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: Antioxidant Activity of Spirulina platensis During Fermentation Using Lactic Acid Bacteria From Bekasam
Abstrak: Spirulina platensis merupakan mikroalga hijau kebiruan jenis cyanobacteria yang memiliki aktivitas antioksidan. Lactobacillus plantarum SK(5) dan Pediococcus pentosaceus BP(20) bersifat sebagai probiotik dan dapat digunakan secara langsung dalam makanan fermentasi. Penelitian ini bertujuan menentukan karakteristik kimiawi, mikrobiologis, dan aktivitas antioksidan S. platensis selama fermentasi menggunakan bakteri asam laktat (BAL) L. plantarum SK(5) atau P. pentosaceus BP(20). Penelitian ini terdiri atas 3 tahap yaitu kultivasi dan pemanenan biomassa S. platensis, penyiapan kultur starter SK(5) dan BP(20), dan fermentasi spirulina menggunakan starter BAL asal bekasam selama 72 jam inkubasi. Spirulina hasil kultivasi dapat dipanen pada hari ke-14. Spirulina fermentasi mengalami penurunan pH selama 48 jam dan peningkatan pada jam ke-72, serta peningkatan total asam tertitrasi (TAT) dan total BAL selama 48 jam kemudian penurunan pada jam ke-72. Peningkatan total fenol dan aktivitas antioksidan pada spirulina fermentasi dengan kultur BP(20) mencapai 25,43% dan 56,77% selama 48 jam, sedangkan peningkatan total fenol dan aktivitas antioksidan dengan kultur SK(5) mencapai 117,73% dan 188,18% selama 72 jam., Spirulina platensis is cyanobacteria (blue-green algae) that has antioxidant activity. Lactobacillus plantarum SK(5) and Pediococcus pentosaceus BP(20) that as probiotics and can be used directly in fermented foods. This study aimed to determine the chemical, microbiological, and antioxidant activity of S. platensis during fermentation using LAB L. plantarum SK(5) and P. pentosaceus BP(20). The procedure of this study consist of 3 stages, namely culturing of S. platensis, the preparation culture starter of SK(5) and BP(20), and fermentation of spirulina using LAB from bekasam for 72 hours. The spirulina culture was harvested on the 14th day. Fermented spirulina decreased in pH for 48 hours and increased at 72 hours, and increased TAT and LAB for 48 hours then decreased at 72 hours. The increase in total phenol and antioxidant in fermented spirulina with BP(20) reached 25,43% and 56,77% for 48 hours, while the increase in total phenol and antioxidant with SK(5) reached 117,73% and 188,18% for 72 hours.
Keyword: antioxidant, fermented spirulina, lactic acid fermentation, Lactobacillus plantarum SK(5), Pediococcus pentosaceus BP(20)

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.
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