Oksidacija katehola u mikroreaktoru slobodnom i imobiliziranom lakazom

master's thesis

• Title (english): Catechol oxidation in a microreactor using dissolved and immobilized laccase
• Author: Valentina Bregović
• Mentor: Želimir Kurtanjek (mentor)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Process Engineering); (Laboratory for Measurement, Regulation and Automatisation); Zagreb
• Defense date and country: 2011-09-16, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Biotechnology

Abstract

Lakaze spadaju u skupinu enzima koji nisu štetni za okoliš. Kataliziraju oksidaciju širokog spektra supstrata radikalnim mehanizmom prilikom čega dolazi do redukcije kisika do vode. U ovom radu postavljen je matematički model koji opisuje oksidaciju katehola kataliziranu lakazom u mikroreaktoru, a kinetika je opisana dvosupstratnom Michaelis-Menten jednadžbom. Procijenjeni su kinetički parametri na osnovu eksperimentalnih podataka u mikroreaktoru te su uspoređeni s vrijednostima procijenjenim u kiveti iz kojih je vidljivo da je vrijednost maksimalne brzine reakcije u mikroreaktoru dvostruko veća. Provedena je i oksidacija katehola pri različitim ulaznim koncentracijama kisika (cu,kisik = 0,186 mmol dm-3, 0,271 mmol dm-3, 0,487 mmol dm-3). Maksimalna konverzija X = 19,85 % postignuta je pri najvećoj ulaznoj koncentraciji kisika (cu,kisik = 0,487 mmol dm-3) nakon 36 s. Također je provedena imobilizacija lakaze na površinu mikrokanala staklenog mikroreaktora i na površinu teflonskog cijevnog reaktora. Enzimom imobiliziranim u mikrokanalu postignuta je 2,5 puta veća konverzija supstrata pri koncentraciji kisika cu,kisik = 0,186 mmol dm-3 nego slobodnim enzimom u istim uvjetima.

Abstract (english)

Laccases are considered environmentally friendly enzymes that catalyze the oxidation of a wide range of substrates by radical-catalyzed reaction mechanism with corresponding reduction of oxygen to water. In this work a mathematical model that describes laccase catalyzed oxidation of catechol was proposed. Reaction kinetic was described with double substrate Michaelis-Menten equation. The kinetic parameters values were estimated based on experimental data collected from the microreactor and were compared with values estimated in the cuvette. It was noticed that the value of maximum reaction rate in microreactor is two times higher. Model and predicted kinetic parameters were validated in an experiment with different inlet concentrations of oxygen (ci,oxygen = 0.186 mmol dm-3, 0.271 mmol dm-3, 0.487 mmol dm-3). The highest conversion of catechol of X = 19.85 % was achieved at highest inlet concentration of oxygen (ci,oxygen = 0.487 mmol dm-3) after 36 s. Immobilization of laccase was performed on the microchannel surface and on the surface of polytetrafluoroethylene (PTFE) tubular reactor. Using immobilized enzyme in the microchannel 2.5 times higher conversion was achieved in comparison to the dissolved enzyme at the same inlet oxygen concentration (ci,oxygen = 0.186 mmol dm-3).

• Keywords: lakaza; mikroreaktor; katehol; oksidacija
• Keywords (english): laccase; microreactor; catechol; oxidation
• Language: croatian
• URN:NBN: urn:nbn:hr:159:576661
• Study programme: Title: Bioprocess Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka bioprocesnog inženjerstva (magistar/magistra inženjer/inženjerka bioprocesnog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2017-05-30 12:50:47