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Isolation and Characterization of Silaffin that Catalyze Biosilica Formation from Marine Diatom Chaetoceros gracilis AGNES IMELDA MANURUNG; ALBERTA RIKA PRATIWI; DAHRUL SYAH; MAGGY THENAWIDJAJA SUHARTONO
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 | Full PDF (292.311 KB) | 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
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 ALBERTA RIKA PRATIWI; DAHRUL SYAH; LINAWATI HARDJITO; LILY MARIA GORETTI PANGGABEAN; MAGGY THENAWIDJAJA SUHARTONO
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)
Pembuatan Biofertilizer sebagai Penunjang Pendapatan di SLB-C Karya Bakti, Purworejo Wulandari, Dyah; Alberta Rika Pratiwi; Theresya Amelia Prabowo; Cindy Fiolita Graciela
Jurnal Atma Inovasia Vol. 6 No. 2 (2026)
Publisher : Lembaga Penelitian dan Pengabdian pada Masyarakat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24002/jai.v6i2.12670

Abstract

The growing global population demands increased food productivity, which can be achieved using fertilizers. However, inorganic fertilizers harm the environment and leave chemical residues, making organic and biofertilizers a sustainable alternative. This initiative aims to enhance skills and inclusive learning for students with special needs while increasing economic and educational value, particularly in biofertilizer production at SLB-C Karya Bhakti, Purworejo. Biofertilizers contain beneficial microorganisms that support soil fertility and plant growth by breaking down nutrients, boosting disease resistance, and enhancing plant development. Unlike chemical fertilizers, biofertilizers are environmentally friendly and leave no harmful residues. They are produced using growth media like husks and fermented through solid-state or submerged fermentation methods. Proper packaging, such as vacuum sealing or PET-nylon-PP materials, is essential to maintain microbial viability and quality. At SLB-C Karya Bhakti, biofertilizers support plant growth in the school garden, actively involving students with special needs. Their use enhances food literacy, influences dietary choices, and improves economic conditions within the school. Additionally, this initiative fosters health and social development among students with disabilities, empowering them with valuable agricultural skills for a more inclusive and sustainable future.
Identifikasi Peptida Umami dan Kokumi pada Rumput Laut Sargassum aquifolium dengan Pendekatan In Silico Bernadeta Pingkan Larasati; Bernadeta Soedarini; Dea Nathania Hendryanti; Christiana Retnaningsih; Dina Fatmawati; Alberta Rika Pratiwi
Jurnal Pascapanen dan Bioteknologi Kelautan dan Perikanan Vol 20, No 1 (2025): Juni 2025
Publisher : Politeknik - Ahli Usaha Perikanan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15578/jpbkp.v20i1.1003

Abstract

Sargassum aquifolium memiliki kandungan protein dan asam glutamat yang tinggi, sehingga dapat dimanfaatkan menjadi bahan penyedap rasa. Rasa umami dapat dihasilkan oleh peptida taste-active yang berkontribusi dalam meningkatkan rasa umami dan memberikan sensasi rasa kokumi. Meskipun banyak penelitian mengenai peptida umami dan kokumi dalam bahan pangan, namun penelitian sejenis pada rumput laut belum banyak ditemukan. Analisis in silico telah banyak dilakukan untuk memprediksi dan mengidentifikasi peptida dengan taste-active umami dan kokumi pada bahan pangan dan efektif dalam mengevaluasi rasa peptida sebelum dilakukan evaluasi secara in vitro dan in vivo. Tujuan penelitian ini adalah memprediksi dan mengidentifikasi keberadaan peptida taste-active yang berkontribusi terhadap rasa umami dan kokumi pada rumput laut S. aquifolium dengan analisis in silico. Ekstraksi peptida S. aquifolium menggunakan pelarut air dengan metode reflux dan ultrasound, isolasi dan purifikasi peptida berdasarkan berat molekul. . Peptida hasil isolasi dianalisis berat molekulnya menggunakan Tricine-SDS-PAGE dan aktivitas sensori potensial secara in silico menggunakan database BIOPEP-UWM. Hasil penelitian menunjukkan analisis Tricine-SDS-PAGE menemukan 5 pita peptida yaitu 673 Da, 797 Da, 1.019 Da, 1.195 Da, dan 1.408 Da. Analisis in silico menunjukkan sekuen DFVEVPTGSN (1.019 Da) dan DTPDFVEVATESP (1.408 Da) diprediksi sebagai peptida umami yang ditandai adanya residu asam amino aspartat (D), dan asam amino glutamat (E), serta peptida ES, EV, TE, VE. Namun, tidak ditemukan peptida yang menunjukkan potensi kokumi. Pendekatan ekstraksi Water Soluble Extraction (WSE) menggunakan metode reflux dan ultrasound, serta pendekatan dengan in silico berhasil mengidentifikasi peptida taste-active umami, namun kurang efektif dalam mengidentifikasi peptida kokumi dari S. aquifolium .ABSTRACTSargassum aquifolium has high protein and glutamic acid to be used as a flavor enhancer. The umami taste can be produced by taste-active peptides which contribute to enhancing umami taste and providing kokumi taste sensation. Although there has been a lot of research on umami and kokumi peptides, similar research on seaweed has not been widely found. In silico analysis has been carried out to predict and identify taste-active peptides umami and kokumi in food and is effective in evaluating the taste of peptides before in vitro and in vivo evaluation. This research aimed to predict and identify taste-active peptides that contributed to umami and kokumi in S. aquifolium using in silico analysis. This research consisted of extracting S. aquifolium peptides using water with reflux and ultrasound methods, isolating and purifying peptides based on molecular weight. The isolated peptides were analyzed for their molecular weight using Tricine-SDS-PAGE and in silico potential sensory activity analysis using the BIOPEP-UWM database. Based on the Tricine-SDS-PAGE analysis, found 5 peptide bands 673 Da, 797 Da, 1,019 Da, 1,195 Da, and 1,408 Da. In silico analysis showed that the sequences of DFVEVPTGSN (1,019 Da) and DTPDFVEVATESP (1,408 Da) were predicted as umami peptides characterized by the presence of aspartate (D) and glutamic (E) amino acid residues, as well as ES, EV, TE, and VE peptides. However, no peptides were found that showed kokumi potential. The Water Soluble Extraction (WSE) approach using the reflux and ultrasound method, as well as in silico approach, succeeded in identifying the taste-active umami peptide, but was less effective in identifying the taste-active kokumi peptide from S. aquifolium.