Farming and hatchery for the edible seaweed Gracilaria. Also known as limu, this seaweed is the most popular edible seaweed in Hawaii and most commonly used in poke.
Digital library
-
-
A protein extract from the brown seaweed Himanthalia elongata (Linnaeus) S. F. Gray was prepared and its func- tional properties, colour and amino acid composition were assessed for its potential future use by the food indus- try. The total content of amino acids was determined as 54.02 ± 0.46 g amino acids/kg dry weight, with high levels of the essential amino acids lysine and methionine. SDS-PAGE showed 5 protein bands with molecular weights of 71.6, 53.7, 43.3, 36.4 and 27.1 kDa. The water holding capacity and oil holding capacity were deter- mined as 10.27 ± 0.09 g H2O/g and 8.1 ± 0.07 g oil/g respectively. Foaming activity and stability were higher at alkaline pH values. The emulsifying capacity and stability of the extract varied depending on the pH and oil used. These results demonstrate the potential use of Himanthalia elongata protein extract in the food industry.
-
The fatty acid (FA) compositions of ten seaweeds representative of Chlorophyta, Rhodophyta, and Ochrophyta from Kuwait in the Arabian Gulf region were determined and are discussed in the context of their potential nutritional perspectives for seaweed valorization. All the seaweeds had higher saturated fatty acid (SFA) and lower monounsaturated (MUFA) and polyunsaturated fatty acid (PUFA) contents than those typical of tropical environments. Palmitic, myristic, stearic, oleic, linoleic, α-linolenic, and stearidonic acids were the major FAs detected. Arachidonic, eicosapentaenoic, and docosahexaenoic acids were detected in minor amounts. Conserved fatty acid patterns revealed phylogenetic relationships among phyla, classes, and orders matching the molecular phylogenies at higher taxonomic ranks. Hierarchical clustering analyses clearly segregated different seaweeds (except Codium papillatum and Iyengaria stellata) into distinct groups based on their FA signatures. All but one species (Chondria sp.) had health-beneficial n6/n3 PUFAs (0.33:1–2.94:1) and atherogenic (0.80–2.52) and thrombogenic indices (0.61–5.17). However, low PUFA/SFA contents in most of the species (except Ulva spp.) may limit their utilization in the formulation of PUFA-rich functional foods. Ulva spp. had substantially high PUFAs with PUFA/SFA > 0.4, n6/n3 (0.33–0.66) and atherogenic (0.80–1.15) and thrombogenic indices (0.49–0.72), providing substantial potential for their utilization in food and feed applications.
-
Differences in ash behavior during hydrothermal treatment were identified based on multivariate data analysis of literature information on 29 different feedstock. In addition, the solubility of individual ele- ments was evaluated based on a smaller data set. As a result two different groups were distinguished based on char ash content and ash yield. Virgin terrestrial and aquatic biomass, such as different types of wood and algae, in addition to herbaceous and agricultural biomass, bark, brewer’s spent grain, com- post and faecal waste showed lower char ash content than municipal solid wastes, anaerobic digestion residues and municipal and industrial sludge. Lower char ash content also correlated with lower ash yield indicating differences in chemical composition and ash solubility. Further evaluation of available data showed that ash in industrial sludge mainly contained anthropogenic Al, Fe and P or Ca and Si with low solubility during hydrothermal treatment. Char from corn stover, miscanthus, switch grass, rice hulls, olive, artichoke and orange wastes and empty fruit bunch had generally higher contents of K, Mg, S and Si than industrial sludge although differences existed within the group. In the future information on ash behavior should be used for enhancing the fuel properties of char based on feedstock type and hydrother- mal treatment conditions.
-
Giant kelp (aka macro algae) are among the most prolific producers of biomass, growing in enormous underwater forests up and down the west coast of North America. For years kelp have been eyed as a source of biofuels. On November 24, 2015, one San Diego company received an award from the Department of Energy’s (DOE) Advanced Research Projects Agency-Energy (ARPA-E) to give their unique cultivation technology a run at producing biocrude from seaweed.
-
Green seaweeds of the genus Ulva are rich in the bioactive sulfated polysaccharide ulvan. Herein we characterise ulvan from Ulva species collected from the Bay of Plenty, Aotearoa New Zealand. Using standardised procedures, we quantified, characterised, and compared ulvans from blade (U. australis, U. rigida, U. sp. B, and Ulva sp.) and filamentous (U. flexuosa, U. compressa, U. prolifera, and U. ralfsii) Ulva species. There were distinct differences in composition and structure of ulvans between morphologies. Ulvan isolated from blade species had higher yields (14.0–19.3 %) and iduronic acid content (IdoA = 7− 18 mol%), and lower molecular weight (Mw = 190− 254 kDa) and storage moduli (G’ = 0.1–6.6 Pa) than filamentous species (yield = 7.2–14.6 %; IdoA = 4− 7 mol%; Mw = 260− 406 kDa; G’ = 22.7–74.2 Pa). These results highlight the variability of the physicochemical properties of ulvan from different Ulva sources, and identifies a morphology-based division within the genus Ulva.
-
This overview examines the status and trends of seafood production, and the positive and negative impacts of aquaculture on biodiversity conservation. Capture fisheries have been stabilized at about 90 million metric tons since the late 1980s, whereas aquaculture increased from 12 metric tons in 1985 to 45 metric tons by 2004. Aquaculture includes species at any trophic level that are grown for domestic consumption or export.
Aquaculture has some positive impacts on biodiversity; for example, cultured seafood can reduce pressure on overexploited wild stocks, stocked organisms may enhance depleted stocks, aquaculture often boosts natural production and species diversity, and employment in aquaculture may replace more destructive resource uses. On the negative side, species that escape from aquaculture can become invasive in areas where they are nonnative, effluents from aquaculture can cause eutrophication, ecologically sensitive land may be converted for aquaculture use, aquaculture species may consume increasingly scarce fish meal, and aquaculture species may transmit diseases to wild fish. Most likely, aquaculture will continue to grow at significant rates through 2025, and will remain the most rapidly increasing food production system.
-
In the past two decades, there has been much debate amongst industry, the state development agencies and the research institutions about the potential of the Irish seaweed sector. Seaweed gathering and processing is a traditional activity in Ireland bringing economic activity and employment to coastal communities. Ireland’s seaweed and biotechnology sector is currently worth €18 million per annum and employs 185 full time equivalent people (Morrissey et al., 2011). The potential to increase employment, exports and wealth from seaweed in Ireland was looked at by the National Seaweed Forum which was established in 1999 to join industry with research bodies, state agencies and departments to make recommendations for the future development of the industry.
One such recommendation was the development of seaweed cultivation. With this in mind, groups such as Bord Iascaigh Mhara (BIM), Taighde Mara Teo (TMT), National University Ireland Galway (NUIG) and Queen’s University Belfast (QUB) initiated seaweed cultivation trials. These early trials had varied success and allowed for experimentation and year-on-year technique improvement. Farming seaweed as opposed to simply gathering seaweed requires a thorough knowledge of seaweeds and perfect manipulation of the seaweed life cycle. Mastering this has concerned Irish seaweed researchers and industry practitioners alike over the last decade.
The Seaweed Hatchery project has focused on developing new techniques, and improving existing knowledge of seaweed cultivation. This manual is one such output of the project. The manual is offered to the industry as a guide to the hatchery techniques required to develop new aquaculture opportunities for Laminaria digitata.
As with all BIM ‘Aquaculture Explained’ manuals, it is based on the research and experiences of the group and includes both hatchery and sea trial cultivation results obtained over several years and sites. An attempt has been made to provide an easy to use document filled with practical advice for those interested in growing kelp.
-
Fucan is a term used to denominate a type of polysaccharide which contains substantial percentages of l-fucose and sulfate ester groups. We obtained five heterofucans from Sargassum filipendula by proteolytic digestion followed by sequential acetone precipitation. These heterofucans are composed mainly of fucose, glucose, glucuronic acid, galactose and sulfate. These fucans did not show anticoagulant activity in PT and aPTT tests. Their antioxidant activity was evaluated using the follow tests; total antioxidant capacity, scavenging hydroxyl and superoxide radicals, reducing power and ferrous ion [Fe(II)] chelating. All heterofucans displayed considerable activity, especially SF-1.0v which showed the most significant antioxidant potential with 90.7 ascorbic acid equivalents in a total antioxidant capacity test and similar activity when compared with vitamin C in a reducing power assay. The fucan antiproliferative activity was performed with HeLa, PC3 and HepG2 cells using MTT test. In all tested conditions the heterofucans exhibited a dose-dependent effect. The strongest inhibition was observed in HeLa cells, where SF-1.0 and SF-1.5 exhibited considerable activity with an IC50 value of 15.69 and 13.83 μM, respectively. These results clearly indicate the beneficial effect of S. filipendula polysaccharides as antiproliferative and antioxidant. Further purification steps and additional studies on structural features as well as in vivo experiments are needed to test the viability of their use as therapeutic agents.
-
The potential of algal biomass as a source of liquid and gaseous biofuels is a highly topical theme, with over 70 years of sometimes intensive research, and considerable financial investment. A wide range of unit operations can be combined to produce algal biofuel, but as yet there is no successful commercial system producing such biofuel. This suggests that there are major technical and engineering difficulties to be resolved before economically viable algal biofuel production can be achieved.
Both gasification and anaerobic digestion have been suggested as promising methods for exploiting bioenergy from biomass and 2 major projects have been funded in the UK on the gasification and anaerobic digestion of seaweed, MacroBioCrude and SeaGas.
Pages
Marine Agronomy Group, CAFNRM, UH-Hilo
200 W. Kawili st., HI 96720, USA
Contact: Marine.Agronomy.Group@gmail.com
Funding for this web portal is provided by the World Wildlife Fund and the University of Hawaii-Hilo.