Growth Profile And Lipid Composition Of Locally Isolated Benthic Diatom Amphora Subacutiuscula (Schoeman, 1972) Under Different Cultivation Conditions
| dc.contributor.author | Ng, Bee Wah | |
| dc.date.accessioned | 2017-02-14T08:19:47Z | |
| dc.date.available | 2017-02-14T08:19:47Z | |
| dc.date.issued | 2016-01 | |
| dc.description.abstract | Benthic diatoms are the natural EPA producers but the amount is notably low under their natural environment, mainly suffer from the limitation of light diffusion. This drawback has prompted research to improve the EPA content and the heterotrophic mode of cultivation presents a new opportunity as a practical solution. The gross chemical composition and fatty acid composition of the locally isolated strain was determined to find a species as feed in tropical aquaculture, especially the diet that strongly influences survival and gross biochemical compositions of ongrown Artemia sp.. However, no studies to date have been conducted to investigate the relationship between PUFA transferred from different cultivation mode of benthic diatom to Artemia sp.. A locally isolated benthic diatom, identified as Amphora subacutiuscula based on phylogeny and silica cell wall classification was used in this study. This EPA producer A. subacutiuscula was screened for its heterotrophic capability and the carbon source preference. Other limiting factors, such as nutritional (carbon, nitrogen silicate) and environmental (pH, temperature and salinity) were taken into account for EPA production. Under a screening study, A. subacutiuscula possesses heterotrophic capabilities by utilizing glucose and sucrose as the carbon source. This investigation is unique as the carbon source preference and its ability to undergo heterotrophic were previously unknown and not reported. Nutritional factors such as carbon source (glucose), silicate, complex nitrogen (yeast extract) and simple nitrogen source (nitrate) were found to significantly affect the EPA content of A. subacutiuscula. Temperature was the sole environmental factor that extensively affected nutritional and metabolite contents of A. subacutiuscula especially the quality of fatty acid methyl ester.Under the optimization studies, the EPA content and total lipid of this newly isolated heterotrophic A. subacutiuscula was enhanced significantly to 34.3mg EPA g-1 biomass and 57% as compared with 5.89 mg EPA g-1 biomass and 8% when it was cultivated under phototrophic mode. A feeding trial using A. subacutiuscula as a feed to Artemia sp. showed that the heterotrophic biomass was a superior diet in improving the growth (specific growth rate, 117.3% day-1), survival (94%) and nutritional content of the ongrown Artemia sp.. The heterotrophic growth of A. subacutiuscula enables the production of higher quality of microalga biomass for application in aquaculture industries by serving as an alternative EPA source, supplemental aquaculture feeds and also as a nutritional supplement for humans. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/3727 | |
| dc.language.iso | en | en_US |
| dc.subject | Benthic diatoms | en_US |
| dc.title | Growth Profile And Lipid Composition Of Locally Isolated Benthic Diatom Amphora Subacutiuscula (Schoeman, 1972) Under Different Cultivation Conditions | en_US |
| dc.type | Thesis | en_US |
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