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Author Senyay-Oncel, Deniz ♦ Yesil-Celiktas, Ozlem
Source World Health Organization (WHO)-Global Index Medicus
Content type Text
Publisher Elsevier
File Format HTM / HTML
Language English
Difficulty Level Medium
Subject Domain (in DDC) Natural sciences & mathematics ♦ Chemistry & allied sciences ♦ Life sciences; biology ♦ Physiology & related subjects ♦ Biochemistry ♦ Natural history of organisms ♦ Technology ♦ Medicine & health ♦ Human physiology ♦ Pharmacology and therapeutics ♦ Diseases ♦ Chemical engineering ♦ Manufacture for specific uses ♦ Precision instruments & other devices
Subject Domain (in MeSH) Eukaryota ♦ Organisms ♦ Inorganic Chemicals ♦ Enzymes and Coenzymes ♦ Chemicals and Drugs ♦ Investigative Techniques ♦ Analytical, Diagnostic and Therapeutic Techniques and Equipment ♦ Physical Phenomena ♦ Biological Sciences
Subject Keyword Discipline Biomedical Engineering ♦ Discipline Microbiology ♦ Aspergillus Oryzae ♦ Enzymology ♦ Carbon Dioxide ♦ Chemistry ♦ Alpha-amylases ♦ Metabolism ♦ Enzyme Stability ♦ Nuclear Magnetic Resonance, Biomolecular ♦ Pressure ♦ Temperature ♦ Journal Article
Abstract Various physical, chemical and genetic approaches have been applied in order to enhance enzyme stability and activity. In this study, the aim was to investigate the capability of sub- and supercritical carbon dioxide to alter the stability and activity of -amylase as an alternative technique. The effects of operational parameters such as pressure (50-300 bar), temperature (28-80 °C), CO2 flow (2-10 g minâ »¹) and time (60-180 min) were evaluated in regard to the activity and stability of fungal based -amylase from Aspergillus oryzea. The activity of untreated enzyme was determined as 17,726 µmol/ml/min. While both sub- and supercritical conditions enhanced the activity, the increase in flow rate had an adverse effect and the activity was decreased by 28.9% at a flow rate of 10 g minâ »¹ under supercritical conditions. Nuclear magnetic resonance (NMR) spectra of untreated enzyme and treated samples exhibiting the lowest and the highest activities were almost identical except for the chemical shifts observed at the lowest activity sample from 4.0 to 4.4 ppm which were assigned to protons of hydrogen-bonded groups. Optimum conditions were determined as 240 bar, 41 °C, 4 g minâ »¹ CO2 flow and 150 min of process duration yielding 67.7% (29,728 µmol/ml/min) higher activity than the untreated enzyme providing fundamental basis for enzymatic applications.
Description Country affiliation: Turkey
Author Affiliation: Senyay-Oncel D ( Department of Bioengineering, Faculty of Engineering, Ege University, 35100 Bornova-Izmir, Turkey.)
ISSN 13891723
Educational Role Student ♦ Teacher
Age Range above 22 year
Educational Use Reading ♦ Research ♦ Self Learning
Interactivity Type Expositive
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2011-11-01
Publisher Place Japan
e-ISSN 13474421
Journal Journal of Bioscience and Bioengineering
Volume Number 112
Issue Number 5


Source: WHO-Global Index Medicus