| 1. |
- Trigo, João Pedro, 1995, et al.
(författare)
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Mild blanching prior to pH-shift processing of Saccharina latissima retains protein extraction yields and amino acid levels of extracts while minimizing iodine content
- 2023
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Ingår i: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 404
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Tidskriftsartikel (refereegranskat)abstract
- The seaweed Saccharina latissima is often blanched to lower iodine levels, however, it is not known how blanching affects protein extraction. We assessed the effect of blanching or soaking (80/45/12 °C, 2 min) on protein yield and protein extract characteristics after pH-shift processing of S. latissima. Average protein yields and extract amino acid levels ranked treatments as follows: blanching-45 °C ∼ control > soaking ∼ blanching-80 °C. Although blanching-45 °C decreased protein solubilization yield at pH 12, it increased isoelectric protein precipitation yield at pH 2 (p < 0.05). The former could be explained by a higher ratio of large peptides/proteins in the blanched biomass as shown by HP-SEC, whereas the latter by blanching-induced lowering of ionic strength, as verified by a dialysis model. Moreover, blanching-45 °C yielded a protein extract with 49 % less iodine compared with the control extract. We recommend blanching-45 °C since it is effective at removing iodine and does not compromise total protein extraction yield.
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| 2. |
- Hargrave, Matthew, et al.
(författare)
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Co-cultivation with blue mussels increases yield and biomass quality of kelp
- 2022
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 550
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Tidskriftsartikel (refereegranskat)abstract
- Integrated multi-trophic aquaculture (IMTA) has to date largely centred on a fed species, often finfish or shrimps, alongside which extractive species, such as bivalves or seaweeds, have been placed. In comparison, IMTA systems excluding a fed component have received little research. Here we report a field study of an IMTA cultivation of the sugar kelp, Saccharina latissima, and the blue mussel, Mytilus edulis, on the Swedish west coast. Kelp were cultivated at two depths, 1-2 m and 3-4 m, either 10 m downstream of commercial scale blue mussel farms, or at control (monoculture) sites at least 500 m from the nearest farm. Significant enhancement of kelp yields in terms of both blade length and biomass was observed in IMTA treatments compared to monoculture, with a mean increase in length of 22% and biomass of 38%. Moreover, kelps co-cultivated with mussels displayed an epiphyte reduction of more than half compared to kelps grown in monoculture, with a 15% coverage in monoculture compared to 6% in co-culture. Significant increases in pigment content were also detected, with higher levels of chlorophyll a, fucoxanthin and phaeophytin in IMTA treatment kelps in comparison to monoculture. This study provides evidence for the potential of IMTA systems containing solely extractive species and presents factors beyond nutrient enrichment as drivers for enhanced growth in these systems. © 2021 The Authors
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| 3. |
- Hargrave, Matthew, et al.
(författare)
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Filtration and fertilisation effects of the bivalves Mytilus edulis and Magallana gigas on the kelp Saccharina latissima in tank culture
- 2021
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Ingår i: Journal of Applied Phycology. - : Springer Science and Business Media LLC. - 0921-8971 .- 1573-5176.
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Tidskriftsartikel (refereegranskat)abstract
- Biofouling by opportunistic epiphytes is a major concern in seaweed aquaculture. Colonisation of fouling organisms contributes to a reduction in algal performance as well as a lower quality crop. Further, epiphyte removal techniques often increase maintenance costs of cultivation systems. There have been a variety of methods to mitigate fouling in tank cultivations of seaweed, including the use of biological controls. Here, we present the use of filter feeding bivalves, the blue mussel (Mytilus edulis) and Pacific oyster (Magallana gigas), as a novel biofilter that also serves as a source of dissolved inorganic nitrogen in tank cultivations of the sugar kelp, Saccharina latissima. We observed significant reductions of fouling epiphytes on seaweed blades of around 50% by bivalve filtration, significant elevations of ammonium (NH4+) and phosphate (PO43-) by bivalves and alterations to kelp tissue quality when co-cultivated with bivalves rather than supplied with ambient seawater. Stable isotope ratios and seawater chlorophyll a concentrations provided evidence for bivalve biofiltration and the incorporation of their by-products into kelp tissue.
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| 4. |
- Hasselström, Linus, et al.
(författare)
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Socioeconomic prospects of a seaweed bioeconomy in Sweden
- 2020
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Seaweed cultivation is a large industry worldwide, but production in Europe is small compared to production in Asian countries. In the EU, the motivations for seaweed farming may be seen from two perspectives; one being economic growth through biomass production and the other being the provisioning of ecosystem services such as mitigating eutrophication. In this paper, we assess the economic potential of large-scale cultivation of kelp, Saccharina latissima, along the Swedish west coast, including the value of externalities. The findings suggest that seaweed farming has the potential of becoming a profitable industry in Sweden. Furthermore, large-scale seaweed farming can sequester asignificant share of annual anthropogenic nitrogen and phosphorus inflows to the basins of the Swedish west coast (8% of N and 60% of P). Concerning the valuation of externalities, positive values generated from sequestration of nitrogen and phosphorus are potentially counteracted by negative values frominterference with recreational values. Despite the large N and P uptake, the socioeconomic value of this sequestration is only a minor share of the potential financial value from biomass production. This suggests that e.g. payment schemes for nutrient uptake based on the socioeconomic values generatedis not likely to be a tipping point for the industry. Additionally, seaweed cultivation is not a cost-efficient measure in itself to remove nutrients. Policy should thus be oriented towards industry development, as the market potential of the biomass will be the driver that may unlock these bioremediationopportunities.
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| 5. |
- Kotta, Jonne, et al.
(författare)
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Assessing the potential for sea-based macroalgae cultivation and its application for nutrient removal in the Baltic Sea
- 2022
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 839
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Tidskriftsartikel (refereegranskat)abstract
- Marine eutrophication is a pervasive and growing threat to global sustainability. Macroalgal cultivation is a promising circular economy solution to achieve nutrient reduction and food security. However, the location of production hotspots is not well known. In this paper the production potential of macroalgae of high commercial value was predicted across the Baltic Sea region. In addition, the nutrient limitation within and adjacent to macroalgal farms was investigated to suggest optimal site-specific configuration of farms. The production potential of Saccharina latissima was largely driven by salinity and the highest production yields are expected in the westernmost Baltic Sea areas where salinity is >23. The direct and interactive effects of light availability, temperature, salinity and nutrient concentrations regulated the predicted changes in the production of Ulva intestinalis and Fucus vesiculosus. The western and southern Baltic Sea exhibited the highest farming potential for these species, with promising areas also in the eastern Baltic Sea. Macroalgal farming did not induce significant nutrient limitation. The expected spatial propagation of nutrient limitation caused by macroalgal farming was less than 100–250 m. Higher propagation distances were found in areas of low nutrient and low water exchange (e.g. offshore areas in the Baltic Proper) and smaller distances in areas of high nutrient and high water exchange (e.g. western Baltic Sea and Gulf of Riga). The generated maps provide the most sought-after input to support blue growth initiatives that foster the sustainable development of macroalgal cultivation and reduction of in situ nutrient loads in the Baltic Sea.
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| 6. |
- Olsson, Joakim, 1988, et al.
(författare)
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Effects of geographical location on potentially valuable components in Ulva intestinalis sampled along the Swedish coast
- 2020
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Ingår i: Applied Phycology. - : Informa UK Limited. - 2638-8081. ; 1:1, s. 80-92
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Tidskriftsartikel (refereegranskat)abstract
- Macroalgal biomass has the potential to become an important source of chemicals and commodities in a future biorefinery. Currently, production of macroalgal biomass is expensive and the content of high-value compounds is often low. Therefore, in this study the biochemical composition of Ulva intestinalis along the Swedish west coast and the east coast up to Stockholm was assessed with the aim of determining how the content of potentially valuable compounds, such as rhamnose, iduronic acid and PUFAs, could be maximized by utilizing natural variation in the choice of marine cultivation site. Along the investigated coastline, the salinity dropped from 19.4‰ at high latitudes along the west coast to 5.4‰ at Stockholm. Nitrogen and phosphorus availability varied, while temperature was similar at all locations. The two major components of biomass, carbohydrates and ash, varied inversely with the highest content of ash in the west and carbohydrates in the east. In addition, total fatty acids were significantly higher in west coast samples at 3.2 g 100 g–1 dw, with a higher proportion of mono- and polyunsaturated fatty acids. Some health-beneficial fatty acids were found, including EPA and DPA, at 10–50 mg 100 g–1 dw, respectively. The metal content and elemental composition varied widely, probably due to the influence of specific local conditions. The P content was correlated with the phosphorus concentration in waters at the locations. In PCA analysis, the monosaccharides constituting the cell wall polysaccharide ulvan were found to vary by geographical location, with higher levels possibly associated with lower salinities. However, only glucuronic acid differed significantly between sites. These results show the considerable geographical variability in the composition of Swedish U. intestinalis and suggest that different salinities could be used to create a lipid- or carbohydrate-rich biomass.
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| 7. |
- Raikova, Sofia, et al.
(författare)
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Effect of Geographical Location on the Variation in Products Formed from the Hydrothermal Liquefaction of Ulva intestinalis
- 2020
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Ingår i: Energy & Fuels. - : American Chemical Society (ACS). - 1520-5029 .- 0887-0624. ; 34:1, s. 368-378
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Tidskriftsartikel (refereegranskat)abstract
- Hydrothermal liquefaction (HTL) of macroalgae offers a promising route to advanced biofuel production, although the distinct biochemical compositions of different macroalgae species can lead to widely different product yields and compositions. On the basis of this, there is an implicit assumption that there exists a universal optimal feedstock species for a bioenergy-based biorefinery, which could be exploited across a wide region. However, no studies to date have examined the effect of this large geographical variation on a single macroalgae species for biofuel production. In this study, 24 samples of Ulva intestinalis were collected along 1200 km of Swedish coastline and assessed as a feedstock for HTL. Significant variation in composition was observed between samples from Baltic and Atlantic regions, but substantial variation also existed between sites within close proximity. This was reflected in the HTL biocrude oil yields, which varied between 9 and 20% (14-28% dry and ash-free basis) across the sample set. In a number of cases, greater variation was seen for adjacent sites than for sites at opposite ends of the sampling spectrum. Biocrude oil yields in this study also differed substantially from those previously obtained for U. intestinalis from the United Kingdom and Vietnam. Localized environmental conditions affected the HTL product composition significantly, in particular, the elemental distribution within the sample set. The variability observed in this study suggests that no single species will be dominant within a macroalgal biorefinery concept, but rather a species would need to be selected to match the needs of the exact local environment.
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| 8. |
- Rugiu, Luca, et al.
(författare)
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Kelp in IMTAs: small variations in inorganic nitrogen concentrations drive different physiological responses of Saccharina latissima
- 2021
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Ingår i: Journal of Applied Phycology. - : Springer Science and Business Media LLC. - 0921-8971 .- 1573-5176. ; 33, s. 1021-1034
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Tidskriftsartikel (refereegranskat)abstract
- © 2020, The Author(s). Kelps can be included in integrated multitrophic aquaculture (IMTA) where their growth and quality might benefit from the nutrient load released by other species like finfish and mussels transforming effluents from the cultured animals into valuable products. We studied how different nutrient concentrations affect growth, photosynthesis, chemical composition and pigment content of the kelp Saccharina latissima. We exposed kelps to natural seawater, water enriched to levels of ammonium and nitrate simulating finfish cage waste (IMTA1) and a combination of such enrichment with natural effluents coming from mussels (IMTA2). The algal biomass was higher and produced elevated total organic content when exposed to both IMTA1 and IMTA2. The photosynthetic responses in terms of relative electron transfer rate (rETRmax), PSII saturation irradiance (Ek) and total nitrogen content were also positively affected by both IMTA1 and IMTA2. We found a significant enhancement in pigment content only when algae were exposed to the strongest enrichment of our study (IMTA2). Finally, we found a positive relationship between rETRmax and growth, and the content of chlorophyll a and fucoxanthin. Our results show significant physiological responses of S. latissima to nutrient enrichment mimicking IMTA settings, as well as the benefit of added nutrients through a boost in photosynthetic activity that leads to higher kelp biomass and pigment production. This study suggests that modest nitrogen enrichment such as the one in our IMTA2 setup is enough to generate not only higher kelp biomass, but also an increased biomass quality with potentially higher market value.
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| 9. |
- Stedt, Kristoffer, 1991, et al.
(författare)
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Cultivation of seaweeds in food production process waters: Evaluation of growth and crude protein content
- 2022
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Ingår i: Algal Research. - : Elsevier BV. - 2211-9264. ; 63
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Tidskriftsartikel (refereegranskat)abstract
- There is an increasing demand for sustainably produced, protein-rich, and nutritious food. Seaweeds are promising protein sources for the future if their protein content can be optimized, something which can be achieved by cultivation in elevated nutrient concentrations. Cultivation of seaweeds in integration with fish farms have received much attention lately, but using nutrient-rich process waters from other food industries as feed stock for seaweed has rarely been studied. Here, we demonstrate a simple and sustainable strategy to answer the increasing world demand for food rich in plant-based proteins by connecting food production process waters with seaweed cultivation. We compared growth rates and crude protein content of four different seaweed species, the brown species Saccharina latissima, and the green species Ulva fenestrata, Ulva intestinalis, and Chaetomorpha linum, when cultivated in two dilutions (providing 20 and 200 μM ammonium) of eight different process waters emerging from recirculating salmon aquaculture systems as well as from herring, shrimp and oat processing. Growth rates of the green seaweeds were up to 64% higher, and crude protein content was almost up to four times higher when cultivated in the food production process waters, compared to seawater controls. Growth rates were generally higher in presence of 20 μM compared to 200 μM ammonium, while crude protein content was either unaffected or positively affected by the increasing ammonium concentration. This study indicates the potential for cultivating seaweeds with food production process waters to generate additional protein-rich biomass while nutrients are being circulated back to the food chain. A new nutrient loop is thus illustrated, in which the costly disposal of food production process waters is instead turned into value by seaweed cultivation.
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| 10. |
- Steinhagen, Sophie, et al.
(författare)
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Sustainable large-scale aquaculture of the northern hemisphere sea lettuce, ulva fenestrata, in an off-shore seafarm
- 2021
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Ingår i: Journal of Marine Science and Engineering. - : MDPI AG. - 2077-1312. ; 9:6
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Tidskriftsartikel (refereegranskat)abstract
- The growing world population demands an increase in sustainable resources for biorefining. The opening of new farm grounds and the cultivation of extractive species, such as marine seaweeds, increases worldwide, aiming to provide renewable biomass for food and non-food applications. The potential for European large-scale open ocean farming of the commercial green seaweed crop Ulva is not yet fully realized. Here we conducted manipulative cultivation experiments in order to investigate the effects of hatchery temperature (10 and 15◦C), nutrient addition (PES and 3xPES) and swarmer density (500 and 10,000 swarmers ml−1 ) on the biomass yield and biochemical composition (fatty acid, protein, carbohydrate, pigment and phenolic content) of off-shore cultivated Ulva fenestrata in a Swedish seafarm. High seedling densities were optimal for the growth of this northern hemisphere crop strain and significantly increased the mean biomass yield by ~84% compared to low seedling densities. Variations of nutrients or changes in temperature levels during the hatchery phase were not necessary to increase the subsequent growth in an open-water seafarm, however effects of the factors on the thallus habitus (thallus length/width) were observed. We found no significant effect of the environmental factors applied in the hatchery on the total fatty acid or crude protein content in the off-shore cultivated Ulva. However, low seedling density and low temperature increased the total carbohydrate content and furthermore, high temperature in combination with high nutrient levels decreased the pigment content (chlorophyll a, b, carotenoids). Low temperature in combination with high nutrient levels increased the phenolic content. Our study confirms the successful and sustainable potential for large-scale off-shore cultivation of the Scandinavian crop U. fenestrata. We conclude that high seedling density in the hatchery is most important for increasing the total biomass yield of sea-farmed U. fenestrata, and that changing temperature or addition of nutrients overall does not have a large effect on the biochemical composition. To summarize, our study contributes novel insights into the large-scale off-shore cultivation potential of northern hemisphere U. fenestrata and underpins suitable pre-treatments during the hatchery phase of seedlings to facilitate a successful and cost-efficient large-scale rope cultivation.
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