Naslov
Scalability of Gallic Acid Biotransformation by Laccase

Autori
Tišma, Marina ; Šibalić, Darijo ; Šimunović, Roberto ; Planinić, Mirela ; Bucić-Kojić, Ana ; Marques, Marco PC ; Szita, Nicolas

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, ostalo, znanstveni

Izvornik
5th International Conference IMPLEMENTATION OF MICROREACTOR TECHNOLOGY IN BIOTECHNOLOGY – IMTB 2019 / - , 2019

Skup
5th International Conference IMPLEMENTATION OF MICROREACTOR TECHNOLOGY IN BIOTECHNOLOGY – IMTB 2019

Mjesto i datum
Cavtat, Hrvatska, 19.05.2019. - 22.05.2019

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
gallic acid ; laccase ; batch reactor ; repetitive batch reactor ; microreactor ; polymerization

Sažetak
Gallic acid is a non-toxic and naturally abundant phenolic compound widely presented in the plants1. It can be used as a substrate for the production of polyconjugated semiconducting polymer in laccase-catalyzed process2. Polyphenolics with highly conjugated structures can find their application in microelectronics, non-linear optics and sensors 2, 3. We present in this work the study of laccase-catalyzed oxidation of gallic acid (Figure 1) in different reactor types, ranging from microreactors to mesoscale reactors. The biotransformation potential is evaluated and scalability assessed. Initial experiments were performed in a 75 mL glass batch reactor using different initial concentrations of gallic acid, laccase and oxygen. Additionally, a repetitive cycles experiment were performed (6 cycles). After all gallic acid is oxidized, a new amount was added in such a way that it was dissolved in the smallest amount of buffer possible in order to avoid concentration and volume fluctuations. The reaction was also performed in a Y shaped glass microreactor with internal volume of 9.5 µL. Laccase was fed from one inlet while gallic acid was fed from the other inlet. Different residence time (constant flow rates of 10, 30 and 50 µL/min), gallic acid and laccase concentrations were tested. Results have shown that laccase has high operational stability at all reactor conditions. Furthermore, it was confirmed that substrate inhibition occurs and oxygen is not a rate-limiting reactant. In a batch reactor, a 98% conversion was reached after 40 min (0.1 mg/mL laccase, 0.1 mM gallic acid). The conversion time was reduced to solely 15 min when the laccase was increased five fold. Significant conversion improvements were obtained in the microreactor with 44% conversion of gallic acid just after 29 s (0.1 mg/mL laccase, 0.1 mM gallic acid). Higher conversion, up to 99%, were obtained when the laccase was increased five fold. These results show the potential of microreactor to perform this industrial relevant reaction in flow. The resulting polymer has been characterized, presenting poor solubility in organic solvents2 while being solubilized in aqueous solution up to 150 mg/mL. To mitigate substrate inhibition while increasing throughput to facilitate industrial uptake, a new microfluidic side-entry reactor was tested 4, 5. Figure 1. Experimental set-up: laccase oxidation of gallic acid in a) batch and repetitive batch, and b) microreactor Figure 2. Laccase oxidation of gallic acid in a) batch, b) repetitive batch, and c) microreactor (Initial conditions: T = 25 °C, pH = 5.0, c0, gallic acid = 0.1 mM, ɣ0, laccase = 0.1 and 0.5 mg/mL, ɣ0, oxygen = 0.165 mM)

Izvorni jezik
Hrvatski

Znanstvena područja
Biotehnologija

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