The Potency of Dextranase from Arthrobacter sp. Strain B7 as Dental Plaque Removal

Dextranase of Arthrobacter sp. strain B7 (B7DEX enzyme) was characterized in this study. This enzyme hydrolyzed sucrose and dextran, but not other glucans (starch, nigeran, cellulose, -soluble glucan). It also hydrolyzed glucan from dental plaque with the activity of 7.38 +/- 66 U/ml, where the activity toward dextran was 31.88 +/- 1.24 U/ml. The enzyme exhibited the pH optimum of 7 and the temperature optimum of 50 0C. Its optimum stability was at pH 7 and 50 0C. The enzyme was inhibited by Fe3+, Cu2+, Zn2+, and Ag+, but not by the anionic detergent (SDS) and the nonionic detergent (Triton-X). The enzyme was activated by Ca2+, Na+, Mg2+, and saliva

Purifikasi dan Karakterisasi α-amilase Termostabil dari Bacillus stearothermophilus TII-12

Purification and Characterization of Thermostableα-amylase from Bacillus stearothermophilus TII-12. PujiLestari, Nur Richana, Abdul A. Darwis, Khaswar Syamsu,and Untung Murdiyatmo. Thermostable α-amylase is apotential enzyme employed in the starch processing andwidely used in food industries, but this enzyme is stillimported. The local enzyme production would be moreeconomist and useful for its broad applications. Here wereport α-amylase from indigenous bacteria TII-12 which waspurified and characterized, as well as analyzed its hydrolysisproduct on cassava starch. The enzyme of Bacillusstearothermophilus TII-12 partially purified by ultrafiltration,acetone precipitation and gel filtration (Sephadex G-100)showed the reduced total activity, total protein and yield, butincreased the specific activity. The enzyme had a Km of 1,06mg/ml and Vmax of 1,21 mol/min, with optimal activity at pH 7and 90oC. An apparent molecular mass was of 192.932,8Dalton, as estimated by Native-Polyacrylamide Agarose Gelelectrophoresis. Its activity was inhibited by the divalentcation chelator such as EDTA and CuSO4 but activated bycalcium ion. Hydrolysis products of this enzyme on cassavastarch were glucose, dextrin, maltose and oligosaccharides.After 24 hours of hydrolysis, the concentration of glucoseand maltose reached 51.970 and 10.090 ppm, respectively.The thermostable α-amylase of TII-12 is an endo-α-amylaseand prospective to be applied on starch liquefaction withhigh temperature process

Studi Komparasi: Produksi Bioetanol Nira Batang Kelapa Sawit oleh Flokulan dan Non- Flokulan Saccharomyces cerevisiae

Two types of yeast were used for bioethanol production from oil palm trunk sap, the flocculant Saccharomyces cerevisiae NCYC­1195 and non­flocculant Saccharomyces cerevisiae Kyokai 7 (NCYC-479). Flocculant Saccharomyces cerevisiae is yeast that has ability to aggregate into flocks which precipitate rapidly in culture medium. The effect of urea as a nitrogen source was also investigated in this study. Some concentrations of urea were added i.e. 0%, 0.1%, 0.2%, and 0.3% (w/v) during fermentation. The purpose of this study is to obtain the best condition by strain of Saccharomyces cerevisiae and urea concentration for the highest ethanol production. The highest ethanol production and yield was obtained at 4.86% (v/v) and 0.52 (g/g) respectively, by nonflocculant Saccharomyces cerevisiae Kyokai 7 (NCYC-479) without the addition of urea

Produksi, isolasi dan karakterisasi enzim dekstranase dari Arthrobacter sp. B7

Dextranase enzyme has been purified and characterized from Arthrobacter sp. B7. This enzyme was purified from the culture supernatant of Arthrobacter sp. B7 by procedure of native PAGE. The molecular size of the enzyme was estimated 72,5 kDa by SDSPAGE. The N-terminal amino acid sequence of this enzyme determined using Edman degradation techniques were APVTADVGNLHT. SDS-PAGE and native-PAGE analysis revealed that the enzyme molecule consisted of one sub-unit

Potensi Enzim Dekstranase dari Arthrobacter sp. Galur B7 sebagai Penghambat Plak Gigi

Dextranase of Arthrobacter sp. strain B7 (B7DEX enzyme) was characterized in this study. This enzyme hydrolyzed sucrose and dextran, but not other glucans (starch, nigeran, cellulose, β-soluble glucan). It also hydrolyzed glucan from dental plaque with the activity of 7.38 ± 0.66 U/ml, where the activity toward dextran was 31.88 ± 1.24 U/ml. The enzyme exhibited the pH optimum of 7 and the temperature optimum of 50 °C. Its optimum stability was at pH 7 and 50 °C. The enzyme was inhibited by Fe3+, Cu2+, Zn2+, and Ag+, but not by the anionic detergent (SDS) and the nonionic detergent (Triton-X). The enzyme was activated by Ca2+, Na+, Mg2+, and saliva

Isolasi dan analisis gen yang responsif terhadap cekaman kekeringan pada tebu

This study was aimed to isolate and identify a gene that was responsive to drought stress in sugar cane variety M442-51, a varietythat is widely used in pastures or dry land. Under drought stress, M442-51 showed an enhance expression of several proteins. One ofthe protein, namely dip22, (drought inducible protein, with a molecular weight of 22KDa) was isolated and analyzed. Amino acidsequence of this protein showed some homology with several stressed related proteins (OsAsr 1 from Oryza sativa leaves, ZM Bss1 ofZea mays leaves, LeAsr 1, LeAsr 2 and LeAsr 3 of Lycopersicum lycopersicon leaves). The 343 bp of dip22-cDNA fragment wasobtained using RT PCR from mRNA of sugar cane leaves that has been exposed to drought stress. The results indicated that the genedip22 plays an important role as a regulatory protein that are usually nested within cytoplasmic matrix or in the nucleus