In this study the efficacy of using marine macroalgae as a source for polyunsaturated fatty acids, which are associated with the prevention of inflammation, cardiovascular diseases and mental ...disorders, was investigated.
The fatty acid (FA) composition in lipids from seven sea weed species from the North Sea (Ulva lactuca, Chondrus crispus, Laminaria hyperborea, Fucus serratus, Undaria pinnatifida, Palmaria palmata, Ascophyllum nodosum) and two from tropical seas (Caulerpa taxifolia, Sargassum natans) was determined using GCMS. Four independent replicates were taken from each seaweed species.
Omega-3 (n-3) and omega-6 (n-6) polyunsaturated fatty acids (PUFAs), were in the concentration range of 2-14 mg/g dry matter (DM), while total lipid content ranged from 7-45 mg/g DM. The n-9 FAs of the selected seaweeds accounted for 3%-56% of total FAs, n-6 FAs for 3%-32% and n-3 FAs for 8%-63%. Red and brown seaweeds contain arachidonic (C20:4, n-6) and/or eicosapentaenoic acids (EPA, C20:5, n-3), the latter being an important "fish" FA, as major PUFAs while in green seaweeds these values are low and mainly C16 FAs were found. A unique observation is the presence of another typical "fish" fatty acid, docosahexaenoic acid (DHA, C22:6, n-3) at ≈ 1 mg/g DM in S. natans. The n-6: n-3 ratio is in the range of 0.05-2.75 and in most cases below 1.0. Environmental effects on lipid-bound FA composition in seaweed species are discussed.
Marine macroalgae form a good, durable and virtually inexhaustible source for polyunsaturated fatty acids with an (n-6) FA: (n-3) FA ratio of about 1.0. This ratio is recommended by the World Health Organization to be less than 10 in order to prevent inflammatory, cardiovascular and nervous system disorders. Some marine macroalgal species, like P. palmata, contain high proportions of the "fish fatty acid" eicosapentaenoic acid (EPA, C20:5, n-3), while in S. natans also docosahexaenoic acid (DHA, C22:6, n-3) was detected.
► Ulva lactuca was characterized as feedstock for the acetone, butanol and ethanol fermentation. ► Hydrolysates were obtained using mild pretreatment conditions and commercial cellulases. ► Ulva ...lactuca hydrolysate was used as substrate for fermentation by two different strains. ► Rhamnose was utilized by C. beijerinckii for production of 1,2-propanediol.
Green seaweed Ulva lactuca harvested from the North Sea near Zeeland (The Netherlands) was characterized as feedstock for acetone, ethanol and ethanol fermentation. Solubilization of over 90% of sugars was achieved by hot-water treatment followed by hydrolysis using commercial cellulases. A hydrolysate was used for the production of acetone, butanol and ethanol (ABE) by Clostridium acetobutylicum and Clostridium beijerinckii. Hydrolysate-based media were fermentable without nutrient supplementation. C. beijerinckii utilized all sugars in the hydrolysate and produced ABE at high yields (0.35g ABE/g sugar consumed), while C. acetobutylicum produced mostly organic acids (acetic and butyric acids). These results demonstrate the great potential of U. lactuca as feedstock for fermentation. Interestingly, in control cultures of C. beijerinckii on rhamnose and glucose, 1,2 propanediol was the main fermentation product (9.7g/L).
During the in situ extraction of β-carotene from Dunaliella salina, the causal relationship between carotenoid extraction and cell death indicated that cell growth and cell death should be at ...equilibrium for a continuous in situ extraction process. In a flat-panel photobioreactor that was operated as a turbidostat cell numbers of stressed cells were kept constant while attaining a continuous well-defined light-stress. In this way it was possible to study the balance between cell growth and cell death and determine whether both could be increased to reach higher volumetric productivities of carotenoids.
In the two-phase system a volumetric productivity of 8.3mgβ-caroteneLRV−1d−1 was obtained. In situ extraction contributed only partly to this productivity. The major part came from net production of carotenoid-rich biomass, due to a high growth rate of the cells and subsequent dilution of the reactor. To reach equilibrium between cell growth and cell death, sparging rates of dodecane could have been increased. However, already at the applied sparging rate of 286LdodLRV−1min−1 emulsion formation of the dodecane in the aqueous phase appeared.
In a turbidostat without in situ extraction a volumetric productivity of 13.5mgβ-caroteneLRV−1d−1 was reached, solely based on the continuous production of carotenoid-rich biomass.
Algae are currently used for production of niche products and are becoming increasingly interesting for the production of bulk commodities, such as biodiesel. For the production of these goods to ...become economically feasible, production costs will have to be lowered by one order of magnitude. The application of two-phase systems could be used to lower production costs. These systems circumvent the costly step of cell harvesting, whilst the product is extracted and prepared for downstream processing. The mechanism of extraction is a fundamental aspect of the practical question whether two-phase systems can be applied for
in situ extraction, viz, simultaneous growth, product formation and extraction, or as a separate downstream processing step. Three possible mechanisms are discussed; 1) product excretion 2) cell permeabilization, and 3) cell death. It was shown that in the case of product excretion, the application of two-phase systems for
in situ extraction can be very valuable. With permeabilization and cell death,
in situ extraction is not ideal, but the application of two-phase systems as downstream extraction steps can be part of a well-designed biorefinery process. In this way, processing costs can be decreased while the product is mildly and selectively extracted.
Thus far none of the algal strains used in two-phase systems have been shown to excrete their product; the output has always been the result of cell death. Two-phase systems can be a good approach as a downstream processing step for these species. For future applications of two-phase
in situ extraction in algal production processes, either new species that show product excretion should be discovered, or existing species should be modified to induce product excretion.
Carotenoid fluorescence in Dunaliella salina Kleinegris, Dorinde M. M.; van Es, Marjon A.; Janssen, Marcel ...
Journal of applied phycology,
10/2010, Letnik:
22, Številka:
5
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Dunaliella salina
is a halotolerant green alga that is well known for its carotenoid producing capacity. The produced carotenoids are mainly stored in lipid globules. For various research purposes, ...such as production and extraction kinetics, we would like to determine and/or localise the carotenoid globules in vivo. In this study, we show that the carotenoid-rich globules emit clear green fluorescence, which can be used in, for example, fluorescence microscopy (e.g. CLSM) to obtain pictures of the cells and their carotenoid content.
In the so-called milking process of Dunaliella salina carotenoids are extracted and simultaneously produced by the culture, whilst the biomass concentration remains constant. Different theories exist ...about the extraction mechanisms although none have been proven yet. In this research, direct contact between dodecane and cells during the extraction process was studied microscopically and effects of direct contact were determined during in situ extraction experiments. Our results showed that water–solvent interphase contact resulted in cell death. This cell death and consequent cell rupture resulted in the release and concomitant extraction of the carotenoids. Furthermore, it has been suggested to add a small amount of dichloromethane to the biocompatible dodecane to create an organic phase with more extraction capacity. Our results showed that the addition of dichloromethane resulted in increased cell death and consequently the extraction rate increased. The improved solubility of carotenoids in an organic phase with dichloromethane did not significantly increase the extraction rate.
Selectivity of Milking of Dunaliella salina Kleinegris, Dorinde M. M; Janssen, Marcel; Brandenburg, Willem A ...
Marine biotechnology,
02/2010, Letnik:
12, Številka:
1
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The process of the simultaneous production and extraction of carotenoids, milking, of Dunaliella salina was studied. We would like to know the selectivity of this process. Could all the carotenoids ...produced be extracted? And would it be possible to vary the profile of the produced carotenoids and, consequently, influence the type of carotenoids extracted? By using three different D. salina strains and three different stress conditions, we varied the profiles of the carotenoids produced. Between Dunaliella bardawil and D. salina 19/18, no remarkable differences were seen in the extraction profiles, although D. salina 19/18 seemed to be better extractable. D. salina 19/25 was not “milkable” at all. The milking process could only be called selective for secondary carotenoids in case gentle mixing was used. In aerated flat-panel photobioreactors, extraction was much better, but selectiveness decreased and also chlorophyll and primary carotenoids were extracted. This was possibly related to cell damage due to shear stress.
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 production 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.
•Designs of two macroalgae cultivation strip systems featuring four longlines side by side interspaced with access corridors•Life cycle environmental impacts of the cultivation, harvest, transport and drying of seaweed biomass•Most important process in terms of environmental impacts was found to be drying•Most important material components identified as stainless-steel chains and polypropylene ropes•Higher productivity of dual layer system makes it a little more environmentally friendly from a life cycle perspective
Taxonomy and cultonomy of beet (Beta vulgaris L.) LANGE, WOUTER; BRANDENBURG, WILLEM A.; DE BOCK, THEO S.M.
Botanical journal of the Linnean Society,
05/1999, Letnik:
130, Številka:
1
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A new classification for the cultivated and weed forms of beet is proposed. The paper includes a short description of concept and rules of the new system for the nomenclature of cultivated plants, as ...published in the 1995 International Code of Nomenclature for Cultivated Plants or Cultivated Plant Code . The classification has an open character, and is formed around the basic elements called culta (singular culton). Culta need not be grouped in a hierarchical way, as in botanical classification (basic elements taxa, singular taxon), but may be grouped according to cultivar. The relevant culta for beet are the named cultivars and the newly formed cultivar groups. A summary of the latest revision of the taxonomy of Beta section Beta , has been included. The description of B. vulgaris subsp. vulgaris is changed, by adding the weed beet populations. Finally, the new classification system for cultivated plants is applied to beet, leading to a proposal to distinguish four cultivar groups: Leaf Beet Group, Garden Beet Group, Fodder Beet Group and Sugar Beet Group. The relationship between the new cultivar groups and those designated by UPOV (International Union for the Protection of New Varieties of Plants) and recommended by the Cultivated Plant Code , is discussed
A new classification for the cultivated and weed forms of beet is proposed. The paper includes a short description of concept and rules of the new system for the nomenclature of cultivated plants, as ...published in the 1995 International Code of Nomenclature for Cultivated Plants or Cultivated Plant Code. The classification has an open character, and is formed around the basic elements called culta (singular culton). Culta need not be grouped in a hierarchical way, as in botanical classification (basic elements taxa, singular taxon), but may be grouped according to cultivar. The relevant culta for beet are the named cultivars and the newly formed cultivar groups. A summary of the latest revision of the taxonomy of Beta section Beta, has been included. The description of B. vulgaris subsp. vulgaris is changed, by adding the weed beet populations. Finally, the new classification system for cultivated plants is applied to beet, leading to a proposal to distinguish four cultivar groups: Leaf Beet Group, Garden Beet Group, Fodder Beet Group and Sugar Beet Group. The relationship between the new cultivar groups and those designated by UPOV (International Union for the Protection of New Varieties of Plants) and recommended by the Cultivated Plant Code, is discussed.
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