The Effect of Temperature on Different Aqueous Two-Phase Diagrams of Polyethylene Glycol (PEG 6000, PEG 8000, and PEG 10000) + Potassium Sodium Tartrate + Water

2019 ◽  
Vol 64 (7) ◽  
pp. 3036-3043 ◽  
Author(s):  
Jacqueline Herbst ◽  
Robert W. M. Pott
2019 ◽  
Vol 13 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Valentina Dobreva ◽  
Boriana Zhekova ◽  
Georgi Dobrev

Background: Purification of enzymes by conventional methods such as precipitation and chromatographic techniques is a costly and time-consuming procedure and may lead to low yields of enzyme activity. Alternative liquid-liquid extraction methods such as Aqueous Two-Phase Systems (ATPS) and Three Phase Partitioning (TPP) are characterized by the high enzyme yields and purification degree. Objective: The objective of this study was the application of partitioning systems ATPS and TPP for purification of lipase produced in solid-state fermentation by Rhizopus arrhizus. Methods: ATPS and TPP were used for purification of lipase, obtained by solid state cultivation of Rhizopus arrhizus. Results: Lipase was isolated with PEG4000/potassium sodium tartrate ATPS and the effect of the system composition, including PEG 4000 and potassium sodium tartrate concentrations on lipase partitioning was studied. When using 30% PEG4000/21% potassium sodium tartrate, lipase was distributed in the top phase, and the highest recovery yield of 217% and purification fold of 6.1 were achieved. It was found that at PEG4000 concentration of or higher than 15%, the enzyme was present in the top polymer-rich phase with a partitioning yield of over 90%. Upon application of TPP for lipase isolation, the effect of t-butanol concentration, ammonium sulfate concentration and pH on enzyme partitioning was investigated. The highest lipase recovery yield of 71% and 19.1-fold purification were achieved in the interfacial phase in the presence of 30% ammonium sulfate saturation with 1.0:0.5 crude extract/t-butanol ratio at pH 7 in a single step. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis and zymographic analysis showed significant purification of lipase by TPP and the presence of two multiple forms of the enzyme. Conclusion: ATPS (PEG4000/ Potassium sodium tartrate) and TPP (1.0:0.5 crude extract/t-butanol ratio, 30% ammonium sulfate saturation, pH 7) proved to be rapid methods for the isolation and purification of lipase and they can be used in downstream processing for industrial preparation of the enzyme.


Author(s):  
V. Dharmalingam ◽  
P. Arockia Sahayaraj ◽  
A. John Amalraj ◽  
R. Shobana ◽  
R. Mohan

The goal of studying corrosion process is to find means of minimizing corrosion or prevent it from occurring. The use of inhibitors is one of the most popular methods for corrosion protection. A protective film has been formed on the surface of the mild steel in a neutral aqueous environment using a synergistic mixture of an eco-friendly inhibitor viz., Potassium Sodium Tartrate (SPT) along with polyacrylic acid (PAA) and Zn2+ ions. The inhibiting effect of SPT, PAA and Zn2+ ions have been investigated by gravimetric studies, Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The investigations revealed that SPT acts as an excellent synergist in corrosion inhibition. Optimum concentrations of all the three components of the ternary formulation are established by gravimetric studies. Potentiodynamic polarization studies inferred that this mixture functions as a cathodic inhibitor. EIS studies of the metal/solution interface indicated that the surface film is highly protective against the corrosion of mild steel. Surface characterization techniques (FTIR, SEM, AFM) are also used to ascertain the nature of the protective film. The mechanical aspect of corrosion inhibition is proposed.


2020 ◽  
Vol 37 (3) ◽  
pp. 595-606
Author(s):  
O. R. R. Gandolfi ◽  
G. R. F. Gonçalves ◽  
I. C. Batista ◽  
R. C. I. Fontan ◽  
C. M. Veloso ◽  
...  

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