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  • We evaluated eight biorefinery processes targeting the extraction of ulvan from Ulva ohnoi. Using a factorial design the effect of three sequential treatments (aqueous extraction of salt; ethanol extraction of pigments; and Na2C2O4 or HCl (0.05 M) extraction of ulvan) were evaluated based on the yield (% dry weight of biomass) and quality (uronic acid, sulfate, protein and ash content, constituent sugar and molecular weight analysis) of ulvan extracted. The aqueous extraction of salt followed by HCl extraction of ulvan gave higher yields (8.2 ± 1.1% w/w) and purity of ulvan than equivalent Na2C2O4 extracts (4.0 ± 1.0% w/w). The total sugar content of HCl extracts (624–670 μg/mg) was higher than Na2C2O4 extracts (365–426 μg/mg) as determined by constituent sugar with ulvan specific monosaccharides contributing 94.7–96.2% and 70.1–84.0%, respectively. Ulvan extracted from U. ohnoi was 53.1 mol% rhamnose, 27.8 mol% glucuronic acid, 10.1 mol% iduronic acid, and 5.3 mol% xylose with molecular weights ranging from 10.5–312 kDa depending on the biorefinery process employed. Therefore, the extraction of high quality ulvan from U. ohnoi is facilitated by an aqueous pre-treatment and subsequent HCl-extraction of ulvan as part of a cascading biorefinery model delivering salt, ulvan, and a protein enriched residual biomass.

    Author(s): Christopher R.K. Glasson, Ian M. Sims, Susan M. Carnachan, Rocky de Nys, Marie Magnusson
  • An innovative integrated biorefinery approach using the green macroalgae Chaetomorpha linum was investigated in the present study for the co-production of bioethanol and biogas. Among three pretreat- ments of C. linum biomass, consisting of acidic, neutral and alkali ones, 3% NaOH pretreatment gave the best result in terms of thallus disintegration, biomass recovery and enzymatic digestibility as demon- strated by scanning electron microscopy and saccharification tests. The hydrolysis of C. linum feedstock with a crude specific enzyme preparation, locally produced from fermentation of Aspergillus awamori, at 45 C, pH 5 for 30 h gave the maximum yield of fermentable sugar of 0.22 ± 0.02 g/g dry substrate. An ethanol yield of 0.41 g/g reducing sugar corresponding to about 0.093 g/g pretreated algae was obtained after alcoholic fermentation by Saccharomyces cerevisiae. In the integrated proposed process, mycelium issued from the fungal fermentation, liquid issued from alkali pretreatment, residual from the non-hydrolysable biomass and all effluents and co-products represent a heterogeneous substrate that feed an anaerobic digester for biogas production. GC-analysis of this later showed that the biomethane yield reached 0.26 ± 0.045 L/gVS. This study presents therefore an eco-friendly biorefining process, which efficiently coproduce bioethanol and biomethane and generate only a single waste (0.3±0.01g/g) allowing an almost complete conversion of the algal biomass.

    Author(s): Nesrine Ben Yahmed, Issam Smaali, Mohamed Amine Jmel, Monia Ben Alaya, Hassib Bouallagui, M. Nejib Marzouki
  • A Bayesian inference method was employed to quantify uncertainty in an Integrated Multi-Trophic Aquaculture (IMTA) model. A deterministic model was reformulated as a Bayesian Hierarchical Model (BHM) with uncertainty in the parameters accounted for using “prior” distributions and unresolved time varying processes modelled using auto-regressive processes. Observations of kelp grown in 3 seeding densities around salmon pens were assimilated using a Sequential Monte Carlo method implemented within the LibBi package. This resulted in a considerable reduction in the variability in model output for both the observed and unobserved state variables. A reduction in variance between the prior and posterior was observed for a subset of model parameters which varied with seeding density. Kullback–Liebler (KL) divergence method showed the reduction in variability of the state and parameters was approximately 90%. A low to medium seeding density results in the most efficient removal of excess nutrients in this simple system.

    Author(s): Catriona K Macleod, Karen wild-allen, Craig R Johnson, Emlyn Jones, Scott Hadley
  • Modern methods of macroalgal cultivation of the large brown seaweeds commonly and collectively referred to as ‘kelp’ began in the early 1950’s in China, with research spearheaded by ‘the father of mariculture’, Prof. CK Tseng and his team. Since this time, kelp aquaculture has steadily grown in China and other Asian countries such as Japan, and the Republic of Korea. Now, almost all of the seaweed produced for human consumption, alginates and other purposes comes from aquaculture, with the extent of cultivation clearly visible on satellite images in some regions. Research in these countries has focused on brown algal species including Saccharina japonica and Undaria pinnatifida, concentrating primarily on developing a number of commercial strains that demonstrate temperature-tolerance of warmer seawater, and latterly, on improved productivity. In China, it is common practice to have centralised seaweed hatchery facilities that produce plantlets for further on-growing at a number of local sea sites.The development of centralised facilities using controlled seaweed strains most likely lends itself to a higher degree of standardised operations during the production cycle.

    In direct contrast to the mass culture of seaweed in China and other Asian countries, commercial cultivation production in Europe remains on a small scale. While European research on kelp has existed at least as long as for that conducted in China, seaweed cultivation techniques have been known (generally only within research facilities) for approximately thirty years. For most of this time, cultivation has existed at a demonstration/pilot-scale only, although this is now changing in a number of countries, primarily across NW Europe. It was recognised early on that the Chinese method of growing seaweed by inserting small plantlets into ropes for on-growing at sea would not be economically efficient in Europe, given the cost of labour. Alternative cheaper seeding techniques, as described in this document, have been developed instead. Longline design is also different in Europe, where sea conditions are generally more challenging than the more sheltered areas that typically support Chinese aquaculture. This influences design and of course the cost of equipment that is used. The concurrent European research on wild strains of kelp species, partnered with a strong requirement for developing site specific cultivation systems has naturally led to some variance in production protocols and systems.

    The EnAlgae project has allowed its research partners in NW Europe the opportunity to use hindsight of the expansion of global seaweed cultivation to full advantage. A theme of the project(WP1, Action 5) has been ‘the development and exchange of best practice for mass production of macroalgae’. For this action to be completed satisfactorily, demonstration/pilot sites (WP1, Action 2)were constructed at the macroalgal partner facilities. The subsequent development of a close working relationship enabled production of comparable data for identified species (Saccharina latissima and Alaria esculenta) on cultivation methodology, data collection (WP1, Action 3) and macroalgal growth results. The standardisation of all of these elements was designed to produce reliable data and share common experiences between macroalgal cultivation stakeholders in NW Europe, culminating in the production of this manual, and the accompanying Macroalgal Best Practice document.

    This document is a manual of collated Standard Operating Protocols (SOPs) that were developed in the three EnAlgae macroalgal hatcheries in the National University of Ireland, Galway(NUIG), Queen’s University, Belfast (QUB) and the Centre d’Etude et de Valorisation des Algues (CEVA). It describes the set-up/requirements of each seaweed hatchery, the hatchery cultivation process, thesea on-growing process, as well as biomass and environmental parameter measurements and sampling. While some SOPs were subject to some inherent differences within each hatchery (e.g. pre-existing seawater pumping and distribution systems), an effort was made to ensure that as many elements of the SOPs were standardised across the partners. For example, the biomass sampling SOP was particularly important to enable the collection of comparable data in Ireland, Northern Ireland and France.

    The SOP manual has been designed for reading with the EnAlgae Macroalgal Best Practice document. This sister document offers further advice and observations of the methods used, including elements of the processes that worked, and equally importantly, where system failures occurred, and revisions were made. It is hoped that both documents will become a valuable resource for those interested in developing European kelp cultivation in NW Europe and beyond, providing information on techniques that can further refined, leading to ever-increasingly efficient seaweed production at sea.

    Author(s): M. Edwards , K. Mooney, E. Gorman Healey , J. Champenois
  • 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 1.5341.852 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.

    Author(s): Boris Brigljević, Jay Liu, Hankwon Lim
  • 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.

    Author(s): Vaibhav A. Mantri , K. Eswaran, M. Shanmugam, M. Ganesan, V. Veeragurunathan, S. Thiruppathi, Abhiram Seth
  • 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.

    Author(s): Gabriela S. Matos, Sara G. Pereira, Zlatina A. Genisheva, Ana Maria Gomes, José A. Teixeira, Cristina M. R. Rocha
  • 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 3040 % 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.

    Author(s): Alex R. Angell, Nicholas A. Paul, Rocky de Nys

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