Journal of Applied Phycology

Published by Springer Nature

Online ISSN: 1573-5176

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Print ISSN: 0921-8971

Articles


Fig. 1 Map of the East China Sea and key locations of this study 
Table 1 Daily maximum wind speed and wind direction observed in March 2012 at Iriomotejima Meteorological Station
Fig. 3 Map showing ship tracks ( black narrow solid lines ) during KT- 12-3 and drifting seaweed rafts ( closed circles ). The water between the two blue solid lines is the main stream of the Kuroshio Current as estimated by the Japan Coast Guard (2012) 
Fig. 4 Surface current distributions in the East China Sea on 1 March 2010 ( a ), 15 February 2011 ( b ), and 15 March 2012 ( c ), estimated by FRA-JCOPE2 data 
Fig. 5 Sea surface wind vector distributions in the East China Sea obtained from NOAA NOMADS. Monthly mean winds in March 2010 ( a ) and February 2011 ( b ) and daily mean winds on 9 ( c ), 10 ( d ), 20 ( e ), and 24 ( f ) March 2012 

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Unusual distribution of floating seaweeds in the East China Sea in the early spring of 2012
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April 2014

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Floating seaweeds play important ecological roles in offshore waters. Recently, large amounts of rafting seaweed have been observed in the East China Sea. In early spring, juveniles of commercially important fish such as yellowtail accompany these seaweed rafts. Because the spatial distributions of seaweed rafts in the spring are poorly understood, research cruises were undertaken to investigate them in 2010, 2011, and 2012. Floating seaweed samples collected from the East China Sea during the three surveys contained only Sargassum horneri. In 2010 and 2011, seaweed rafts were distributed only in the continental shelf and the Kuroshio Front because they had become trapped in the convergence zone of the Kuroshio Front. However, in 2012, seaweed was also distributed in the Kuroshio Current and its outer waters, and massive strandings of seaweed rafts were observed on the northern coast of Taiwan and on Tarama Island in the Ryukyu Archipelago. Environmental data (wind, currents, and sea surface height) were compared among the surveys of 2010, 2011, and 2012. Two factors are speculated to have caused the unusual distribution in 2012. First, a continuous strong north wind produced an Ekman drift current that transported seaweed southwestward to the continental shelf and eventually stranded seaweed rafts on the coast of Taiwan. Second, an anticyclonic eddy covering northeast Taiwan and the Kuroshio Current west of Taiwan generated a geostrophic current that crossed the Kuroshio Current and transported the rafts to the Kuroshio Current and its outer waters. Such unusual seaweed distributions may influence the distribution of fauna accompanying the rafts.
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Mean proportions (% of total fatty acid) of saturated (SFA), monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) of Pavlova lutheri and Chaetoceros muelleri at T1 (8 June), T2 (22 June) and T3 (6 July). Error bars indicate STD, a indicate significant increase (p < 0.05) and b indicate significant decrease (p < 0.05)
Principal component (PC) analysis plot. For Pavlova lutheri, all replicates from the three bags from the first sampling are located within the oval marked T1, all replicates from the three bags from the second sampling are located within the oval marked T2, and replicates from the three bags from the third sampling are located within the oval marked T3. For Chaetoceros muelleri the replicates from each bag at each sampling are located within the circles marked with 1, 2 and 3 for each of the bags. The circles with lightest shading are from the first sampling, circles from the second sampling are darker and those from the third sampling have the darkest shading. The position of the fatty acids in the plot indicates their importance for the spread of the samples: the closer the samples are located to a fatty acid the more they contain of this fatty acid relative to the other samples. The percentage of the total variation among the samples which is described by the two PCs is shown
Principal component (PC) analysis plot of the Pavlova lutheri samples. The replicates from each bag at each sampling are located in and around the circles marked with 1, 2 and 3 for each of the bags. The circles with lightest shading are from the first sampling, circles from the second sampling are darker and those from the third sampling have the darkest shading. The position of the fatty acids in the plot indicates their importance for the spread of the samples: the closer the samples are located to a fatty acid the more they contain of this fatty acid relative to the other samples. The percentage of the total variation among the samples which is described by the two PCs is shown
Effects of reduced diameter of bag cultures on content of essential fatty acids and cell density in a continuous algal production system

January 2012

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57 Reads

Cell density and fatty acid (FA) content of Pavlova lutheri and Chaetoceros muelleri were analysed in a continuous algal production system (250-L bags) with reduced diameter. The cell density and FA content and composition in the algal production system were determined in replicate bags over a period of 5 weeks. The results showed that the cell density and essential FAs increased during the experiment for both species. After 5 weeks the mean cell numbers had increased to 6.0 ± 0.3 × 106 cells mL−1 in the P. lutheri bags and 6.0 ± 0.4 × 106 cells mL−1 in the C. muelleri bags. The content of total FAs increased significantly (p < 0.05) in all of the bags during the experiment. At the end of the experiment the mean total FA content were 2.7 ± 0.3 pg cell−1 in the P. lutheri bags and 1.8 ± 0.1 pg cell−1 in the C. muelleri bags. Maximum total FA content registered was 3.0 pg cell−1 in one of the P. lutheri bags. The content of the essential FAs (ARA, EPA, DHA) increased over time in both of the species. At the end of the experiment the content of EPA (0.6 ± 0.1 pg cell−1) and DHA (0.3 ± 0.0 pg cell−1) were highest in the P. lutheri bags, while ARA (0.1 ± 0.0 pg cell−1) was highest in C. muelleri. EPA and DHA constituted 22% and 11%, respectively, of total FA content in P. lutheri, while ARA constituted 6% of total FA content in C. muelleri. The results from this experiment indicate that flagellates such as P. lutheri perform better in narrow bags with improved light conditions, while diatoms like C. muelleri perform better in wider bags under light limitation. Implications for bivalve hatcheries are discussed. Electronic supplementary material The online version of this article (doi:10.1007/s10811-011-9655-6) contains supplementary material, which is available to authorized users.

Fig. 3 Spectrum of fatty acids palmitic (C16:0), palmitoleic (C16:1), stearic (C18:0), oleic (C18:1 ω 9), linoleic (C18:2 ω 6) and α -linolenic (C18:3 ω 3) given as relative amounts to 100% in Chlorella sp. 800 under different cultivation temperatures: 15°C ( 1 ), 25°C ( 2 ), 35°C ( 3 ) 
Fig. 6 Correlation of biomass productivity with lipid productivity (a; r 2 0 0.683), with 
of laboratory algal strains (screened strains and reference strain), cultivation media and culture collection
Biomass productivity and productivity of fatty acids and amino acids of microalgae strains as key characteristics of suitability for biodiesel production

December 2012

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1,370 Reads

Microalgae are discussed as an alternative source for the production of biofuels. The lipid content compared to cultivation time of used species is the main reason for any choice of a special strain. This paper reviews more analytical data of 38 screened microalgae strains. After the cultivation period, total content of lipids was analysed. The extracted fatty acids were quantified as fatty acid methyl esters by GC analysis. The amino acids were analysed by HPLC. Chlorella sp., Chlorella saccharophila, Chlorella minutissima and Chlorella vulgaris were identified as species with the highest productivity of fatty acids relevant to transesterification reactions. The components were mainly linoleic acid, palmitic acid and oleic acid. To increase productivity of highly saturated fatty acids, cultivation parameters light intensity and temperature were varied. In this manner, the ideal conditions for biodiesel production were defined in this publication. Electronic supplementary material The online version of this article (doi:10.1007/s10811-012-9795-3) contains supplementary material, which is available to authorized users.

Antioxidant activities of sulfated polysaccharides from brown and red seaweeds

May 2007

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426 Reads

The in vitro antioxidant activities of the following six sulfated polysaccharides were investigated: iota, kappa and lambda carrageenans, which are widely used in the food industry, fucoidan (homofucan) from the edible seaweed Fucus vesiculosus and fucans (heterofucans) F0.5 and F1.1 from the seaweed Padina gymnospora. With respect to the inhibition of superoxide radical formation, fucoidan had an IC(50) (the half maximal inhibitory concentration) of 0.058 mg.mL(-1), while the IC(50) for the kappa, iota and lambda carrageenans were 0.112, 0.332 and 0.046 mg.mL(-1), respectively. All of the samples had an inhibitory effect on the formation of hydroxyl radicals. The results of peroxidation tests showed that fucoidan had an IC(50) of 1.250 mg.mL(-1) and that the kappa, iota and lambda carrageenans had an IC(50) of 2.753 and 2.338 and 0.323 mg.mL(-1), respectively. Fucan fractions showed low antioxidant activity relative to fucoidan. These results clearly indicate the beneficial effect of algal polysaccharides as antioxidants.

Supply chain and marketing of sea grapes, Caulerpa racemosa (ForsskAyenl) J. Agardh (Chlorophyta: Caulerpaceae) in Fiji, Samoa and Tonga

April 2014

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1,638 Reads

This report describes for the first time the supply chain of Caulerpa racemosa in three Pacific Island countries. The harvesting and marketing of C. racemosa are important subsistence activities for villagers in Fiji and Samoa, less so in Tonga. At least 150 harvesters are involved in Fiji, some 100 in Samoa and only a handful in Tonga. The annual combined crop is of some 123 t valued at around US$266,492. In Fiji, it is projected that supply does not meet local demand and there is a potential export market that is currently operating at a pilot project level. In Samoa, the supply is considered adequate for the current market. In Tonga, harvesting is carried out by a few families and supplies a niche market in that country. The possibilities of field cultivation of Caulerpa have been explored but, at present, with only limited success in Samoa. The supply chain is simple in all three countries, and only in Fiji are middlemen involved in the distribution process. The limitations for marketing include the fact that only a few sites supply most of the crop in all the three countries, that all sites need to be conserved through sustainable harvesting methods, the short shelf life of the crop and a lack of information on the carrying capacity of harvest sites. Caulerpa remains a crop that fulfils a niche market but has the potential to be scaled up for additional livelihood development in the future. Electronic supplementary material The online version of this article (doi:10.1007/s10811-014-0254-1) contains supplementary material, which is available to authorized users.

Allelopathic effects of Ulva pertusa, Corallina pilulifera and Sargassum thunbergii on the growth of the dinoflagellates Heterosigma akashiwo and Alexandrium tamarense

May 2007

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64 Reads

The allelopathic effects of fresh tissue, dry powder and aqueous extracts of three macroalgae, Ulva pertusa, Corallina pilulifera and Sargassum thunbergii, on the growth of the dinoflagellates Heterosigma akashiwo and Alexandrium tamarense were evaluated using coexistence culture systems in which concentrations of the three macroalga were varied. The results of the coexistence assay showed that the growth of the two microalgae was strongly inhibited by using fresh tissue, dry powder and aqueous extracts of the three macroalga; the allelochemicals were lethal to H. akashiwo at relatively higher concentrations of the three macroalga. The macroalgae showing the most allelopathic effect on H. akashiwo and A. tamarense using fresh tissue were U. pertusa and S. thunbergii, using dry powder were S. thunbergii and U. pertusa, and using aqueous extracts were U. pertusa and C. pilulifera. We also examined the potential allelopathic effect on the two microalgae of culture filtrate of the three macroalga; culture medium filtrate initially exhibited no inhibitory effects when first added but inhibitory effects became apparent under semi-continuous addition, which suggested that continuous release of small quantities of rapidly degradable allelochemicals from the fresh macroalgal tissue were essential to effectively inhibit the growth of the two microalgae.

Table 1 Measured and certified values of Cu concentration in the BCR 414 plankton and BCR 482 lichen reference material 
Fig. 2 Influence of the gram equivalent fraction of copper in the initial solution on the magnitude of the concentration quotient at point A  
Fig. 4 Langmuir isotherms determined for: a Cu 2+ cations; and b the sum of Cu 2+ and H + cations  
Fig. 1 Variation of the concentration quotients of copper and hydrogen in algae and in solution during sorption  
Fig. 3 Kinetics of sorption approximated with the pseudo secondorder model: a Cu2+ cations; b sum of Cu 2+ and H + cations  
Influence of hydrogen cations on kinetics and equilibria of heavy-metal sorption by algae-sorption of copper cations by the alga Palmaria palmata (Linnaeus) Weber & Mohr (Rhodophyta)

October 2013

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100 Reads

The influence of hydrogen cations on kinetics and equilibria of sorption of copper cations by the marine alga Palmaria palmata (Linnaeus) Weber & Mohr was studied under static conditions. The competitive effect of the H(+) cations is described, which influenced the uncertainty of evaluation of the alga sorption capacity. Under static conditions, the variation of the Cu(2+)/H(+) concentration ratio during sorption was found nonmonotonic. The Langmuir isotherm model was used to determine the sorption capacity of the alga, namely 12.4 mg g(-1) of dry algae mass. A similar value was determined from the kinetic parameters of the ionic exchange which is considered a pseudo-second-order chemical reaction. The consistent results indicated that the mathematical models used correctly described the equilibria and kinetics of the ionic exchange between algae and solutions.

Table 5 Non-green micro-algal FAME composition at stationary phase expressed in absolute values (%DW) comparing direct and Folch methods
Representative GC-FID traces from aD. tertiolecta CCAP 19/27; bT. pseudonana CCAP 1085/12 and c blank runs, focussing on the region where minor non-fatty acid peaks were typically located. Overlaid traces are from direct-derivatization (black) and Folch (grey) preparations from the same cultures. The anti-oxidant BHT and FAMES peaks (identified according to mass spectra and DMOX-derivatization) are labelled. Arrows indicate non-FAMEs peaks that were specific to the Folch (grey) or direct-derivatization (black) methods; open arrows indicate peaks also present in blank runs and closed arrows indicate peaks absent from blank runs
Comparison of screening methods for high-throughput determination of oil yields in micro-algal biofuel strains

August 2013

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136 Reads

The phenotypic and phylogenetic diversity of micro-algae capable of accumulating triacylglycerols provides a challenge for the accurate determination of biotechnological potential. High-yielding strains are needed to improve economic viability and their compositional information is required for optimizing biodiesel properties. To facilitate a high-throughput screening programme, a very rapid direct-derivatization procedure capable of extracting lyophilized material for GC analysis was compared with a scaled-down Folch-based method. This was carried out on ten micro-algal strains from 6 phyla where the more rapid direct-derivatization approach was found to provide a more reliable measure of yield. The modified Folch-based procedure was found to substantially underestimate oil yield in one Chlorella species (P < 0.01). In terms of fatty acid composition however, the Folch procedure proved to be slightly better in recovering polyunsaturated fatty acids, in six out of the ten strains. Therefore, direct-derivatization is recommended for rapid determination of yields in screening approaches but can provide slightly less compositional accuracy than solvent-based extraction methods.

An improved method for estimating R-phyoerythrin and R-phycocyanin contents from crude aqueous extracts of Porphyra (Bangiales, Rhodophyta)

May 2007

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1,077 Reads

One frequently-cited method for determining phycoerythrin (PE) and phycocyanin (PC) contents from crude aqueous extracts of red seaweeds utilizes peaks and troughs of absorbance spectra. The trough absorbance values are used to establish a linear or logarithmic baseline attributable to background scatter of particulate cellular debris not removed by centrifugation. Pigment contents are calculated by subtracting baseline values from PE and PC absorbance peaks. The baseline correction is intended to make the method independent of centrifugation time and/or speed. However, when crude extracts of Porphyra were analyzed using this protocol, R-PE and R-PC estimates were significantly affected by centrifugation time, suggesting that the method was not reliable for the genus. The present study has shown that with sufficient centrifugation, background scatter in Porphyra extracts can be removed, the remaining spectrum representing the overlapping absorbance peaks of water-soluble pigments in the extract. Using fourth derivative analysis of Porphyra extract absorbance spectra, peaks corresponding to chlorophyll, R-PE, R-PC, and allophycocyanin (APC) were identified. Dilute solutions of purified R-PE, R-PC and chlorophyll were scanned separately to identify spectral overlaps and develop new equations for phycobilin quantification. The new equations were used to estimate R-PE and R-PC contents of Porphyra extracts and purified R-PE, R-PC and chlorophyll solutions were mixed according to concentrations corresponding to the sample estimates. Absorbances and fourth derivative spectra of the sample extract and purified pigment mixtures were compared and found to coincide. The newly derived equations are more accurate for determining R-PE and R-PC of Porphyra than previously published methods.

Table 2 Fatty acid composition (percentage of individual lipid class) of Cyclotella cryptica biomass grown under heterotrophic conditions (n=1)
Table 2 (continued)
Growth dynamics and the proximate biochemical composition and fatty acid profile of the heterotrophically grown diatom Cyclotella cryptica

April 2010

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156 Reads

To investigate the nutritional value of the diatom Cyclotella cryptica as an alternative feed for aquaculture, its heterotrophic growth characteristics were studied. First, the proximate biochemical composition and fatty acid profiles were studied under a controlled heterotrophic growth condition. The approximate total ash, carbohydrate, lipid, and protein content were 245 mg g(-1) (dry weight), 360 mg g(-1), 165 mg g(-1) and 260 mg g(-1), respectively. Polyunsaturated fatty acids accounted for 24.5, 31.3, 45.1 and 17.3% of the total lipids in the phospholipid, sterol, free fatty acid and triglyceride classes. Secondly, the effect of aeration and agitation rates on the specific growth rate of C. cryptica under heterotrophic conditions was studied. The maximum specific growth rate was not significantly affected (P > 0.05) by the rate of agitation within the range of 100 to 160 rpm, but it was significantly affected (P > 0.05) by the rate of aeration. Optimal growth occurred when the aeration rate was within the range of 0.44 to 1.07 v/v/min. Viability measurements throughout the growth period showed that the C. cryptica cells remained viable in spite of the varied cultivation conditions. Hydrodynamic forces are an important parameter within biological systems, and optimisation is crucial for the successful scale-up of microalgal cultivation systems. Whilst the investigation was preliminary in nature, the information gained in this study will be useful for the continual development of an alternative and cost-effective feed for bivalve spat rations.

Fig. 1 This cross section reveals the stratified structure of a thick freshwater phototrophic biofilm. The dark top layer consists predom- inantly of Oscillatoria like cyanobacteria. Scale bar indicates 1 mm 
Table 1 Nitrogen and phosphorus removal rates obtained with different phototrophic biofilm based wastewater treatment systems
Phototrophic biofilms and their potential applications

July 2008

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390 Reads

Phototrophic biofilms occur on surfaces exposed to light in a range of terrestrial and aquatic environments. Oxygenic phototrophs like diatoms, green algae, and cyanobacteria are the major primary producers that generate energy and reduce carbon dioxide, providing the system with organic substrates and oxygen. Photosynthesis fuels processes and conversions in the total biofilm community, including the metabolism of heterotrophic organisms. A matrix of polymeric substances secreted by phototrophs and heterotrophs enhances the attachment of the biofilm community. This review discusses the actual and potential applications of phototrophic biofilms in wastewater treatment, bioremediation, fish-feed production, biohydrogen production, and soil improvement.

Biomass of Spirulina maxima enriched by biosorption process as new feed supplement for swine

April 2013

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192 Reads

This paper deals with the new mineral feed additives with Cu produced in a biosorption process from a semi-technical scale. The natural biomass of edible microalga Spirulina sp. was enriched with Cu(II) and then used as a mineral supplement in feeding experiments on swine to assess its nutrition properties. A total of 24 piglets divided into two groups (control and experimental) were used to determine the bioavailability of a new generation of mineral feed additives based on Spirulina maxima. The control group was feed using traditional inorganic supplements of microelements, while the experimental group was fed with the feed containing the biomass of S. maxima enriched with Cu by biosorption. The apparent absorption was 30 % (P < 0.05) higher in the experimental group. No effect on the production results (average daily feed intake, average daily gain, feed conversion ratio) was detected. It was found that copper concentration in feces in the experimental group was 60 % (P < 0.05) lower than in the control group. The new preparation-a dietary supplement with microelements produced by biosorption based on biomass of microalgae S. maxima-is a promising alternative to currently used inorganic salts as the source of nutritionally important microelements.

Growth and reproductive patterns of Undaria pinnatifida sporophytes in a cultivation farm in Busan, Korea

May 2007

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39 Reads

Monthly growth and reproduction of Undaria pinnatifida sporophytes were examined over a period of 5 months in a cultivation farm in Korea. A total of 11 characters of Undaria were measured to determine a reliable morphological character representing its growth and reproduction. Plant weight of Undaria sporophytes increased steadily over the experimental period, but it increased in four different ways. Undaria pinnatifida increased body weight by growth in length and width (October-early December), and by growth in width with the thickening of blade and stipe when sporophytes began to be fertile (December-January). In the middle of January, growth in length and width had almost stopped with the maturation of Undaria sporophytes. Finally, the weight of Undaria increased again by growth in width at the end of February. Present results indicate that Undaria sporophytes increase body weight by growth in length and width at different times, and the relationship between reproduction and vegetative growth is exclusive. Plant weight was positively correlated and fitted well with stipe width and blade width. The blade of Undaria was very thin (ca. 254 mum) and breakable by wave action, but its stipe was strong and relatively thick (ca. 8.7 mm). Furthermore, the fertility of U. pinnatifida was fitted better with stipe width than blade width. Thus, we suggest that the stipe width is the most feasible character with which to estimate the growth and reproduction of U. pinnatifida sporophytes in the cultivation farm.

Table 1 Gene-specific oligonucleotide sequences used in this study 
Fig. 2 Growth of Haematococcus pluvialis WT (a) and MT 2877 (b) under various PFDs. During the first 4 days, algae grew under 20 μmol photons m −2 s −1 of light in basal growth medium described by Kobayashi et al. (1991) under a light/dark cycle of 12 h. Afterwards, the cultures were subjected to continuous illumination at 
Table 2 Transcript levels of plastid terminal oxidase and phytoene desaturase genes in MT 2877 and WT at 300 μmol photons m −2 s −1 of PFD 
Effect of photon flux densities on regulation of carotenogenesis and cell viability of Haematococcus pluvialis (Chlorophyceae)

June 2010

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195 Reads

The green alga Haematococcus pluvialis produces large amounts of the pink carotenoid astaxanthin under high photon flux density (PFD) and other oxidative stress conditions. However, the regulation and physiological role of carotenogenesis leading to astaxanthin formation is not well understood. Comparative transcriptional expression of five carotenoid genes along with growth and pigment composition as a function of PFD was studied using a wild-type and an astaxanthin-overproduction mutant of H. pluvialis NIES144. The results indicate that astaxanthin biosynthesis was mainly under transcriptional control of the gene encoding carotenoid hydroxylase, and to a lesser extent, the genes encoding isopentenyl isomerase and phytoene desaturase, and to the least extent, the genes encoding phytoene synthase and carotenoid oxygenase. The expression of a plastid terminal oxidase (PTOX) gene ptox2 underwent transient up-regulation under elevated PFDs, suggesting that PTOX may be functionally coupled with phytoene desaturase through the plastoquinone pool and may play a role in reducing redox-potential-dependent and oxygen-concentration-dependent formation of reactive oxygen species in the chloroplast. Over-expression of both the carotenogenic and PTOX genes confers to the astaxanthin-overproduction mutant more effective photoprotective capability than that of the wild type under photooxidative stress.

a, b Bright field microscopy picture of non-stressed (a) and stressed (b) D. salina cells. Scale bars=20 μm. c, d Fluorescence microscopy pictures (CLSM) of non-stressed (c) and stressed (d) D. salina cells. Scale bars=10 μm. The CLSM pictures are combination images of three channels: DIC microscopy, green fluorescence (505–530 nm) and red fluorescence (>650 nm). e–h Isolated carotenoid-containing globules. e Isolated globules in Tris–HCl buffer (pH 8.0). f Bright field picture of the carotenoid-containing globules. g, h CLSM pictures of the carotenoid-containing globules. Scale bars=10 μm (g) and 2 μm (h). Green fluorescence comes from the globules, red fluorescence from chlorophyll remains
Absorbance spectrum of carotenoid-containing globules. Peak from 400 to 550 nm was carotenoid absorbance. The peak at 670 nm was absorbance from chlorophyll
Emission spectra of carotenoid-containing globules for three different excitation wavelengths (450, 488 and 510 nm)
Carotenoid fluorescence in Dunaliella salina

October 2010

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795 Reads

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.

Figure 1 Mean values of optical density of cultures of Synechococcus sp. immobilized in chitosan, with 80 s ( ______ ) 140 s (-) and 300 s ( _ _ _ ) of contact time with 0.1 M NaOH. Bars indicate one standard deviation. 
Figure 2 Mean number of total cell divisions (Σμ) of cultures of Synechococcus sp. cells, free (-) or immobilized in chitosan ( ______ ). Bars indicate one standard deviation. 
Growth of marine Synechococcus sp. immobilized in chitosan with different times of contact with NaOH

May 2007

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127 Reads

The thickness of the walls of the capsules of chitosan-immobilized Synechococcus cultures was dependent on the time of contact with NaOH and was directly related to culture growth. After an initial lag phase, probably caused by cell damage, the capsules obtained after 80 s in a 0.1 N NaOH solution showed better growth than that of free cell cultures (6.9 and 5.2 divisions in 10 days, respectively).

Fig. 1 Volumetric productivity (P v , ■) and biomass yield on light energy (Y x,E , ♦) during chemostat cultivation at 800 μmol photons m-2 s-1 and optimal growth temperature of C. sorokiniana (38°C). Open symbols correspond to suboptimal growth temperature (20°C) 
Performance of Chlorella sorokiniana under simulated extreme winter conditions

August 2012

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384 Reads

High annual microalgae productivities can only be achieved if solar light is efficiently used through the different seasons. During winter the productivity is low because of the light and temperature conditions. The productivity and photosynthetic efficiency of Chlorella sorokiniana were assessed under the worst-case scenario found during winter time in Huelva, south of Spain. The maximum light intensity (800 μmol photons m-2 s-1) and temperature (20°C) during winter were simulated in a lab-scale photobioreactor with a short light-path of 14 mm. Chemostat conditions were applied and the results were compared with a temperature-controlled situation at 38°C (optimal growth temperature for C. sorokiniana). When temperature was optimal the highest productivity was found at a dilution rate of 0.18 h-1 (P v = 0.28 g Kg-1 h-1), and the biomass yield on light energy was high (Y x,E = 1.2 g mol-1 photons supplied). However, at suboptimal temperature, the specific growth rate of C. sorokiniana was surprisingly low, not being able to support continuous operation at a dilution rate higher than 0.02 h-1. The slow metabolism under suboptimal temperature resulted in a decline of the light energy requirements of the cells. Consequently, the maximum winter irradiance was experienced as excessive, leading to a low photosynthetic efficiency and productivity (Y x,E = 0.5 g mol-1 photons supplied, P v = 0.1 g Kg-1 h-1). At suboptimal temperature a higher carotenoid-to-chlorophyll ratio was observed indicating the activation of light-dissipating processes. We conclude that temperature control and/or light dilution during winter time will enhance the productivity.

Light respiration in Chlorella sorokiniana

December 2011

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616 Reads

Respiration and photosynthesis are two important processes in microalgal growth that occur simultaneously in the light. To know the rates of both processes, at least one of them has to be measured. To be able to measure the rate of light respiration of Chlorella sorokiniana, the measurement of oxygen uptake must be fast, preferably in the order of minutes. We measured the immediate post-illumination respiratory O(2) uptake rate (OUR) in situ, using fiber-optic oxygen microsensors, and a small and simple extension of the cultivation system. This method enables rapid and frequent measurements without disturbing the cultivation and growth of the microalgae. Two batch experiments were performed with C. sorokiniana in a short light-path photobioreactor, and the OUR was measured at different time points. The net oxygen production rate (net OPR) was measured online. Adding the OUR and net OPR gives the gross oxygen production rate (gross OPR), which is a measure for the oxygen evolution by photosynthesis. The gross OPR was 35-40% higher than the net OPR for both experiments. The respiration rate is known to be related to the growth rate, and it is suggested that faster algal growth leads to a higher energy (ATP) requirement, and as such, respiratory activity increases. This hypothesis is supported by our results, as the specific OUR is highest in the beginning of the batch culture when the specific growth rate is highest. In addition, the specific OUR decreases toward the end of the experiments until it reaches a stable value of around 0.3 mmol O(2) h(-1) g(-1). This value for the specific OUR is equal to the maintenance requirement of C. sorokiniana as determined in an independent study of (Zijffers et al. 2010 (in press)). This suggests that respiration could fulfill the maintenance requirements of the microalgal cells.

Figure 1 Gas-tight photobioreactor, r reactor vessel, s sensors for pH and dissolved oxygen tension, f foam trap, p pressure gauge, d open ended tubing submerged in 15 cm of water, c catalytic column containing Pd catalyst, a air compressor, v1-v4 solenoid valves controlling addition of N 2 , release of excess pressure, addition of H 2 , and addition of CO 2 , respectively. 
Table 2 Ratio between PQ values during nitrogen sufficient and nitrogen depleted growth phases of different biomasses 
Figure 2 Batch culture of Chlamydomonas reinhardtii grown on NH 4 + as nitrogen source. (a) Concentration of biomass dry weight (□), starch (○), NH 4 + ( ▿ ), and chlorophyll a ( ⋄ ). Symbols are experimental values, broken lines are calculated from Eqs. 11-13. Parameters used in Eqs. 11-13, q N,max = 0.01 mol Cmol −1 h −1 , K N = 0.05 mM, q C,max = 0.06 C-mol C-mol −1 h −1 , S max = 0.6 C-mol C-mol −1 , Y x/N = 5 C-mol mol-1. (b) Specific 
Figure 3 Batch culture of Chlamydomonas reinhardtii grown on NO 2 − as nitrogen source. (a) Concentration of biomass dry weight (□), starch (○), NO 2 − ( ▿ ), and chlorophyll a ( ⋄ ). Symbols are experimental values, broken lines are calculated from Eqs. 11-13. Parameters used in Eqs. 11-13, q N,max = 0.01 mol Cmol −1 h −1 , K N = 2.2 mM, q C,max = 0.08 C-mol C-mol −1 h −1 , S max = 0.6 C-mol C-mol −1 , Y x/N = 7 C-mol mol −1. (b) Specific concentrations of chlorophyll a ( ⋄ ) and starch (○). Symbols are 
Figure 4 Batch culture of Chlorella sp. grown on NO 3 − as nitrogen source. (a) Concentration of biomass dry weight (□), NO 3 − ( ▿ ), and specific concentrations of chlorophyll a ( ⋄ ). Symbols are experimental values, broken lines are calculated from Eqs. 11-13. Predicted concentration of starch (Eq. 12) indicated by dotted line. Parameters used in Eqs. 11-13, q N,max = 0.01 mol C-mol −1 h −1 , K N = 0.5 mM, q C,max = 0.05 C-mol C-mol −1 h −1 , S max = 1 C-mol C-mol −1 , Y x/N = 5 C-mol mol −1. (b) Estimated amounts of produced O 2 and assimilated CO 2 from Eqs. 5 and 6, respectively (broken lines), and PQ values estimated from Eq. 7 (solid line). 
On-line estimation of O2 production, CO2 uptake, and growth kinetics of microalgal cultures in a gas-tight photobioreactor

May 2007

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442 Reads

Growth of the green algae Chlamydomonas reinhardtii and Chlorella sp. in batch cultures was investigated in a novel gas-tight photobioreactor, in which CO(2), H(2), and N(2) were titrated into the gas phase to control medium pH, dissolved oxygen partial pressure, and headspace pressure, respectively. The exit gas from the reactor was circulated through a loop of tubing and re-introduced into the culture. CO(2) uptake was estimated from the addition of CO(2) as acidic titrant and O(2) evolution was estimated from titration by H(2), which was used to reduce O(2) over a Pd catalyst. The photosynthetic quotient, PQ, was estimated as the ratio between O(2) evolution and CO(2) up-take rates. NH(4) (+), NO(2) (-), or NO(3) (-) was the final cell density limiting nutrient. Cultures of both algae were, in general, characterised by a nitrogen sufficient growth phase followed by a nitrogen depleted phase in which starch was the major product. The estimated PQ values were dependent on the level of oxidation of the nitrogen source. The PQ was 1 with NH(4) (+) as the nitrogen source and 1.3 when NO(3) (-) was the nitrogen source. In cultures grown on all nitrogen sources, the PQ value approached 1 when the nitrogen source was depleted and starch synthesis became dominant, to further increase towards 1.3 over a period of 3-4 days. This latter increase in PQ, which was indicative of production of reduced compounds like lipids, correlated with a simultaneous increase in the degree of reduction of the biomass. When using the titrations of CO(2) and H(2) into the reactor headspace to estimate the up-take of CO(2), the production of O(2), and the PQ, the rate of biomass production could be followed, the stoichiometrical composition of the produced algal biomass could be estimated, and different growth phases could be identified.

Table 2 Percent composition and feeding value of mixtures for fatteners 
Table 3 The nutrient content of the diets with amino acids of mixtures for fatteners 
Table 5 Average production yields in different periods of feeding experiments: starter, grower and finisher 
Table 10 Digestibility coefficients, %, mean ± SD 
Table 11 The division of classes of pork due to the pH, colour and consistency (Murray 1995) 
Effect on supplementation of Spirulina maxima enriched with Cu on production performance, metabolical and physiological parameters in fattening pigs

October 2013

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274 Reads

In this paper, the effect of addition of the biomass of Spirulina maxima enriched with copper (Sm-Cu) to the animal feed is discussed. The biomass was cultivated in the photobioreactor with the capacity of 10 m(3). After the biosorption process, the enriched biomass was investigated as the source of valuable nutrients. The feeding experiment was conducted for 87 days. The study was performed in individual rearing pens, with controlled microclimate, feed and water were available semi-ad libitum. Piglets (24) were divided into two groups (control and experimental). The experimental group was fed with addition of the biomass of Sm-Cu instead of inorganic salts. There were no statistically significant differences between the average daily and periodic weight gain, daily and periodic feed collection, as well as feed conversion ratio. There were no statistically significant differences between the amount of N excreted in faeces and urine, when considering the retention of N, both in relation to the consumed N, and relative N digested which was at a similar level. In the experimental group in comparison to the control group, the lower low-density lipoprotein cholesterol by 17.05 % (P < 0.05) and total cholesterol by 9.43 % (P < 0.05) were observed. Additionally, the increase of parameter a* of 13 % (P < 0.05) and the reduction of the natural leakage by 34 % (P < 0.05) were found.

Figure 1 Structure of levoglucosan isolated from the green seaweed Monostroma Nitidum. 
Microalgal growth enhancement by levoglucosan isolated from the green seaweed Monostroma nitidum

May 2007

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82 Reads

Microalgal growth was enhanced by the addition of levoglucosan to the culture medium. The growth-enhancing compound levoglucosan was isolated from the green seaweed Monostroma nitidum using water extraction, molecular fractionation, DEAE-cellulose column chromatography, and high-performance liquid chromatography. Yield of the compound from seaweed powder was 5 x 10(-3)% (w/w). At 10 mM concentration, levoglucosan enhanced cell growth and the specific growth rate of all feed microalgal species tested (Chaetoceros gracilis, Chlorella ellipsoidea, Dunaliella salina, Isochrysis galbana, Nannochloris oculata, Navicula incerta, Pavlova lutheri, Tetraselmis suecica) in most culture media by approximately 150%. Cellular fatty acid profiles and cell size differed marginally between cultures with and without levoglucosan.

Combination of solid phase extraction and a microalgal test system based on pulse-amplitude modulated fluorescence to detect photosystem 11 herbicides up to 0.05 μeq l−1

March 1996

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15 Reads

This note reports a microalgal test system which usesin-vivo chlorophyll a-fluorescence in combination with a solid phase extraction procedure to monitor photosystem II-herbicides in natural waters up to 0.05 g L–1.

Table 1 . Antibacterial activities of fatty acids in agar plate diffusion test.
Fatty acids with antibacterial activity from the cyanobacterium Oscillatoria redekei HUB 051

January 2003

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482 Reads

Bioassay-guided fractionation of the n-hexane extract prepared from the biomass of the cyanobacterium Oscillatoria redekei syn. Limnothrix redekei HUB 051 by silica gel and RP-18 column chromatography followed by HPLC resulted in the isolation of a mixture of two unsaturated hydroxy fatty acids. Their further separation using normal phase HPLC resulted in the identification of -dimorphecolic acid, a 9-hydroxy-10E, 12Z-octadecadienoic acid (9-HODE) and of coriolic acid, a 13-hydroxy-9Z, 11E-octadecadienoic acid (13-HODE). In agar plate diffusion test these fatty acids inhibited the growth of the Gram-positive bacteria Bacillus subtilis SBUG 14, Micrococcus flavus SBUG 16 and Staphylococcus aureus SBUG 11 and ATCC 25923, but no activity was observed against multiresistant Staphylococcus aureus strains. This is the first report about antibacterial activity of these hydroxylated unsaturated fatty acids and about the occurrence of coriolic acid in cyanobacteria.

Figure 1. Changes in paramylon cellular levels in Euglena wild type and WZSL mutant under the two growth conditions and with the different carbon sources. Bars represent S.D. (n = 3).
Figure 2. Changes in paramylon level per volume of batch culture. The curves show the growth of the WZSL mutant in the light with the different carbon sources. Bars represent S.D. (n = 3).
Figure 3. a) WZSL cell 24 h after inoculation: the cell appears almost deformed, completely filled with paramylon granules; b) wild type cell 72 h after inoculation: the cell has regained its fusiform morphology; paramylon granules are few and very small. (Bars: 10 µm).
Figure 4. Scanning electron micrograph of a paramylon granule: the highly ordered structure of concentric layers around an inner central core is well visible. (Bar: 0.5 µm).
Paramylon (??-1,3-glucan) content in wild type and WZSL mutant of

February 2001

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1,541 Reads

The effects of growth conditions on paramylon (a -1,3-glucanreserve carbohydrate) content were examined in the photosyntheticwild-type and a spontaneous non-photosynthetic WZSL mutant of theunicellular flagellate Euglena gracilis. This carbohydrate is known toshow interesting applications in human and veterinary medicine, asimmunostimulant and immunopotentiator. For both strains, the synthesisof reserve depends mainly on the growth conditions, i.e. light or dark. Thehighest amount of paramylon is accumulated by the mutant (90% dryweight) under dark conditions and with glucose as the carbon source. Thesefindings are discussed in terms of feasibility of exploitation of both strainsas an alternative source of -glucan, and of the importance of thechloroplast compartment in the synthesis of this compound.

Liquefaction of dulse (Palmaria palmata (L.) Kuntze) by a commercial enzyme preparation and a purified endo ,β-1,4-D-xylanase

January 1992

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197 Reads

Liquefaction of dry and freshPalmaria palmata by food grade enzyme preparations and a purified endo-β-1,4-D-xylanase was studied. The endo-β-1,4-D-xylanase (EC 3.2.1.8) was purified to homogeneity from a commercial food grade enzyme prepared fromAspergillus niger. It has a molecular weight of 22 500, a pI of 3.5, is inactive toward corn arabinoxylan,p-nitrophenyl-β-D-xylose, carboxymethyl cellulose but shows a weak activity toward microcrystalline cellulose. It hydrolyzes oat and dulse xylan equally well in seawater and deionized water essentially into xylose and xylobiose. It is stable between pH 5.5 to 9.0 and 0 to 30 °C and its activity is optimal at pH 4.5–5.5 and 40–60 °C. It has a Km of 2.2 and 2.8 mg ml-1 and Vmax of 3600 and 3900 nkat mg-1 of protein on oat and dulse xylan, respectively. Acetate buffer, deionized water and seawater alone extracted 62.6 to 64.5 % of the dry weight of dry dulse, but the use of commercial food grade enzyme preparations or the purified xylanase improved liquefaction to 81.2–87.1 %. Xylose and galactose were the only sugars present in the soluble extracts. Deionized and seawater extracted 58.8–52.7 and 39.1–42.2% of the dry weight of the fresh algae collected in fall and summer, respectively. Only galactose was found in the seawater extract, while some xylose with galactose were measured in the deionized water extract of the fresh autumn algal sample. Purified and crude xylanase improved liquefaction of fresh algae to 79.8–81.4 and 71.9–77.9% of the fresh dry weight (fall and summer, respectively) in deionized and seawater, respectively, and increased the xylose content of the soluble fractions. Polysaccharides in the soluble residues were composed of 1,3/1,4-linked xylose, 1-linked galactose (floridoside) and 1,4-linked glucose (cellulose) and contained essentially 1,4-linked xylose and 1,4-linked glucose in insoluble fractions obtained after enzymatic treatment. The use of xylanase-containing food grade enzyme preparations improves liquefaction ofPalmaria palmata, particularly from fresh alga. This study indicates that processing such as drying may modify markedly the solubility ofP. palmata cell wall polysaccharides, which would imply the existence of some organization and/or other components in the fresh cell wall that lower xylan solubility in seawater.

Increased activity of the non-regulated enzymes fructose-1,6-bisphosphate aldolase and triosephosphate isomerase in Anabaena sp. strain PCC 7120 increases photosynthetic yield

June 2007

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48 Reads

Non-regulated enzymes in the Calvin cycle are generally presumed to be less important for the regulation of photosynthetic yield. Here, to investigate the relationship between the activity of non-regulated enzymes and photosynthetic yield, two non-regulated enzymes in the Calvin cycle—a rice cytosolic fructose-1,6-bisphosphate aldolase (FBA) and a spinach chloroplast triosephosphate isomerase (TPI)—were cloned and co-expressed in cells of the cyanobacterium Anabaena sp. strain PCC 7120. The activity of FBA and TPI and the photosynthetic yield reflected by photosynthetic O2 evolution and cell dry weight were measured and compared between wild-type and transgenic cells. Our results demonstrated that the activity of FBA and TPI were increased in transgenic cells relative to wild-type cells, and that activity was further increased in a transgenic strain harboring two sets of FBA-TPI tandem genes relative to cells containing one copy of the FBA-TPI tandem gene. The increased activity of FBA and TPI in Anabaena sp. strain PCC 7120 increased photosynthetic yield, with increased activity levels correlating closely with the degree of changes in photosynthetic yield. This implies that the photosynthetic yield is limited by the activity of the non-regulated enzymes FBA and TPI, and that the endogenous activity of non-regulated enzymes is not sufficient to increase photosynthetic yield. We discuss the various roles of FBA and TPI, and regulated and non-regulated enzymes, in modulating photosynthetic yield.

Increased activity of the tandem fructose-1,6-bisphosphate aldolase, triosephosphate isomerase and fructose-1,6-bisphosphatase enzymes in Anabaena sp. strain PCC 7120 stimulates photosynthetic yield

August 2007

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35 Reads

The regulation of photosynthetic yield at the genetic level has largely focused on manipulation of the catalytic enzymes in the Calvin cycle by genetic engineering. In order to investigate the contribution of increased enzymatic activity in the Calvin cycle on photosynthetic yield, the rice fructose-1,6-bisphosphate aldolase (FBA), spinach triosephosphate isomerase (TPI) and wheat fructose-1,6-bisphosphatase (FBPase) genes were cloned in tandem and co-overexpressed in cyanobacterium Anabaena sp. strain PCC 7120 cells. The enzymatic activities of FBA, TPI and FBPase, as well as sedoheptulose-1,7-bisphosphatase (SBPase), were remarkably increased in transgenic cells relative to the wild-type. The photosynthetic yield, as reflected by photosynthetic O2 evolution and dry cellular weight, was also markedly increased in transgenic cells versus wide-type cells. The activity of SBPase is considered the most important factor for ribulose-1,5-bisphosphate (RuBP) regeneration in the Calvin cycle, and increased activity of TPI alone in transgenic cells does not stimulate photosynthetic yield. Thus, the increased activity of FBA and FBPase, but not TPI, significantly improved photosynthetic yield in transgenic cells by stimulating SBPase activity and consequently accelerating the RuBP regeneration rate.

Exogenous expression of the wheat chloroplastic fructose-1,6-bisphosphatase gene enhances photosynthesis in the transgenic cyanobacterium, Anabaena PCC7120

May 2005

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26 Reads

The paper reports a study on the genetic regulation of photosynthesis by introducing the gene encoding wheat chloroplastic fructose-1,6-bisphosphatase (FBPase) into the cyanobacterium Anabaena PCC7120. The gene was RT-PCR amplified from wheat and modified by replacement of the 5′-terminal encoding sequence with optimal and A/T-rich codons to promote prokaryotic expression. The resultant FBPase gene was ligated downstream of the strong promoter, PpsbA of expression vector pRL-439, then inserted into of shuttle vector pDC-08. The resulting shuttle expression vector (pDC-fbp) was transferred into the filamentous, heterocystour cyanobacterium, Anabaena PCC7120, by the tri-parental conjugation transfer method. Protein expression of FBPase in the transgenic Anabaena was 126.5% higher than in wild type cells, and the enzyme activity of transgenic cells was 1.41-fold higher than that of wild type cells. Under atmospheric conditions of 360 μmol mol−1 CO2, Anabaena cells overexpressing the FBPase gene further showed increases in net photosynthesis (117.2%) and true photosynthesis (122.5%) as compared to wild type cells. In addition, transgenic Anabaena grew faster and contained more Chl a than did wild type cells. Together, these results indicate that introduction of the wheat chloroplastic FBPase gene into Anabaena increase photosynthesis and cell growth; furthermore, these trends were more evident under stress condition (higher CO2 concentration). This is the first report of enhanced photosynthesis in cyanobacteria expressing genes from higher plants.

Growth inhibition of the cyanobacterium Spirulina (Arthrospira) platensis by 1.7 MHz ultrasonic irradiation

January 2003

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44 Reads

Ultrasonic waves of high frequency (1.7 MHz) and low intensity (0.6 W cm–2) were employed to prevent cyanobacterial cells from growing fast and the effects of this growth inhibition were investigated. At least five minutes of ultrasonic irradiation was essential for effective inhibition. The growth rate of irradiated cells was reduced to 38.9% of the control during short-term culture. Longer exposure did not significantly enhance the inhibition. For a particular level of energy input, distributed ultrasonic exposure (more short intermittent exposures) was more effective in inhibiting growth than fewer, but longer exposures. For instance, the final biomass decreased to 30.1% of the control after ultrasonic irradiation for 4 minutes every 3 days, whereas it only decreased to 60% of the control with exposure for 12 minutes every 11 days. It is suggested that distributed ultrasonic irradiation is a practical method to prevent cyanobacterial cells from fast growth. A possible explanation for the inhibition is discussed in relation to cell structure, the absorption spectrum of intact cells, chlorophyll level and oxygen evolution.

Antibiotic effect of linolenic acid from Chlorococcum strain HS-101 and Dunaliella primolecta on methicillin-resistant Staphylococcus aureus

April 1995

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72 Reads

Methanol extracts fromChlorococcum strain HS-101 andDunaliella primolecta strongly inhibited the growth of a strain of methicillin-resistantStaphylococcus aureus (MRSA), which is causing serious problems in Japanese hospitals. So that the anti-MRSA substance(s) could be purified and identified, the growth medium was improved for antibiotic production. When the two strains were cultured in their improved media, antibiotic production byChlorococcum strain HS-101 was 1.8-fold that in the standard BG-11 medium, and production byD. primolecta was 2.3-fold. The activity pattern of fractions eluted by silica-gel or gel-permeation chromatography suggested that both strains produced two antibiotic substances. Identification of the purified substances by NMR and GC-MS showed that one of the active substances in both strains was-linolenic acid. Ten fatty acids from other sources were tested, and it was found that unsaturated fatty acids had antibiotic activity against MRSA, with the highest activity that of -linolenic acid.

Heterotrophic production of ascorbic acid by microalgae. Journal of Applied Phycology, 6 99-104

April 1994

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87 Reads

An aerobic fermentation process has been developed for the production of L-ascorbic acid (vitamin C). After an extensive screening program for microorganisms capable of heterotrophically synthesizing L-ascorbic acid, a unicellular green microalga,Chlorella pyrenoidosa, was selected. This organism has a number of characteristics that recommend it as an industrial organism: (1) it can double every 3.5 h when growing aerobically in the dark on a glucose-minimal salts medium; (2) its small size and tough cell wall make it very insensitive to shear, allowing very high impeller velocities; (3) it can be grown to 100 g L–1 cell dry weight; (4) it is readily mutable by classical mutagenesis techniques; and (5) it has efficient growth kinetics with respect to yield of cell mass on glucose and oxygen. Fermentation process development and classical strain improvement have resulted in a greater than 70-fold increase in intracellular ascorbic acid concentration compared to the parent strainC. pyrenoidosa UTEX 1663. The process is compatible with existing industrial fermentation technology and equipment and is described in U.S. Patent 5,001,059. Patents have been submitted for a process in which the ascorbic acid accumulates extracellularly.

Table 1 . Lipid and fatty acid content (mg g-dry wt) and composition of lipid fractions of the 11 marine macroalgae. Distribution of fatty acids (%)
Table 2 . Fatty acid composition of marine algae (values are wt % of total fatty acids).
Table 3 . Fatty acid composition (molar %) of neutral lipids, gly- colipids and phospholipids in the two Chlorophyceae.
Table 4 . Fatty acid composition (molar %) of neutral lipids, glycolipids and phospholipids in the five Pheophyceae.
Table 6 . Content of some important fatty acids in the 11 marine macroalgae (mg g-] dry wt).
Fatty acids from 11 marine macroalgae of the French Brittany coast

December 1994

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902 Reads

Four species of red marine algae (Rhodophyceae), five species of brown marine algae (Pheophyceae) and two species of green marine algae (Chlorophyceae) were examined for the fatty acid composition of the three lipid groups separated by silica gel column chromatography (neutral lipids, glycolipids, phospholipids). The four red algae had high contents of 16:0 and C20-polyunsaturated fatty acids (PUFA), 20:5n-3 ranging from 18 to 49% of the total fatty acid content and 20:4n-6 from 1.4 to 22.5%, these fatty acids were evenly distributed in all lipid groups. The five brown algae had high contents of 18:1n-9, 18:2n-6 and 18:3n-3 but low content of 20:5n-3. No precise trend was detected for the distribution of these fatty acids in the three lipid groups. The two green algae had high contents of 16:0, 18:1n-7 and 18:3n-3 and a very low content of PUFA. They contained also large amounts of 16:4n-3 together with 16:2n-6 and 16:3n-3. While 16:2n-6 was mainly found in phospholipids, 16:4n-3 was mainly distributed in neutral lipids and glycolipids.Porphyra umbilicalis represents the richest source of 20:5n-3 whileUndaria pinnatifida can be selected when a balanced mixture of (n-6) and (n-3) PUFA is required.

Figure 1: Study sites along the coast of Talibong island, Trang Province, Andaman Sea, Southern Thailand, which were affected by the 2004 tsunami
Table 1 List of species and their distribution 
Figure 2: Variations in percentage cover of some dominant macroalgae. a Padina sanctae-crucis, b Laurencia composita, c Sargassum stolonifolium. Bars Standard error (n = 5). Letters a–c indicate significant group of means found with the Tukey HSD tests
Can macroalgae recover, 13 months after the 2004 Tsunami?: A case study at Talibong Island, Trang Province, Thailand

November 2009

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238 Reads

The tsunami that hit the coast of Thailand along the Andaman Sea on 26 December 2004 caused great damage to human life, property and coastal resources. Here we report the effect of the tsunami on the seaweed community, and its recovery, at Talibong Island, one of the affected areas in Trang province. We made surveys at three sites around the island from April 2004 to January 2006. Fifteen 0.5m ×0.5m permanent plots were set up on the west coast of the island to monitor changes in the seaweed community. Eighteen species were found. Sargassum stolonifolium and Laurencia composita were the most abundant, covering 90% and 39%, respectively, of the rocky substrate. Thirteen species varied among sites and seasons. Eleven species, however, were strongly affected by the tsunami. L. composita and Padina sanctae-crucis, for example, were initially washed up onto the shore by the strong wave action, which clearly resulted in a decrease in percentage cover. Also, many permanent plots were covered by sediment causing anoxic conditions, an indirect impact of the tsunami. A difference in species composition revealed a change in overall diversity. Particular morphologies and life forms were more sensitive to the extremes of the tsunami than others. Therefore, the recovery ability of populations of the affected species varied. We did not find any seasonal pattern to the recovery of seaweed after the tsunami within the 13months of this study.

Use of the Green Alga Ulva rigida C. Agardh as an Indicator Species to Reassess Metal Pollution in the Thermaikos Gulf, Greece, after 13 Years

January 2000

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192 Reads

The concentrations of metals (Mn, Pb, Fe, Zn, Cu, Cd,Co, Ni, Cr, Na, K, Ca, Mg) were determined in thegreen alga Ulva rigida, in the sediment andseawater of Thermaikos Gulf (Greece) during monthlysamplings in 1994–1995. This Gulf is the recipientof domestic and industrial effluents. Pb, Fe, Cu, Coand Cr concentrations in U. rigida at the studyarea were higher than those 13 years earlier andapparently came from different sources than those forZn, Cd and Ni. The relative abundance of metals inthe alga decreased in the order: Mg > Na > K >Ca > Pb > Fe > Mn > Zn > Cr, Cu > Ni >Co > Cd. Only Cu concentrations in the alga fromKalochori and Cd ones from Viamyl showed significantseasonal changes. Cu and Cd concentrations ingeneral followed the same pattern of variation, withminimum values in winter-spring. This pattern isdiscussed in relation to growth dynamics and tissueage. Only Pb concentrations in the alga showed asignificant positive correlation with concentrationsin the seawater. There were both positive andnegative correlations among some metals in the alga. It is concluded that U. rigida can be used as anindicator species, especially for Pb.

An overview of seaweed resources in Chile.J. appl. Phycol. 5: 133-139

April 1993

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198 Reads

The seaweed harvest in Chile has doubled during the past decade, and export values have increased by 300% because of diversification and increase in the volume of products with greater value added. The export value of seaweed products increased from US 18 million in 1980 to18 million in 1980 to 52 million in 1991. During the past decade, the successful cultivation of Gracilaria was implemented, and this has compensated for the large decrease in yields from natural beds. In the short term, it will be necessary to develop techniques for the cultivation of other resources such as Iridaea, Gigartina, Lessonia and Gelidium. Alternative biotechnological methods must also be developed, such as the use of Gracilaria strains with increased quality and production for growth in cultivation centers.

Adsorption of Radionuclides (134Cs, 85Sr, 226Ra, 241Am) by Extracted Biomasses of Cyanobacteria ( Nostoc Carneum , N. Insulare , Oscillatoria Geminata and Spirulina Laxis-Sima ) and Phaeophyceae ( Laminaria Digitata and L. Japonica ; Waste Products from Alginate Production) at Different pH

April 2006

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132 Reads

The extracted biomasses of four cyanobacteria (Nostoc carneum, Nostoc insulare, Oscillatoria geminata, and Spirulina laxissima) grown in axenic mass cultures, and of four samples of Laminaria obtained from different locations (L. digitata I and II, France; L. japonica I and II, China; all waste products from alginate production) were tested for their ability to adsorb four radionuclides (134Cs, 85Sr, 226Ra, and 241Am) under different pH regimes. In addition, two of the cyanobacterial biomasses (N. carneum. and O. geminata) and the four Laminaria biomasses were phosphorylated before being tested as radionuclide adsorbers. The non-phosphorylated cyanobacterial biomasses showed very low adsorption of 134Cs but substantially higher removal of 85Sr and 226Ra, which increased with increasing pH. 241Am was almost completely removed from the solution at low pH, but less at higher pH. After phosphorylation, removal of 134Cs, 85Sr and 226Ra by the cyanobacterial biomasses was improved, particularly at lower pH, but there was almost no adsorption of 241Am. The non-phosphorylated Laminaria biomasses showed good removal of 134Cs and very good adsorption of 85Sr and 226Ra. Removal of 241Am was high at low pH but decreased with increasing pH. After phosphorylation, adsorption of 134Cs by Laminaria samples was slightly improved; removal of 85Sr and 226Ra was increased at low pH with a tendency towards decrease in adsorption with increasing pH; but almost no 241Am was adsorbed. The origin of the cyanobacterial and Laminaria materials appeared to have little effect on the adsorption of the radionuclides.

Figure 1. Chemical structure of the two major repeating units in ulvan. 
Figure 2. 13 C NMR spectrum of ulvan extracts from U. rotundata (Spain), U. armoricana (St Brieuc, 1993), U. scandinavica (Roscoff 1995), 
Table 4 . 13 C NMR chemical shifts (ppm) of main repeating units in ulvans.
Chemical composition and 13C NMR spectroscopic characterisation of ulvans from Ulva (Ulvales, Chlorophyta)

February 1999

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647 Reads

The chemical composition and structures of several ulvan extracts isolated from various Ulva species were studied. They were all composed mainly of rhamnose, glucuronic acid, xylose, glucose and sulphate with smaller amounts of iduronic acid and traces of galactose. Proteins were also present, most likely as contaminants. Precise quantification of the uronic acid content by chemical-enzymatic hydrolysis coupled to HPAEC-PAD analysis and by colorimetry was not achieved, most likely due to the incomplete hydrolysis of glucuronan segments, inadequate HPAEC-pulsed-amperometric response factor for iduronic acid and to a possible differential colorimetric response of the two uronic acids. 13C NMR spectroscopic investigation of different ulvans demonstrated that they were all based on ulvanobiuronic acid 3-sulphate A and B repeating units [β-D-Glc pA-(1->4)-α-L-Rhap3S and α-L-IdopA-(1->4)-α-L-Rha p3S, respectively] as well as contiguous β 1->4 linked D-glucuronic acids possibly occurring either in ulvan or as a separate glucuronan. Marked variations in the content of the repeating structures were seen among the different samples. However, due to the limited number of samples studied, no conclusion was reached concerning the effects of species and ecophysiological conditions on the chemistry of ulvan.

Table 1 . Harvested volume, biomass concentration and weight of lyophilized material measured during the operation of the system.
Figure 2. Variation of culture parameters during a batch culture of P. tricornutum using 12 CO 2 . 
13 C in fatty acids of the biomass produced using 13 CO 2 as a source of carbon in the growth of P. tricornutum.
Production of 13C polyunsaturated fatty acids from the microalga Phaeodactylum tricornutum

January 2003

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64 Reads

An integrated process for the indoor production of 13C labelled PUFA from Phaeodactylum tricornutum is presented. The core of the process is a bubble column photobioreactor from which the exhaust gas from the reactor is returned to the culture by a low pressure compressor. To avoid accumulation of dissolved oxygen in the culture medium, the exhaust gas is bubbled through a sodium sulphite solution before returning it to the reactor. Carbon is removed from the medium before inoculating the alga, then labelled 13CO2 is injected for pH control and carbon supply. The reactor has been operated in semicontinuous mode at a dilution rate of 0.01 h–1, a biomass productivity of 0.1 g L–1 d–1 being obtained. Under this conditions both pH and dissolved oxygen were correctly controlled and the adequacy of the system for autotrophic production of labelled biomass was demonstrated. Analysis by GC-MS revealed that the fatty acids content of the biomass obtained was 10% d.wt., the content of eicosapentaenoic acid was 2.5% d.wt. All the fatty acids were labelled, more that 90% of the carbon present in these fatty acids was 13C. Element analysis of biomass and supernatant showed that 59.5% of injected carbon was assimilated into the biomass whereas 33% remained in the supernatant, and 7.5% remained undetected. Due to the high cost of 13CO2 different strategies for the optimisation of labelled carbon use are proposed.

In vitro binding of the carcinogen N-[methyl-14C]-nitrosodimethylamine by algal dietary fibers and their role in reducing its bioaccumulation

April 1993

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10 Reads

The present study was initiated to determine if algal dietary fibers (DF) bind the carcinogen N-[methyl-14C]-nitrosodimethylamine (DMNA) in vitro and how bioaccumulation of orally-given carcinogen is affected by a diet containing algal DF. Eight kinds of algal DF, including powdered fronds of Laminaria religiosa (LRP) and agar (from Gracilaria verrucosa) were used in the in vitro test. Cellulose powder (CP) was used as a control DF. In vitro binding rates of DMNA by CP, LRP and agar were 0.28%, 0.65% and 0.21% of the initial dose, respectively. Rats fed a diet containing 2% LRP or 2% agar were examined at 3 or 24 h after dosing. There was reduced retention of the orally-ingested DMNA in the liver, possibly because of reduced DMNA-absorption from the intestinal tract earlier than 3 h after dosing. Binding rates of DMNA by algae were neither related to the DF values nor to the extent of reduction of DMNA-absorption from the intestinal tract.

Table 1 Seaweed species from which tissue culture have been accomplished
Table 1 (continued)
Seaweed micropropagation techniques and their potentials: an overview. Dev Appl Phycol Ninet Inter Seaweed Symp 2:159-167

February 2009

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7,009 Reads

The seaweed industry worldwide uses 7.5–8.0 million tonnes of wet seaweeds annually with a majority of it derived from cultivated farms, as the demand for seaweed based-products exceeds the supply of seaweed raw material from natural stocks. The main advantage of cultivation is that it not only obviates overexploitation of natural populations but also facilitates the selection of germplasm with desired traits. To enhance the economic prospects of seaweed cultivation, varied practices, such as simple and cost effective cultivation methods, use of select germplasm as seed stock coupled with good farm management practices, etc., are adopted. Nevertheless, in vitro cell culture techniques have also been employed as they facilitate development and propagation of genotypes of commercial importance. There are more than 85 species of seaweeds for which tissue culture aspects have been reported. Although the initial aim of these techniques focuses mostly on genetic improvement and clonal propagation of seaweeds for mariculture, recently the scope of these techniques has been extended for use in bioprocess technology for production of high value chemicals of immense importance in the pharmaceutical and nutraceutical sectors. Recently, there has been a phenomenal interest in intensifying seaweed tissue and cell culture research to maximize the add-on value of seaweed resources. This paper deals with the status of seaweed micropropagation techniques and their applications in the context of the marine biotech industry. Further, it also provides an analysis of the problems to be resolved for removing the barriers that are impeding the true realization of potentials offered by these techniques for sustainable development and utilization of seaweed resources.

16S rRNA-Targeted identification of cyanobacterial genera using oligonucleotide-probes immobilized on bacterial magnetic particles

August 2001

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17 Reads

16S rRNA-targeted identification of cyanobacterial genera, Anabaena,Microcystis, Nostoc, Oscillatoria, Synechococcus wasdeveloped using bacterial magnetic particles (BMPs). 16S rRNA-targetedcapture probes designed from the genus specific region of the 16S rRNAsequence were immobilized on BMPs. Identification of cyanobacteria wasperformed by a sandwich hybridization using the capture probes – BMPconjugates and a digoxigenin (DIG)-labeled detector probe complementaryto the highly conserved 16S rRNA sequence for cyanobacteria. Theluminescence intensity of the probe/target-BMP hybrids was measured afterreaction with alkaline phosphatase conjugated anti-DIG antibody. Fivespecies of cyanobacteria from five different genera were successfullydiscriminated using this magnetic capture system.

Efficient 5' ETS walking from conserved 18S rDNA sequences of the dinoflagellates Alexandrium and Akashiwo sanguinea (Dinophyceae)

December 2005

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42 Reads

An external transcribed spacer (ETS) walking PCR technique was developed for the isolation of unknown sequences adjacent to the 18S rDNA. This strategy relied on four "walking primers", which were designed to bind unknown sequences upstream from the 18S rDNA, and a specially programmed series of thermocycles. This method was successful in the isolation of the 5' ETS regions from harmful dinoflagellates, including Alexandrium affine, A. catenella, A. minutum, A. tamarense, and Akashiwo sanguinea. Mono-directional sequencing reactions revealed the PCR products to be 392–962 nucleotides in length, and the 5' ETS in these products were longer than 362 bp. These are the first such sequences available for A. sanguinea and the Alexandrium. In comparisons of the ETS sequences, genetic distance was considerably high within the Alexandrium. Furthermore, the sequences were significantly variable among the different strains of identical species: genetic distance was recorded at 0.0420 for A. tamarense strains and as less than 0.7841 within strains of A. sanguinea. The 5'-start nucleotide of 18S rDNA was variable between the two genera: the five species of Alexandrium contained a T base, and A. sanguinea contained an A base. These results demonstrate the effectiveness of the ETS walking PCR method. This method will be valuable in directional ETS walking from known regions to unknown regions, particularly concerning the boundary sequences of rRNA genes.

Increasing the transient expression of GUS gene in Porphyra yezoensis by 18S rDNA targeted homologous recombination

September 2003

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23 Reads

In order to test whether 18S rDNA can influence positively GUS gene transient expression in the red alga Porphyra yezoensis, a targeting vector pQD-GUS was constructed containing a portion of the 18S rDNA of P. yezoensis and transformed it into the same strain protoplasts. The results showed that GUS protein activity was increased markedly with pQD-GUS compared to the parent pBS-GUS. It is suggested that this system can be used to enhance the expression of exogenous genes in transgenic P. yezoensis.

Figure 1. Bootstrap 50% majority-rule consensus tree resulting from parsimony analysis of 18S rDNA sequence data for 41 Ban- giophycidean samples. Bootstrap values of 50% and over are shown for each resolved internode. New Zealand entities are shown in bold. 
Species recognition in New Zealand Porphyra using 18S rDNA sequencing

October 1999

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238 Reads

The long geographic isolation of New Zealand, an archipelago with a large latitudinal range (29°to 54°S) and an extensive coastline, has resulted in a high level of endemism in both land and coastal marine flora. The genus Porphyra in NZ is represented by 5 epiphytic species and a number of epilithic species, many of which are undescribed. Systematic studies aimed at understanding variation inmorphology and life history are underway, and have led to the description of a number of new species. The present study uses sequence data from the18S rDNA locus to investigate genetic variation in New Zealand Porphyra. Sequences have been fully determined for 10 epilithic species. A subset of these data has been shown to be sufficient to distinguish established taxa and to identify new entities. Our data indicate that New Zealand harbours at least 12 epilithic species of Porphyra, establishing the NZ coastline as a repository of diversity for this genus. Phylogenetic trees based on division in complete 18S rDNA sequence data show a deep division in the genus that is not obviously correlated with existing morphological characters, and indicate that representatives of the New Zealand flora have undergone long reproductive isolation.

Hypervariable regions (V1–V9) of the dinoflagellate 18S rRNA using a large dataset for marker considerations

October 2011

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828 Reads

DNA sequencing methods have been used for the molecular taxonomic discrimination of dinoflagellate protists, particularly using partial 18S rRNA sequences. This study evaluated the taxonomic discrimination power of rRNA gene hypervariable regions (V1 to V9) in dinoflagellates from a large dataset. These included 77 dinoflagellate species (9 orders, 17 families, 40 genera). The complete 18S rRNA sequences of the dinoflagellates ranged from 1,787 to 1,813bp in length, and consisted of eight V regions with a total combined length of 678 to 699bp. Regions longer than 100bp were recoded for V2, V4, and V8 regions; high nucleotide divergences were detected in V1, V2, and V4 regions. Statistic tests showed that the divergences of individual V regions were significantly different (t-test, P < 0.05) compared with the complete 18S rRNA. The V2 region showed the highest score (83.5%) for PI sites. Moreover, intra-genus DNA similarities of the V2 were considerably low (<93%). Neighbor-joining analyses showed that phylogenetic resolution in the V2–V4 region was 1.32-fold higher than that of the complete 18S rRNA. These results demonstrate that V2 has the highest taxonomic resolving power within the 18S rRNA gene of dinoflagellates, suggesting the V2 and adjacent regions (e.g., V1 to V4) may be the best for marker considerations. KeywordsDinoflagellate–Hypervariable region–18S rRNA–Nucleotide divergence–DNA taxonomy

The 18S rRNA gene sequences of four commercially important seaweeds

November 1992

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284 Reads

18S rRNA gene sequences are presented for Ahnfeltia plicata, Chondrus crispus, Furcellaria lumbricalis and Palmaria palmata, commercially important marine algae of the North Atlantic. The sequences range from 1765 to 1777 nucleotides in length, with guanine + cytosine content of 50.1% to 52.4%. Sequence divergence between species in different orders was 11.3–12.3%, whereas the variation between C. crispus and F. lumbricalis, both from the Gigartinales, was only 3.6%. Based on limited experience with other groups of Rhodophyta, these sequences obtained from single populations are likely to be representative of the species as a whole, with little variation expected among conspecifics regardless of morphological aberration or apparent genetic isolation.

A mutant ofDunaliella parva CCAP 19/9 leaking large amounts of glycerol into the medium

December 1991

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10 Reads

A mutant of the halotolerant green algaDunaliella parva, which leaks large amounts of intracellular glycerol into the surrounding medium, was isolated. The mutant has potential applications in the commercial production of glycerol on a large scale since there is no need to extract glycerol from the cells. The mutant was compared with the wild type and it was found that, despite the leakage of glycerol, the mutant showed the same growth rate as the wild type. However, when the rates of oxygen evolution and uptake and intracellular starch content between mutant and wild type were compared at high salinity, considerable differences were found.



Light, temperature and nitrogen starvation effects on the total lipid and fatty acid content and composition of Spirulina platensis UTEX 1928

November 1989

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72 Reads

The total lipid and fatty acid content ofSpirulina platensis UTEX 1928 was 7.2 and 2.2% respectively of cellular dry weight under controlled conditions supporting high growth rates. With increases in irradiance from 170 to 870 μmol photon m−2 s−1, growth rate increased, total lipid decreased, and fatty acid composition was unaffected. At 1411 μmol photon m−2 s−1, total lipid increased slightly and percent composition of the fatty acid gamma linolenic acid increased. Growth and total lipid content ofS. platensis were affected by changes in growth temperature from 25 to 38 °C. With increased growth rate, total lipid content increased. This suggests that the storage of carbon increases at temperatures supporting high growth rates. The degree of saturation increased with temperature. Although the percent composition of gamma linolenic acid was higher at lower growth temperature, production was still primarily a function of growth rate. The effect of temperature on fatty acid content and degree of saturation was of secondary importance. Nitrogen starvation increased total lipid content but decreased fatty acid content as a percentage of dry weight; composition of the fatty acids was unaffected. N-starvation appeared to suspend synthesis of long chain fatty acids inS. platensis, suggesting that some other compound stores fixed carbon when nitrogen is limiting. It was concluded that fatty acid production inS. platensis is maximized by optimizing culture conditions for growth.

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