Diatom bentik tergolong dalam bahagian Bacillariophyta. Diatom adalah kelompok alga yang paling umum di banyak sungai, dan merupakan komponen penting dalam ekosistem ini. Acid eikosapentaenoik (EPA) merupakan salah satu daripada banyak Omega-3 asid lemak yang diperlukan oleh tubuh manusia dan ia boleh didapati daripada lemak yang tersimpan di dalam diatom bentik. Penyelidikan terbaru telah membuktikan bahawa asid lemak EPA boleh mengurangkan gejala depresi dan megurangkan risiko serangan sakit jantung ketika mengambil EPA. Pertumbuhan diatom bentik boleh dipengaruhi oleh beberapa faktor seperti kepekatan silikat, karbon dan sumber nitrogen, tekanan gelangsar, salinitas, pH, kekuatan cahaya dan tempoh penyinaran. Oleh itu, kajian ini bertujuan untuk mengkaji pengaruh kepekatan sumber karbon dan silikat terhadap berat sel kering dan pengeluaran EPA Amphora sp. Sel alga itu ditumbuh menggunakan kepekatan glukosa, sukrosa dan silikat yang berbeza. Selepas tujuh hari pertumbuhan, berat sel kering dan hasil EPA Amphora sp. ditentukan. Keputusan kajian menunjukkan bahawa untuk sumber karbon, berat sel kering tertinggi dicapai pada kepekatan glukosa 10g /L, iaitu 0.2004g/ L manakala hasil EPA tertinggi ialah 9.192 mg EPA / gram biojisim pada kepekatan sukrosa 10g/L. Selain itu, untuk kepekatan silikat, berat sel kering tertinggi ialah 0.2172g /L pada kepekatan silikat 75mg/L manakala hasil EPA tertinggi ialah 9.192 mg EPA / gram biojisim pada kepekatan silikat 67mg/L. Peningkatan kepekatan glukosa meningkatkan biojisim dan kandungan lemak dalam biojisim. Biasanya, kandungan EPA diatom bentik meningkat ketika silikat menjadi faktor pengehad. Ini adalah kerana dalam medium di mana silikat terhad, sel alga lebih cenderung untuk menukarkan metabolisme dan mengalihkan tenaga yang sebelum ini diperuntukkan untuk penyerapan silikat kepada penyimpanan lemak. Kesimpulannya, pertumbuhan Amphora sp. menggunakan kepekatan sukrosa 10g/L dan kepekatan silikat 67mg/L memberi hasil EPA yang tertinggi. Untuk berat sel kering yang tertinggi, penggunaan glukosa pada kepekatan 10g/L dan kepekatan silikat 75mg /L dapat mencapai tujuan ini.
Heterotrophic Cultivation Of Amphora sp. For Biomass And Eicosapentaenoic Acid Production
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Benthic diatoms are in Division Bacillariophyta. Diatoms are the most common and diverse group of algae in many rivers and streams, and thus are important components of these ecosystems.
Eicosapentaenoic acid (EPA) is one of many Omega-3 fatty acids needed by the human body and it can be found from the lipid stored inside the benthic diatom. Recent studies have produced evidence that the fatty acid pure ethyl EPA reduces the symptoms of depression and those who are prone to heart attacks are less likely to have them while taking EPA. The growth of benthic diatom can be affected by several factors such as different concentration of silicate, carbon and nitrogen source, shear stress, salinity, pH, light intensity and photoperiod. Therefore, this study is carried out to study the effect of different carbon source and silicate concentration towards dry cell weight and EPA production of Amphora sp. The algae cells were cultivated under different concentration of glucose, sucrose and silicate. After seven days of cultivation, the dry cell weight and EPA yield of Amphora sp. were determined. The results showed that for carbon source, the highest dry cell weight was achieved at glucose concentration of 10g/L, which was 0.2004g/L whereas the highest EPA yield was 9.192 mg EPA / g biomass at sucrose concentration of 10g/L. Besides that, for silicate concentration, the highest dry cell weight was 0.2172g/L at silicate concentration of 75mg/L whereas highest EPA yield was 9.192 mg EPA / g biomass at silicate concentration of 67mg/L. Increasing the glucose concentration in the medium increased biomass and the lipid content of the biomass. Usually, the EPA content of benthic diatom increased when silicate became the limiting factor. The reason for this phenomenon is that in silicate-limited cultures, the cell tends to alter its metabolism and divert energy which was previously allocated for silicate uptake into lipid storage. In conclusion, cultivation of Amphora sp. using sucrose concentration of 10g/L and silicate concentration of 67mg/L produces the highest EPA yield. For highest dry cell weight, using glucose at concentration of 10g/L and 75mg/L of silicate can achieve this target.
Heterotrophic cultivation of Amphora sp. for biomass and eicosapentaenoic acid (epa) production_Chia Zi Sheng_K4_2011_875003892_NI