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Production and properties of an extracellular protease from thermophilic Bacillus sp
Nascimento, Wellingta Cristina Almeida do;Martins, Meire Lelis Leal;
Brazilian Journal of Microbiology , 2004, DOI: 10.1590/S1517-83822004000100015
Abstract: protease production by thermophilic bacillus sp strain smia-2 cultivated in liquid cultures containing trisodium citrate reached a maximum in 9h, with levels of 1.93u/mg protein. the microorganism utilized several carbon sources for the production of protease. starch was the best substrate, followed by trisodium citrate, citric acid and sucrose. among the various organic and inorganic nitrogen sources, ammonium nitrate was found to be the best. studies on the protease characterization revealed that the optimum temperature of this enzyme was 60oc. the enzyme was stable for 2h at 30oc, while at 40oc and 80oc, 14% and 84% of the original activities were lost, respectively. the optimum ph of the enzyme was found to be 8.0. after incubation of crude enzyme solution for 24h at ph 5.5, 8.0 and 9.0, a decrease of about 51%, 18% and 66% of its original activity was observed respectively. a stronger inhibitory effect was observed in the presence of k+, hg2+and cu2+. hg+ resulted in the complete loss of activity at 1mm concentrations. activity was stimulated by mn2+ and ca+2, indicating that these ions had a functional role in the molecular structure of the enzyme.
Purification and characterization of a protease from Thermophilic bacillus strain HS08
H Guangrong, Y Tiejing, H Po, J Jiaxing
African Journal of Biotechnology , 2006,
Abstract: The purification and characterization of a thermophilic neutral protease from Thermophilic bacillus strain HS08, originally isolated from a soil sample collected from the Tulufan Crater of China, is presented in this paper. The purification steps included ammonium sulfate precipitation, with columns of DEAE-Sepharose anion exchange chromatography and Sephacryl S-100HR on AKTA purifier 100 protein liquid chromatography. The method gave a 4.25 fold increase of the specific activity and had a yield of 5.1%. The molecular weight of the protease was found to be around 30.9 kDa by SDS-PAGE technique. The optimal pH and optimal temperature of the protease were at pH 7.5 and 65oC, respectively. The protease was found stable during the 1 h incubation at 50°C. The protease activity showed wide range of variation in the presence of different reagents: it was inhibited remarkably by EDTA or PMSF and was almost activated by 2 mM Zn2+, even though it was only marginally inhibited by other inhibitors. We concluded that the protease was a Zn2+-acitived serine protease. Substrates specificity tests indicated that azocasein was the best substrate among the three substrates tested (azocasein, casein, and BSA).
Expression, purification, and characterization of a thermophilic neutral protease from Bacillus stearothermophilus in Bacillus subtilis
Min Zhang,Cong Zhao,LianXiang Du,FuPing Lu,Chen Gao
Science China Life Sciences , 2008, DOI: 10.1007/s11427-008-0009-9
Abstract: The gene coding for a thermophilic neutral protease from Bacillus stearothermophilus was expressed in Bacillus subtilis DB104, under the control of the sacB gene promoter. This was followed by either the native signal peptide sequence of this protease or the signal peptide sequence of the sacB gene. The protease was purified 3.8-fold, with a specific activity of 16530 U mg 1. As analyzed by SDS-PAGE, the molecular mass of the expressed protease was about 35 kDa, and the optimal temperature and pH of the protease were 65°C and 7.5, respectively. Moreover, it still had about 80% activity after 1 h reaction at 65 °C.
Expression, purification, and characterization of a thermophilic neutral protease from Bacillus stearothermophilus in Bacillus subtilis

Min Zhang,Cong Zhao,LianXiang Du,FuPing Lu,Chen Gao,

中国科学C辑(英文版) , 2008,
Abstract: The gene coding for a thermophilic neutral protease from Bacillus stearothermophilus was expressed in Bacillus subtilis DB104, under the control of the sacB gene promoter. This was followed by either the native signal peptide sequence of this protease or the signal peptide sequence of the sacB gene. The protease was purified 3.8-fold, with a specific activity of 16530 U mg 1. As analyzed by SDS-PAGE, the molecular mass of the expressed protease was about 35 kDa, and the optimal temperature and pH of the protease were 65°C and 7.5, respectively. Moreover, it still had about 80% activity after 1 h reaction at 65 °C. Supported by the “863” High-Tech Research Project of China (Grant No. 2007AA 02Z212)
Effect of the culture conditions on the production of an extracellular protease by thermophilic Bacillus sp and some properties of the enzymatic activity
Silva, Camila Rocha da;Delatorre, Andréia Boechat;Martins, Meire Lelis Leal;
Brazilian Journal of Microbiology , 2007, DOI: 10.1590/S1517-83822007000200012
Abstract: protease production by thermophilic bacillus sp strain smia-2 cultivated in liquid cultures containing 1% maltose as a carbon source and supplemented with whey protein (0.1%) and corn steep liquor (0.3%) reached a maximum at 14 h, with levels of 42 u/mg protein. the microorganism was capable of utilizing a wide range of carbon sources, but protease activity varied according the carbon source. starch and maltose were the best carbon sources in the present study for protease secretion, while lactose and sucrose were less effective. increasing maltose concentration in the medium until 1%, improved the growth of the organism and the enzyme activity. regarding the amounts of corn steep liquor and whey protein in the medium, the concentrations of 0.2% and 0.1% respectively, were considered the most effective for protease secretion by the organism. studies on the protease characterization revealed that the optimum temperature of this enzyme was 70oc. thermostability profile indicated that the enzyme retained 80% of the original activity after 2 h heat treatment at 60oc. at 70oc, 70% of the original activity was retained after 15 min heat treatment. the optimum ph of the enzyme was found to be 8.5. after incubation of crude enzyme solution at room temperature for 2 h at ph 6.0-10.0, a decreased of about 15% of its original activity at ph 8.5 was observed. at ph 10.0, the decrease was 24%. in the presence of 1.0 m and 5.0 m nacl, 76% and 37% of protease activity was retained after 2 h incubating at 45oc respectively.
A novel neutral protease from thermophilic Bacillus strain HUTBS62  [PDF]
HAZEM AQEL,FAROUK AL-QUADAN,TAHANI K. YOUSEF
Journal of BioScience and Biotechnology , 2012,
Abstract: A novel neutral highly thermostable protease was detected in the culture medium of thermophilic Bacillus strain HUTBS62 isolated from hot-spring located near to the Dead Sea, Jordan. The enzyme was purified by precipitation with 55-60% ammonium sulfate, gel filtration on Sephadex G-100 and DEAE ion exchange chromatography. The enzyme was purified 53-fold with 2% yield. The optimum pH and temperature for catalytic activity of protease was pH 6.8 and 80oC, respectively, and 31% activity of protease remained even after heat treatment at 100oC for 60 min. The relative activity of the enzyme was highly stable (90%) at 50oC for 2 h. The half-life of the enzyme at 90oC, 80oC and 70oC was estimated to be 3, 4 and 6 h, respectively. The activation energy of denaturation of purified enzyme was 21.7 kJmol-1. Iron, sodium, calcium, and manganese increased protease activity. On the other hand, magnesium, cobalt and zinc variably decreased the residual activity. But cadmium and copper drastically inhibited the enzyme activity. The enzymatic activity was highly stable in the presence of 1 and 2 mM EDTA at pH 6.8 and 80oC. The neutral protease therefore could be defined as a highly thermostable with new properties make the present enzyme applicable for many biotechnological purposes.
PRODUCTION AND SOME PROPERITIES OF A THERMOPHILIC PROTEASE FROM BACILLUS STEAROTHERMOPHILUS WF146
嗜热脂肪芽孢杆菌高温蛋白酶的产生条件及酶学性质

Tang Bing,Zhou Linfeng,Chen Xiangdong,Dai Xuan,Peng Zhenrong,
唐兵
,周林峰,陈向东,戴玄,彭珍荣

微生物学报 , 2000,
Abstract: The factors affecting Bacillus stearothermophilus WF146 for thermophilic protease producing have been investigated, more than 600 units of enzyme in 1 mL of fermented culture could be achieved under suitable condition. The protease had a molecular weight around 34 kD estimated by SDS-PAGE, and functioned optimally at pH 8.0 and 80 degrees C, respectively. In addition, the enzyme exhibited high temperature tolerance and was stable at a wide range of pH, and Ca2+ played a key role for the stability of the enzyme. While the protease activity of the enzyme was strongly inhibited by PMSF, DFP and IAA, and was not affected by DTT.
立春时节话竖蛋  [PDF]
刘延柱
力学与实践 , 2013, DOI: 10.6052/1000-0992-20130125
Abstract: 从立春竖蛋的习俗谈起,叙述哥伦布竖蛋,特斯拉利用电磁感应的哥伦布蛋,以及用手捻鸡蛋直立旋转等现象.解释竖蛋现象的力学原理.
湛江市公园绿地花境应用及配置调查  [PDF]
黎海利,谭飞理,刘锴栋,谭彩珠
北方园艺 , 2015, DOI: 10.11937/bfyy.201514021
Abstract: 针对湛江市主要公园绿地的花境植物应用及配置模式进行了实地调查,以期了解粤西地区花境应用现状及配置特色。结果表明目前湛江市应用于花境的植物共99种,隶属于46个科84个属;配置模式根据花境立地环境划分主要有林缘花境、路沿花境、临水花境、建筑物周围花境、草坪花境等。并对花境植物应用及花境配置等方面存在的问题进行了探讨。
苏童作品色彩构图三境  [PDF]
加晓昕?
天府新论 , 2010,
Abstract: 书画品评有四格之说。文学作品中的色彩构图与之有异曲同工之妙,构图也分三境。苏童作品善于用色,其色彩构图在物境、妙境、神境均表现充分,丰富了作品的审美空间。
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