Μελέτη ακινητοποιημένων βιολογικά ενεργών μορίων σε μη υδατικά συστήματα: μικρογαλακτώματα - οργανογέλες

• Main Authors: Ζουμπανιώτη, Μαρία, Zoumpanioti, Maria
• Format: Doctoral or Postdoctoral Thesis
• Language: Greek
• Published: National Technical University of Athens (NTUA) 2007
• Subjects: Βιοκατάλυση; Ένζυμα; Λιπάσες; Μικρογαλακτώματα; Οργανοπηκτώματα; Βιομηχανική βιοτεχνολογία; Σύνθεση εστέρων; Υπερκρίσιμο CO2; Biocatalysis; Enzymes; Lipase; Microemulsions; Organogels; Industrial biotechnology; Ester synthesis; Supercritical CO2; Επιστήμες Μηχανικού και Τεχνολογία; Επιστήμη Χημικού Μηχανικού; Engineering and Technology; Chemical Engineering; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/10442/hedi/16211; https://doi.org/10.12681/eadd/16211

This study was made in the field of industrial biotechnology and its purpose was the development and optimization of systems which would be used for biocatalysis. Enzymes -and specifically lipases entrapped in microemulsions- have been used for achieving ester synthesis. Series of experiments have been done on structure and kinetic studies to solve several problems that occur, such as catalyst recovery and system stability, in order to be able to move further to using these systems in high added value products production. In order to overcome the problems that occur on catalyst recovery due to the presence of surfactant molecules in conventional microemulsions, surfactantless ternary solutions were studied. Structural studies have indicated that these are systems with defined water structures and propanol-reach interface between water and the organic solvent (hexane). When lipase from Rhizomucor miehei and lipase from Candida antarctica were entraped in the surfactantless microemulsions, they both retained their catalytic activity and showed very good stability. Remarkable is also the possibility of using these systems for the esterification of phenolic acids (anti-oxidants). Moreover, gels were prepared based on lecithin, AOT or surfactantless microemulsions, using natural polymers such as agar, gelatine or cellulose derivatives (HPMC). These organogels are stable in non polar organic solvents and consist a suitable matrix for lipase immobilization. They can effectively be used for enzymatic synthesis of fatty or phenolic acid esters. The stability of the lipases immobilized in these media is very good and appears to be better than their stability in relative microemulsions. Furthermore, the reusability of the catalyst was successful. The kinetic study revealed the ping pong bi bi mechanism with inhibition by alcoholic substrate. The external organic solvent can successfully be replaced by environmentally friendly supercritical CO2, without affecting systems efficiency. Finally, it has been proved that these ...