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Stefan Schouten - One of the best experts on this subject based on the ideXlab platform.
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Biosynthesis of Long Chain Alkyl Diols and Long Chain Alkenols in Nannochloropsis spp. (Eustigmatophyceae)
Plant & cell physiology, 2019Co-Authors: Sergio Balzano, Laura Villanueva, Caglar Yildiz, Eric Marechal, Josselin Lupette, Marijke W De Bar, Diana X. Sahonero Canavesi, Julia C. Engelmann, Jaap S. Sinninghe Damsté, Stefan SchoutenAbstract:We investigated potential biosynthetic pathways of long chain alkenols (LCAs), long chain alkyl diols (LCDs), and long chain hydroxy fatty acids (LCHFAs) in Nannochloropsis oceanica and Nannochloropsis gaditana, by combining culturing experiments with genomic and transcriptomic analyses. Incubation of Nannochloropsis spp. in the dark for 1 week led to significant increases in the cellular concentrations of LCAs and LCDs in both species. Consistently, 13C-labelled substrate experiments confirmed that both LCA and LCD were actively produced in the dark from C14-18 fatty acids by either condensation or elongation/hydroxylation, although no enzymatic evidence was found for the former pathway. Nannochloropsis spp. did, however, contain (i) multiple polyketide synthases (PKSs) including one type (PKS-Clade II) that might catalyze incomplete fatty acid elongations leading to the formation of 3-OH-fatty acids, (ii) 3-hydroxyacyl dehydratases (HADs), which can possibly form Δ2/Δ3 monounsaturated fatty acids, and (iii) fatty acid elongases (FAEs) that could elongate 3-OH-fatty acids and Δ2/Δ3 monounsaturated fatty acids to longer products. The enzymes responsible for reduction of the long chain fatty acids to LCDs and LCAs are, however, unclear. A putative wax ester synthase/acyl coenzyme A (acyl-CoA): diacylglycerol acyltransferase is likely to be involved in the esterification of LCAs and LCDs in the cell wall. Our data thus provide useful insights in predicting the biosynthetic pathways of LCAs and LCDs in phytoplankton suggesting a key role of FAE and PKS enzymes.
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Biosynthesis of Long Chain Alkyl Diols and Long Chain Alkenols in Nannochloropsis spp. (Eustigmatophyceae)
Plant and Cell Physiology, 2019Co-Authors: Sergio Balzano, Laura Villanueva, Marijke De Bar, Diana Sahonero Canavesi, Caglar Yildiz, Julia Engelmann, Eric Marechal, Josselin Lupette, Jaap Sinninghe Damsté, Stefan SchoutenAbstract:We investigated potential biosynthetic pathways of long chain alkenols (LCAs), long chain alkyl diols (LCDs), and long chain hydroxy fatty acids (LCHFAs) in Nannochloropsis oceanica and Nannochloropsis gaditana, by combining culturing experiments with genomic and transcriptomic analyses. Incubation of Nannochloropsis spp. in the dark for one week led to significant increases in the cellular concentrations of LCAs and LCDs in both species. Consistently, 13C-labeled substrate experiments confirmed that both LCA and LCD were actively produced in the dark from C14-18 fatty acids by either condensation or elongation/hydroxylation, although no enzymatic evidence was found for the former pathway. Nannochloropsis spp. did, however, contain (1) multiple polyketide synthases (PKSs) including one type (PKS Clade II) that might catalyse incomplete fatty acid elongations leading to the formation of 3-OH-fatty acids, (2) 3-hydroxyacyl dehydratases (HADs), which can possibly form Δ2/Δ3 monounsaturated fatty acids, and (3) fatty acid elongases (FAEs) that could elongate 3-OH-fatty acids and Δ2/Δ3 monounsaturated fatty acids to longer products. The enzymes responsible for reduction of the long chain fatty acids to LCDs and LCAs are, however, unclear. A putative wax ester synthase/acyl coenzyme A (acyl-CoA):diacylglycerol acyltransferase (WS-DGAT) is likely to be involved in the esterification of LCAs and LCDs in the cell wall. Our data thus provide useful insights in predicting the biosynthetic pathways of LCAs and LCDs in phytoplankton suggesting a key role of FAE and PKS enzymes.
Feng Chen - One of the best experts on this subject based on the ideXlab platform.
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direct enzymatic ethanolysis of potential Nannochloropsis biomass for co production of sustainable biodiesel and nutraceutical eicosapentaenoic acid
Biotechnology for Biofuels, 2019Co-Authors: Xiaofei Wang, Bilian Chen, Hehong Wei, Jianzhi Zhang, Feng ChenAbstract:Background Marine microalga Nannochloropsis is a promising source for the production of renewable and sustainable biodiesel in replacement of depleting petroleum. Other than biodiesel, Nannochloropsis is a green and potential resource for the commercial production of nutraceutical eicosapentaenoic acid (EPA, C20:5). In recent studies, low-value biodiesel can be achieved by transesterification of Nannochloropsis biomass. However, it is undoubtedly wasteful to produce microalgal biodiesel containing EPA from nutritional and economical aspects. A new strategy was addressed and exploited to produce low-value bulky biodiesel along with EPA enrichment via enzymatic ethanolysis of Nannochloropsis biomass with a specific lipase.
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Direct enzymatic ethanolysis of potential Nannochloropsis biomass for co-production of sustainable biodiesel and nutraceutical eicosapentaenoic acid
BMC, 2019Co-Authors: Xiaofei Wang, Bilian Chen, Hehong Wei, Jianzhi Zhang, Feng ChenAbstract:Abstract Background Marine microalga Nannochloropsis is a promising source for the production of renewable and sustainable biodiesel in replacement of depleting petroleum. Other than biodiesel, Nannochloropsis is a green and potential resource for the commercial production of nutraceutical eicosapentaenoic acid (EPA, C20:5). In recent studies, low-value biodiesel can be achieved by transesterification of Nannochloropsis biomass. However, it is undoubtedly wasteful to produce microalgal biodiesel containing EPA from nutritional and economical aspects. A new strategy was addressed and exploited to produce low-value bulky biodiesel along with EPA enrichment via enzymatic ethanolysis of Nannochloropsis biomass with a specific lipase. Results Cellulase pretreatment on Nannochloropsis sp. biomass significantly improved the biodiesel conversion by direct ethanolysis with five enzymes from Candida antarctica (CALA and CALB), Thermomyces lanuginosus (TL), Rhizomucor miehei (RM), and Aspergillus oryzae (PLA). Among these five biocatalysts, CALA was the best suitable enzyme to yield high biodiesel conversion and effectively enrich EPA. After optimization, the maximum biodiesel conversion (46.53–48.57%) was attained by CALA at 8:1 ethanol/biomass ratio (v/w) in 10–15% water content with 10% lipase weight at 35 °C for 72 h. Meanwhile, EPA (60.81%) was highly enriched in microalgae NPLs (neutral lipids and polar lipids), increasing original EPA levels by 1.51-fold. Moreover, this process was re-evaluated with two Nannochloropsis species (IMET1 and Salina 537). Under the optimized conditions, the biodiesel conversions of IMET1 and Salina 537 by CALA were 63.41% and 54.33%, respectively. EPA contents of microalgal NPLs were 50.06% for IMET1 and 53.73% for Salina 537. Conclusion CALA was the potential biocatalyst to discriminate against EPA in the ethanolysis of Nannochloropsis biomass. The biodiesel conversion and EPA enrich efficiency of CALA were greatly dependent on lipidic class and fatty acid compositions of Nannochloropsis biomass. CALA-catalyzed ethanolysis with Nannochloropsis biomass was a promising approach for co-production of low-value biodiesel and high-value microalgae products rich in EPA
C. Schulz - One of the best experts on this subject based on the ideXlab platform.
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Marine microalgae Pavlova viridis and Nannochloropsis sp. as n-3 PUFA source in diets for juvenile European sea bass (Dicentrarchus labrax L.)
Journal of Applied Phycology, 2016Co-Authors: S. Haas, J. L. Bauer, A. Adakli, S. Meyer, S. Lippemeier, K. Schwarz, C. SchulzAbstract:In the present study, the potential of the microalga Pavlova viridis (= Diacronema viridis ) as an n-3 polyunsaturated fatty acid (PUFA) source was evaluated and compared to Nannochloropsis sp. in diets for juvenile European sea bass ( Dicentrarchus labrax L.) (initial weight ~12.8 ± 1.7 g) in an 8-week feeding trial. Six different isoenergetic and isonitrogenous test diets were used: (1) fish oil diet (FO), major lipid source fish oil (100 %), (2) basal diet, 40 % fish oil and 60 % plant oil (in equal parts rapeseed, sunflower, and linseed oil), (3) Pavlova 50 % (P50), 50 % of the fish oil of the basal diet was substituted by lipid content of P. viridis meal, (4) Pavlova 100 % (P100), 100 % of the fish oil of the basal diet was substituted by lipid content of P. viridis meal, (5) Nannochloropsis 50 % (N50), 50 % of the fish oil of the basal diet was substituted by lipid content of Nannochloropsis sp. meal, and (6) Nannochloropsis 100 % (N100), 100 % of the fish oil of the basal diet was substituted by lipid content of Nannochloropsis sp. meal. The specific growth rate was highest and feed conversion ratio was lowest in the P100 group (SGR 1.77 ± 0.10 % day^−1; FCR 1.17 ± 0.01), although not significantly different to the results for the FO and the other algae-groups. Furthermore, the sum of PUFA was also highest in the P100 group, followed by the P50, N100, N50, and B group (mainly due to the high content of linoleic and linolenic acids coming from plant oils and microalgal products) with the lowest levels in the FO group. The highest amounts of docosahexaenoic acid (DHA) of total fatty acids were found in the FO and B group, although not significantly higher than in groups P50 and P100. The significantly highest amount of eicosapentaenoic acid (EPA, % of total fatty acids) was in the P100 samples and the lowest amount was in samples of the basal group. The histological analyses of liver and intestine samples did not reveal any negative effects caused by the experimental treatments. Based on the basal diet, a 50 % fish oil replacement by Nannochloropsis sp. meal and a total replacement by P. viridis meal were possible without negative effects on the growth performance and nutrient utilization of juvenile sea bass.
Assaf Sukenik - One of the best experts on this subject based on the ideXlab platform.
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CHARACTERIZATION OF A GENE ENCODING THE LIGHT-HARVESTING VIOLAXANTHIN-CHLOROPHYLL PROTEIN OF Nannochloropsis SP. (EUSTIGMATOPHYCEAE)
Journal of phycology, 2000Co-Authors: Assaf Sukenik, Alexander Livne, Kirk E. Apt, Arthur R. GrossmanAbstract:In contrast to vascular plants, green algae, and diatoms, the major light-harvesting complex of the marine eustigmatophyte genus Nannochloropsis is a violaxanthin-chlorophyll a protein complex that lacks chlorophylls b and c. The isolation of a single polypeptide from the light-harvesting complex of Nannochloropsis sp. (IOLR strain) was previously reported (Sukenik et al. 1992). The NH2 -terminal amino acid sequence of this polypeptide was significantly similar to NH2 -terminal sequences of the light-harvesting fucoxanthin, chlorophyll a/c polypeptides from the diatom Phaeodactylum tricornutum Bohlin. Using polyclonal antibodies raised to the Nannochloropsis light-harvesting polypeptide, a gene encoding this polypeptide was isolated from a cDNA expression library. The deduced amino acid sequence of the Nannochloropsis violaxanthin-chlorophyll a polypeptide reveals a 36 amino acid presequence followed by 173 amino acids that constitute the mature polypeptide. The mature polypeptide has 30%-40% sequence identity to the diatom fucoxanthin-chlorophyll a/c polypeptides and less then 27% identity to the green algal and vascular plant light-harvesting chlorophyll polypeptides that bind both chlorophylls a and b. Its molecular mass, as deduced from the gene sequence, is 18.4 kDa with three putative transmembrane helices and several residues that may be involved in chlorophyll binding. The cDNA encoding the violaxanthin-chlorophyll a polypeptide was used to isolate and characterize a 10 kb genomic fragment containing the entire gene. The open reading frame was interrupted by five introns ranging in size from 123 to 449 bp. The intron borders have typical eukaryotic GT … AG sequences.
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potential advantages of frozen algae Nannochloropsis sp for rotifer brachionus plicatilis culture
Aquaculture, 1995Co-Authors: Esther Lubzens, Odi Zmora, O Gibson, Assaf SukenikAbstract:Abstract The eustigmatophyte Nannochloropsis is widely used in many aquaculture hatcheries to establish the initial step of an artificial food chain. The advantage of Nannochloropsis over other unicellular algae is primarily its unique fatty acid composition. Rotifers which consume the algae carry these fatty acids to the fish larvae. Cultivation of large quantities of algal biomass to support this food chain is a heavy burden in many hatcheries, and in many other locations it cannot be carried out all year round. In this study we examined the possibility of substituting frozen biomass for fresh Nannochloropsis as a sole food source for rotifer cultures or as an enrichment treatment prior to feeding the rotifers to the larvae. Relatively high reproductive rates were found in rotifers of three strains which were fed frozen Nannochloropsis biomass. Total fatty acid content of these rotifers and fatty acid distribution were related to the chemical composition of the algae. Although seasonal variations in biochemical composition and fatty acid distribution were found in the algal biomass, the quality of the long-term frozen algae was adequate to provide the rotifers with the essential fatty acids almost all year round. No differences were found in the fatty acid composition of rotifers fed with algae stored at − 20 °C or − 70 °C. The thawed algal biomass could be kept at 4 °C for 7 days and be used for rotifer feeding without a significant adverse effect on the fatty acid content and composition in the rotifers. The results of this study suggest that application of frozen Nannochloropsis biomass may promote easier management in biomass production of lipid-enriched rotifers. This provides the artificial food chain with essential fatty acids, which are crucial for the development and cultivation of fish larvae, with a relatively limited effort for algae production on the hatchery site.
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biochemical quality of marine unicellular algae with special emphasis on lipid composition ii Nannochloropsis sp
Aquaculture, 1993Co-Authors: Assaf Sukenik, Odi Zmora, Yael CarmeliAbstract:Abstract The eustigmatophyte, Nannochloropsis sp., contains relatively large amounts of valuable lipids and is commonly grown as food source for commercial application in aquaculture. In this study we evaluated the effect of environmental conditions such as light intensity, nitrogen availability and temperature on cellular chemical composition with special emphasis on fatty acid distribution in cultures of Nannochloropsis sp. continuously grown under laboratory-controlled conditions. Seasonal variations in cellular chemistry were further assessed using large-scale outdoor shallow ponds, aimed at mass production of Nannochloropsis for application in an aquaculture hatchery. The percentage of the polyunsaturated long-chain fatty acid, eicosapentaenoic acid, in the algal biomass varied between 1.6 and 3.8% (w/w). In spite of significant variations in cellular protein content, the amino acid composition of Nannochloropsis biomass remained fairly constant during the different production seasons. Variations in the fatty acid composition of the algal biomass are attributed to differences in seasonal climatic conditions and diurnal cycles in light intensity and temperature. This study demonstrates the feasibility of culturing algal biomass of a high chemical quality for various applications in aquaculture hatcheries.
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alterations in lipid molecular species of the marine eustigmatophyte Nannochloropsis sp
Journal of Phycology, 1993Co-Authors: Assaf Sukenik, Yuji Yamaguchi, Alexander LivneAbstract:The molecular species of triacylglycerol and monogalactosyl diacylglycerol from the marine eustigmatophyte Nannochloropsis were analyzed by high-performance liquid chromatography with a flame ionization detector. Four major molecular species of triacylglycerol composed of C 14:0, C 16:0, and C 16:1 fatty acids at different combinations were identified. Six molecular species of monogalactosyl diacylglycerol were detected. Three of them contained C 20:5 fatty acid in the sn-1 position, and one component accommodated C 20:5 fatty acid in both the sn-1 and sn-2 positions. Variations in the relative distribution of the molecular species were further monitored in Nannochloropsis cultures grown under different irradiance levels and temperatures. The relative distribution of 16: 0/16:1/16:0 triacylglycerol increased in cells grown in high light and in high temperature. Variations in cellular fatty acid composition in Nannochloropsis grown under different environmental conditions of irradiance level and temperature were attributed to alterations in relative cellular content of lipid classes as well as in the relative composition of lipid class molecular species.
Sergio Balzano - One of the best experts on this subject based on the ideXlab platform.
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Biosynthesis of Long Chain Alkyl Diols and Long Chain Alkenols in Nannochloropsis spp. (Eustigmatophyceae)
Plant & cell physiology, 2019Co-Authors: Sergio Balzano, Laura Villanueva, Caglar Yildiz, Eric Marechal, Josselin Lupette, Marijke W De Bar, Diana X. Sahonero Canavesi, Julia C. Engelmann, Jaap S. Sinninghe Damsté, Stefan SchoutenAbstract:We investigated potential biosynthetic pathways of long chain alkenols (LCAs), long chain alkyl diols (LCDs), and long chain hydroxy fatty acids (LCHFAs) in Nannochloropsis oceanica and Nannochloropsis gaditana, by combining culturing experiments with genomic and transcriptomic analyses. Incubation of Nannochloropsis spp. in the dark for 1 week led to significant increases in the cellular concentrations of LCAs and LCDs in both species. Consistently, 13C-labelled substrate experiments confirmed that both LCA and LCD were actively produced in the dark from C14-18 fatty acids by either condensation or elongation/hydroxylation, although no enzymatic evidence was found for the former pathway. Nannochloropsis spp. did, however, contain (i) multiple polyketide synthases (PKSs) including one type (PKS-Clade II) that might catalyze incomplete fatty acid elongations leading to the formation of 3-OH-fatty acids, (ii) 3-hydroxyacyl dehydratases (HADs), which can possibly form Δ2/Δ3 monounsaturated fatty acids, and (iii) fatty acid elongases (FAEs) that could elongate 3-OH-fatty acids and Δ2/Δ3 monounsaturated fatty acids to longer products. The enzymes responsible for reduction of the long chain fatty acids to LCDs and LCAs are, however, unclear. A putative wax ester synthase/acyl coenzyme A (acyl-CoA): diacylglycerol acyltransferase is likely to be involved in the esterification of LCAs and LCDs in the cell wall. Our data thus provide useful insights in predicting the biosynthetic pathways of LCAs and LCDs in phytoplankton suggesting a key role of FAE and PKS enzymes.
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Biosynthesis of Long Chain Alkyl Diols and Long Chain Alkenols in Nannochloropsis spp. (Eustigmatophyceae)
Plant and Cell Physiology, 2019Co-Authors: Sergio Balzano, Laura Villanueva, Marijke De Bar, Diana Sahonero Canavesi, Caglar Yildiz, Julia Engelmann, Eric Marechal, Josselin Lupette, Jaap Sinninghe Damsté, Stefan SchoutenAbstract:We investigated potential biosynthetic pathways of long chain alkenols (LCAs), long chain alkyl diols (LCDs), and long chain hydroxy fatty acids (LCHFAs) in Nannochloropsis oceanica and Nannochloropsis gaditana, by combining culturing experiments with genomic and transcriptomic analyses. Incubation of Nannochloropsis spp. in the dark for one week led to significant increases in the cellular concentrations of LCAs and LCDs in both species. Consistently, 13C-labeled substrate experiments confirmed that both LCA and LCD were actively produced in the dark from C14-18 fatty acids by either condensation or elongation/hydroxylation, although no enzymatic evidence was found for the former pathway. Nannochloropsis spp. did, however, contain (1) multiple polyketide synthases (PKSs) including one type (PKS Clade II) that might catalyse incomplete fatty acid elongations leading to the formation of 3-OH-fatty acids, (2) 3-hydroxyacyl dehydratases (HADs), which can possibly form Δ2/Δ3 monounsaturated fatty acids, and (3) fatty acid elongases (FAEs) that could elongate 3-OH-fatty acids and Δ2/Δ3 monounsaturated fatty acids to longer products. The enzymes responsible for reduction of the long chain fatty acids to LCDs and LCAs are, however, unclear. A putative wax ester synthase/acyl coenzyme A (acyl-CoA):diacylglycerol acyltransferase (WS-DGAT) is likely to be involved in the esterification of LCAs and LCDs in the cell wall. Our data thus provide useful insights in predicting the biosynthetic pathways of LCAs and LCDs in phytoplankton suggesting a key role of FAE and PKS enzymes.
