Digital library

  • The nutritional value of six tropical seaweeds (Sargassum wightii, Ulva lactuca, Kappaphycus alvarezii, Hypnea musciformis, Acanthophora spicifera and Gracilaria corticata) as complementary source of dietary proteins for human and animal nutrition based on amino acid profile was evaluated. All these species showed similar non-essential amino acid patterns in which aspartic and glutamic acids constituted together a large part of the amino acid fraction (25.2% to 29.5%). Among these, Hypnea musciformis possessed higher amino acid content and better amino acid profile and all of them were generally rich in phenylalanine, tyrosine, threonine and tryptophan and deficient in methionine, cysteine, leucine and lysine. Except U. lactuca all others showed a balanced amino acid profile comparable to FAO reference pattern. Seaweeds being rich in minerals, vitamins, polyunsaturated fatty acids as well as phycocolloids, partial substitution of costly protein sources in animal feeds with seaweed protein may improve feed quality while reducing the cost.

    Author(s): Vinoj Kumar, V, Kaladharan, P
  • Prospecting macroalgae (seaweeds) as feedstocks for bioconversion into biofuels and commodity chemical compounds is limited primarily by the availability of tractable microorganisms that can metabolize alginate polysaccharides. Here, we present the discovery of a 36–kilo–base pair DNA fragment from Vibrio splendidus encoding enzymes for alginate transport and metabolism.

    The genomic integration of this ensemble, together with an engineered system for extracellular alginate depolymerization, generated a microbial platform that can simultaneously degrade, uptake, and metabolize alginate. When further engineered for ethanol synthesis, this platform enables bioethanol production directly from macroalgae via a consolidated process, achieving a titer of 4.7% volume/volume and a yield of 0.281 weight ethanol/weight dry macroalgae (equivalent to ~80% of the maximum theoretical yield from the sugar composition in macroalgae).

    Author(s): Adam J. Wargacki, Effendi Leonard, Maung Nyan Win, Drew D. Regitsky, Christine Nicole S. Santos, Peter B. Kim, Susan R. Cooper, Ryan M. Raisner, Asael Herman, Alicia B. Sivitz, Arun Lakshmanaswamy, Yuki Kashiyama, David Baker, Yasuo Yoshikuni
  • Seaplants (a better alternative to the misnomer “Seaweeds”), by all means, are “future plants”; they have been projected as the future viand for ever-increasing human populations, viable and sustainable source for biofuel without disturbing global food scenario, as potential candidates for carbon capture and sequestration that is considered as a practical remedy for global warming, and they have a number of pharmaceutical, industrial and biotechnological applications. However, information on its cultivation methods or life history remain obscure to a majority of marine botanists. While life histories of seaweeds have traditionally been an exotic topic for specialists-language of which is ciphered with scientific jargons incomprehensible to general scientific audience, its agronomy had been a trade secret for coastal communities in East Asian countries, especially Japan, the Philippines and Indonesia. In this up-to-date illustrated review, current scientific understanding on the life-histories of agronomically pertinent seaweeds are presented in a fashion akin to popular science journalism with an overview of major coastal and offshore seaweed mariculture techniques, presented with the aid of clear-tounderstand illustrations. Also discussed in this report are recent advances in the algal natural products; including uses in hydrocolloid and pharmaceutical industries, Integrated Multi Trophic Aquaculture, energy production, environmental impacts of the seafarming and its counter measures, before concluding with an overview of future research avenues.

  • A PDF of a demonstration project on "An Integrated System to Produce Food, Fuel, Energy in Hawai'i".

    Author(s): Bob Shleser
  • The Farm Aquaculture Resource Management (FARM) model has been applied to several shellfish species and aquaculture types. The performance of the FARM model, developed to simulate potential harvest, key financial data, and water quality impacts at the farm-scale, was tested in five systems in the European Union: Loch Creran, Scotland (Pacific oyster), Pertuis Breton, France (blue mussel), Bay of Piran, Slovenia (Mediterranean mussel), Chioggia, Italy (Mediterranean mussel) and Ria Formosa, Portugal (Manila clam). These systems range from open coasts to estuaries, and are used for shellfish aquaculture by means of different cultivation techniques (e.g. oyster bottom culture in Loch Creran and mussel longlines and poles in Pertuis Breton). The drivers for the FARM model were supplied by measured data, outputs of system–scale models or a combination of both.

    The results (given in total fresh weight) generally show good agreement with reported annual production (shown in brackets) at each farm: simulated production of 134 t of Pacific oyster in Loch Creran (150 t, −10%), 2691 t of blue mussel in Pertuis Breton (2304 t, +17%), 314 t of Mediterranean mussel in the Bay of Piran (200 t, +57%), 545 t of Mediterranean mussel in Chioggia (660 t, −17%) and 119 t of Manila clam in Ria Formosa (104 t, +15%). The nitrogen mass balance for each farm was also determined with the FARM model. The net removal of nitrogen (N) by the farms was estimated to correspond to 1151 population equivalents per year (PEQ y−1) in Loch Creran, 39505 PEQ y−1 in Pertuis Breton, 210 PEQ y−1 in the Bay of Piran, 7108 PEQ y−1 in Chioggia and 8748 PEQ y−1 in Ria Formosa. The aggregate income due to both the shellfish sale and substitution value of land-based fertilizer reduction or nutrient treatment was estimated to be about 680 k€ y−1 in Loch Creran, 14930 k€ y−1 in Pertuis Breton, 220 k€ y−1 in the Bay of Piran, 2560 k€ y−1 in Chioggia, and 5040 k€ y−1 in Ria Formosa. Outputs of FARM may be used to analyse the farm production potential and profit maximization according to seeding densities and/or spatial distribution. Results of a marginal analysis for all the study sites were determined. As an example, profit maximization in Loch Creran was obtained with 97 t of seed, resulting in a total production of 440 t (profit of 2100 k€ for a culture period of about 2 years). FARM additionally integrates the well-known ASSETS model, for assessment of farm-related eutrophication impacts. The assessment results for the five study sites show that water quality is either maintained or improved in all farms under standard conditions of culture practice.

    FARM results may be used by farmers to analyse farm production potential and by managers for environmental assessment of farm-related water quality impacts, whether positive or negative. It is a useful tool for all stakeholders for the valuation of nitrogen credits, which may be traded as part of an integrated catchment management plan.

    Author(s): J.G. Ferreira, A. Sequeira, A.J.S. Hawkins, A. Newton, T.D. Nickell, R. Pastres, J. Forte, A. Bodoy, S.B. Bricker
  • Aqueous extract of seven species of marine macroalgae were screened for their antimicrobial potency against ten pathogenic bacterial strains. Ulva fasciata, Gracilaria corticata, Sargassum wightii and Padina tetrastromatica showed significantly higher activity against 70% of the tested bacterial isolates. The maximum zone of inhibition was noted for the red alga G.corticata against Proteus mirabilis (17mm) and brown alga P. tetrastromatica against the pathogens Staphylococcus aureus and Vibrio harveyi (15mm). The general trend of inhibitory activity was higher towards Gram negative bacteria.

    Author(s): Christabell, Jonsy , Lipton, A P , Aishwarya, M S , Sarika, A R, Udayakumar, A
  • Marine algae are known to contain a wide variety of bioactive compounds, many of which have commercial applications in pharmaceutical, medical, cosmetic, nutraceutical, food and agricultural industries. Natural antioxidants, found in many algae, are important bioactive compounds that play an important role against various diseases and ageing processes through protection of cells from oxidative damage. In this respect, relatively little is known about the bioactivity of Hawaiian algae that could be a potential natural source of such antioxidants. The total antioxidant activity of organic extracts of 37 algal samples, comprising of 30 species of Hawaiian algae from 27 different genera was determined.

    The activity was determined by employing the FRAP (Ferric Reducing Antioxidant Power) assays. Of the algae tested, the extract of Turbinaria ornata was found to be the most active. Bioassay-guided fractionation of this extract led to the isolation of a variety of different carotenoids as the active principles. The major bioactive antioxidant compound was identified as the carotenoid fucoxanthin. These results show, for the first time, that numerous Hawaiian algae exhibit significant antioxidant activity, a property that could lead to their application in one of many useful healthcare or related products as well as in chemoprevention of a variety of diseases including cancer.

    Author(s): Dovi Kelman, Ellen Kromkowski Posner, Karla J. McDermid, Nicole K. Tabandera, Patrick R. Wright, Anthony D. Wright
  • The underlying physiology of algal antioxidant compounds is reviewed in the context of seaweed biology and utilization. The application of seaweed antioxidants in foods, food supplements, nutraceuticals and medicine is considered from the perspective of benefits to human health. We advocate that direct consumption of seaweed products for their antioxidant composition alone provides a useful alternative to non-natural substances, while simultaneously providing worthwhile nutritional benefits. Economic utilization of seaweeds for their antioxidant properties remains in its infancy. This review provides examples ranging from laboratory studies through to clinical trials where antioxidants derived from seaweeds may provide major health benefits that warrant subsequent investigative studies and possible utilization.

  • Discussion of Tyler Cowen's book, ‘The Great Stagnation’.


    Author(s): John Forster
  • Aquaculture is the fastest growing food production sector in the world and has come under increasing scrutiny and criticism because of coastal pollution. Effluents' from intensive farming contain much organic matter, nitrogen compounds, phosphorus and other nutrients, makes the water unfit for aquaculture and lead to eutrophication. Macroalgae plays a vital role in controlling toxic wastes to reasonable and cultivable limits and also improves water quality. Aquaculture - management can be done effectively by integrating seaweeds into aquaculture systems. This method can be done either by stocking seaweeds along with shrimp in optimum stocking density or by recycling the water through a pond supplemented with seaweeds. In the present study an attempt has been made to find out the species of seaweed suitable for integrated farming with shrimp in brackish water tide-fed system on southwest coast and sea water in pump-fed system on southeast coast of India.

    The removal of nitrogenous compounds such as ammonia, nitrate, nitrite and total nitrogen was found to be 65 to 82%, 34 to 53%, 28 to 77% and 53 to 60% respectively by seaweeds in the treatment ponds inrhen compared to the control ponds. The species of Gracilaria verrucosa, proved to be an ideal seaweed for integrated farming with shrimp in the brackishwater ponds and post monsoon period is the most favourable period for integrated farming as the growth performance of seaweed and shrimp were found to be more than the monsoon period in the tide-fed system of southeast coast of India. Eventhough the accumulation of toxic waste was less compared to southwest coast, the growth rate was comparatively lower in sea water system of southeast coast of India. G. verrucosa integrated with Enteromorpha intestinalis in optimum stocking density can reduce stress on shrimp by utilizing excess nitrogenous wastes either through bacterial mineralization or direct use by seaweeds.

    In the Present context, luxuriant growth of G. verrucosa in the first year of experiment leading to harvest of 880kg was due to the heavy amount of nutrient loaded in the Pond for age long aquaculture activity, which enabled the proliferation of algal growth and maximum removal of nitrogenous load from the system. It was also observed that growth of alga in the pond was able to minimize the disease problems in shrimp.

    Author(s): Seema, C