Showing 5 results for Organic Solvent
Mohamad Pazhang, , , ,
Volume 4, Issue 1 (10-2013)
Abstract
The use of enzymes in organic solvents has biotechnological and industrial importance. Organic solvents can decrease the stability of enzymes that is a challenge for the use of enzymes in organic media. There are several approaches such as protein engineering, chemical modification, and use of additives for stabilization of enzymes in organic solvents. In this study, activity and stability of trypsin were investigated in the presence of different organic solvents. Then the effect of sucrose on the stability of the enzyme was investigated in the absence and prescence of solvents. The result showed that the activity and stability of trypsin were decreased in the presence of organic solvents. DMF had a lowest effect on the activity and stability of the enzyme. The use of sucrose increased the stability of trypsin in the presence of organic solvents. The stabilization effect of sucrose in the presence of DMF was more than other solvents. Consequently, a mixture of DMF and sucrose is proposed for the use of trypsin in industrial applications.
Arastoo Badoei-Dalfard, , ,
Volume 6, Issue 1 (10-2015)
Abstract
In this study, a Bacillus species was identified from the Dosarri mineral spring in Jiroft microflora. This strain produce clear halo in casein agar media. It has been identified as Bacillus Pumilus (KHB3) based on biochemical tests and 16S rRNA gene sequencing. To enzyme production, this strain was cultured in specific medium for 48 h. Supernatant was partially purified after precipitation with ammonium sulphate (85 %), dialysis and ion exchange chromatography (Q-Sepharose). KHB3 protease was characterized in the presence of different pHs, ions and detergents. Results indicated that the enzyme showed maximum activity and stability in pH 8.0. This enzyme retained about 100 % of its activity in the presence of 1.0 and 1.5 M NaCl. KHB3 protease showed 33 and 10 % increase in protease activity in the presence of MnSO4 and FeSO4. KHB3 protease retained at least 45 % of its activity and stability in the presence of commercial detergents. In addition, it show 12 % increase in enzyme activity in the presence of Banoo detergent. Activity and stability in alkaline pH, organic solvents and detergent compounds show that this protease has high value capacity in detergent industry.
, Kolsoom Shahdadnejad,
Volume 8, Issue 1 (4-2017)
Abstract
Aspartic proteases (APs) (EC 3.4.23.X) catalyze the hydrolysis of peptide bonds, a reaction that is fundamental to many biological processes. All of the vertebrate and most of the fungal APs are synthesized as zymogens. Porcine pepsin (EC 3.4.23.1) belongs to the aspartic protease family. Pepsin is a gastric aspartic protease and one of the three principal protein degrading enzymes in the digestive system. Pepsin is an industrial enzyme in the food industry. In this study, thermal stability of pepsin investigated in the different concentrations of aluminium in presence and absence of organic solvents ) butanol, ethanol, 1,4-Butanediol and glycerol). Thermal stability of pepsin increased in the presence of aluminium and decreased in presence of organic solvents ) butanol, ethanol, 1,4-butanediol ) and unchanged in presence of glycerol .Thermal stability of pepsin increased in presence organic solvents with adding of aluminium to its absence. possibly aluminum ions through electrostatic and dative interactions with carboxylate groups of Aspartic acid and Glutamic acid residues are bonded to pepsin structure, and causing to condense enzyme structure which leading to increasing thermal stability of pepsin. Mechanism of increasing thermal stability of pepsin is unknown in presence of aluminium. Therefore, we can reduce the instability of pepsin in presence of organic solvents by
Aluminium.
B. Shareghi , E. Yadollahi , A. Rabie ,
Volume 9, Issue 1 (1-2018)
Abstract
Aims: Proteinase K is an extracellular endopeptidase, which is secreted by Tritirachium album Limber and belongs to the serine endopeptidase class. This enzyme is extensively applied to protein-related studies. The present study aimed at evaluating the effect of urea, guanidine hydrochloride (GnHCl), and organic solvents on the kinetic activity of proteinase K enzyme.
Materials and Methods: In this experimental study, kinetics studies were performed, using UV-Vis spectrophotometer on different concentrations of substrate, urea, and GnHCl at 40˚C and pH 7.4.
Findings: Urea decreased the Vmax and Km of enzyme at 1 and 2molar concentrations, but at higher concentrations such as 3 and 4molar, it increased enzyme activity. GnHCl had an inhibitory effect on the enzyme activity, resulting in a decrease in Vmax and Km in 1, 2, and 3molar concentrations and acted as an uncompetitive inhibitor. Organic solvents including methanol, ethanol, and isopropanol had activatory effect at low concentrations and inhibitory effect at high concentrations on the kinetic activity of proteinase K enzyme.
Conclusion: Urea has an inhibitory effect at low concentrations and an activatory effect on the activity of the enzyme at a concentrations above 2molar, but GnHCl has an inhibitory effect at all concentrations and can be used as an enzyme inhibitor. The effect of organic solvents including methanol, ethanol, and isopropanol on the activity of the proteinase K enzyme depends on their volume/volume percent; they cause enzyme activation at low percentages, but have inhibitory effect at high percentages, so that activates methanol below 30% and isopropanol below 50%.
M. Nasre Taheri , Gh.h. Ebrahimipour , H. Sadeghi ,
Volume 10, Issue 1 (3-2019)
Abstract
The Stability of protease in organic solvent media has been widely discussed for more than two decades. Proteases can catalyze synthetic reactions in organic media, by this way solvent stabilities of proteases are very important. In this study, we reported a bacterium isolated from hot spring of Geinarje, Iran producing an organic solvent stable protease. Protease producing bacteria were screened on skim milk agar and the formation of a clear zone around the bacterial colony was investigated. Proteolytic activity was assayed by a modified caseinolytic method using casein as a substrate. The best alkaline protease producing bacterium was selected and identified on the basis of 16S rDNA gene sequencing and morphological and biochemical characteristics. The effect of organic solvents, temperature, pH, and NaCl on proteolytic activity were examined. According to phylogenetic analysis, morphological and physiological tests, isolated, the bacterium was identified as a new strain of Brevibacillus borstelensis. This strain was able to produce an extracellular organic solvent-stable protease with 0.53U/ml enzyme activity. After 2 hour incubation at 30°C the protease of Brevibacillus borstelensis AMN was active in wide ranges of organic solvents, and its activity was enhanced in the presence of 25% (V/V) isopropanol. The biochemical properties of the enzyme revealed that the optimal pH and temperature for protease activity were 9.0 and 60°C, respectively. Our finding indicated that these robust properties of protease, like outstanding activity and stability in organic solvents and alkaline medium, might be applicable for various industrial biotechnologies.
