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UJI STABILITAS ENZIM LIPASE TERIMOBILISASI PADA KITOSAN SERBUK MELALUI TEKNIK TAUT SILANG

PROSIDING SEMINAR NASIONAL 2015: Prosiding Bidang MIPA dan Kesehatan The 2nd University Research Colloquium
Publisher : Universitas Muhammadiyah Semarang

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Abstract

Lipase has a great catalytic power, but easily influenced by environments and difficult to separate at the ends of the reaction, so it can not be re-used. Based on that, one solution to overcome that problem is through the enzyme immobilization. Immobilization of lipase on chitosan powder was performed via cross linking technique. Chitosan was prepared from crab shell with deacetylation degree 82,34% and crosslinked with glutaraldehide. The aims of this research is to determine the thermal stability and multiple-use stability through the hydrolysis reaction of palm oil. Immobilized lipase on chitosan powder was able to maintain its activity at 50 oC, and still can produce free fatty acid as much as 48,55%. The immobilized lipase was also able to maintain its activity after multiple-uses up to five reaction cycles, and still can produce free fatty acid as much as 40,82%.Keywords: lipase, immobilization, chitosan, cross linking

Bioassay-Guided Isolation of an Antibacterial Compound from the Indonesian Soft Coral

Squalen, Buletin Pascapanen dan Bioteknologi Kelautan dan Perikanan Vol 11, No 2 (2016): August 2016
Publisher : Research and Development Center for Marine and Fisheries Product Processing and Biotechnol

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Abstract

With the aim of searching for new antibacterial compound from marine soft corals, the investigation had been conducted on antibacterial activity of an extract from soft corals Sarcophyton trocheliophorum in the n-hexane, ethyl acetate, n-butanol, and aqueous fractions. The antibacterial activity was tested against two Gram-positive bacteria, viz. Bacillus subtilis (ATCC 6633) and Staphylococcus aureus (ATCC 25923), and two Gram-negative bacteria, viz. Escherichia coli (ATCC 25922) and Vibrio cholerae (ATCC 14035) using the agar disc diffusion assay. Among them, the n-hexane fraction was the most active against three tested bacteria, viz. Bacillus subtilis, Staphylococcus aureus and Vibrio cholerae at the concentration 125 µg/ml, with inhibition zone 14.2, 18.2, 13.8 mm, respectively. Isolation and purification of the active component from the n-hexane fraction led to a known cembranoid-type diterpene, sarcophytoxide. The chemical structure of the isolated compound was determined by IR, MS and NMR, as well as compared to data from the literature. Sarcophytoxide showed moderate activity against B. subtilis, S. aureus and V. cholerae, with a minimum inhibitory concentration (MIC) of 125, 100, 125 mg/ml, respectively.

Characterization and Photocatalytic Activity of TiO2(rod)-SiO2-Polyaniline Nanocomposite

Indonesian Journal of Chemistry Vol 18, No 2 (2018)
Publisher : Universitas Gadjah Mada

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Abstract

A study of TiO2(rod)-SiO2 composites coated with polyaniline (PANI) has been performed. PANI was synthesized through in-situ polymerization of aniline at various concentration (0.0137, 0.0274, and 0.0411 M) on the composite under acidic condition. PANI was confirmed by the appearance of C=N, C=C vibrations and the redshift of the band-gap from 3.14 eV for the TiO2(rod)-SiO2 into 3.0 eV for the TSP01 composite. It is also shown that the polymerization does not change the crystal structure of TiO2(rod)-SiO2 as confirmed by the XRD pattern. The TEM image shows a mixed structure of SiO2 coated by TiO2(rod)-PANI layers and the oxides coated by PANI layers. Therefore, the surface area of the resulted TiO2(rod) and the composites did not change significantly. The T TiO2(rod)-SiO2-PANI composite give small improvement under visible irradiation from 20.25 to 25.59% (around 5% from the bulk of TiO2(rod)) and from 25.03 to 25.59% (around 2% from TiO2(rod)-SiO2 composite). The mixed structure of the composites, as well as the formation of excessive layers of PANI, are possibly the case for the low photoactivity. Further improvement to obtain a core-shell structure with a thin layer of PANI is still sought.

1H NMR Fingerprinting of Medicinal Herbs Contain Chemical Drug Material Allopurinol

Majalah Obat Tradisional Vol 23, No 3 (2018)
Publisher : Faculty of Pharmacy, Universitas Gadjah Mada

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Abstract

A study to differentiate the pure medicinal herbs from the mix medicinal herbs with chemical drug material has been done. For this purpose, we conducted fingerprinting of commercial medicinal herbs and chemical drug material allopurinol using 1H-NMR followed with chemometrics analysis. Nine commercial traditional herbal medicines claimed for rheumatic were used as samples as well as allopurinol as the chemical drug standard. Extraction of samples was done by ultrasonicator for 15 min in methanol-d4 containing 0.01% TMSP as an internal standard. Each type of herbal medicine was prepared in three replicates. The phytochemical analysis was done by 500 MHz JEOL NMR. The chemometrics analysis was done using SIMCA software following the 1H NMR spectra processing with MNOVA software. All spectra showed no contamination with allopurinol. The specific signals of allopurinol at aromatic regions were confirmed not present when the spectra were stacked together. Hence, the result of OPLS-DA analysis convinced that the herbs were clearly separated the medicinal herbs into 3 classes. Jamu 1 is separated from others showed very high intensity of several signals which may indicate an addition of chemical medicines but not allopurinol. The clear separation of other two groups may corresponds to the similarity of ingredients. These results also showed that most of traditional medicines which produced by small industries, the traditional medicines contain no active pharmaceutical ingredients (allopurinol) indicating a high safety of Indonesia traditional medicines.

Short Time Synthesis of Titania Nanotubes: Effect of Pre-Mixing Prior Hydrothermal

Indonesian Journal of Chemistry Vol 19, No 1 (2019)
Publisher : Universitas Gadjah Mada

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Abstract

The effect of pre-mixing by mechanical stirring before hydrothermal and hydrothermal time on the crystalline phases and morphology of titania has been studied. It was shown that nanotubes titania can be obtained after 5 h hydrothermal at 150 °C. The XRD patterns and Raman spectra of the produced powders showed the existence of anatase and titanate crystalline phases. At the longest stirring, TiO2 (B) was observed. High textural coefficient for [200] plane of anatase (TC200) confirmed oriented growth of one-dimensional anatase along [200]. All powders resulted at various stirring time were nanotubes, as confirmed by Transmission Electron Microscope (TEM). It was found that the longer the stirring, the higher the surface area of the nanotubes. All powders showed type-IV isotherm for nitrogen gas adsorption/desorption, indicating the existence of mesoporous materials. However, long hydrothermal induced the nanospheres formation, hence reducing the surface area. The band-gap of the resulted titania nanotubes were ranging from 3.11–3.16 eV. The photocatalytic performance toward the degradation of methylene blue of the titania nanotubes was higher (~50%) compared to the bulk TiO2 (~5%) under visible-light and was comparable under UV-light (~60%). These results pave a way of producing visible-sensitive TiO2 photocatalyst by altering the morphology.

Konversi Limbah Cangkang Kepiting Menjadi Chitosan Beads sebagai Matriks Pendukung pada Proses Imobilisasi Lipase

Biomedika Vol 7 No 2 (2014): Jurnal Ilmiah Biologi dan Kesehatan
Publisher : Fakultas Ilmu Kesehatan Universitas Setia Budi

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Abstract

Limbah cangkang kepiting dapat diproses menjadi kitosan melalui reaksi deproteinasi, demineralisasi dan deasetilasi. Penelitian ini bertujuan untuk mengetahui pengaruh penggunaan chitosan beads sebagai matriks pendukung pada proses imobilisasi lipase yang mampu meningkatkan stabilitas termal enzim lipase bebas. Kitosan yang diperoleh dianalisis dengan FTIR dan dikarakterisasi kadar air, kadar abu dan kadar nitrogen. Tahap selanjutnya, kitosan dimodifikasi bentuknya menjadi chitosan beads melalui proses penggembungan kemudian diikat silang dengan glutaraldehid. Chitosan beads yang sudah diikat silang diimobilisasikan ke dalam larutan lipase 1% yang dilarutkan dalam bufer fosfat pH 6. Enzim lipase terimobilisasi diuji stabilitas termalnya melalui reaksi transesterifikasi antara minyak kelapa dengan metanol serta diamati aktivitas transesterase enzim lipase bebas dan enzim lipase terimobilisasi. Hasil penelitian menunjukkan bahwa kitosan memiliki derajat deasetilasi 70,53% berdasarkan baseline-a dan 82,84% berdasarkan baseline-b. Kadar air, kadar abu dan kadar nitrogen kitosan berturut-turut yaitu 14,13±0,01%, 0,75±0, 13% dan 7,27±0,09%. Stabilitas termal enzim lipase terimobilisasi mengalami penurunan sebesar 20-40%, sedangkan enzim lipase bebas mengalami penurunan sebesar 30-45% pada temperatur pemanasan awal 35-45 °C. Penurunan aktivitas terbesar terjadi pada saat temperatur pemanasan awal 45-50 oC yaitu 51,81% untuk enzim lipase terimobilisasi dan 97,29% untuk enzim lipase bebas.