Encimska dimerizacija tirozol acetata v mikroreaktorju z večfaznim tokom tekočin

Štorek, Vesna (author), Žnidaršič Plazl, Polona (mentor)

Nadomeščanje šaržnih procesov s kontinuirnimi, prav tako pa menjava velikih kemijskih reaktorjev z mikroreaktorji, pridobivata vedno večji pomen in omogočata intenzifikacijo procesov, medtem ko vključevanje bioloških katalizatorjev v procese prispeva k izboljšanju trajnostnega vidika proizvodnje. Majhne dimenzije mikroreaktorjev omogočajo kratke difuzijske poti in visoko razmerje med površino in prostornino, kar izboljšuje prenos mase in toplote. Z ustvarjanjem različnih tokovnih režimov v večfaznem sistemu lahko vplivamo na nastanek večje medfazne površine. V diplomskem delu smo obravnavali z lakazo katalizirano dimerizacijo tirozol acetata do 1,1′-ditirozol-8,8′-diacetata v mikropretočnem reaktorju. Najprej smo izvajali reakcijo v steklenem mikroreaktorju s tremi vhodi in opazovali tokovni režim z optičnim mikroskopom. Ob straneh mikroreaktorja smo črpali etil acetat z raztopljenim tirozol acetatom, na sredini pa acetatni pufer z raztopljeno lakazo. Kapljevine so tekle paralelno in med seboj ustvarjale dve fazni meji. Reakcija poteka le na fazni meji, kamor se lakaza in substrat premikata z difuzijo. Ob nižjih pretokih sta se vodni fazi združili in ostala je samo ena fazna meja, kar je močno zmanjšalo površino in možnost konverzije. Mikroreaktor nam ni omogočal dovolj velikih zadrževalnih časov, da bi reakcija v celoti potekla, zato smo jo ponovili v daljši cevki. V tem primeru je nastal segmentiran tok, kjer je pufer z lakazo predstavljal kontinuirno fazo. Fazna površina je bila večja in zadrževalni čas daljši, zato je reakcija lahko potekla. Reakcijo smo nato ponovili tako, da smo v sistem črpali še tretjo fazo ̶ zrak. Ponovno je nastal segmentiran tok, v katerem je etil acetat zaobjel mehurček zraka in tako preprečil difuzijo kisika do encima, raztopljenega v kontinuirni fazi acetatnega pufra. Kljub temu je bila v tem sistemu dosežena največja konverzija tirozol acetata do 1,1′-ditirozol-8,8′-diacetata, ki je znašala 3,7 %.

• Language: Slovenian
• Keywords: lakaza, mikroreaktor, tokovni režim, večfazni sistem
• Work type: Bachelor thesis/paper
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2024
• PID: 20.500.12556/RUL-161074
• Publication date in RUL: 06.09.2024

Secondary language

• Language: English
• Title: Enzymatic dimerization of tyrosol acetate in a multiphase fluid flow microreactor

Abstract

The replacement of batch processes with continuous ones, as well as the replacement of large chemical reactors with microreactors, are gaining more and more importance and enable the intensification of processes, while the inclusion of biological catalysts in processes contributes to improving the sustainable aspect of production. The small dimensions enable short diffusion paths and a high surface-to-volume ratio, which improves mass and heat transfer. By creating different flow regimes in a multiphase system, we can influence the formation of a larger interphase surface. In the thesis, we discussed the laccase-catalyzed dimerization of tyrosol acetate to 1,1′-dityrosol-8,8′-diacetate in a microflow reactor. First, we performed the reaction in a glass microreactor with three inlets and observed the current regime with an optical microscope. Ethyl acetate with dissolved tyrosol acetate was pumped on the sides of the microreactor, and acetate buffer with dissolved laccase was pumped in the middle. The liquids flowed parallel and created two phase boundaries between them. The reaction takes place only at the phase boundary, where the laccase and substrate move by diffusion. At lower flow rates, the two aqueous phases merged and only one phase boundary remained, greatly reducing the surface area and conversion potential. The microreactor did not allow us long enough retention times for the reaction to take place completely, so we repeated it in a longer tube. In this case, a segmented flow was formed where the buffer with laccase represented the continuous phase. The phase surface was larger and the retention time was longer, so the reaction could proceed. The reaction was then repeated by pumping a third phase ̶ air into the system. Again, a segmented flow was formed in which the ethyl acetate trapped the air bubble and thus prevented the diffusion of oxygen to the enzyme dissolved in the continuous phase of the acetate buffer. Nevertheless, the highest conversion of tyrosol acetate to 1,1′-dityrosol-8,8′-diacetate was achieved in this system, which was 3,7 %.

• Keywords: laccase, microreactor, current regime, multiphase system