ALBERTA RIKA PRATIWI
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Journal : HAYATI Journal of Biosciences

Isolation and Characterization of Silaffin that Catalyze Biosilica Formation from Marine Diatom Chaetoceros gracilis MANURUNG, AGNES IMELDA; PRATIWI, ALBERTA RIKA; SYAH, DAHRUL; SUHARTONO, MAGGY THENAWIDJAJA
HAYATI Journal of Biosciences Vol 14, No 3 (2007): September 2007
Publisher : Bogor Agricultural University, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.4308/hjb.14.3.119

Abstract

The method of making silica in industries requires extreme conditions. The finding of proteins involved in the formation of biosilica from diatoms, has opened up an alternative way of production. Chaetoceros gracilis is one of the diatoms, which is potential in producing silaffin protein. This study aimed to isolate and to characterize the protein. We also analyzed the protein activity toward tetraethoxyorthosilicate (TEOS) substrate in in vitro reaction. Diatom biomass was harvested and further kept in 2% SDS/100 mM EDTA solution. Protein isolation was conducted by dissolving the silica and separating the protein by soaking in 2 M HF/8 M NH4F. Protein concentration was analyzed using Bradford method and the molecular weight was estimated through SDS-PAGE. Protein activity was observed by reacting it with TEOS substrate to form silica polymer and measured by colorimetric molibdate assay. Protein concentration was 1.20 mg/ml and appeared filamentous. The apparent molecular weights consisted of 12, 23, 42, 44 kDa. These protein was able to polymerize the silica at room temperature within 10 min. As much as 85.65 umol TEOS was polymerized per 1.4 x 106 silaffin protein per min. SEM analysis showed the formation of spherical, aggregate biosilica. Key words: Chaetoceros gracilis, silaffin protein, biosilica, polymerization
Fatty Acid Synthesis by Indonesian Marine Diatom, Chaetoceros gracilis PRATIWI, ALBERTA RIKA; SYAH, DAHRUL; HARDJITO, LINAWATI; PANGGABEAN, LILY MARIA GORETTI; SUHARTONO, MAGGY THENAWIDJAJA
HAYATI Journal of Biosciences Vol 16, No 4 (2009): December 2009
Publisher : Bogor Agricultural University, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.4308/hjb.16.4.151

Abstract

Since the primary storage nutrients in diatoms consist of lipid, they are potential for the industrial fatty acid production. High value fatty acids include arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid. This study aimed to analyze fatty acid synthesis by Chaetoceros gracilis diatom during growth. There was a large increase in lipid yield from 4pg cell-1 mass of lipid per cell at the exponential phase to 283pg cell-1 at stationary phase. The lipid concentrations also increased significantly from the stationary phase to the death phase, but not significantly from the end exponential phase to the stationary phase. The relative percentage of saturated fatty acid (SAFA) of the total fatty acid was higher than that of monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) at all of growth phase. The highest PUFA was found at stationary phase at the same time when SAFA was being the lowest. The majority of SAFA was palmitic acid (24.03-40.35%). MUFA contained significant proportion of oleic acid (19.6-20.9%). Oleic acid, linoleic acid and α-linolenic acid were found at every stage growth. These fatty acids are considered as precursor for production of long chain PUFA-Docosahexaenoic acid (DHA/22:6ω3) through series of desaturation and elongation step with all of desaturase enzyme (Δ8-D, Δ9-D, Δ12-D, Δ15-D, Δ17-D, Δ6-D, Δ5-D, and Δ4-D) and elongase enzyme (E).         Key words: Chaetoceros gracilis, fatty acid, synthesis, saturated fatty acid (SAFA), monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA)
Since the primary storage nutrients in diatoms consist of lipid, they are potential for the industrial fatty acid production. High value fatty acids include arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid. This study aimed to analyze fatty acid synthesis by Chaetoceros gracilis diatom during growth. There was a large increase in lipid yield from 4pg cell-1 mass of lipid per cell at the exponential phase to 283pg cell-1 at stationary phase. The lipid concentrations also increas PRATIWI, ALBERTA RIKA; SYAH, DAHRUL; HARDJITO, LINAWATI; PANGGABEAN, LILY MARIA GORETTI; SUHARTONO, MAGGY THENAWIDJAJA
HAYATI Journal of Biosciences Vol 16, No 4 (2009): December 2009
Publisher : Bogor Agricultural University, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.4308/hjb.16.4.151

Abstract

Since the primary storage nutrients in diatoms consist of lipid, they are potential for the industrial fatty acid production. High value fatty acids include arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid. This study aimed to analyze fatty acid synthesis by Chaetoceros gracilis diatom during growth. There was a large increase in lipid yield from 4pg cell-1 mass of lipid per cell at the exponential phase to 283pg cell-1 at stationary phase. The lipid concentrations also increased significantly from the stationary phase to the death phase, but not significantly from the end exponential phase to the stationary phase. The relative percentage of saturated fatty acid (SAFA) of the total fatty acid was higher than that of monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) at all of growth phase. The highest PUFA was found at stationary phase at the same time when SAFA was being the lowest. The majority of SAFA was palmitic acid (24.03-40.35%). MUFA contained significant proportion of oleic acid (19.6-20.9%). Oleic acid, linoleic acid and ?-linolenic acid were found at every stage growth. These fatty acids are considered as precursor for production of long chain PUFA-Docosahexaenoic acid (DHA/22:6?3) through series of desaturation and elongation step with all of desaturase enzyme (?8-D, ?9-D, ?12-D, ?15-D, ?17-D, ?6-D, ?5-D, and ?4-D) and elongase enzyme (E).         Key words: Chaetoceros gracilis, fatty acid, synthesis, saturated fatty acid (SAFA), monounsaturated fatty acid (MUFA), polyunsaturated fatty acid (PUFA)
Isolation and Characterization of Silaffin that Catalyze Biosilica Formation from Marine Diatom Chaetoceros gracilis MANURUNG, AGNES IMELDA; PRATIWI, ALBERTA RIKA; SYAH, DAHRUL; SUHARTONO, MAGGY THENAWIDJAJA
HAYATI Journal of Biosciences Vol 14, No 3 (2007): September 2007
Publisher : Bogor Agricultural University, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.4308/hjb.14.3.119

Abstract

The method of making silica in industries requires extreme conditions. The finding of proteins involved in the formation of biosilica from diatoms, has opened up an alternative way of production. Chaetoceros gracilis is one of the diatoms, which is potential in producing silaffin protein. This study aimed to isolate and to characterize the protein. We also analyzed the protein activity toward tetraethoxyorthosilicate (TEOS) substrate in in vitro reaction. Diatom biomass was harvested and further kept in 2% SDS/100 mM EDTA solution. Protein isolation was conducted by dissolving the silica and separating the protein by soaking in 2 M HF/8 M NH4F. Protein concentration was analyzed using Bradford method and the molecular weight was estimated through SDS-PAGE. Protein activity was observed by reacting it with TEOS substrate to form silica polymer and measured by colorimetric molibdate assay. Protein concentration was 1.20 mg/ml and appeared filamentous. The apparent molecular weights consisted of 12, 23, 42, 44 kDa. These protein was able to polymerize the silica at room temperature within 10 min. As much as 85.65 umol TEOS was polymerized per 1.4 x 106 silaffin protein per min. SEM analysis showed the formation of spherical, aggregate biosilica. Key words: Chaetoceros gracilis, silaffin protein, biosilica, polymerization