No abstract

Kedelai edamame mengandung senyawa isoflavon yang berfungsi sebagai antioksidan. Senyawa tersebut berupa senyawa yang berikatan dengan gula melalui ikatan glikosida. Biokonversi senyawa isoflavon glikosida menjadi isoflavon aglikon yang sangat berpotensi tinggi sebagai antioksidan terjadi selama proses fermentasi oleh aktivitas enzim β-glukosidase. Dilaporkan enzim β-glukosidase dihasilkan oleh Rhizopus spp. Selain itu, selama proses fermentasi Bacillus subtilis menghasilkan enzim nattokinase yang juga dapat meningkatkan aktivitas antioksidan. Pada penelitian ini proses fermentasi dilakukan menggunakan inokulum Rhizopus oligosporus, B. subtilis serta campuran keduanya dengan lama fermentasi 24 jam, 48 jam dan 72 jam. Kemudian aktivitas antioksidan diuji menggunakan larutan DPPH (1,1-difenil-2-pikrilhidrazil). Proses fermentasi pada pembuatan tempe edamame dengan inokulum R. oliosporus dan B. subtilis dapat meningkatkan aktivitas antioksidan eksogenous. Aktivitas antioksidan eksogenous tertinggi oleh R. oligosporus sebesar 97% pada fermentasi 72 jam. Kata Kunci: Kedelai edamame, Isoflavon aglikon, DPPH

An improvement hydrolysis to produce a sugar-rich palm oil empty fruit bunches (POEFB) through a two-step solid state fermentation using Aspergillus niger and Tricodhermaviride has been investigated. Initial solid state fermentation was done in a hundred grams of water saturated POEFB medium in the 5L flaskwithout the addition of any nutrient. The medium was sterilized, inoculated with A. niger, and incubated at 30 C for 5 days. The sugar-rich hydrolysates in POEFB medium were harvested through filtration by adding 100 ml distilled water. Then POEFB sugar-rich free hydrolysates were subsequent re-sterilized, inoculated with T. viride and at the same temperature. After for 4 days incubation,sugar-rich hydrolysates also extracted and pooled. The analysis proves that the sugar-rich hydrolysates containing 6.52% (33.4 g sugar in a total volume of 512 ml or 65.2 mg/ml) as a reducing sugar. Further analysis by Gas Chromatograph (GC)astransmethylated sugar as alditol acetates revealed that 63% of POEFB hydrolysates are monosaccharides (41.1 mg/ml). Anaerobic fermentation of sugarrich hydrolysates using Saccharomyces cerreviseae at 30 C for 36 hours gave yield maximum 19.1 mg/ml ethanol concentration with efficiency 46.5%, respectively.

Hidrolisis limbah kulit buah kopi oleh enzim ekstraseluler Pestalotiopsis sp. VM 9 telah dilakukan. Hasil hidrolisis menunjukkan bahwa dalam hidrolisat mengandung gula reduksi 392,35μg/ml setelah masa inkubasi hari ke-6. Analisis lanjutan menunjukkan bahwa hidrolisat dapat digunakan sebagai medium pertumbuhan Protein Sel Tunggal (PST) S. cerevisiae dengan tingkat pertumbuhan hingga mencapai kepadatan sel 8,5x10 6 sel/ml selama 72 jam kultivasi. Selama pertumbuhannya S. cerevisiae terbukti mengkonsumsi sumber karbon dari gula reduksi sebanyak 211,91 μg/ml.

An α-L-Rhamnosidase released by Aspergillus niger during solid-state fermentation (SSF) using coffee pulp (CP) wastes media has been investigated. The activity of α-L-Rhamnosidase based on reducing sugar production against 2% CP alkali extract substrate in 50 mM acetate buffer pH 5. The maximum activity of α-L-Rham-nosidase was obtained in sixth-day SSF with reducing sugar pro-duction of 13 μg/mL. The enzyme is actively hydrolyzed 0.1% p-ni-trophenyl-α-L-rhamnopyranoside (PNP-Rha) to 95% from initial concentration. Purification using DEAE-Toyopearl 650M increased hydrolysis activity ten times against the substrate, reaching 134 μg/mL of reducing sugar. Optimum enzyme activity at pH 4.5 and 50°C, while stable at pH and temperature in a pH range of 3.5-7 and below 50°C.