| 1. |
- 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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| 2. |
- 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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