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UPV Theses and Dissertations

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AGROVOC Keyword: search.filters.agrovoc.lipid contentDepartment: search.filters.department.College of Fisheries and Ocean Sciences

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    Effect of elevated carbon dioxide and phosphorus on nitrogen uptake, lipid content, and growth of Tetraselmis sp.
    Ferriols, Victor Marco Emmanuel N. (Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2011-04)
    Effect of elevated carbon dioxide (CO2) and phosphorus levels on nitrogen uptake, lipid content, and growth of Tetraselmis sp. were investigated. Cultures of Tetraselmis sp. were added with CO2 and phosphorus at concentrations above those currently used in aquaculture practices in a factorial experiment. Three levels of CO2 (no addition, 5% v/v, and 10% v/v of the incoming air for aeration) and three levels of phosphorus added as NaH2PO4 (5, 10, 20 mg L’1) in modified F medium with NH4+ as the primary nitrogen source were used. Optical density (680 nm) and residual NH3-N in the culture medium were monitored daily over a culture period of 6 days. Relative growth rate (k'), nitrogen uptake (pg NH3-N cell’1 day1), and lipid content (% dry weight) were calculated and determined at the end of the culture period. No interactive effect between phosphorus and CO2 levels was observed in all variables measured (p > 0.05). Highest growth rate (k = 1.82±0.04), nitrogen uptake (0.316±0.008 μg NH3-N cell1 day1), and lipid content (10.95±0.15 %DW) were exhibited at 10% CO2 supplementation. Growth and nitrogen uptake were similar in treatments with elevated levels of phosphorus, but lipid yield (9.41±0.27 %DW) was lowest at 20 mg L1 of phosphorus supplementation (p < 0.05). These results showed the critical role of CO2 in nitrogen uptake, lipid content, and growth of Tetraselmis sp. It also indicates the potential of this algal species for waste water remediation, biofuel production, and carbon sequestration.
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    Analysis of the lipid content of micro algae species used in Philippine aquaculture for their potential in biodiesel production
    Ferriols, Victor Marco Emmanuel N. (Institute of Aquaculture, College of Fisheries and Ocean Sciences, University of the Philippines Visayas, 2008-03)
    This study looked into the proximate lipid content of four micro algal species (Chaetoceros calcitrans, Tetraselmis tetrahele, Nannochloropsis sp., and Chlorella sp) and one macrophyte (Chaetomorpha sp.) commonly used in Philippine aquaculture. Prior to the proximate analysis using the method described by Bligh and Dyer (1959), the four micro algal species were cultured for five days in 1 L vessels fertilized with TMRL enrichment media. Proximate gravimetric analysis showed that the average lipid content of Tetraselmis tetrahele at 24.11% was significantly higher (p < 0.01) when compared to all the algal species tested. Comparing the mean lipid content of all micro algal species against that of the macrophyte also revealed a significantly higher (p < 0.01) lipid content at 17.40%. Growth rates for all the micro algal species over the culture period was also measured, with the highest growth rate exhibited by T. tetrahele at 1.15 divisions per day. Projected estimates for micro algal production yields of oil from a 1-hectare pond at 0.5 m depth were also calculated from the lipid analysis data, a showing that the highest yield of oil (7.29 tons) can be attained by culturing T. tetrahele. This number was higher than estimated reports for oil production from an area of 1 hectare dedicated to either jatropha (1.7 tons) or coconuts (5.0 tons). This makes the culture of micro algal species a potential option for producing feedstock for biodiesel production.