ increase. The results revealed that the photosynthetic efficiency and increased growth rate of P. haitanensis benefitted from light spectrums such as blue, green, and fluorescent tubes light by pigment composition and photochemical efficiency manipulation, whereas red light has disadvantageous effects. Accordingly, the results for improving quality and the economic yield of algae species in some extent and the combination of different wavelengths could allow better economic resource exploitation.
The objective of this study was to evaluate two seaweed species, Solieria filiformis and Macrocytis piryfera, both as dry-meal powder and predigested meal, to be used as ingredients in artificial diets for the juvenile four-sided sea cucumber, Isostichopus badionotus. Four diets were tested in triplicate: S. filiformis dry-meal powder and predigested meal and M. piryfera dry-meal powder and predigested meal, mixed with 70% of beach sand. Survival exceeded 90% in all the treatments, and there were no differences in the growth of juveniles using dry-meal powder or predigested meal. Weight gain was calculated for all the diets, and the highest values were obtained by animals fed S. filiformis. No differences between using dry-meal powder and predigested meal were found, so these diets were excluded from the second trial. The ingestion rate was the same with both algae, but the feed conversion ratio was twice as high for M. piryfera. Solieria filiformis exhibited a number of differences in fatty acid and amino acid profiles, including higher proline, arginine, and saturated fatty acid levels. The results indicate that S. filiformis has better nutritional characteristics to be an ingredient for an artificial I. badionotus juvenile diet.
This work focuseson the proximate compositionof the eight seaweeds belonging to Chlorophyta(Chaetomorphaantennina, Enteromorphaproliferaand Ulva fasciata) and Rhodophyta(Acanthophoraspicifera, Gracilaria corticata, G.corticata var.cylindrica, G.foliifera and Gelidiumpusillum), collected from the south west coast of India. The total protein, carbohydrate, lipid, iodine, ash, crudefiber, calorific value and moisture contents were estimated.Total protein content varied from 5.98 to 25.12% and total carbohydrate from 31.02 to 75.95%, where as total lipid levels were only 1.49to 10.76 %. Greater sources of ions, minerals and metalsin seaweeds were evidenced from 13.06to 27.71 %of ash contents. Comparatively, higher levels of crude fiber contentwere observed (37.57to 63.39%) in the seaweed species. Seaweeds also remarked with their iodine concentrations which varyfrom 41.46 to185.38mgkg-1. Calorific values ranged from1.39 to 3.52kcalg-1.The water holding capacity of the seaweeds wasobserved between 72.52and 89.15 %.Correlationstudyof biochemical constituents withthe corresponding species/genus/division had determined the interdependence of compositional groups,which helped in judging the cross compositional relation. Recommended Daily Intake (RDI)values recommended by the Council for Responsible Nutrition (CRN), United States Food and Drug Administration (USFDA)and Electronic Code of Food Regulations (ECFR)showed its potential importance in dietwithgenusGracilaria as the major contributor to the nutraceutical sectors.
Temporal and spatial variations in the proximate composition, amino acid content, and mineral content of Pyropia yezoensis were evaluated at Jindo, Haenam, and Seochun on the southern and western coasts of Korea. The proximate composition of P. yezoensis showed a specific pattern where carbohydrate, lipid, and ash increased over time, while protein decreased over time from January to April. Amino acids from P. yezoensis, such as alanine, aspartic acid, glutamic acid, leucine, and glycine, as well as 14 different minerals, were identified. Among them, aspartic acid, alanine, and glutamic acid were present at the highest concentrations. The concentration of alanine ranged from 3.40 ± 0.22 to 0.97 ± 0.07 g (100 g)−1 at all sites. Five macro minerals (Ca, K, Mg, Na, and P) and seven micro minerals (Mn, Co, Fe, Ni, Cu, Zn, and Cr) were measured at three different sites. The macro mineral K was present at the highest concentration, followed by P, Na, Ca, and Mg. The concentration of K showed spatial and temporal variations. P. yezoensis at Haenam contained 3249.39 ± 100.82 mg (100 g)−1 in January, but decreased to 55.39 ± 209.95 and 426.00 ± 389.74 mg (100 g)−1 in February and March, and then increased to 2120.42 ± 454.53 mg (100 g)−1 in April. The micro mineral, Fe, was present at the highest concentrations, followed by Zn and Co. The concentration of Fe ranged from 42.71 ± 57.23 to 12.08 ± 1.55 mg (100 g)−1 in March and April at Haenam. The concentration of Zn was highest in January and then gradually decreased from February to April, while Jindo and Haenam did not show spatial and temporal variations in Zn concentrations. In this study, temporal and spatial variations in the proximate composition, amino acid content, and mineral content of Pyropia were determined to analyze the protein, amino acid, lipid, carbohydrate, and mineral contents, which showed temporal and spatial variations during cultivation from October to April.
Dictyota menstrualis (Hoyt) Schnetter, Hörning & Weber-Peukert (Dictyotales, Phaeophyceae) was studied for the production of oil-based bioproducts and co-products. Experiments were performed to evaluate the effect of carbon dioxide (CO2) concentration, under nitrogen (NO3 (-)) limiting and saturation conditions, on growth rate (GR), photosynthesis, as well as nitrate reductase (NR), carbonic anhydrase (CA), and Rubisco activities. In addition, the biochemical composition of D. menstrualis under these conditions was estimated. GR, protein content, and N content in D. menstrualis were higher in treatments containing NO3 (-), irrespective of CO2 addition. However, when CO2 was added to medium saturated with NO3 (-), values of maximum photosynthesis, Rubisco, and NR activity, as well as total soluble carbohydrates and lipids, were increased. CA activity did not vary under the different treatments. The fatty acid profile of D. menstrualis was characterized by a high content of polyunsaturated fatty acids, especially the omega-3 fatty acids, making it a possible candidate for nutraceutical use. In addition, this species presented high GR, photosynthetic rate, and fatty acid content, highlighting its economic importance and the possibility of different biotechnological applications.
Seaweeds have various chemical components with beneficial effects for human use; however, their nutritional values in Brazilian species are not well known. This study aimed to evaluate the content of water, ash, protein, carbohydrate, and lipid in four seaweeds (Hypnea musciformis, Solieria filiformis, Caulerpa cupressoides and C. mexicana). Algal constituents were determined by difference, gravimetric or colorimetric method, being the values expressed as g 100 g-1 dehydrated weight (d.w.). Results revealed that the water (10.7 ± 0.18-15.06 ± 1.14 g 100 g-1 d.w.), ash (7.79 ± 0.87-15.12 ± 0.51 g 100 g-1 d.w), protein (17.12 ± 0.99-20.79 ± 0.58 g 100 g-1 d.w.), lipid (0.33 ± 0.01-3.77 ± 0.13 g 100 g-1 d.w.) and carbohydrate (38.07 ± 0.32-54.24 ± 0.157 g 100 g-1 d.w.) contents varied between the species (p < 0.05). H. musciformis and S. filiformis (Rhodophyta) had highest ash contents (14.14 ± 1.23-15.12 ± 0.51 g 100 g-1 d.w.), whereas lipids were higher for Caulerpa species (Chlorophyta) (1.52 ± 0.17-3.77 ± 0.13 g 100 g-1 d.w.) (p < 0.05). Protein and carbohydrate were the most sources in all the species. Therefore, the studied seaweeds could be a potential source of food ingredients for diets.
Brown seaweed Fucus vesiculosus has a high potential as a source of natural antioxidants due to a high diversity of bioactive compounds in its composition. In this study, four extracts were characterized with respect to composition of bioactive compounds, in vitro antioxidant properties and their partitioning between water and octanol. Additionally, the antioxidant activity of the extracts was evaluated in a fish-oil-enriched mayonnaise. Acetone and ethanol were found to extract the highest amount of phenolic compounds and carotenoids. Water used as extraction solvent, extracted some phenolic compounds but also higher amount of metals and chlorophyll derivates. It was proposed that extracts with high phenolic content and low iron content, such as the acetone and ethanol extract, would have the highest potential as antioxidants in foods. This was confirmed in the storage trial, where these extracts showed higher antioxidant activity.
The ongoing increases in atmospheric CO2 concentrations and coastal eutrophication have affected the coastal environment and marine macroalgae. In this study, the interactive effects of CO2 (390 and 1000 μL L−1) and nutrient levels (nitrogen and phosphorus supplied simultaneously) on the physiological properties of the maricultured macroalga Pyropia haitanensis (Bangiales, Rhodophyta) were investigated. The results showed that elevated CO2 significantly enhanced P. haitanensis growth and NO3− uptake, but lowered the pH compensation points, regardless of nutrient levels, and enhanced photosynthesis and apparent photosynthetic efficiency (α) when the nutrient levels were high. However, CO2 had little effect on photosynthetic rates at low nutrient levels. At each nutrient level, CO2 elevation lowered both the phycobiliproteins (PB) and soluble protein contents, but enhanced biomass accumulation. Chlorophyll a (Chl a) and carotenoid (Car) contents were markedly increased by high CO2 concentrations at low nutrient levels. Increasing nutrient supply significantly enhanced growth, pH compensation points, and photosynthesis in P. haitanensis at each CO2 level, but the differences of the effects between intermediate and high nutrient levels on this alga were not significant for photosynthesis, pigment content, and nutrient uptake, regardless of CO2 levels. Our results suggest that the growth and physiological responses of P. haitanensis to CO2 levels are largely dependent on the supplement of nutrients. However, the interactive effects of elevated CO2 and nitrogen-phosphorus supplies on the physiological properties of P. haitanensis were limited through respective regulation by the CO2 levels in the atmosphere and the nutrient concentrations in the seawater.
Pyropia haitanensis, a commercially important species, was cultured at two CO2 concentrations (390×10−6 and 700×10−6 (parts per million)) and at low and high nutrient levels, to explore the effect of elevated CO2 on the species under nutrient enrichment. Results show that in CO2-enriched thalli, relative growth rate (RGR) was enhanced under nutrient enrichment. Elevated CO2 decreased phycobiliprotein (PB) contents, but increased the contents of soluble carbohydrates. Nutrient enrichment increased the contents of chlorophyll a (Chl a) and PB, while soluble carbohydrate content decreased. CO2 enrichment enhanced the relative maximum electronic transport rate and light saturation point. In nutrient-enriched thalli the activity of nitrate reductase (NRA) increased under elevated CO2. An instantaneous pH change in seawater (from 8.1 to 9.6) resulted in reduction of NRA, and the thalli grown under both elevated CO2 and nutrient enrichment exhibited less pronounced reduction than in algae grown at the ambient CO2. The thermal optima of NRA under elevated CO2 and/or nutrient enrichment shifted to a lower temperature (10–15°C) compared to that in ambient conditions (20°C). We propose that accelerated photosynthesis could result in growth increment. N assimilation remained high in acidified seawater and reflected increased temperature sensitivity in response to elevated CO2 and eutrophication.
Recently, H. pluvialis has been demonstrated to have significant potential for biofuel production. To explore the correlation between total lipid content and other physiological parameters under s tress conditions, the responses of H. pluvialis to high light intensity (HL), nitrogen deprivation (-N), and high light intensity with nitrogen deprivation (HL-N) were investigated. The total lipid content in the control cells was 12.01% dw, whereas that of the cells exposed to HL, -N, and HL-N conditions was 56.92, 46.71, and 46.87% dw, respectively. The fatty acid profile was similar under all conditions, with the main components including palmitic acid, linoleic acid, and linolenic acid. A good correlation was found between individual carotenoid and total lipids, regardless of culture conditions. P hotosynthetic parameters and lipid content were also found to be well-correlated.
The green algae genus Caulerpa is coenocytic, and the thallus consists of only one cell with many nuclei. It is widely distributed in the tropical seas. In the Southeast Asian waters, there are at least ten known species. Three species, particularly Caulerpa racemosa var. clavifera f. macrophysa (Kützing) Weber-van Bosse, C. racemosa var. laetevirens (Montagne) Weber-van Bosse, and Caulerpa lentillifera J. Agardh are widely consumed. The proximate analysis and secondary metabolite composition of these three species were determined to describe their lipid and nutritional values. Glycolipids and phospholipids were the major lipid classes, with significant levels of triacylglycerol. Polyunsaturated fatty acids (PUFA) were the major fatty acids of all the three species. Typical n-3 and n-6 PUFA such as 18:3n-3, 18:4n-3, 20:5n-3, 18;2n-6, and 20:4n-6 were found in significant amount in all these three species. All three species contained a red-pigmented secondary metabolite determined as caulerpin. All three extracts exhibited potent antimicrobial activity against human food pathogenic bacteria and anti-inflammatory activity against the murine macrophage cell line, RAW 264.7.
The present work aims to compare the effects of ultraviolet radiation on the morphology, ultrastructure, and photosynthetic pigments of two species of Ceramiales: Laurencia catarinensis and Palisada flagellifera. To accomplish this, plants were cultivated and exposed to photosynthetically active radiation (PAR) at 60 μmol photons m−2 s−1 and PAR + ultraviolet B radiation (UVBR) at 0.35 W m−2 at 3 h per day for 7 days. Subsequently, the apical segments of L. catarinensis and P. flagellifera were analyzed under light and transmission microscopy, and both growth rates and photosynthetic pigments were studied. After exposure to PAR + UVBR, L. catarinensis exhibited a high reduction in growth rate and loss of biomass, in addition to a reduction in the concentration of chlorophyll a when compared with treated plants of P. flagellifera. However, after 7 days of exposure to PAR + UVBR, both plants showed a reduction in phycobiliprotein content. Toluidine blue reaction did not show cell wall changes in treated species with PAR + UVBR. Staining of L. catarinensis and P. flagellifera with periodic acid–Schiff (PAS) after UVBR exposure showed an increase in the number of starch grains in both species. When observed by transmission electron microscopy, treated samples of both species also showed disrupted thylakoids of the chloroplasts and an increased number of plastoglobuli. Based on this line of evidence, the present study demonstrates that ultraviolet radiation negatively affects the intertidal macroalgae L. catarinensis and P. flagellifera.
A bioeconomy can be defined as an economy where the basic building blocks for materials, chemicals and energy are derived from renewable biological resources. This paper provides an overview of the bioeconomy in Europe, examining it from a policy framework and concept perspective. The role of bioenergy in the bioeconomy is discussed particularly through biofuels for transport and biorefineries. The study finds that the definitions of the bioeconomy are evolving and vary depending on the actor, but display similarities such as the emphasis on economic output and a broad, cross-sectoral focus. While there is great optimism about the benefits and opportunities associated with developing an advanced bioeconomy in Europe, significant risks and trade-offs are also expressed. Furthermore, the bioeconomy concept has been criticised for presenting a technical fix and pre-empting alternative visions. To advance a competitive and sustainable bioeconomy, this paper calls for attention on two important themes: participatory governance that engages the general public and key stakeholders in an open and informed dialogue as well as a commitment by government and industry to innovation that drives concerted efforts on sustainable development of the bioeconomy.
The marine red alga Gracilaria crassa was investigated for its proximate composition, minerals, fatty acids,
amino acids, and agar content to decipher its nutritional implications.The growth performance and pigments were studied under different combinations of temperature and salinity. On a dry weight basis the total lipid content was 1.30±0.05 %, protein was 5.18±0.64 %, carbohydrate was 42.0±1.2 %, ash was 43.18±1.15 %, and agar content was 21.52±0.73 %. Appreciable amounts of macro-, micro-nutrients (K>Na, Ca, Mg, and Fe), and essential amino acids (Ileu, His, Thr, Leu, and Lys) were found. Palmitic, stearic acid, and arachidonic acid were major fatty acids detected. The alga showed maximum daily growth rate (DGR %) 5.8±0.09 % at 25 °C, 35‰ salinity. The highest content of pigment R-phycoerythrin (444.7±1.9 μg g−1 fresh weight (FW) basis) was obtained at 25 ‰ salinity at 35 °C while that of R-phycocyanin (476.3± 2.3 μg g−1FW) at 30‰salinity at 30 °C. This study revealed that this alga can be utilized as a potential source for food and
feed. The data generated on best growth conditions will be very useful for farming of G. crassa in open sea. This alga could be used for production of natural colorants at defined control condition.
"Sea grapes" is a collective term for the edible varieties of the green seaweed genus Caulerpa. Here we conduct comparative analyses of the biomass productivities and biochemical properties of C. lentillifera and C. racemosa from tropical Australia. Commercial-scale production was evaluated using 1 m(2) culture units with high stocking densities (> 5 kg m(-2)). Productivity of C. lentillifera in a 6-week period yielded, on average, 2 kg week(-1), whereas C. racemosa yielded < 0.5 kg week(-1). Morphometric comparisons of the harvestable biomass revealed that C. lentillifera had a higher proportion of fronds (edible portions) to horizontal runners (stolons) and a higher density of fronds per unit area. C. racemosa fronds, however, were significantly longer. The nutritional value of C. racemosa was higher than C. lentillifera for both polyunsaturated fatty acids (10.6 vs. 5.3 mg g(-1) DW) and pigments (9.4 vs. 4.2 mg g(-1) DW). The content of eicosapentaenoic acid (EPA) and beta-carotene decreased with increasing frond size in both species. Trace element contents also varied substantially between the species, including higher levels of zinc, magnesium and strontium in C. lentillifera, and higher levels of selenium in C. racemosa. Some less desirable elements were higher in C. lentillifera, including arsenic (1 vs. 0.1 ppm) and cadmium, whereas others were higher in C. racemosa, including lead, copper and vanadium. Overall C. lentillifera has a high biomass production potential in monoculture and distinct nutritional properties that warrant a focus on its commercialisation as a new aquaculture product in tropical Australia and in Southeast Asia more broadly.
We investigated the potential of seaweeds as feedstock for oil-based products, and our results support macroalgae (seaweeds) as a biomass source for oil-based bioproducts including biodiesel. Not only do several seaweeds have high total lipid content above 10% dry weight, but in the brown alga Spatoglossum macrodontum 50% of these lipids are in the form of extractable fatty acids. S. macrodontum had the highest fatty acid content (57.40 mg g �1 dw) and a fatty acid profile rich in saturated fatty acids with a high content of C18:1, which is suitable as a biofuel feedstock. Similarly, the green seaweed Derbesia tenuissima has high levels of fatty acids (39.58 mg g �1 dw), however, with a high proportion of PUFA (n-3) (31% of total lipid) which are suitable as nutraceuticals or fish oil replacements. Across all species of algae the critical parameter of fatty acid content (measured as fatty acid methyl esters, FAME) was positively correlated (R2 = 0.67) with total lipid content. However, the proportion of fatty acids to total lipid decreased markedly with total lipid content, generally between 30% and 50%, making it an inaccurate measure of the potential to identify seaweeds suitable for oil-based bioproducts. Finally, we quantified within species variation of fatty acids across locations and sampling periods supporting either environmental effects on quantitative fatty acid profiles, or genotypes with specific quantitative fatty acid profiles, thereby opening the possibility to optimize the fatty acid content and quality for oil production through specific culture conditions and selective breeding.
A wide variety of pigments, like chlorophyll, carotenoids and phycobiliproteins, which exhibit colours ranging from green, yellow, brown to red are present in algae. Increasing awareness of harmful effects of synthetic dyes and inclination of society towards the usage of natural products, such as plant / microbial based colours in food and cosmetics, has led to the exploitation of microalgae as a source of natural colours. Algal pigments have great commercial value as natural colorants in nutraceutical, cosmetics and pharmaceutical industry, besides their health benefits. Spirulina, Dunaliella capsules are now commonly prescribed health foods for improving vitality and longevity of human beings. This review describes the distribution, structure of these pigments in algae, with emphasis on specific techniques for extraction and purification, along with different methods of biomass production and commercially feasible techniques documented in literature. An overview of the industrial applications of these natural colouring agents in diagnostics, food and cosmetics industry is also provided.
Several factores affect the quality of modern life, therefore the population should be aware about the importance of foods containing substances that promote health, causing an improvement in the nutricional state. The incident of death due to cardiovascular problems, cancer, arteriosclerosos, hepatic diseases, among others, might be controlled trought good habits of feeding. Functional foods and nutraceutics have been considered to be synonymous. However, functional foods must be in the form of regular foods, be consumed as part of the diet and produce specific benefits to health, such as the reducing of the risk of several diseases and the maintenance of mental and physical well-being. The biologically active substances found in functional foods can be classified in groups, which will be presented in the development of this paper, for their important benefits to health. On the other hand, nutraceuticals are foods or part of foods that bring benefits to health, including prevention and/or treatment of diseases. It may include the isolated nutrients, dietary supplements, designed products, herbal products and processed foods. The aim of this work was to compare functional foods and nutraceuticals, based on definition and legislation, presenting the different classes of these compounds their beneficial effects to health.
Four species of marine benthic algae (Laurencia filiformis, L. intricata, Gracilaria domingensis and G. birdiae) that belong to the phylum Rhodophyta were collected in Espírito Santo State, Brazil and investigated concerning their biochemical composition (fatty acid, total lipid, soluble proteins, amino acid and ash). The total content of lipid (% dry weight) ranged from 1.1% to 6.2%; fatty acid from 0.7% to 1.0%; soluble protein from 4.6% to 18.3%, amino acid from 6.7% to 11.3% and ash from 22.5% to 38.4%. Judging from their composition, the four species of algae appear to be potential sources of dietary proteins, amino acids, lipids and essential fatty acids for humans and animals.
Comparison of data of protein content in algae is very difficult, primarily due to differences in the analytical methods employed.
The different extraction procedures (exposure to water, grinding, etc.), protein precipitation using different amounts of
25% trichloroacetic acid and quantification of protein by two different methods and using two protein standards were evaluated.
All procedures were tested using freeze-dried samples of three macroalgae: Porphyra acanthophora var. acanthophora, Sargassum vulgare and Ulva fasciata. Based on these results, a protocol for protein extraction was developed, involving the immersion of samples in 4.0 mL ultra-pure
water for 12 h, followed by complete grinding of the samples with a Potter homogeniser. The precipitation of protein should
be done with 2.5:1 25% TCA:homogenate (v/v). The protocol for extraction and precipitation of protein developed in this study
was tested with other macroalgae (Aglaothamnion uruguayense, Caulerpa fastigiata, Chnoospora minima, Codium decorticatum, Dictyota menstrualis, Padina gymnospora and Pterocladiella capillacea) and microalgae (Amphidinium carterae, Dunaliella tertiolecta, Hillea sp., Isochrysis galbana and Skeletonema costatum). Comparison with the actual protein content determined from the sum of amino acid residues, suggests that Lowry's method
should be used instead of Bradford's using bovine serum albumin (BSA) as protein standard instead of casein. This may be related
to the reactivity of the protein standards and the greater similarity in the amino acid composition of BSA and algae. The
current results should contribute to more accurate protein determinations in marine algae.
In this study, we examined the effect of ultraviolet radiation (UV) at the thalli of Aglaothamnionuruguayense (W.R. Taylor) N.E. Aponte, D.L. Ballantine & J.N. Norris exposed to two different conditions of radiation: PAR (control) and PAR + UVA + UVB for 3 h per day during 7 days. The effects of radiation on growth rates, photosynthetic pigments, cell viability, phenolic compounds and total soluble sugar and starch were analyzed. The morphology and the ultrastructure were also assessed. Algae were cultivated and then exposed to photosynthetically active radiation (PAR) at 14 W m−2 and PAR + UVA (0.70 W m−2) + UVB (0.35 W m−2) 3 h per day for 7 days. After exposure to PAR + UVA + UVB, A. uruguayense exhibited a 75% reduction in growth. Photosynthetic pigments, in particular, phycobiliproteins (allophycocyanin, phycocyanin and phycoerythrin), increased after exposure to PAR + UVA + UVB. UVR exposure changed the synthesis of carotenoids, including decreased of lutein by 67.1% and increased of β-carotene by 64.3% and of zeaxanthin by 23%. Phenolic compounds were reduced while flavonoids decreased by approximately 12.9% compared with samples exposed to PAR (control). Moreover, as determined by PAS, TEM and total starch extraction, the amount of starch grains decreased in algae exposed to UV. When observed under confocal microscopy, treated samples showed a significant reduction in the number and shape alteration of chloroplasts. TEM revealed changes in ultrastructure, including increased cell wall thickening and disorganization of cellulose microfibrils. Chloroplasts showed disrupted thylakoid membranes, damage to envelope membranes, and increased number of plastoglobuli. From these results, it can be concluded that UVB is a factor that negatively affects the growth and development of the macroalga A. uruguayense.
Economically feasible production of conventional bioenergies such as biofuels, biopower and bioheat is a challenge in biorefineries because they have to compete with inexpensive fossil fuel energies while external production costs are rarely included into the present-day policies. Biomass consists of unique complex chemical structures that cannot be easily artificially synthesized and may be beneficially employed in various practical applications. Therefore, strategies relying on complete biomass disintegration through combustion, gasification or fermentation only to simple usable bioenergies do not lead to optimal utilization of biomass feedstock. Instead, cascading approaches are required in order to maximize biomass valorization. Consequently, high-value low-volume bioproducts coupled to bioenergies with potential to improve economic viability of biorefineries and biomass resource utilization are urgently required. Integrated production of bioenergies and bioproducts may be achieved by coupling existing biofuel plants with new bioindustries, by retrofitting existing bioindustries with new bioenergy facilities or by erecting completely new integrated facilities.
Glycoprotein (GLP) with a molecular mass of ~48 kDa was isolated from Codium decorticatum. Further, characterization of GLP and its potent anti-cancer activities was discussed. GLP is a glycoprotein with 36.24% carbohydrate, composed of rhamnose, galactose, glucose and mannose with a mole ratio of 38:30:26:6. Rhamnose and galactose are thus the main monosaccharides in GLP. FT-IR and NMR spectra proved that GLP contained protein and carbohydrate portions with (1→4)-linked β-galactose residues and β-linked glucose residues. Secondary structure of GLP was estimated using circular dichroism (CD) analysis. Furthermore mass spectrometric analysis was performed for identification of protein using mascot search. The findings of this study serve as a reference for better understanding of the bioactivity of glycoprotein in green algae. Analysis of anticancer potential of this GLP revealed a remarkable inhibition of cell growth in breast, cervical and lung cancer cells.
B-phycoerythrin (B-PE) was separated and purified from microalga Porphyridium cruentum using one-step chromatographic method. Phycobiliproteins in Porphyridium cruentum was extracted by osmotic shock and initially purified by ultrafiltration. Further purification was carried out with a SOURCE 15Q exchange column and analytical grade B-PE was obtained with a purity ratio (A545/A280) of 5.1 and a yield of 68.5%. It showed a double absorption peaks at 545 nm and 565 nm and a shoulder peak at 498 nm, and displayed a fluorescence emission maximum at 580 nm. The analysis by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS–PAGE) showed a bulky band between 18 and 20 kDa which could be assigned to subunits α and β and a low intensity band of 27 kDa assigned to γ subunit. Our protocol provides attractive alternative to consider for the purification procedure to obtain analytical grade B-PE at commercial level.
Carbon stable isotopes combined with fatty acid (FA) profiles were used as trophic markers to investigate the uptake of different food sources, including brown alga Sargassum muticum, red alga Gracilaria lemaneiformis, green alga Ulva lactuca and benthic matter mainly consisted of microalgae, bacteria and fine clay particles by sea cucumber Apostichopus japonicus. A 70-day feeding experiment was conducted to examine the carbon isotopic signatures and FA profiles of A. japonicus feeding on 4 different types of diets with the ingredient of mixture of algal powder and benthic matter, i.e., mixture (1:1) of S. muticum and benthic matter (SB), mixture (1:1) of G. lemaneiformis and benthic matter (GB), mixture (1:1) of U. lactuca and benthic matter (UB) and mixture (1:1:1:1) of S. muticum, G. lemaneiformis, and U. lactuca and benthic matter (SGUB). The carbon isotope compositions and FA profiles of A. japonicus showed obvious changes over the experimental period and were remarkably affected by corresponding diets. Based on the isotope mixing model, the proportional contributions of benthic matter to the diet of A. japonicus fed with SB, GB, UB and SGUB were 35.58%, 67.01%, 31.98% and 17.40%, respectively. FA trophic markers revealed that the contribution of benthic matter was mainly derived from diatoms and bacteria. Results of the present study suggested that green alga U. lactuca and brown alga S. muticum constituted the highly preferred food sources of A. japonicus, followed by autotrophic diatoms and heterotrophic bacteria present in benthic matter. Sea cucumber A. japonicus tended to reject red alga G. lemaneiformis in the presence of multiple food choices.
To investigate the response of the Gracilaria lemaneiformis (Gracilariales, Rhodophyta) to light stress, algae were grown at low (LL), intermediate (IL), and high light (HL) conditions. The relationship between photoacclimatory plasticity, light energy utilization and antioxidant capacity, and many physiological and biochemical parameters, including growth rate, pigment composition, ratio of variable fluorescence to maximum fluorescence (Fv/Fm), photochemical quenching coefficient (qP), non-photochemical quenching coefficient (NPQ), superoxide dismutase (SOD) and catalase (CAT) were determined in this study. With the increase in light intensity from LL to HL, the RGR, Chl a, Car contents, and maximal photochemical efficiency of photosystem II (PSII) increased significantly at 72 h and 120 h. However, algae growing at LL exhibited reduced photochemical efficiency of PSII and physiological activity as compared to that at HL, that is characterized by NPQ, SOD and CAT enhancement, but Chl a measuring at LL was significant higher than that at IL. Meanwhile, high Chl a value was also observed at HL after 72 h and 120 h culture compared with that at ML. The results suggest that under the low light irradiance, the G. lemaneiformis performed a negative vegetal and physiological strategy for adapting the environmental stress via regulating PSII reaction centers normalization and ROS metabolization, and so forth.
The biochemical profile of the Pyropia yezoensis-AP1 strain, a strain which shows resistance to red rot disease, was compared with that of a normal P. yezoensis cultivar. Levels of chlorophyll a, phycoerythrin, and phycocyanin were higher in P. yezoensis-AP1 than those in the normal P. yezoensis cultivar. Two-dimensional electrophoresis found a total of 132 and 128 distinct spots for total protein samples of P. yezoensis-AP1 and P. yezoensis, respectively. About 89.6 % of the total components were common to both P. yezoensis-AP1 and P. yezoensis, and 10.4 % were more abundant in the P. yezoensis-AP1 than P. yezoensis. The amount of total free amino acid in P. yezoensis-AP1 was less than that in the P. yezoensis cultivar, but taurine, glutamic acid, citrulline, and arginine content were higher in the P. yezoensis-AP1 strain. The porphyran content of P. yezoensis-AP1 (11.9 ± 0.5 % dry weight) was higher than that of P. yezoensis cultivar (9.5 ± 0.4 % dry weight). In the porphyran fraction, the content of 3,6-anhydro-L-galactose was higher in P. yezoensis-AP1 than P. yezoensis, and sulfate content was higher in the P. yezoensis cultivar than P. yezoensis-AP1. The results indicate that the difference of chemical composition between P. yezoensis-AP1 and P. yezoensis cultivar helps to explain the increased resistance to red rot disease in the AP1 strain. This finding provides a good starting point for the development of more resistant strains of P. yezoensis that will reduce the incidence of red rot disease on Pyropia farms.
Phycobiliproteins fromred seaweeds are pigment–protein complexes constituting three different pigments such
as phycocyanin, allophycocyanin and phycoerythrin. The present investigation is focused on phycobiliproteins in
red seaweed Gracilaria crassa collected from Pudumadam coast, Rameswaram. Three different solvents such as
phosphate buffer, distilled water and seawater were used for extraction of pigments and quantity and purity
were compared. Among the three different solvents, distilled water showed better results for phycoerythrin
extraction; seawater proved to be a good solvent as well as preservative for all phycobiliproteins. The purity
index (PI) was 3.79 for R-phycoerythrin (R-PE), purified by DEAE (Diethylaminoethyl) cellulose 52. The stability
of phycobiliproteins was assessed using different preservatives. NaCl at 5% proved to be suitable for long-term
preservation of phycoerythrin.
Phycobiliproteins extraction (primary refining) from Gracilaria gracilis seaweed, harvested in Lesina Lagoon (Italy) and further valorization of the residual algal via pyrolysis (secondary refining), were investigated with a cascade biorefinery approach. R-phycoerythrin (7mg/g d.w.), allophycocyanin (3.5mg/g d.w.) and phycocyanin (2mg/g d.w.) were the main phycobiliproteins extracted. Pyrolysis of G.gracilis residue followed, aiming to investigate the production of bio-oil and biochar within a pyrolysis temperature range of 400-600°C. Results showed that the bio-oil yield is high (∼65wt%) at pyrolysis temperature ∼500°C, but its high content in nitrogenous compounds prevents its use as a biofuel, unless some further de-nitrogenation takes place. Biochar yield ranged between 33wt% (400°C) and 26.5wt% (600°C). Interestingly, inorganic nutrients including P, K, Ca, Fe and Mg were detected in biochar, suggesting its potential use as recovering system of natural mineral resources from the oceanic reservoir.
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The marine red alga Gracilaria crassa was investigated for its proximate composition, minerals, fatty acids,
amino acids, and agar content to decipher its nutritional implications. The growth performance and pigments were studied under different combinations of temperature and salinity. On a dry weight basis the total lipid content was 1.30±0.05 %, protein was 5.18±0.64 %, carbohydrate was 42.0±1.2 %, ash was 43.18±1.15 %, and agar content was 21.52±0.73 %. Appreciable amounts of macro-, micro-nutrients (K>Na, Ca, Mg, and Fe), and essential amino acids (Ileu, His, Thr, Leu, and Lys) were found. Palmitic, stearic acid, and arachidonic
acid were major fatty acids detected. The alga showed maximum daily growth rate (DGR %) 5.8±0.09 % at 25 °C, 35‰ salinity. The highest content of pigment R-phycoerythrin (444.7±1.9 μg g−1 fresh weight (FW) basis) was obtained at 25‰ salinity at 35 °C while that of R-phycocyanin (476.3±2.3μ g g−1DW) at 30‰ salinity at
30°C. This study revealed that this alga can be utilized as a potential source for food and feed. The data generated on best growth conditions will be very useful for farming of G. crassa in open sea. This alga
could be used for production of natural colorants at defined control condition.
In this paper, phycocyanin and one component (PY-D2) in polysaccharide were obtained from Porphyra yezoensis to study for their potential anti-tumor effects. MTT proliferation assays showed that, at concentration of 500 mg/L for 72 h, PY-D2 treatment significantly inhibited the growth of four tumor cell lines, HO-8910, MCF-7, K562 and SMMC-7721, with the respective inhibition rates of 21.2%, 23.6%, 19.8%, and 21%. Flow cytometry analysis indicated that the anti-tu-mor effect of PY-D2 was associated with the cell cycle arrest at G0/G1 or G2/M check-points. Two cancer cell lines, Hep-2 and A375 were treated by different concentrations of phyco-cyanin, followed by radiation with He-Ne laser at the density of 20 J/cm 2 and the wavelength of 632 nm. MTT assays dis-played the minimal survival rate of 29.8% (Hep-2) and 16.2% (A375) at 100 μg/ml and 165 μg/ml respectively. These re-sults suggest that both polysaccharide and phycocyanin from Porphyra yezoensis might be useful in the treatment of human cancers. These results suggest that phycocyanin and one component (PY-D2) in polysaccharide which had been ob-tained both from Porphyra yezoensis were potential medica-ments in the treatment of some kinds of human cancers.
A 56‐day feeding trial was conducted to determine the effects of supplementing diets of juvenile Japanese flounder, Paralichthys olivaceus, with Eucheuma denticulatum (EDP). Isonitrogenous and isolipidic test diets were prepared using a fishmeal‐based positive control diet (PC) and a fishmeal‐soy protein concentrate negative control diet (NC) supplemented with 3 (D3%), 6 (D6%) and 9% (D9%) EDP. The test diets were assigned to tanks (12 fish tank−1, initial mean body weight of 0.42 ± 0.01 g) in triplicates. Results of the feeding trial indicated that growth rates and feed efficiency significantly improved (P P P P Keywords: Eucheuma denticulatum; Paralichthys olivaceus; blood chemistry; carcass composition; growth performance Document Type: Research Article DOI: http://dx.doi.org/10.1111/are.12211 Publication date: March 1, 2015 (document).ready(function() { var shortdescription = (".originaldescription").text().replace(/\\&/g, '&').replace(/\\, '<').replace(/\\>/g, '>').replace(/\\t/g, ' ').replace(/\\n/g, ''); if (shortdescription.length > 350){ shortdescription = "" + shortdescription.substring(0,250) + "... more"; } (".shortdescription a").click(function() { (".originaldescription").slideDown(); return false; }); }); Related content In this: publication By this: publisher In this Subject: Aquaculture & Fisheries By this author: Ragaza, Janice Alano ; Koshio, Shunsuke ; Mamauag, Roger Edward ; Ishikawa, Manabu ; Yokoyama, Saichiro ; Villamor, Shiela S GA_googleFillSlot("Horizontal_banner_bottom");
The water extracts from red seaweeds Laurencia obtusa and Laurencia filiformis comprise complex sulfated agarans. Those from L. obtusa have 3-linked β-d-galactose units in part sulfated on 2-position or methylated on 6-position, while the 4-linked units are mostly 3,6-anhydro-α-l-galactose and α-l-galactose 6-sulfate, some of the latter units are substituted with β-d-xylose on 3-position, precluding alkaline cyclization. The 3-linked β-d-galactose units of the agarans from L. filiformis are mostly sulfated on 2-position, but approximately half of these residues also carry the 4,6-O-(1-carboxyethylidene) group. The 4-linked 3,6-anhydro-α-l-galactose units are methylated or substituted in part with single stubs of β-d-xylose on 2-position. This is the first time that substitution with xylose of 3,6-anhydro-α-l-galactose is reported. Besides, α-l-galactose 2-sulfate carrying single stubs of β-d-xylose on 3-position was also detected. These galactans have some common structural characteristics with those of other species of this genus, but also others that are specific for these species.
A checklist of 1058 species of benthic marine algae has been compiled for the tropical and subtropical W Atlantic, covering the region from North Carolina through S Brazil. This list comprises 655 species of Rhodophyceae, 150 of Phaeophyceae, and 253 of Chlorophyceae. -from Author
In the past, ecophysiologically oriented photosynthesis research has been governed by gas-exchange measurements, mainly involving sophisticated (and costly) systems for simultaneous detection of CO2 uptake and H2O evaporation (see, e.g., Field et al. 1989). With the help of these methods, fundamental knowledge on in situ photosynthesis has been gained. Only recently, progress has been made in the development of alternative practical methods for nonintrusive assessment of in vivo photosynthesis which have the potential of not only evaluating overall quantum yield and capacity, but also allowing insights into the biochemical partial reactions and the partitioning of excitation energy (see, e.g., Snel and van Kooten 1990). As a consequence, photosynthesis research at the level of regulatory processes has been greatly stimulated, leading to important new concepts (see reviews by Foyer et al. 1990; Demmig-Adams 1990; Melis 1991; Allen 1992). In particular, chlorophyll fluorescence has evolved as a very useful and informative indicator for photosynthetic electron transport in intact leaves, algae, and isolated chloroplasts (reviews by Briantais et al. 1986; Renger and Schreiber 1986; Schreiber and Bilger 1987, 1992; Krause and Weis 1991; Karukstis 1991).
A male gametophyte of the endemic Antarctic red macroalga Palmaria decipiens (Reinsch) Ricker was cultivated under fluctuating daylengths, simulating the seasonal changes at the site of collection (King George Island, Antarctica). The plant was maintained at 0±1 C, an irradiance of 25 μmol m-2 s-1 and under growth-saturating nutrient conditions. Samples were taken at intervals of 3 6 weeks to measure growth, photosynthesis, dark respiration and pigment content. The growth optimum in spring coincided with a higher photosynthetic activity. Whereas dark respiration was constantly low over the year, there was a rapid increase in maximum photosynthetic rate (P(max)) in conditions corresponding to September and October. This was correlated with a change in the initial slope (α) of the photosynthesis versus irradiance (P vs 1) curve. Higher activity in photosynthesis mainly resulted from higher Chl a and phycobilin concentrations during Antarctic spring, an indication of an increase in absorption cross-section areas of photosynthetic reaction centres. These changes in physiology are discussed in relation to the seasonal growth 'strategy' of the species, which is controlled by seasonal variation in daylength.
Nutrient and photon fluence effects were tested to determine if high and low light characteristics of red and green pigmented forms of the Philippine red seaweed, Eucheuma denticulatum would show acclimation in the laboratory. Cultivars of E, denticulatum? that had been in culture in the laboratory for three years were used. Branches were grown under 10 and 100 mu mol photons m(-2) s(-1) using high (7 days ESS media every other week) and low enrichment (4 h ESS media wk(-1)) in a factorial experiment. The red form showed significant increases in growth, concentrations of chlorophyll a and phycoerythrin, and shifts in photosynthetic parameters (P-max, I-c, I-k, alpha) when grown under low photon fluence and high levels of nutrients. The green form showed mixed responses indicating limitations of this strain to further acclimation to low light conditions. The study demonstrates that photosynthetic responses can be modified with nutrients and light within the physiological limitations set by high and low light-adapted forms.
A new empirical equation is introduced that describes the photosynthesis by phytoplankton as a single, continuous function of available light from the initial linear response through the photoinhibited range at the highest levels liable to be encountered under any natural conditions. The properties of the curve are derived, and a procedure is given for fitting it to the results of light-saturation experiments for phytoplankton. The versatility of the equation is illustrated by data collected on natural phytoplankton assemblages from the eastern Canadian arctic and from the continental shelves of Nova Scotia and Peru.
All available action spectra of photosynthesis for benthic marine algae have been multiplied by the spectral distribution of the light at different depths in all Jerlov water types to predict the photosynthesis per unit quantum irradiance of each species in each habitat. Comparison of the predictions indicates that red algae are best adapted chromatically to photosynthesize at all depths (including 0 m) in all except the clearest oceanic waters. The results show little correlation with the patterns of vertical distribution of green, brown, and red algae in benthic marine habitats, and suggest, therefore, that light quality is not a major factor in the control of that distribution. A review of physiological evidence supports the hypothesis that the changes in pigment composition that are observed with increasing depth in marine algae are largely adaptations to low irradiance, and not to the spectral composition of underwater light.
The qualitative and quantitative occurrence of low molecular weight carbohydrates (LMWCs) in the Bangiophyceae is surveyed. Members of the orders Erythropeltidales (Sahlingia and Erythrotrichia), Compsopogonales (Compsopogon), and Bangiales (Bangia and Porphyra) all contain floridoside and, in some cases, D- and L-isofloridoside, making the group chemotaxonomically the most homogeneous; L-isofloridoside occurred only in the Bangiales. The Porphyridiales showed great variation in carbohydrate types: Chroodactylon contained only sorbitol, Porphyridium contained only floridoside, Dixoniella and Rhodella species exhibited only mannitol, and Rhodosorus showed digeneaside and sorbitol, whereas Stylonema contained floridoside, D-isofloridoside, digeneaside, and sorbitol. The extensive variation in LMWC composition within and between the different orders suggests that the enzyme systems for each might have developed repeatedly in different Bangiophyceae and Florideophyceae. Nonetheless, a phylogenetic tree based on small-subunit ribosomal RNA supports the LMWC patterns in the Bangiophyceae.