| 1. |
- Albers, Eva, 1966, et al.
(författare)
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Influence of preservation methods on biochemical composition and downstream processing of cultivated Saccharina latissima biomass
- 2021
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Ingår i: Algal Research. - : Elsevier BV. - 2211-9264. ; 55
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Tidskriftsartikel (refereegranskat)abstract
- Saccharina latissima biomass cultivated along the Swedish west coast was subjected to four different scalable preservation methods after harvest; freezing, sun-drying, oven-drying and ensiling. Freeze-drying and freezing at -80 ?C were also included to provide dry and wet references. The effects of the different preservation methods on the composition of Saccharina biomass (on dry weight, DW, basis), and the recovery as well as properties of high-quality protein, alginate and biogas were evaluated. Sun-drying significantly reduced protein, alginate and fatty acid content of the seaweeds and thereby concentrated ash in the biomass compared to the other methods. Protein/amino acids and fatty acids were significantly concentrated in ensiled biomass, while mannitol and laminarin were reduced compared to the other biomasses. Oven-drying and -20 ?C freezing affected the composition the least, with lower ash content and alterations in some specific amino and fatty acids. Sun-drying and ensiling resulted in significantly lower protein solubility at high pH compared to the other biomasses which translated into the lowest total seaweed protein recovery using the pH-shift process. Highest protein yield was obtained with the freeze-dried reference. Ensiling lead to a significant decrease in the molecular weight of alginate, while sun-drying caused a negative effect on alginate by inducing a shift in the guluronic and mannuronic acids composition of alginate. Sun-drying gave the lowest methane yield in the anaerobic digestion experiments while freezing at -80 ?C gave the highest yield, closely followed by freezing at -20 ?C and ensiling. To conclude, preservation methods must be carefully chosen to protect the valuable component in Saccharina latissima, and to achieve an efficient downstream processing ultimately yielding high quality products as part of a seaweed biorefinery.
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| 2. |
- Mayers, Joshua, 1988, et al.
(författare)
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Identifying a marine microalgae with high carbohydrate productivities under stress and potential for efficient flocculation
- 2018
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Ingår i: Algal Research. - : Elsevier BV. - 2211-9264. ; 31, s. 430-442
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Tidskriftsartikel (refereegranskat)abstract
- Microalgal biomass represents a potential third generation feedstock that could be utilised as a source of carbohydrates for fermentative production of a range of platform biochemicals. Identifying microalgal strains with high biomass and carbohydrate productivities while also being amenable to downstream processes is key in improving the feasibility of these processes. Utilising marine microalgae capable of growing in seawater will decrease reliance on freshwater resources and improve the sustainability of production. This study screened several marine microalgae believed to accumulate carbohydrates to find new high performing strains. Four strains had high growth rates and accumulated carbohydrates > 35% DW under stress. The strain Chlorella salina demonstrated the highest biomass and carbohydrate productivity, and alkaline autoflocculation (4 mM NaOH) enabled biomass recoveries > 95% efficiency, resulting in an 8–10 × concentration of the culture. Under nutrient replete conditions, biomass productivity reached 0.6 g L −1 d −1 , significantly greater than that of nitrogen starved cultures. However, nitrogen starvation rapidly increased carbohydrate content to > 50% DW in 2 days, resulting in carbohydrate productivities > 0.20 g L −1 d −1 . Chlorella salina partitions the products of photosynthesis preferentially into carbohydrate synthesis under nitrogen starvation. A greater understanding of cellular physiology and carbon partitioning in response to nutrient stress will enable better control and optimisation of the bio-processes. This study has identified a potentially high performance marine microalga for carbohydrate production that is also amenable to low-cost harvesting.
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| 3. |
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| 4. |
- Olsson, Joakim, 1988, et al.
(författare)
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Composition and processing of Ulva intestinalis from 8 different sites along the Swedish coast
- 2018
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Seaweed has the potential to provide a large quantities of biomass as feedstocks for production of energy and chemicals. Compared to terrestrial biomasses, seaweed does not require arable land or fertilizer for cultivation, effectively not competing with food production. Significant efforts are now being made to improve both cultivation, extraction techniques and product development of seaweed to enable a seaweed industry in the future. An aspect that has thus far received little attention is on the optimisation of cultivation siting to maximise the content of valuable components in the biomass (and minimize waste), despite it being well known that variation in ambient conditions cause significant changes in biomass composition. In this study, we have investigated the opportunistic summer seaweed Ulva intestinalis, which is of commercial interest due to its high growth rate and broad distribution along the entire Swedish coast. To evaluate where cultivation could be most beneficial from a biomass composition perspective, samples were collected from 8 sites along the Swedish coastline between Tjärnö on the west coast to Stockholm on the east. At each site, 3 separate populations were sampled. For each sample the content and profile of metals, sugars, ash and lipids were measured. These measures are being evaluated to highlight trends relating to differences in location conditions. The largest impact could be seen on the sugar compostition, as monosaccharides present in the polysaccharide ulvan showed, roughly, a 2-fold increase on the east coast compared to the western coast.
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| 5. |
- Olsson, Joakim, 1988, et al.
(författare)
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Composition and processing of Ulva intestinalis from 8 different sites along the Swedish coast
- 2017
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Seaweed has the potential to provide a large quantities of biomass as feedstocks for production of energy and chemicals. Compared to terrestrial biomasses, seaweed does not require arable land or fertilizer for cultivation, effectively not competing with food production. Significant efforts are now being made to improve both cultivation, extraction techniques and product development of seaweed to enable a seaweed industry in the future. An aspect that has thus far received little attention is on the optimisation of cultivation siting to maximise the content of valuable components in the biomass (and minimize waste), despite it being well known that variation in ambient conditions cause significant changes in biomass composition. In this study, we have investigated the opportunistic summer seaweed Ulva intestinalis, which is of commercial interest due to its high growth rate and broad distribution along the entire Swedish coast. To evaluate where cultivation could be most beneficial from a biomass composition perspective, samples were collected from 8 sites along the Swedish coastline between Tjärnö on the west coast to Stockholm on the east. At each site, 3 separate populations were sampled. For each sample the content and profile of metals, sugars, ash and lipids were measured. These measures are being evaluated to highlight trends relating to differences in location conditions. As a processing example to compare performance between the sites, all samples were run in hydrothermal liquefaction, which is a promising method for production of bio oil.
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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. |
- Vaiciulyte, Sigita, 1988, et al.
(författare)
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Sufficient CO2 concentration is crucial for high biomass formation of marine microalgae
- 2015
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Ingår i: Proceedings of 4th Latin-American Society of Environmental and Algal Biotechnology Congress (SOLABIAA), November 8-13, Brazil.
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Konferensbidrag (refereegranskat)abstract
- The effect of low and high CO2 concentration for the growth of marine green microalgae genera Chlorella and Picochlorum were investigated. Chlorella sp. A, Chlorella sp. B, Chlorella sp. C and Picochlorum sp. strains were grown in a batch culture under 20:4 hours of light:dark photoperiods and with either 0.035 % (ambient air) or 2.0 % of CO2 supply. Picochlorum sp. and Chlorella sp. C achieved the highest maximum growth rate (d-1) 1.06 and 1.05, respectively, when cultured with a high CO2 supply (2.0 %). Cultures supplied with low CO2 (0.035 %), did not enter into exponential growth phase, but formed biomass in a steady linear growth pattern, suggesting significant carbon limitation. Thus, it is clear that the supply of CO2 is critical for high rates of microalgal biomass production, and optimal CO2 ¬supply rate should be identified that also improves carbohydrate formation.
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| 9. |
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| 10. |
- Forghani Targhi, Bita, 1973, et al.
(författare)
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Cultivation of microalgae- Chlorella sorokiniana and Auxenochlorella protothecoides- in shrimp boiling water residues
- 2022
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Ingår i: Algal Research. - : Elsevier BV. - 2211-9264. ; 65
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Tidskriftsartikel (refereegranskat)abstract
- Based on the ability of microalgae to purify industrial processing waters, the overall aim of this study was to evaluate whether currently wasted shrimp processing waters could be used as microalgal growth media to produce new protein-enriched food and feed ingredients. Low molecular weight (LMW) fractions of shrimp boiling water (SBW) which had been pre-flocculated using alginate (AL), carrageenan (CA), chitosan (CH) or Superfloc C-592 to recover shrimp protein via flotation, were used for cultivation of Chlorella sorokiniana and Auxenochlorella protothecoides to produce a protein-enriched microalgal biomass. CH-derived media induced the highest growth rates for both species with A. protothecoides out-performing C. sorokiniana. A. protothecoides best assimilated phosphate-phoshorous (P-PO4) and total phosphorous (TP) in all media; <63 mg/L and < 45 mg/L after 4 days, respectively. In upscaled aerated cultures of A. protothecoides in CH- and AL-derived media, P and TP uptake increased up to 85 and 127 mg/L, respectively. Further, 63% of the free amino acids (AA) were assimilated in both waters. Biomasses derived from SBW contained 37-43% protein and 15.0-17.4% fatty acids (FA) per DW; with 38-40% essential AA (EAA) and 21.3-22.5% polyunsaturated FA (PUFA), respectively Corresponding numbers for biomass cultivated in control media were 11 and 53%, protein and FA, respectively, and with 38% and 15.6% EAA and PUFA, respectively. Ability of A. protothecoides to assimilate TP and AA, and to generate a protein-rich biomass from LMW-fractions derived from SBW was thus revealed for the first time, and paves the way for a SBW-based biorefinery comprising chemical, physical and microbial processes to produce multiple products.
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| 11. |
- Levering, Jennifer, et al.
(författare)
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Genome-Scale Model Reveals Metabolic Basis of Biomass Partitioning in a Model Diatom
- 2016
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203 .- 1932-6203. ; 11:5
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Tidskriftsartikel (refereegranskat)abstract
- Diatoms are eukaryotic microalgae that contain genes from various sources, including bacteria and the secondary endosymbiotic host. Due to this unique combination of genes, diatoms are taxonomically and functionally distinct from other algae and vascular plants and confer novel metabolic capabilities. Based on the genome annotation, we performed a genome-scale metabolic network reconstruction for the marine diatom Phaeodactylum tricornutum. Due to their endosymbiotic origin, diatoms possess a complex chloroplast structure which complicates the prediction of subcellular protein localization. Based on previous work we implemented a pipeline that exploits a series of bioinformatics tools to predict protein localization. The manually curated reconstructed metabolic network iLB1027_lipid accounts for 1,027 genes associated with 4,456 reactions and 2,172 metabolites distributed across six compartments. To constrain the genome-scale model, we determined the organism specific biomass composition in terms of lipids, carbohydrates, and proteins using Fourier transform infrared spectrometry. Our simulations indicate the presence of a yet unknown glutamine-ornithine shunt that could be used to transfer reducing equivalents generated by photosynthesis to the mitochondria. The model reflects the known biochemical composition of P. tricornutum in defined culture conditions and enables metabolic engineering strategies to improve the use of P. tricornutum for biotechnological applications.
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| 12. |
- Mayers, Joshua, 1988, et al.
(författare)
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An approaching global phosphorus crisis and microalgal biotechnology: A growing problem & strategies for effective use
- 2015
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Phosphorus (P) is a critical element for life on Earth. However, readily extractable ores are being exhausted rapidly and a combination of increasing usage, rising costs and numerous geopolitical problems are expected to impact food security and industry sectors within the next few decades. This hence represents another great anthropogenic challenge and near-future issue. P is needed in the production of microalgal biomass; indeed the value of P in microalgae is similar or exceeds that of the potential biofuels, demanding a 100% recovery and recycling of P. However, unlike nitrogen (N) sources (that can be synthesised) for which the relationship of cell-contents and growth is linear, the need for P is less clearly understood. We have empirically explored the interaction between P supply and microalgal production and biochemical composition. P usage could be at least halved relative to the use of N, while maintaining adequate growth of Nannochloropsis. Indeed, by deploying certain strategies, the amount of P required to produce 1 kg of biomass can be decreased from 2.4 g to 0.85 g (65% reduction). The quantitative effects of dual N- and P-limitation on biochemical composition, fatty acid profile and biodiesel quality were also evaluated in a greater detail than has previously been reported. The replacement of inorganic nutrients with those obtained from waste nutrient streams was examined and also proved to be a successful strategy in decreasing resource consumption. P usage in the broader context of large-scale microalgal cultivation will be put into context with information critical for algal physiology, practitioners and LCA development.
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| 13. |
- Mayers, Joshua, 1988, et al.
(författare)
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An energy and resource efficient alkaline flocculation and sedimentation process for harvesting of Chromochloris zofingiensis biomass
- 2020
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Ingår i: Bioresource Technology Reports. - : Elsevier BV. - 2589-014X. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Harvesting microalgal cultures is often energetically intensive and costly. To improve efficiencies, a two-step harvesting method utilising alkaline flocculation and sedimentation to pre-concentrate cultures can be used prior to centrifugation. When applied to the microalga Chromochloris zofingiensis, high rates of sedimentation (>90%) were found at low concentrations of base (<10 mM), with the addition of magnesium to the media (via NaOH/MgSO4 or Ca(OH)2/Mg(OH)2) to form Mg(OH)2. The process was scaled to 180 L, where sedimentation was as efficient as that achieved at bench scale. Characterisation of the harvested biomass showed comparable composition (following neutralisation of pH) to biomass recovered solely by centrifugation. The alternative two-step processes were assessed for environmental impacts and cost, which indicated that a two-step harvesting generally performs better than centrifugation alone, but that the locally available electricity source is a critical parameter for optimal solution.
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| 14. |
- Mayers, Joshua, 1988, et al.
(författare)
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Influence of the N: P supply ratio on biomass productivity and time-resolved changes in elemental and bulk biochemical composition of Nannochloropsis sp.
- 2014
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 169, s. 588-595
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Tidskriftsartikel (refereegranskat)abstract
- This work reports for the first time the detailed impacts of dual nitrogen (N) and phosphorus (P) stress on growth dynamics and biochemical composition in the Eustigmatophyte Nannochloropsis sp. P-stress concurrent with N-stress had subtle effects on culture bulk biochemical composition, but negatively influenced biomass productivity. However, the N:P supply ratio can be raised to at least 32:1 without compromising productivity (yielding a maximum lipid content of 52% of dry weight and volumetric lipid concentration of 233mgL-1). The maximum biomass and lipid yields per unit of cell-P were 1.2kgDW (gP)-1 and 0.54kglipid (gP)-1. The P concentration of many common media is thus in surplus for optimal Nannochloropsis sp. biomass and lipid production, offering potential for significant savings in P usage and improving the sustainability of algal cultivation. © 2014 Elsevier Ltd.
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| 15. |
- Mayers, Joshua, 1988, et al.
(författare)
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Integrating Microalgal Production with Industrial Outputs - Reducing Process Inputs and Quantifying the Benefits
- 2016
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Ingår i: Industrial Biotechnology. - : Mary Ann Liebert Inc. - 1550-9087 .- 1931-8421. ; 12:4, s. 219-234
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Tidskriftsartikel (refereegranskat)abstract
- The cultivation and processing of microalgal biomass is resource- and energy-intensive, negatively affecting the sustainability and profitability of producing bulk commodities, limiting this platform to the manufacture of relatively small quantities of high-value compounds. A biorefinery approach where all fractions of the biomass are valorized might improve the case for producing lower-value products. However, these systems are still likely to operate very close to thresholds of profitability and energy balance, with wide-ranging environmental and societal impacts. It thus remains critically important to reduce the use of costly and impactful inputs and energy-intensive processes involved in these scenarios. Integration with industrial infrastructure can provide a number of residual streams that can be readily used during microalgal cultivation and downstream processing. This review critically considers some of the main inputs required for microalgal biorefineries - such as nutrients, water, carbon dioxide, and heat - and appraises the benefits and possibilities for industrial integration on a more quantitative basis. Recent literature and demonstration studies will also be considered to best illustrate these benefits to both producers and industrial operators. Additionally, this review will highlight some inconsistencies in the data used in assessments of microalgal production scenarios, allowing more accurate evaluation of potential future biorefineries.
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| 16. |
- Mayers, Joshua, 1988, et al.
(författare)
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Nutrients from anaerobic digestion effluents for cultivation of the microalga Nannochloropsis sp. - Impact on growth, biochemical composition and the potential for cost and environmental impact savings
- 2017
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Ingår i: Algal Research. - : Elsevier BV. - 2211-9264. ; 26, s. 275-286
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Tidskriftsartikel (refereegranskat)abstract
- Microalgal biotechnology has yielded a range of products for different consumer markets, but large scale production for bulk commodities is limited by the cost and environmental impact of production. Nutrient requirements for large-scale production contribute significantly to the cost and environmental impact of microalgal biomass production and should subsequently be addressed by more careful sourcing of nutrients. This study assessed the use of nitrogen and phosphorus contained in effluents from anaerobic digestion of food waste to cultivate the marine microalga Nannochloropsis sp. With suitable dilution, effluent could replace 100% of nitrogen demands and 16% of required phosphorus, without significant impacts on growth or biomass productivity. Additional phosphorus requirements could be decreased by increasing the N:P molar ratio of the media from 16:1 to 32:1. Nannochloropsis sp. accumulated lipid up to 50% of dry weight under N-stress, with significant increases in the content of saturated and mono-unsaturated fatty acids. Using empirical data generated in this study, the cost and environmental impact of nitrogen and phosphorus supply was assessed versus the use of fertilizers for biomass and biodiesel production. Nutrient requirements predicted by the Redfield Ratio overestimating impacts by as much as 140% compared to empirical data. By utilising residual nutrients and optimising nutrient supply, the cost and environmental impact of nitrogen and phosphorus were decreased by >90% versus the use of artificial fertilizers. This study demonstrates the importance of using empirical data for process evaluation and how anaerobic digestate effluent derived nutrients can contribute to the sustainability of algal biomass production.
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| 17. |
- Mayers, Joshua, 1988, et al.
(författare)
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Rapid determination of bulk microalgal biochemical composition by Fourier-Transform Infrared spectroscopy
- 2013
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Ingår i: Bioresource Technology. - : Elsevier BV. - 0960-8524 .- 1873-2976. ; 148, s. 215-220
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Tidskriftsartikel (refereegranskat)abstract
- Analysis of bulk biochemical composition is a key in fundamental and applied studies of microalgae and is essential to understanding responses to different cultivation scenarios. Traditional biochemical methods for the quantification of lipids, carbohydrates and proteins are often time-consuming, often involve hazardous reagents, require significant amounts of biomass and are highly dependent on practitioner proficiency. This study presents a rapid and non-destructive method, utilising Fourier-Transform Infrared (FTIR) spectroscopy for the simultaneous determination of lipid, protein and carbohydrate content in microalgal biomass. A simple univariate regression was applied to sets of reference microalgal spectra of known composition and recognised IR peak integrals. A robust single-species model was constructed, with coefficients of determination r2>0.95, high predictive accuracy and relative errors below 5%. The applicability of this methodology is demonstrated by monitoring the time-resolved changes in biochemical composition of the marine alga Nannochloropsis sp. grown to nitrogen starvation. © 2013 Elsevier Ltd.
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| 18. |
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| 19. |
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| 20. |
- Veide Vilg, Jenny, 1973, et al.
(författare)
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Seasonal and spatial variation in biochemical composition of Saccharina latissima during a potential harvesting season for Western Sweden
- 2015
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Ingår i: Botanica Marina. - : Walter de Gruyter GmbH. - 0006-8055 .- 1437-4323. ; 58:6, s. 435-447
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Tidskriftsartikel (refereegranskat)abstract
- This study monitored the biomass composition of Saccharina latissima during a potential harvesting season on the West coast of Sweden, in order to find suitable harvest times for biorefinery purposes. Specimens of S. latissima were sampled at three locations in June, August and October and the biomass was analysed for its macromolecular composition, as well as for the content of several specific compounds, e.g. sugars and fatty acids. PERMANOVA analyses showed that there was a significant difference in the biomass composition among time points. The total carbohydrate concentration was lowest in June and peaked at 360 mg g-1 dry weight in August, while the mannitol content was highest, 90 mg g-1, in June and decreased throughout the sampling period. Total protein and fatty acid concentrations were found to be approximately 80 and 3 mg g-1, respectively, with relatively little variation over time. Overall, there was little spatial variation in the macromolecular composition, although the concentration of some specific monosaccharides and fatty acids, as well as the total phenolic content, differed among localities. We discuss the implications of the observed variation in biomass composition of S. latissima for future biorefinery purposes.
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