Aims and Scope
Antimicrobials Misuse/Overuse: Adverse Effect, Mechanism, Challenges and Strategies to Combat ResistanceAmit K. Mittal, Rohit Bhardwaj, Priya Mishra, Satyendra K. Rajput
Overuse and misuse of antibiotics are the first risk factors for the development of antibiotics resistance. Inadequate professional competence of health care physicians might worsen the complications associated with antibiotics resistance. Antibiotic resistance is a global issue; however, the epicenter of this misfortune is Asian regions due to the easy accessibility of the strongest antibiotics without prescriptions or diagnoses. High effectiveness and easy accessibility of antibiotics lead to overuse/misuse and encouraging bacteria to develop the resistance. The over-usage and mis-usage of antibiotics are antibiotic abuse, which increase the potentially serious impact on human health. Bestowing to WHO guidelines, the resistance has led to spread worldwide and classifying resistance is a serious health problem. Furthermore, resistance claims uncertainty to predict the future. This review summarizes the major antibiotics involved in drug resistance, mechanism, prescribed dosage with a disease condition, proposed policies and guidelines to combat antibiotic resistance associated problems.
September 08, 2020
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Use of Aqueous Two-Phase and Three-Phase Partitioning Systems for Purification of Lipase Obtained in Solid-State Fermentation by Rhizopus arrhizusValentina Dobreva, Boriana Zhekova, Georgi Dobrev
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.
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.
ATPS and TPP were used for purification of lipase, obtained by solid state cultivation of Rhizopus arrhizus.
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.
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.
April 24, 2019
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