Judul: Purifikasi, amobilisasi, dan karakterisasi β-galaktosidase dari Enterobacter cloacae serta potensinya terhadap susu UHT
Abstrak: Enzymatic hydrolysis of lactose is an important biotechnological process because the hydrolyzed products can be consumed by people with lactose intolerance. The aim of this study was purification, immobilization, and characterization of β-galactosidase from E. cloacae. This research also studied the hydrolysis of lactose in UHT milk. The stages of this research were production and purification β-galactosidase from E. cloacae; characterization of enzyme; optimization of immobilization formula; and hydrolisis of UHT milk. The β- galactosidase from E. cloacae was purified and showed a purification of 30.26- fold, a yield of about 6.18%, and a specific activity of 101.781 U/mg. Free and immobilized enzyme exhibited maximum activity at an optimal pH of 7.0 and an optimum temperature of 40°C. This enzyme was activated by Co2+, Mn2+, and Mg2+; however, was inhibited by Ca2+, Zn2+, Cu2+, and Hg2+. KM for free and immobilized β-galactosidase were 0.434 and 2.068 mM, respectively. Optimal formulation of cell and enzyme immobilization were consist of 10% (w/v) cell with 5% (w/v) sodium alginate and 10% (v/v) purified enzyme with 5% (w/v) sodium alginate, respectively. This researh found that entrapped β-galactosidase was higher in the hydrolysis of lactose present in milk (28.09%) after 6 hours in batch process as compared to entrapped E. cloacae (22.01%) after 18 hours. Free β-galactosidase was higher in the hydrolysis of lactose present in milk (78.20%) after 6 hours as compared to free E. cloacae (55.14%) after 18 hours.
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Judul: Amobilisasi β-galaktosidase Bakteri Asam Laktat Indigenos Strain D-210 dengan Natrium Alginat dan Potensi Hidrolisisnya pada Susu UHT
Abstrak: Lactose intolerance is a symptom who cannot produce the β-galactosidase enzyme (lactase) an enzyme that catalyzes hydrolysis of lactose into glucose and galactose, in their digestive system. In most cases this causes symptoms which may include abdominal bloating and cramps, flatulence, diarrhea and nausea. Immobilization of Indigenous Lactic Acid Bacteria strain D-210 β-galactosidase with natrium alginate and its potential in UHT milk has not been reported yet. Indigenous Lactic Acid Bacteria strain D-210 was found as bacteria producing β-galactosidase which was culture in MRS (Mann Rogosa Sharpe) and substrate lactose 3%. The β-galactosidase was dialyzed for getting the partial pure. The research results showed that the optimum production of β-galactosidase in Indigenous Lactic Acid Bacteria Strain D-210 was reached on 24 hours with activity 26.605 U/ml and total activities was 27.669 U, and Indigenous Lactic Acid Bacteria Strain D-210 optimum growth was reached on 24 hours with optimum optical density 1.984 and amount of cell was 1.81x10-8 cell/ml. The total activities partial purification of crude β-galaktosidase was 138.396 U, total activities after presipitation with amonium sulfat the total activities was 87.030 U and total activities after dialysis was 50.420 U. The inhibitors of β-galaktosidase were Hg and Cu with relative activities were 56.82% and 1.04%, while the activators were Mg,Mn,Ca,Co,Zn. Kinetic parameter of enzyme showed that the values of Km: 0.491 mM and Vmax:0.093 μmol/minute (free β-galactosidase), and values of Km:15.54 mM and Vmax 0.474 μmol/minute (immobilized β-galactosidase) . The optimum activity of the free β-galactosidase was reached on pH: 6.5 with activity 252.341 U/ml, and temperature: 45 oC with activity 180.093 U/ml. The optimum concentration of Na alginate for immobilized cell and β-galactosidase were 2% and 3% respectively. The concentration of Na alginat used for hydrolysis lactose in cell was 12% with the released total product 58.884 μmol and for the β-galactosidase was 20% with the released total product 91.752 μmol. The optimum activity of the immobilized β-galactosidase was reached on pH:6 with activity 40.428 U/ml, and on temperature: 40 oC with activity 41.194 U/ml. The optimum potential of cell imobilized and β-galactosidase for lactose hidrolysis in UHT milk were reached for 6 hours and 18 hours with relative activity 76.72% and 62.78% respectively. Repeated use of cell and enzyme β-galactosidase immobilized was 6 times with the use of relative hydrolisis activity were 39.52% and 53.68% respectively.
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Judul: Warna bulu kucing ras Persia : variasi pola warna dan pewarisannya
Abstrak: Kucing Persia merupakan kucing ras yang paling umum dijumpai di Indonesia. Kucing Persia memiliki bulu yang panjang dengan variasi warna bulu yang sangat beragam. Perkawinan yang lebih terarah sangat perlu dilakukan untuk meningkatkan kualitas genetik warna dan pola warna bulu kucing. Penelitian ini bertujuan untuk mempelajari variasi warna dan pola warna bulu kucing Persia yang terdapat di Indonesia, yang dilakukan di kantor pusat Cat Fancy Indonesia mulai bulan Oktober 2000 sampai Januari 2001. Data yang digunakan merupakan data pedigree kucing Persia yang tercatat di Cat Fancy Indonesia dari tahun 1997 sampai Oktober 2001 yang terdiri dari 187 jantan dan 258 betina, selain itu juga dilakukan pengamatan langsung kepada tiga penyayang dan breeder kucing yang ada di Bandung. Secara umum tercatat 104 penyayang dan breeder kucing ras di Indonesia, 74,04% terdapat di Jawa Barat dan sisanya (25%) terdapat di daerah Jakarta. Jumlah kucing Persia yang lahir di Indonesia adalah 387 kucing (87,16%), yang terdiri dari 163 (42,12%) jantan dan 224 (57,88%) betina. Jumlah kucing Persia yang diimpor ke Indonesia adalah sebanyak 57 (12,845%) yang terdiri dari 23 (40,35%) jantan dan 34 (59,65%) betina. Jumlah kucing Persia yang terdapat di Jawa Barat (84,14%) lebih banyak dibanding jumlah kucing Persia yang ada di Jakarta (14,86%). Secara umum warna bulu cream (9,01%) dan pola warna solid (34,01%) memiliki persentase tertinggi. Warna cream merupakan warna dilusi dari warna merah (red) yang dapat dihasilkan dari berbagai macam kombinasi warna bulu yang dimiliki tetua sebelumnya, sebagai contoh dari perkawinan tetua yang memiliki warna bulu cream dengan red smoke. Perkawinan antara tetua yang memiliki warna dan pola warna bulu yang tidak murni dapat menghasilkan turunan yang memiliki warna dan pola warna bulu yang bervariasi.
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