Bioethanol is an alternative energy of fuels produced from vegetable materials. Vegetable materials that can be used as rawmaterial for bioethanol is ganyong because it contains 22.60 g starch in 100 g ganyong. The production of bioethanol fromstarch material consisted of two steps, hydrolysis and fermentation. One of the steps to increase the value of bioethanolfrom starch of ganyong was hydrolysis process using thermostable amylase enzyme isolated from Flavoacterium sp.PTBT I bacteria was isolated from hot spring of Pancuran Tujuh Baturraden. The aim of this research was to use thermostableamylase to hydrolyze starch of ganyong and glucose produced to result bioethanol. The result of this research showed thatthe optimum condition hydrolysis starch of ganyong was using thermostable amylase acquired at substrate concentrationof 3% (b/v), and incubation time of about 75 minutes. The value of bioethanol increased with time of fermentation, from thefirst to fourth day, which was 0.8361; 2.2379; 5.7590 and 10.5787% (v/v), respectively.
Protease has been used in large application industrial process such as detergent, leather, textil, softdrink, andmedicine. In order to find unique protease, many substances were explored as proteases of bacteria sources. Inthis study, tofu liquid waste was used as a source of bacteria producing proteases. Waste sample was growth inskim milk agar medium showing proteases activity, it was used to produce extracellular protease. The microbialcolonies were identified as Staphyllococcus sp. Protease was extracted with 5000 g centrifugation at 4 0C, andpurificated with ammonium sulphate precipitation continued with dialisis. Optimum production time, pH, metal ion,EDTA, specific activity, KM, and Vmaks were studied for enzyme characterization. Volume of crude enzyme was 300ml, with spesific activity of 3.55 U/mg. Protease obtained from 60% ammonium sulphate fraction had the highestspecific activity of 68.22 U/mg. Study on the protease characterization revealed that optimum temperature of thisenzyme was 400C. The optimum pH of the enzyme was found to be 8.0. The kinetic parameters K M dan Vmaks withcasein as substrate were 0.31% and 51.55 U/ml. Some inhibitory effect was observed in the presence of EDTA, Cu +2,Co+2, Zn+2, and enzyme activity was stimulated by Mg+2, indicating that this ion had a functional role in the molecularstructure of the enzyme.
A bacterial lipase producer was isolated from garbage dump soil and was identified its genus. Lipase was extractedaccording to production time optimized, purified using ammonium sulfate fractionation and gel chromatograph.Determination of enzyme characteristic studied were influence of pH, temperature, various metals to lipaseactivity. The result of this research shows that the genus of isolated bacteria which produced lipase wasAcinetobacter sp., the lipase optimum production time is about 18 hours with the activity is about 115 unit/mL. Thehighest activity of lipase fractionation using ammonium sulfate is about 45% and the highest activity of purifyingwith filtration gel chromatograph column using Sephadex G-150 at 24 th fraction. Lipase from crude extract andpurifying product at this fraction has optimum pH 6 and optimum temperature is about 40 oC. Lipase to be classifiedas metalloenzyme that shows with decreasing the activity after added the EDTA. Metals ion, such as Cu 2+ and Zn2+were inhibited the lipase activity. Ca 2+ ion could increase lipase crude extract activity but inhibited the activity oflipase purifying product. Hg2+ ion could increase the activity of lipase purifying product.
Urease merupakam enzim yang digunakan dalam hidrolisis urea menjadi amoniak dan asam bikarbonat dan telah banyak digunakan dalam proses industri. Tujuan penelitian adalah isolasi dan pemurnian urease dari kacang panjang serta karakterisasinya. Penelitian dimulai dengan melakukan perkecambahan biji kacang panjang selama 8 hari. Kecambah biji kacang panjang selanjutnya diekstraksi dengan menggunakan buffer fosfat pH 7 dan dipisahkan menggunakan sentrifugasi sehingga diperoleh ekstrak kasar urease. Ekstrak kasar urease selanjutnya difraksinasi menggunakan aseton pada tingkat konsentrasi 20, 40, 60 dan 80%. Fraksi yang mempunyai aktivitas spesifik paling tinggi selanjutnya dianalisis menggunakan metode SDS-PAGE untuk menentukan berat molekulnya dan dikarakterisasi lanjut meliputi: pengaruh suhu, pH, konsentrasi substrat dan penambahan ion logam terhadap aktivitas urease. Aktivitas urease ditentukan dengan metode Nessler. Hasil penelitian menunjukkan aktivitas spesifik urease dari kacang panjang paling tinggi ditemukan pada fraksi aseton (FA) 20. Hasil analisis berat molekul dengan metode SDS-PAGE diperoleh beberapa pita protein yang diduga berukuran sekitar 25 KDa dan 17 KDa. Kondisi optimum dari aktivitas urease diperoleh pada suhu 30 ÂºC, pH 7 dan konsentrasi urea 16,6 mM dengan nilai aktivitas 407,62 U/mL. EDTA dan ion logam dalam CaCl2, NaCl, NiCl2 dan CuCl2 pada variasi konsentrasi 10-3, 10-4 Â dan 10-5 M merupakan inhibitor urease FA 20 dari kacang panjang.Partial Purification and Characterization of Urease from Asparagus Bean (Vigna unguiculata subsp sesquipedalis L.). Urease is an enzyme used in urea hydrolysis to ammonia and bicarbonate acid and has been widely used in industrial processes. The study focused on isolation and purification of urease from asparagus beans and its characterization. The study was started with germination of asparagus beans for 8 days. Germinated asparagus beans were further extracted using phosphate buffer pH 7 and separated by centrifugation to obtain a crude extract of urease. The crude extract of urease was further fractionated using acetone at concentrations of 20, 40, 60 and 80%. The fraction with highest specific activity was then analyzed using SDS-PAGE method to determine its molecule weight and characterized further including the influence of temperature, pH, substrate concentration, and metal ion addition to urease activity. The urease activity was determined by the NesslerÌ• s method. The results showed that the specific activity of urease from asparagus beans was found with highest activity in fraction of acetone (FA) 20. Analytical result using SDS-PAGE method was obtained some protein bands having molecular weights about 25 KD and 17 KDa. The optimum conditions of urease activity was obtained at 30 Â°C, pH 7, incubation time 20 min and urea concentration 16.6 mM with activity value 407.62 U/mL. EDTA and metal ions contained in CaCl2, NaCl, NiCl2 and CuCl2 at concentrations of 10-3, 10-4 and 10-5 M were FA 20 urease inhibitors.
Sangat penting untuk mengetahui pandangan calon guru kimia tentang Nature of Science karena akan mempengaruhi kinerja disaat menjadi guru yang sesungguhnya. Guru yang memiliki pandangan mengenai nature of science (VNOS) yang benar, akan mentransfer kemampuan tersebut kepada para siswanya, begitu juga sebaliknya pemahaman yang salah juga akan tertularkan kepada para siswa. Aspek VNOS yang akan dibahas meliputi (1) Tentativeness, (2) Empirical basis, (3)Subjectivity, (4) Creativity, (5) Social/cultural embeddedness, dan (6) Theories and laws. Metode yang digunakan dalam penelitian ini adalah deskriptif. Instrumen yang digunakan dalam penelitian ini adalah kuisioner VNOS form B yang telah diadopsi dari Lederman dan pedoman wawancara. Pandangan calon guru kimia dijelaskan dan dikategorikan sebagai naÃ¯ve, eclectic, dan informed untuk setiap aspek NOS. Hasil penelitian menunjukkan bahwa calon guru kimia memiliki pandangan yang cukup memadai tentang Nature of Science.
Free enzyme in solution react with substrates to result in products which cannot be recovered for reuse. TheseÂ problemsÂ canÂ beÂ overcomeÂ to a certain extent by the use of enzyme immobilization method. Immobilized enzymes are more robust and more resistant to condition changes. More importantly, the heterogeneous immobilized enzyme systems allow an easy recovery of both enzymes and products, multiple re-uses of enzymes, and continuous operation of enzymatic processes. Entrapment of enzymes in Ca-alginate is one of the simplest methods of immobilization. The aim of this research was to obtain the optimum condition of the making of immobilized amylase beads using a Ca-alginate bead and to determine its characteristics. The optimization of immobilized amylase beads includes variation of sodium alginates and variations of enzyme contact time with CaCl2. The characterization of immobilized amylase includes determination of optimum substrate concentration, optimum pH, and optimum incubation time as well as amylase stability test. Amylase activity was determined by using dinitro salicylic (DNS) method. The results showed that the optimum immobilized amylase obtained at alginate concentrations of 5% (w/v), contact time of 60 minutes and immobilization efficiency of 67.5%. Furthermore, immobilized amylase showed optimum substrate concentration of 1.5-2.5% (w/v), optimum pH of 6, an optimum incubation time of 20 minutes with the activity of 179.8 U/mL. The KM value for free amylase and immobilized amylases were 0.3 mM and 0.12 mM respectively. Vmax value for free amylase and immobilized amylases were 105.3 U/mL and 10.1 U/mL respectively. Immobilized Amylase can be used up to six times with the residual activity of 52.7%.
Penggunaan protease pada umumnya, dalam bentuk enzim bebas yang hanya sekali pakai, sehingga biaya produksi yang melibatkan enzim ini menjadi mahal. Amobilisasi enzim dapat mengatasi masalah ini, yang memungkinkan penggunaan enzim berulang kali. Dalam penelitian ini, protease dari Bacillus sp. BT 1, yang diperoleh dari sumber air panas, diamobilisasi dengan jebakan menggunakan poliakrilamida. Ekstrak kasar dalam bentuk enzim protease bebas dan enzim amobil dikarakterisasi termasuk suhu optimum, pH optimum, waktu inkubasi dan stabilitas enzim amobil pada penggunaan berulang. Aktivitas protease diukur dengan menggunakan metode Kunitz yang modifikasi. Hasil penelitian menunjukkan waktu produksi optimum protease adalah 36 jam yang berada pada akhir fase eksponensial pertumbuhan bakteri. Amobilisasi ekstrak kasar protease Bacillus sp BT 1 dapat menjebak 47,18% dari protease. Suhu optimum protease bebas 60 oC dan meningkat menjadi 70 oC pada penggunaan protease amobil. Protease bebas dan protease amobil memiliki pH optimum yang sama yaitu 11. Protease amobil tidak kehilangan aktivitas secara signifikan sampai empat kali penggunaan.
The Relationship between Service Quality with the Student's Trusty. The objective of this research to know the lecturer’s and education service with competence, guarante of work fast and education service with student’s trusty in Polytechnic LP3I Jakarta Pasar Minggu campus. The research is carried out in campus Pasar Minggu due to the efficiency of time and place of respondent. The method of this research is by using descriptive statistic and hypothesis test. Base on the relation of service qualiy with students trusttuidance for the managerial, mainly in upgrading the service quality in term of upgrading the student's recommendation. The purpose of this research is to exa, it will result: lecturer’s competences have the significant relation eith student’s trusty. Promotion of guarantee of work fast has the significant relation with the students trusty, education service has the significant relation with the student’s trusty.Keyword : Studnts’s trusty, Lecturer’s Competence, Education Service
The development of biosensors using biological components has an important role in detecting the disease early because it has good selectivity and accuracy. In this study, a biosensor which made is a urea biosensor, based on immobilization urease in chitosan using adsorption techniques, to measure urea levels by colorimetric analysis with bromothymol blue (BTB) as an indicator. The purpose of this study was to find out how to measure urea levels using biosensors based on urease immobilization in chitosan and find out the biosensor performance including optimum enzymatic reaction time, linearity, the limit of detection, repetition, and determination of disrupting compounds. The study began with the making of an immobilization supporting matrix using chitosan which was made in the form of cryogel through an ionic gelation process which adsorbs the urease enzyme. Cryogel urease catalyzes the hydrolysis of urea into NH4+ and CO2-. The reaction product was added with the BTB indicator, and the color change formed was measured using a spectrophotometer. The results showed that the performance of urea biosensors was good enough for urea level detection systems by producing enzymatic reaction times at 15 minutes, linearity at 0.9951, detection limit at 0.018 mM, not affected by the addition of 0.05 mM ascorbic acid and 0.4 mM uric acid. This urea biosensor can be used up to 5 repetitions.