Judul: Chemical Characterization of Fermented Spirulina and Screening of Metabolic Compounds Produced by it
Abstrak: Spirulina platensis dapat menstimulasi pertumbuhan mikroba non patogenik. Penelitian sebelumnya menunjukkan Spirulina fermentasi memiliki karakteristik kimiawi dan aktivitas antioksidan. Pengeringan beku (liofilisasi) dilakukan dan digunakan dalam penelitian ini. Penelitian bertujuan menentukan karakteristik kimiawi dan penapisan senyawa metabolit dari Spirulina fermentasi setelah liofilisasi. Spirulina fermentasi liofilisasi memiliki nilai pH 4,15 ± 0,00, total asam tertitrasi (TAT) 11,96 ± 0,00 %, dan total bakteri asam laktat (BAL) <2,5 × 101 ± 0,00. Spirulina fermentasi mengandung komponen aktif flavonoid, steroid, tanin, saponin dan fenol hidrokuinon, serta negatif alkaloid. Penapisan senyawa metabolit menggunakan LC-MS/MS menghasilkan 88 senyawa, terdiri dari golongan terpen atau terpenoid, fenolik, dan alkaloid, serta kelompok asam amino, asam lemak, asam organik, natural pigmen, gula dan kelompok lainnya. Senyawa dominan teridentifikasi diantaranya propenyl pyrazine, ribonic acid, pyroglutamic acid, phenyllactic acid, 1,2-cyclohexanedicarboxylic acid, didecyl ester, cis-caftaric acid, malic acid, 1,2-cyclohexanedicarboxylic acid, cyclohexylmethylnonyl ester, dan gallic acid., Spirulina platensis can stimulate the growth of non-pathogenic microbes. Previous studies have shown that lyophilized fermented Spirulina and Spirulina biomass have antioxidant activity. The study aims to determine the chemical characteristics and screening of metabolites produced by lyophilized fermented Spirulina and Spirulina biomass. Lyophilized fermented Spirulina had a pH value of 4,15 ± 0,00, total titrated acid (TAT) 11,96 ± 0,00%, and total lactic acid bacteria (LAB) < 2,5 × 101 ± 0,00. Fermented Spirulina contains active components of flavonoids, steroids, tannins, saponins and phenol hydroquinone, as well as negative alkaloids. Screening of metabolites using LC-MS/MS resulted in 88 compounds, consisting of terpenes or terpenoids, phenolics, and alkaloids, as well as groups of amino acids, fatty acids, organic acids, natural pigments, sugars and other groups. The dominant compounds identified were propenyl pyrazine, ribonic acid, pyroglutamic acid, phenyllactic acid, 1,2- cyclohexanedicarboxylic acid, didecyl ester, cis-caftaric acid, malic acid, 1,2- cyclohexanedicarboxylic acid, cyclohexylmethylnonyl ester, and gallic acid.
Keyword: Lactobacillus plantarum SK (5), Spirulina, metabolomic, metabolites

Judul: Fermentation of Spirulina platensis Using Lactobacillus plantarum SK (5) from of Bekasam
Abstrak: Spirulina platensis mengandung protein (60-69%), karbohidrat (16-20%), serta lemak (5-12%) dan beberapa komponen bioaktif antara lain fenolik, teroid, flavonoid, dan saponin. Lactobacillus plantarum SK (5) dapat digunakan sebagai starter dalam fermentasi spirulina yang berperan sebagai prebiotik. Tujuan penelitian ini untuk menentukan pengaruh jumlah spirulina yang berbeda terhadap perubahan mikrobiologis dan kimiawi selama fermentasi S. platensis menggunakan L. plantarum SK (5). Penelitian ini meliputi kultivasi spirulina, penyiapan kultur L. plantarum SK(5) serta fermentasi S. platensis dengan L. plantarum SK(5) dalam media air. Biomassa spirulina 3, 5, dan 7 g ditambahkan dengan 25 mL ddH2O dan L. plantarum SK (5), kemudian diinkubasi selama 0, 24, 48, dan 72 dengan suhu 37oC. Selama fermentasi penambahan spirulina pada konsentrasi berbeda menunjukkan pola perubahan total BAL, TAT, dan pH sama. Penambahan biomassa spirulina sebanyak 5 g dengan waktu inkubasi 48 jam merupakan perlakuan terpilih dengan karakteristik total BAL 8,09 log cfu/mL, nilai TAT 0,21%, dan nilai pH 3,86., Spirulina platensis contain protein (60-69%), carbohydrates (16-20%), as well fat (5-12%) and contains several bioactive components like phenolic, steroid, flavonoid, and saponin. Lactobacillus plantarum SK (5) can be used as a starter in spirulina fermentation. The aims of this study are to determine the effect of adding S. platensis on microbiological and chemical changes during fermentation using the L. plantarum SK (5). The study includes spirulina cultivation, the preparation of the L. plantarum SK (5), and the fermentation of S. platensis using the L. plantarum SK (5) in the water media. Spirulina powder of 3, 5, and 7 g was added with ddH2O of 25 mL and incubated at 0, 24, 48, and 72 h at a temperature of 37 oC. During spirulina fermentation, different amounts showed the same trend in the total microbe, TAT, and pH. The addition of 5 g spirulina and an incubation time of 48 h was the chosen treatment with characteristics of 8,09 log cfu/mL, 0,21% TAT, and pH 3,86.
Keyword: Fermentation, Lactobacillus plantarum, Spirulina platensis

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
Keyword: