Carbohydrate-rich and fast-growing seaweeds such as the S. japonica species are increasingly becoming the 3rd generation biomass of choice. Environmentally friendly as well as economically sound processes for biofuel production are essential if the benefits of these novel marine feedstocks are to be harnessed. This study features an experiment-based process design that combines a fluidized bed fast pyrolysis reactor system, non-intensive pretreatment, and a Bryton power cycle in an, energy-wise, nearly self-sustainable system, considerably reducing the utilization of fossil fuel-derived utilities. Complex liquid products of pyrolysis and catalytic upgrading were modeled using a specialized software ensuring strict adherence to experimental data, hence retaining a highly realistic simulation. Results of comprehensive techno-economic and market uncertainty assessments have shown a capital investment of 170 mil. USD, and a minimum selling price range of 1.534–1.852 USD/L. When compared to traditional oil and gas extraction and refining processes, the designed process yielded a 12.8-fold reduction of the total CO2 emitted, indicating a superior process in terms of environmental sustainability.
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Seaweeds are presently explored as an alternative source to meet the future protein demand from a growing world population with an increasing welfare level. Present seaweed research largely focuses on agri-technical and economic aspects. This paper explores directions for optimizing the cultivation, harvesting, transport and drying of seaweed from an environmental point of view. An environmental life cycle assessment (LCA) and detailed sensitivity analysis was made for two different system designs. One system design is featuring one layer of cultivation strips (four longlines side by side) interspaced with access corridors. The other system design is featuring a doubling of cultivation strips by dual layers in the water column. Impact profiles and sensitivity analysis showed that the most important impacts came from drying the harvested seaweed, and from the pro- duction of the chromium steel chains and polypropylene rope in the infrastructure. This indicates that caution should be used when designing cultivation systems featuring such materials and processes. Furthermore, the high-density productivity of the dual layer system decreases absolute environmental impacts and so found to be a little more environmentally friendly from a life cycle perspective.
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Seven case studies are presented on commercial seaweed resources; five on wild crops, respectivelyAscophyllum nodosum, Chondrus crispus, Gelidium, Laminaria longicrurisandMacrocystis,are provided along with case studies of the farmed crops ofEucheumaandLaminaria japonica.Individually the cases range from descriptions of the wild crops and their management to themanaged production of farmed crops including, in several examples, some information on economics and/or processing. These initial seven cases range from those emphaizing but one speciesfrom but one part of one country, to studies of a genus as it occurs commercially throughout the world.
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Strategies for sustainably increasing sugarcane productivity without any negative implications to the environment are challenging. In the present investigation, field trials were conducted to demonstrate the potential of an agro-technique involving foliar applications of Kappaphycus alvarezii seaweed based biostimulant in combination with recommended rate of synthetic fertilizers (RRF) for sustainably enhancing sugarcane production and mitigating environmental impacts. Kappaphycus seaweed extract (KSWE) applied at 5% concentration enhanced cane productivity by 12.5 and 8%, respectively, in plant and ratoon crops. Interestingly, the treatment involving 6.25% KSWE +50% RRF showed yield parity (p < 0.05) with control (water+100% RRF) in ratoon while there was 7.9% reduction over control in plant crop with a concomitant savings of 50% RRF. These results revealed that KSWE application in addition to recommended rate of fertilizer application, can reduce gap between potential and real yield which otherwise requires application of incremental inputs in the form of synthetic fertilizers to obtain similar yields. The findings confirmed our hypothesis that the use of KSWE not only results in hypothetical savings in the incremental application of synthetic fertilizers but also can be used for achieving target yields sustainably. The sugar yield too was enhanced thus increasing the returns on investment. The technique is practically feasibility and scalability. The potential of the KSWE in lowering GHGs is manifested by the way of saving at least 260 kg CO2 equivalents (Mg cane production)−1 ha−1 when applied at 5% concentration. This would translate in to savings of ca. 9.3 million Mg of CO2 equivalents if one assumes employing KSWE for at least 10% of the total cane production in India for the year 2015–16. Therefore, the present study advocates a paradigm shift in policy to encourage use of biostimulants in the context of mitigating adverse effects of global climate change and expecting better returns from sugarcane cultivation.
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Marine macroalgae have evolved a different mechanism to maintain physiological concentrations of essential metal ions and non-essential metals. The objective of the present work was to evaluate the antioxidant response and DNA damage of copper and cadmium ions in three halophytes, namely, Acanthophora spicifera, Chaetomorpha antennina, and Ulva reticulata. Accumulation of copper was significantly higher (P < 0.05) than that of cadmium. Biochemical responses showed that copper was considerably more toxic than cadmium (P < 0.05). Decreases in glutathione content and fluctuations of super oxide dismutase, catalase, and glutathione peroxidase activities were observed corresponding to time and concentration of exposure. Interestingly, it was also observed that antioxidant levels decreased as a result of metal accumulation, which may be due to free radicals generated by copper and cadmium in seaweeds. The present study also showed that copper and cadmium increased oxidative stress and induced antioxidant defense systems against reactive oxygen species. The order of toxicity for metals in the studied seaweeds was U. reticulata > A. spicifera > C. antennina. DNA damage index analysis supported that copper was significantly (P < 0.05) more toxic than cadmium. Bioaccumulation, biochemical responses, and DNA damage observed in the here analyzed marine macroalgae after exposure to selected metals indicate that these marine organisms represent useful bioindicators of marine pollution.
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Best management practices (BMPs) were developed for management of bottom soil in freshwater aquaculture ponds in Thai- land. These practices were based on a survey of production practices in tilapia, catfish, carp, and freshwater prawn culture and upon findings of studies of physical and chemical characteristics of bottom soil from ponds of different ages. Fifteen BMPs were designed to encourage the following: pond dry-out between crops; aeration of bottoms by tillage; liming of acidic bottoms; use of sedimentation basins; responsible disposal of sediment; erosion control; application of proper construction techniques; reduction in suspended solids in effluents. The BMPs have been translated into Thai for distribution to farmers, and several of the BMPs have a high rate of adoption by Thai farmers.
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There is an urgent need for diversifying livelihoodof low-income artisanal fishermen due to rapidly dwindlingfishery resources. CSIR-Central Salt and Marine ChemicalsResearch Institute takes pride in being first for pioneeringKappaphycus alvareziicultivation, heralding an era of com-mercial seaweed farming in India. The invention of liquefyingfresh seaweed biomass to obtain two products in an integratedmanner, one being a granular residue rich inκ-carrageenanand the other being sap rich in potash and micronutrients(ca. 2 %w/v), with proven efficacy has provided a boost tocommercial farming. The production has been substantiallyincreased from 21 dry tonnes in 2001 to 1490 dry tonnes in2013 with concomitant purchase value of <4.5 to 35 Rs kg−1(dry). India is fast emerging as important production center inSoutheast Asia forK. alvareziiproduction with estimated765,000 man-days of employment, having annual turnoverof around Rs 2 billion. At present, commercial farming iscarried out following three techniques, namely floatingbamboo raft, tube net, and longline method of which formertwo are widely practiced. Thecultivation activity is wellestablished in southern state of Tamil Nadu and progressingrapidly to other areas namely Gujarat, Andhra Pradesh, andMaharashtra. The socioeconomic benefits accrued in this pro-ject are overwhelmingly positive, but evidence-based policiesare required for addressing prevailing environmental issues.The steps toward developing value-added products with nicheapplications coupled with biotechnological interventionsaimed at seed production through tissue culture for developingelite germplasm, etc. could further improve the prospects oftaking this project to pan India level. The present review pro-vides a detailed account of developments of commercial farm-ing that has witnessed successful diversification of livelihoodconsistently for the last 10 years.
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Seaweeds are a renewable natural source of valuable macro and micronutrients that have attracted the attention of the scientists in the last years. Their medicinal properties were already recognized in the ancient traditional Chinese medicine, but only recently there has been a considerable increase in the study of these organisms in attempts to demonstrate their health benefits. The extraction process and conditions to be used for the obtention of value-added compounds from seaweeds depends mainly on the desired final product. Thermochemical conversion of seaweeds, using high temperatures and solvents (including water), to obtain high-value products with more potential applications continues to be an industrial practice, frequently with adverse impact on the environment and products’ functionality. However more recently, alternative methods and approaches have been suggested, searching not only to improve the process performance, but also to be less harmful for the environment. A biorefinery approach display a valuable idea of solving economic and environmental drawbacks, enabling less residues production close to the much recommended zero waste system. The aim of this work is to report about the new developed methods of seaweeds extractions and the potential application of the components extracted.
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Seaweeds or marine algae comprise a grouping of very diverse photosynthetic organisms whose relatively simple vegetative structure is called “ thallus ”. They have been traditionally set apart from higher plants, whose more complex level of organisation is differentiated as stems, leaves and roots, through which run sap-carrying conductive tissues.
Algae are autotrophic organisms, which are able to manufacture their own organic molecules from elements containing carbon and nitrogen. Their energy is obtained directly from sunlight, which is trapped by the pigment chlorophyll during the process of photosynthesis. Water and mineral nutrients are directly taken from their environment through their cell surfaces.
While seaweeds are an essential part of the marine ecosystem, they are mostly overlooked as they are overshadowed by their more conspicuous neighbours such as corals, fishes and molluscs. Nevertheless, they occupy the bottom of the food chain and are direct food for a large number of marine organisms, and also for humans in many parts of the world. A host of useful products are also extracted from marine algae, with applications ranging from cosmetics to medicine and the food industry.
Disruptions in seaweed growth patterns caused by unnatural sources such as pollution and deliberate introduction can have quite harmful consequences on the marine ecosystem. For instance, in the Mediterranean sea, the tropical green alga Caulerpa taxifolia has in recent years become a pest, as it clogs waterways and displaces other marine organisms after having escaped from an aquarium in Monaco. In the Cook Islands, fluctuations in the numbers of the patito or sea hare (Stylocheilus longicauda) has been linked to the disappearance and reappearance of the blue-green alga Lyngbya majuscula, on which it primarily feeds. These fluctuations have been also linked to blooms in the green alga Boodlea kaeneana, which could be caused by an increase in organic nitrates flushed into the lagoon (for instance from piggeries) or an increase in global seawater temperatures caused by climatic factors such as the greenhouse effect and El Niño.
It is hence important to recognise seaweeds in their natural environment, and realise their major role in the balance and well-being of the coral reef community, on whose biodiversity and health the livelihood of many island communities such as the Cook Islands closely depends
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We compared protocols to isolate and concentrate protein from the green seaweed Ulva ohnoi. We quantified the effect of three factors on protein and essential amino acid yields and concentrations in protein isolates and residuals in a factorial experimental design. The three factors were starting material (as dry and milled or fresh and pulped), aqueous solvent-to-biomass ratio (20:1 or 5:1 v/w) and the incubation time in the aqueous solvent (incubated for 16 h at 30 °C or incubated for <1 min at ambient temperature). The protein isolation protocols increased the concentration of protein, total essential amino acids, methionine and lysine ~3 to 5- fold compared to whole U. ohnoi and were considerably more effective than the different protein concentrating combinations, which only increased protein and amino ac- id concentrations by 30–40 % in the residual biomass. The use of fresh and pulped biomass as the starting material, an incubation time of <1 min at ambient temperature and a low aqueous solution volume resulted in the highest pro- tein isolate yield of 22 % of the protein found in seaweed. This study demonstrated that proteins from U. ohnoi were most effectively isolated by adopting protocols for terres- trial leaves compared to the protocols employed for seed crops as traditionally applied to seaweeds.
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