Since the establishment of abalone farming, there has been an increase in the demand for Macrocystis as a food source. Therefore, the pressure on natural stock has also augmented and the sustainability of the actual harvesting practices has been questioned. In this article, an attempt to farm Macrocystis pyrifera by zoospores in northern Chile is described; initially under laboratory conditions and subsequently by cultivation in the sea. The experiments were executed during 1 year and two different cultivation methodologies were used: a direct and an indirect method. A maximum frond length of 175 cm was reached and 22 kg m−1 of rope was produced after 120 to 150 days of cultivation in the sea. The algae grew under both methodologies, and no differences in algal length and biomass were detected between the two cultivation systems. However, the direct culture method can be recommended for productive and practical reasons.
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Macrocystis pyrifera (Giant Kelp), a dominant macroalgal species in southern California, produced I71 ng per g fresh wt (gfwt) per day of CHBr, and 48 ng gfwt-' d-' of CH,Br, during laboratory incubations of whole blades. Comparable rates were measured during in situ incubations 01 intact fronds. Release of CHBr, and CH,Br, by M. pyr$eru was affected by light and algal photosynthetic activity, suggesting that environmental factors influencing kelp physiology can affect halomethane release to the atmosphere. Data from H,O, additions suggest that brominated methane production during darkness is limited by bromide oxidant supply. A bromine budget constructed for a region of southern California indicated that bromine emitted from the use of CH,Br as a fumigant (1 X 1 Ox g BI yr -I) dominates macroalgal sources (3 X 10" g Br yr-I). Global projections, however, suggest that combined emissions of marine algae (including microalgac) contribute substantial amounts of bromine to the global cycle, perhaps on the same order of magnitude as anthropogenic sources.
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Data on fractionation and depolymerization of the matrix ulvan polysaccharides, and studies on the biological activities on skin cells, are very scarce. In this work, crude ulvans were produced by using EAE (enzyme-assisted extraction) and compared to maceration (an established procedure). After different fractionation procedures—ethanolic precipitation, dialysis, or ammonium sulfate precipitation—the biochemical composition showed that EAE led to an increased content in ulvans. Coupling EAE to sulfate ammonium precipitation led to protein enrichment. Oligosaccharides were obtained by using radical depolymerization by H2O2 and ion-exchange resin depolymerization. Sulfate groups were partially cleaved during these chemical treatments. The potential bioactivity of the fractions was assessed using a lipoxygenase inhibition assay for anti-inflammatory activity and a WST-1 assay for human dermal fibroblast viability and proliferation. All ulvans extracts, poly- and oligosaccharidic fractions from EAE, expanded the fibroblast proliferation rate up to 62%. Our research emphasizes the potential use of poly- and oligosaccharidic fractions of Ulva sp. for further development in cosmetic applications.
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Green seaweed Ulva lactuca harvested from the North Sea near Zeeland (The Netherlands) was characterized as feedstock for acetone, ethanol and ethanol fermentation. Solubilization of over 90% of sugars was achieved by hot-water treatment followed by hydrolysis using commercial cellulases. A hydrolysate was used for the production of acetone, butanol and ethanol (ABE) by Clostridium acetobutylicum and Clostridium beijerinckii. Hydrolysate-based media were fermentable without nutrient supplementation. C. beijerinckii utilized all sugars in the hydrolysate and produced ABE at high yields (0.35 g ABE/g sugar consumed), while C. acetobutylicum produced mostly organic acids (acetic and butyric acids). These results demonstrate the great potential of U. lactuca as feedstock for fermentation. Interestingly, in control cultures of C. beijerinckii on rhamnose and glucose, 1,2 propanediol was the main fermentation product (9.7 g/L).
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The current work aimed to develop a cultivation method for macroalgae that can be applicable and economically profitable in the Atlantic Ocean. An offshore long-line macroalgal cultivation rig was designed by Ocean Rainforest Sp/f, tested in the Faroe Islands from 2010, and found suitable for cultivation in exposed and deep- water locations (water depth > 50 m). The economic risk related to lost cultivation structures was hereafter considered to be low. Saccharina latissima and Alaria esculenta were cultivated in commercial scale (5 km of growth lines). A high cost of seeding material and cost of deployment was reduced by testing multiple partial harvesting. Four non-destructive harvests were carried out in a two-year growth period without re-seeding of lines. In total, 3.2 t dry weight (dw) biomass was harvested and sold to customers within the food and cosmetic industries. The productivity was 1437.5 kg dw ha−1 yr−1 (including handling space). The 10-meter vertical growth lines had an average yield of 0.29 kg dw m−1 per harvest and four partial harvests were made over a 2- year period. An economic analysis showing the cost structure of important aspects of offshore macroalgae cultivation was conducted. The total cost per kg dw of cultivated S. latissima decreased when the number of possible harvests without re-seeding was increased (from € 36.73 to € 9.27). This work has demonstrated that large-scale kelp cultivation is possible using multiple partial harvesting in the Faroe Islands, and highlighted the need for further innovation to lower the cost per unit macroalgal produced.
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The publication describes the production, properties and main applications of the three major phyco-colloids extracted from seaweed: agar, alginate and carrageenan. There is also a supplementary chapter on the preparation and marketing of seaweeds as food. Although this is based mainly as Japanese experience it is included in order to encourage increased consumption of seaweeds as human food.
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Sea cucumbers cultured in ponds or in the sea are potentially lucrative commodities, but their export value can be gained or lost through the processing used. The gutting, water temperature, cooking times, handling and drying techniques should all be carefully controlled in order to achieve the highest grade possible for export. Farmed sea cucumbers may have thinner body walls than wild animals, but have the advantage of being of consistent size, can be processed immediately after being removed from the water, and can be processed in bulk. Processors must understand the preferences of overseas importers, as desired processing approaches may vary. The use of fuel for boiling sea cucumber to make beche-de-mer can be an ecological concern. Body organs and muscle bands may offer new products for value-adding of cultured sea cucumbers. Likewise, markets are more open to fresh and canned product. Training and providing guides in the best methodologies and new market opportunities to processors present fruitful scope for improving the cost-effectiveness of farming and sea ranching tropical sea cucumbers.
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Atremendousincreaseinpopulationhasalsoledtoasignificantincrease in the demand for energy leading to search for alternatives which can match up with the current requirement quantitatively and also qualitatively as a green energy carrier. Fuels derived from algal biomass can be one of the potential alternatives, as microalgae possess higher nutrients, required lipids and CO2 uptake capacity and can be grown quickly on nonarable land throughout the year without their inter- ference in food supply chain. The quantum of biodiesel produced from microalgae can be about 10–20 times higher than that obtained from terrestrial plants. Microalgae also help in reducing global warming by capturing CO2. The cost of production of biofuels from microalgae is the current setback which can be over- come by taking into consideration a biorefinery approach which can give multiple products with same expenditure as well as using some process intensification approaches. Process intensification plays a major role in reducing the cost and also can lead to use of less quantum of materials and lower operating temperatures. The present chapter will focus on analyzing the process intensification aspects applied to biofuels production from microalgae. The initial sections will cover the details of the types of microalgae and their harvesting techniques, followed by the discussion on the different approaches used to extract bio-oil from microalgae, and then the production of different biofuels. Intensification can be applied to both the extraction and the actual reaction for production of biofuels. The chapter will also focus on the mechanism of intensification using different approaches such as ultrasound, microwave, ultraviolet, and oscillatory baffled reactors. An overview of the litera- ture will be presented so as to give guidelines about the possible reactor designs and operating parameters also highlighting the process intensification benefits that can be obtained. Overall, the work is expected to bring out critical analysis of the different approaches and the expected benefits due to the use of process intensifi- cation also enabling understanding of the reactor designs and operating parameters.
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The rapid development of modern society has resulted in an increased demand for energy and, consequently, an increased use of fossil fuel reserves, compromising the energy sector sustainability. Moreover, the use of this source of energy led to the accumulation of greenhouse gases (GHGs) in atmosphere, which are associated with climate change. In this context, European Union has established new directives regarding GHG emissions and the renewable energy use. Microalgae may have an important role in the achievement of these goals. These photosynthetic microorganisms have a high growth rate, are able to capture CO2, the biomass can be used to produce biofuels, constituting an undeniable economic potential. Microalgae may also be a source of low carbon fuel, being one of the most studied biofuels feedstock. They are considered a sustainable energy resource, able to reduce sig- nificantly the dependence on fossil fuel. They can grow on places that are unsuitable for agriculture, not competing with land for food production. The use of wastewater as microalgal culture medium will reduce the required amount of freshwater and nutrients, achieving simultaneously an effluent with low nutrient concentrations. An important step to increase the competitiveness (promoting simultaneously the environmental sustainability) of microalgal biofuels regarding fossil fuels is the optimization of culture parameters using wastewater as culture medium. Thus, this chapter aims to present the recent studies regarding the integration of wastewater treatment and microalgal cultivation for biomass/biofuel production.
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Culture of seaweeds is practiced since ages in countries such as Japan, Ctiina and Korea. Seaweed cultivation is an industry in Japan as a part-time avocation for land farmers and fishermen. The seaweeds cultured mainly in these countries are Porphyra, Undaria, Laminaria, Enteromorpha and Monostroma. In India seaweed culture is yet to develop on commercial lines. While the demand for these seaweeds is for food purposes in foreign countries, their demand in India is for the extraction of two phytochemicals namely agar-agar and algin. In recent years many factories manufaauring these chemicals have come up in India as a consequence of which the demand for the agarophytes and alginophytes has gone up. In order to maintain a continuous supply of this raw material to the industry, methods to augment the supplies through culture practices have to be developed.
In recent years the Central Marine Fisheries Research Institute has been engaged in the cultivation of several economically important seaweeds such as Sargassum wightii, Twbinaria spp., Gracilaria edulis, G. corticata and Gelidiella acerosa which indicated great scope for cultivation. The production rate has been found to be 4.4 kg/m' in the case of G. edulis and 3 kg/m* in the case of G. acerosa in about 80 days for 0.30 kg and 1 kg of seed material introduced respectively. In the case of alginophytes the growth was not encouraging. These culture experiments were conducted by introducing small fragments of the seaweed into the twists of the coir ropes fabricated in the form of a S x 2 m net and tied to fixed poles in inshore waters. In the case of G. acerosa, the substratum along with the plant fragments was tied to the ropes.
The agarophytes thus grown can be processed further for extraction of agar-agar. The extraction could be done by a simple cottage industry method not involving any costly equipment. In the case of Gelidiella agar, freezing and thawing are required to remove the insoluble chemicals. A total of 90 tonnes of G. edulis can be obtained from 3 harvests in a year from a hectare area.
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