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  • In the Hawaiian Islands, many species of marine macroalgae are eaten by people, as well as by many marine herbivores, notably Hawaiian green sea turtles. The total dietary fiber (TDF) content, which may affect the palatability, digestibility, and nutritional value of seaweed, was determined for 26 species (15 Rhodophyta, 5 Phaeophyta, and 6 Chlorophyta) using an enzymaticgravimetric procedure.

    The highest TDF (dry weight) values were found in the following three native Hawaiian species: Ahnfeltiopsis concinna 59.8%, Gayralia oxysperma 55.8%, and Sargassum obtusifollium 53.7%. Codium reediae contained the lowest amount of TDF (23.5% dry weight). Thirteen species contained more TDF than wheat bran.

    Author(s): Karla J. McDermid, Brooke Stuercke, Owen J. Haleakala
  • 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 g1 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 g1 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.

    Author(s): Bjorn J. Gosch, Marie Magnusson, Nicholas A. Paul, Rocky de Nys
  • With the increase in the world’s population, demand for food and other products is continuously rising. This has put a lot of pressure on the agricultural sector. To fulfill these demands, the utilization of chemical fertilizers and pesticides has also increased. Consequently, to overcome the adverse effects of agrochemicals on our environment and health, there has been a shift towards organic fertilizers or other substitutes, which are ecofriendly and help to maintain a sustainable environment. Microalgae have a very high potential of carbon dioxide (CO2) capturing and thus, help in mitigating the greenhouse effect. It is the most productive biological system for generating biomass. The high growth rate and higher photosynthetic efficiency of the algal species compared to the terrestrial plants make them a wonderful alternative towards a sustainable environment. Moreover, they could be cultivated in photobioreactors or open ponds, which in turn reduce the demand for arable land. Biochar derived from algae is high in nutrients and exhibits the property of ion exchange. Therefore, it can be utilized for sustainable agriculture by partial substituting the chemical fertilizers that degrade the fertility of the soil in the long run. This review provides a detailed insight on the properties of algal biochar as a potential fertilizer for sustainable agriculture. Application of algal biochar in bio-refinery and its economic aspects, challenges faced and future perspective are also discusses in this study. 

    Author(s): Sharma Mona, Sandeep K. Malyan, Neha Saini, Bansal Deepak, Arivalagan Pugazhendhi, Smita S. Kumar
  • In 2008, Qingdao (36-060 N, 120-250 E, PR China) experienced the world largest drifting macroalgal bloom composed of the filamentous macroalga Ulva prolifera. No convincing biologic evidence regarding the algal source is available so far. A series of field collections of both Ulva sp. and waters in various sites along Jiangsu coasts were conducted in March to May of 2009. Density of microscopic Ulva germlings in the waters sampled from different sites ranged from 7 to 3140 individuals L1 , indicating the wide-spreading and long-term existence of the algae in the investigated region. Morphological and the nuclear ribosomal internal transcribed spacer ITS nrDNA and the chloroplast-encoded rbcL gene comparisons of 26 algal samples revealed that the algae collected from land-based animal aquaculture ponds mostly resembled the dominating blooming alga in 2008. Mismatch of Porphyra farming period with the occurrence of the green tide bloom, as well as the negative identification results of the sampled green algae from the Porphyra rafts eliminated Porphyra rafts as the principal and original source of the dominating blooming alga

    Author(s): Shao Jun Pang, Feng Liu, Ti Feng Shan, Na Xu , Zhi Huai Zhang, Su Qin Gao, Thierry Chopin, Song Sun
  • In 2008, Qingdao (36 degrees 06'N, 120 degrees 25'E, PR China) experienced the world largest drifting macroalgal bloom composed of the filamentous macroalga Ulva prolifera. No convincing biologic evidence regarding the algal source is available so far. A series of field collections of both Ulva sp. and waters in various sites along Jiangsu coasts were conducted in March to May of 2009. Density of microscopic Ulva germlings in the waters sampled from different sites ranged from 7 to 3140 individuals L(-1), indicating the wide-spreading and long-term existence of the algae in the investigated region. Morphological and the nuclear ribosomal internal transcribed spacer ITS nrDNA and the chloroplast-encoded rbcL gene comparisons of 26 algal samples revealed that the algae collected from land-based animal aquaculture ponds mostly resembled the dominating blooming alga in 2008. Mismatch of Porphyra farming period with the occurrence of the green tide bloom, as well as the negative identification results of the sampled green algae from the Porphyra rafts eliminated Porphyra rafts as the principal and original source of the dominating blooming alga.

    Author(s): Shao Jun Pang, Feng Liu, Ti Feng Shan, Na Xu , Zhi Huai Zhang, Su Qin Gao, Thierry Chopin, Song Sun
  • Integrated Multi-Trophic Aquaculture (IMTA) systems are designed to mitigate the environmental problems caused by several forms of fed aquaculture. Gracilaria chilensis is commercially cultivated in Chile and experimental studies recommend it as an efficient biofilter in IMTA systems. Traditional bottom culture Gracilaria farms face production problems mainly related to the cultivation system and seasonal changes in nitrogen availability and irradiance. IMTA may offer a solution to some of these problems.

    This study intended to investigate the productivity of G. chilensis near salmon farms and assess its nitrogen removal and photosynthetic performance. The most appropriate cultivation methodologies (i.e. floating long-lines vs. bottom cultivation) for Gracilaria production were also evaluated. During austral summer and autumn, 3 long-line cultivation units were set at different distances from a salmon farm, one of them being away from the influence of salmonid aquaculture. Additionally, a similar cultivation unit was installed as a traditional bottom culture.

    Gracilaria growth performance was always higher on the suspended cultures near the salmon cages. Summerdaily mean growth rates at those sites reached 4% (±0.29) with a mean biomass production of over 1600 gm−2 month−1(±290) which was double the unimpacted site. The productivity of bottom cultured Gracilaria was highly reduced by biomass losses. N removal and photosynthetic performances provided possible explanations for the differences found. The long-line cultivation unit proved to be the most efficient technology for nutrient removal with monthly removal of up to 9.3 g (±1.6) N per meter of long-line.

    The proximity to the salmon farm also mitigated the decrease in photosynthetic activity after the midday irradiance peak. G. chilensis at those sites maintained daily average values of ΦPSII around 0.6 and rETR close to 40 μmol e− m−2 s−1. Fv/Fm values (0.6) were similar at all cultivation areas. Our results clearly indicated the advantages of integrating G. chilensis aquaculture with salmon farms. Within the IMTA system, the productivity and physiological performance of G. chilensis  ere greatly improved and this seaweed's biofiltration efficacy was confirmed. We suggest that a 100 ha G. chilensis long-line systemwill effectively (ca. 100%) reduce the N inputs of a 1500 tonnes salmon farm.

    Author(s): Maria H. Abreu, Daniel A. Varela, Luis Henríquez, Adrián Villarroel, Charles Yarish, Isabel Sousa-Pinto, Alejandro H. Buschmann
  • Gracilaria is a group of warm water seaweeds. There are more than one hundred species in the world, some of which have very important economic value. Gracilaria is used as food and in the preparation of food products. It is also an important raw material in agar-agar production. At present, the world's annual output of Gracilaria is about 30,000 tons, dry weight, most of which comes from natural production. For example, the natural production in Chile, Argentina, and Brazil accounts for one third of this total output. With the increasing demand for Gracilaria, greater attention has been focused on the development of its artificial culture by many countries, especially those in Southeast Asia. China is the earliest country that artificially cultured Gracilaria. Today, the culture area in South China is about 2,000 ha producing 3,000 tons dried material annually. Taiwan produces 1,000 tons dried Gracilaria yearly from 400 hectares under cultivation.

    Nowadays, Gracilaria is cultured mainly using the following methods: bottom culture, raft culture, stake-rope culture and pond culture. Pond culture can be divided into two systems, monoculture and polyculture with shrimp and other species. The varieties of culture methods can be adapted for different areas.

    In view of the importance of Gracilaria as a seafarming commodity, the National Coordinators of the Regional Seafarming Project recommended the dissemination of its culture and processing technology, through a regional training and demonstration activity, as a means to further increase the opportunities to develop the seafarming industry of the region.

    This manual has been prepared for the training course on Gracilaria culture under the Regional Seafarming Development and Demonstration Project (RAS/90/002) to be held at Zhanjiang Fisheries College, Zhanjiang, China in August, 1990. The training course includes processing of seaweeds, thus the manual devotes a chapter on the properties, manufacture and application of agar, algin and carragenan.

    The manual was edited by Professor Wu Chaoyuan who also reviewed all the manuscripts, Professor Ji Minghuo, Mrs. Li Renzhi, Associate Professor and Mr. Wang Xiaohang, Associate Professor, all of the Institute of Oceanology in Qingdao; Professor Liu Sijian of the Zhenjiang Fisheries College; and Mr. Miao Zenian, Associate Professor of the Yellow Sea Fisheries Research Institute, Qingdao. Mr. Sun Jimin of the Yellow Sea Fisheries Research Institute computer-processed the text and images. The staff of the Seafarming Development Project in Bangkok provided the final editing and prepared the manual for publication.

    We would like to acknowledge the support of the Intergovernmental Network of Aquaculture Centres in Asia and the Pacific (NACA), the Institute of Oceanology of Academia Sinica, the Yellow Sea Fisheries Research Institute under the Chinese Academy of Fishery Sciences, and the Zhanjiang Fisheries College in the organization and implementation of the training course including the development and publication of this manu

    Author(s): Wu Chaoyuan , Ji Minghuo, Li Renzhi, Wang Xiaohang, Liu Sijian, Miao Zenian, Sun Jimin
  • With the objective of extending the methods of preparation of seaweed as food which can help to increase the income generating opportunities and nutrient consumption of fishermen, a three month training programme was conducted at Rameswaram for 30 fisher-women under the 'Training Rural Youth For Self Employment Scheme (TRYSEM)". This was conducted by the Centre For Women in Agriculture and Rural Development (CFWARD), a voluntary agency at Rameswaram in collaboration with CMFRl. The study was conducted aiming assessing the usefulness of the training in terms of knowledge gained, impressions of trciiness and constraints involved in the utilization of the knowledge

    Author(s): Immanuel, Sheela
  • Background: We have previously shown that lipophilic components (LPC) of the brown seaweed Ascophyllum nodosum (ANE) improved freezing tolerance in Arabidopsis thaliana. However, the mechanism(s) of this induced freezing stress tolerance is largely unknown. Here, we investigated LPC induced changes in the transcriptome and metabolome of A. thaliana undergoing freezing stress.

    Results: Gene expression studies revealed that the accumulation of proline was mediated by an increase in the expression of the proline synthesis genes P5CS1 and P5CS2 and a marginal reduction in the expression of the proline dehydrogenase (ProDH) gene. Moreover, LPC application significantly increased the concentration of total soluble sugars in the cytosol in response to freezing stress. Arabidopsis sfr4 mutant plants, defective in the accumulation of free sugars, treated with LPC, exhibited freezing sensitivity similar to that of untreated controls. The 1H NMR metabolite profile of LPC-treated Arabidopsis plants exposed to freezing stress revealed a spectrum dominated by chemical shifts (δ) representing soluble sugars, sugar alcohols, organic acids and lipophilic components like fatty acids, as compared to control plants. Additionally, 2D NMR spectra suggested an increase in the degree of unsaturation of fatty acids in LPC treated plants under freezing stress. These results were supported by global transcriptome analysis. Transcriptome analysis revealed that LPC treatment altered the expression of 1113 genes (5%) in comparison with untreated plants. A total of 463 genes (2%) were up regulated while 650 genes (3%) were down regulated.

    Conclusion: Taken together, the results of the experiments presented in this paper provide evidence to support LPC mediated freezing tolerance enhancement through a combination of the priming of plants for the increased accumulation of osmoprotectants and alteration of cellular fatty acid composition.

    Author(s): Balakrishnan Prithiviraj, David Hiltz, Alan T Critchley, Mark D Hodges, Bernhard Benkel, Chris Kirby, Xiuhong Ji, Junzeng Zhang, Saveetha Kandasamy, Prasanth Nair
  • Seaweeds of the Laurencia genus have a broad geographic distribution and are largely recognized as important sources of secondary metabolites, mainly halogenated compounds exhibiting diverse potential pharmacological activities and relevant ecological role as anti-epibiosis. Host-microbe interaction is a driving force for co-evolution in the marine environment, but molecular studies of seaweed-associated microbial communities are still rare. Despite the large amount of research describing the chemical compositions of Laurencia species, the genetic knowledge regarding this genus is currently restricted to taxonomic markers and general genome features. In this work we analyze the transcriptomic profile of L. dendroidea J. Agardh, unveil the genes involved on the biosynthesis of terpenoid compounds in this seaweed and explore the interactions between this host and its associated microbiome. Results A total of 6 transcriptomes were obtained from specimens of L. dendroidea sampled in three different coastal locations of the Rio de Janeiro state. Functional annotations revealed predominantly basic cellular metabolic pathways. Bacteria was the dominant active group in the microbiome of L. dendroidea, standing out nitrogen fixing Cyanobacteria and aerobic heterotrophic Proteobacteria. The analysis of the relative contribution of each domain highlighted bacterial features related to glycolysis, lipid and polysaccharide breakdown, and also recognition of seaweed surface and establishment of biofilm. Eukaryotic transcripts, on the other hand, were associated with photosynthesis, synthesis of carbohydrate reserves, and defense mechanisms, including the biosynthesis of terpenoids through the mevalonate-independent pathway. Conclusions This work describes the first transcriptomic profile of the red seaweed L. dendroidea, increasing the knowledge about ESTs from the Florideophyceae algal class. Our data suggest an important role for L. dendroidea in the primary production of the holobiont and the role of Bacteria as consumers of organic matter and possibly also as nitrogen source. Furthermore, this seaweed expressed sequences related to terpene biosynthesis, including the complete mevalonate-independent pathway, which offers new possibilities for biotechnological applications using secondary metabolites from L. dendroidea.

    Author(s): Louisi Souza de Oliveira, Gustavo Bueno Gregoracci, Genivaldo Gueiros Zacarias Silva, Leonardo Tavares Salgado, Gilberto Amado Filho, Marcio Alves-Ferreira, Renato Crespo Pereira, Fabiano L Thompson

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