High silicate concentration facilitates fucoxanthin and eicosapentaenoic acid (EPA) production under heterotrophic condition in the marine diatom Nitzschia laevis

2020 ◽  
Vol 52 ◽  
pp. 102086
Author(s):  
Xuemei Mao ◽  
Stephenie Hiu Yuet Chen ◽  
Xue Lu ◽  
Jianfeng Yu ◽  
Bin Liu
Keyword(s):  
Eicosapentaenoic Acid ◽  
Marine Diatom ◽  
Silicate Concentration ◽  
Nitzschia Laevis ◽  
Heterotrophic Condition ◽  
High Silicate

scholarly journals Tracing latitudinal gradient, river discharge and water masses along the subtropical South American coast using benthic Foraminifera assemblages

2012 ◽  
Vol 72 (3 suppl) ◽  
pp. 723-759 ◽  
Author(s):  
PPB Eichler ◽  
AR Rodrigues ◽  
BB Eichler ◽  
ES Braga ◽  
EJD Campos
Keyword(s):  
Benthic Foraminifera ◽  
River Discharge ◽  
Latitudinal Gradient ◽  
South American ◽  
Shelf Water ◽  
Silicate Concentration ◽  
Tropical Water ◽  
Freshwater Influence ◽  
Antarctic Shelf ◽  
High Silicate

More than 30% of Buccella peruviana (D'Orbigny), Globocassidulina crassa porrecta (Earland & Heron-Allen), Cibicides mackannai (Galloway & Wissler) and C. refulgens (Montfort) indicate the presence of cold Sub Antarctic Shelf Water in winter, from 33.5 to 38.3º S, deeper than 100 m, in the southern part of the study area. In summer, the abundance of this association decreases to less than 15% around 37.5-38.9º S where two species (Globocassidulina subglobosa (Brady), Uvigerina peregrina (Cushman) take over. G. subglobosa, U. peregrina, and Hanzawaia boueana (D'Orbigny) are found at 27-33º S in both seasons in less than 55 m deep in the northern part, and are linked with warm Subtropical Shelf Water and Tropical Water. Freshwater influence was signalized by high silicate concentration and by the presence of Pseudononion atlanticum (Cushman), Bolivina striatula (Cushman), Buliminella elegantissima (D'Orbigny), Bulimina elongata (D'Orbigny), Elphidium excavatum (Terquem), E. poeyanum (D'Orbigny), Ammobaculites exiguus (Cushman & Brönnimann), Arenoparrella mexicana (Kornfeld), Gaudryina exillis (Cushman & Brönnimann), Textularia earlandi (Parker) and thecamoebians in four sectors of the shelf. The presence of Bulimina marginata (D'Orbigny) between 34.1-32.8º S in the winter and 34.2-32.7º S in the summer indicates that the influence of the Subtropical Shelf Front on the sediment does not change seasonally, otherwise, the presence of Angulogerina angulosa (Williamson) in the winter, only in Mar del Plata (38.9º S), show that Malvinas currents are not influencing the sediment in the summer.

scholarly journals High Productivity of Eicosapentaenoic Acid and Fucoxanthin by a Marine Diatom Chaetoceros gracilis in a Semi-Continuous Culture

2020 ◽  
Vol 8 ◽  
Author(s):  
Saki Tachihana ◽  
Norio Nagao ◽  
Tomoyo Katayama ◽  
Minamo Hirahara ◽  
Fatimah Md. Yusoff ◽  
...  
Keyword(s):  
Eicosapentaenoic Acid ◽  
Continuous Culture ◽  
Dilution Rate ◽  
Cell Size ◽  
Light Condition ◽  
Dry Weight ◽  
Marine Diatom ◽  
High Productivity ◽  
Chaetoceros Gracilis ◽  
High Production Rate

Significantly high eicosapentaenoic acid (EPA) and fucoxanthin contents with high production rate were achieved in semi continuous culture of marine diatom. Effects of dilution rate on the production of biomass and high value biocompounds such as EPA and fucoxanthin were evaluated in semi-continuous cultures of Chaetoceros gracilis under high light condition. Cellular dry weight increased at lower dilution rate and higher light intensity conditions, and cell size strongly affected EPA and fucoxanthin contents. The smaller microalgae cells showed significantly higher (p < 0.05) value of 17.1 mg g-dw–1 fucoxanthin and 41.5% EPA content per total fatty acid compared to those observed in the larger cells. Chaetoceros gracilis can accumulate relatively higher EPA and fucoxanthin than those reported previously. In addition, maintenance of small cell size by supplying sufficient nutrients and light energy can be the key for the increase production of valuable biocompounds in C. gracilis.

scholarly journals Transcriptomics and Metabolomics Analyses Provide Novel Insights into Glucose-Induced Trophic Transition of the Marine Diatom Nitzschia laevis

Marine Drugs ◽  
2021 ◽  
Vol 19 (8) ◽  
pp. 426
Author(s):  
Xuemei Mao ◽  
Mengdie Ge ◽  
Xia Wang ◽  
Jianfeng Yu ◽  
Xiaojie Li ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Carotenoid Biosynthesis ◽  
Marine Diatom ◽  
Physiological Data ◽  
Biomass Density ◽  
Nitzschia Laevis ◽  
Transcriptome Resource ◽  
Rate Limiting ◽  
Molecular Framework ◽  
Glucose Supplementation

Diatoms have important ecological roles and are natural sources of bioactive compounds. Nitzschia laevis is a member of marine diatoms that accumulates high-value products including fucoxanthin and eicosapentaenoic acid (EPA). In this study, physiological data showed that comparing to autotrophic growth, mixotrophic cultivation with glucose supplementation led to a decrease of chlorophyll and fucoxanthin content in N. laevis, and an increase of biomass density and EPA yield. To further examine the metabolic barriers for fucoxanthin and EPA biosynthesis, comparative transcriptomic and metabolome analyses were conducted, with a focus on the genes related to carotenoids biosynthesis and fatty acid metabolism. The results indicated that phytoene desaturase (PDS) and zeta-carotene isomerase (ZISO) could be the rate-limiting enzymes in carotenoid biosynthesis. The transcription regulation of 3-ketoacyl-CoA synthase (KCS) and elongation of very long chain fatty acids protein (EVOVL) are important contributors associated with polyunsaturated fatty acids (PUFAs) accumulation. Furthermore, we also investigated the glucose-associated regulatory genes using weighted gene co-expression network analysis, and identified potential hub genes linked with cell cycle, carbohydrate metabolism, purine biosynthesis, and lipid metabolism. This study offers a high-quality transcriptome resource for N. laevis and provides a molecular framework for further metabolic engineering studies on fucoxanthin and EPA production.

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