Khaswar Syamsu

The use of dilution rate cycling to stabilise recombinant plasmids in continuous culture of recombinant Saccharomyces cerevisiae

Abstract The use of dilution rate cycling to stabilise multiple copies of recombinant plasmid pLG669-z in continuous culture of recombinant Saccharomyces cerevisiae over different amplitudes and different frequencies of cycling was studied. Nutrient concentrations in the feed were maintained at constant values. In the first set of experiments, the cycling amplitudes were varied over a dilution rate range of 0.1 h −1 to 0.4 h −1 at a constant cycling frequency of 3 h. In the second set of experiments, the cycling frequencies were varied between 4 and 12 h at a constant dilution rate cycling of 0.1 h −1 to 0.4 h −1 . Plasmid stability was dependent on cycling amplitude and cycling frequency applied in that the plasmid stability was improved with a dilution rate range of 0.1 h −1 to 0.3 h −1 for a fixed cycling period of 3 h; and with a cycling period of 8 h for a fixed dilution rate range of 0.1 h −1 to 0.4 h −1 . The cycling amplitude and cycling frequency are important parameters for successful plasmid stabilisation through dilution rate cycling.

Penentuan Teknologi Proses Pembuatan Gambir Murni dan Katekin Terstandar dari Gambir Asalan

Uncaria gambir Roxb. is an industrial crop commodity that has a high economic value and good prospect for farmers and exporter. Gambier of traditional processed products (raw gambier) generally have various catechin content, so it is required further handling to increase the purity of catechins from raw gambier. The research was aimed to get a process technology on the making of pure gambier and standardized catechins. Sources of raw materials was obtained from extraction process through steaming leaves and twigs of gambier (KA) using equipment from aluminum (RA) and from iron (RF). Purification of raw gambier through repeated extraction with water could decrease tannin content from 24% to 2.4% and increase catechin levels between 40% to 74%. Gambier with a low tannin content (catechin KA) through re-extraction using water had the highest increase of catechin content with a color of yellowish white product. The iron-containing equipment affected the color of the pure gambier produced, which was reddish-brown. The effect of solvent on further extraction using ethyl acetate solvent resulted in higher catechin content (up to 99%) compare to ethanol (95%). The catechin purity of KA samples was tested by looking at its stability at varying levels of acidity, showing catechins of gambier was stabile at pH 6. ABSTRAK Uncaria gambir Roxb. merupakan komoditas tanaman industri yang memiliki nilai ekonomi tinggi serta mempunyai prospek cukup baik bagi petani dan pemasok negara-negara asing. Gambir hasil olahan tradisional (gambir asalan), umumnya memiliki kandungan katekin yang beragam, sehingga diperlukan penanganan lebih lanjut untuk meningkatkan kemurnian katekin dari gambir asalan. Tujuan penelitian adalah untuk mendapatkan teknologi proses pembuatan gambir murni dan katekin terstandar. Sumber bahan baku diperoleh dari proses ekstraksi melalui pengukusan daun dan ranting tanaman gambir (KA) menggunakan peralatan dari aluminium (RA) dan dari besi (RF). Pemurnian gambir asalan melalui ekstraksi berulang dengan air dapat menurunkan kadar tanin, yaitu dari 24% sampai 2,4% dan meningkatkan kadar katekin, yaitu antara 40% sampai 74%. Gambir dengan kandungan tanin rendah (katekin KA) melalui ekstraksi ulang menggunakan air memiliki peningkatan kadar katekin tertinggi dengan warna produk putih kekuningan. Peralatan mengandung besi berpengaruh terhadap warna dari gambir murni yang dihasilkan, yaitu berwarna coklat kemerahan. Pengaruh pelarut terhadap ekstraksi lanjut menggunakan pelarut etil asetat menghasilkan kadar katekin lebih tinggi (sampai 98%) dibandingkan etanol (95%). Kemurnian katekin sampel KA diuji dengan melihat stabilitasnya pada berbagai tingkat keasaman, menunjukkan katekin dari gambir stabil pada pH 6.

Effect of natural Bayah zeolite particle size reduction to physico-chemical properties and absortion against potassium permanganate (KMnO4)

Recently, researches on nanotechnology have been developed very rapid, as well as the utilization of nano-zeolites. Nano-sized material has several advantages which are expanding absorptive surfaces so it will enhance the material absorption and shorten the absorption time. Zeolite as a KMnO4 binder, has been widely recognized for its ability to extend the shelf life of vegetables and fruits. This study was conducted to determine zeolites physico-chemical characters from different particle size and the effect on KMnO4 absorption. Potassium permanganate (KMnO4) is a strong oxidizer for reducing the quantity of ethylene in storage process of fresh horticultural products. The treatment consisted of (1) different length of milling time (10, 20, 30, 40, and 60 minutes) and (2) the duration of chemical activation with 1 N KOH solution. Physical and chemical characters of zeolite were analyzed using BET, PSA, XRD and SEM. The research design was randomized design. The result implied that milling time was signifi...

Production of Omega 6 Probiotic by Isolation and Fermentation of Lactobacillus plantarum JR64

Application of lactic acid probiotic bacteria in health food diversification currently is progressing rapidly. It is encouraged the study of searching the potential strains from local resources (Ponorogo Residence) namely noni fruits (badeg pace) and noni wine. Aims of this study were to perform the isolation, identification, and production of probiotic Lactobacillus sp. JR64 fermentation process as a producer of Omega-6 (ω-6) lowering cholesterol and design of probiotic creamy product. Beginning stages of research was strains isolating and in-vitro testing, the best result were used in molecular identification technology development for the production of metabolites through the manipulation of environmental variation of glucose 20 g / l, 30 g / l and 40 g / l that influenced the substrate concentration of linoleic acid productivity. The result of new isolates isolation showed that isolates that obtained from noni wine, Lactobacillus plantarum JR64, was potential as probiotic condidate. The effieciency of fermentation substrates using Yx/s and Yp /s in the exponential phase was the highest value for the fermentation of 24 hours of Yx/ s; 17.03% and Y p/s; 74.72%, while the results of design and the best formulation for viability cells of lactobacillus plantarum probiotics JR64 was composed of 15 g and 50g butter 15 g icing sugar as well as during storage of the refrigerant temperature was 8.92 x 108 CFU / ml.