Integrated biocatalytic platform based on aqueous biphasic systems for the sustainable oligomerization of rutin

Rutin is a known antioxidant compound that displays a broad range of biological activities and health-related benefits but presents a low water solubility that can be overcome by its polymerization. In this work, biocompatible aqueous biphasic systems composed of the ionic liquid cholinium dihydrogen phosphate ([CH][DHph]) and the polymer poly(ethylene glycol) 600 (PEG 600) were investigated as an efficient integrated reaction–separation platform for the laccase-catalyzed oligomerization of rutin. Two different approaches were studied to reuse laccase in several oligorutin production cycles, the main difference between them being the use of monophasic or biphasic regimes during the oligomerization reaction. The use of a biphasic regime in the second approach (heterogeneous reaction medium) allowed the successful reuse of the biocatalyst in three consecutive reaction–separation cycles while achieving noteworthy rutin oligomerization yields (95% in the first cycle, 91% in the second cycle, and 89% in the last cycle). These remarkable results were caused by the combination of the increased solubility of rutin in the PEG-rich phase together with the enhanced catalytic performance of laccase in the [Ch][DHph]-rich phase, alongside with the optimization of the pH of the reaction medium straightly linked to enzyme stability. Finally, a life-cycle assessment was performed to compare this integrated reaction–separation platform to three alternative processes, reinforcing its sustainabilityThis research was supported by the Spanish Government (AEI) through the RTI2018-094482-J-I00 project. This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES. The programme is cofunded by FEDER (UE). A.P.M.T. thanks the FCT for the research contract CEECIND/2020/01867. G.E. thanks the Spanish MICIU for her Ramón y Cajal contract (RYC2018- 024846-I). A.M.-M. thanks the Programa de axudas á etapa predoutoral da Xunta de Galicia (ED481A-2018/023)S

Enzymatic technology for the production of high added value oligomers from natural antioxidants

The undeniable shift to worldwide aged population and the increasing attraction of consumers towards natural products has induced a growing demand of polyphenolic antioxidants. However, the applicability of these substances is often hindered by their scarce bioavailability. The enzymatic polymerization of these compounds has been proven an efficient method leading to products with enhanced aqueous solubility. The present PhD thesis focuses on the oligomerization of natural antioxidants with pharmacological and nutraceutical properties, catalyzed by fungal enzymes. The achieved results allowed to identify the operational parameters affecting the properties of the obtained oligomers, as well as to perform a preliminary environmental and economic assessment of the reuse of the biocatalyst in biocompatible reaction media.2023-04-0

Novos solventes químicos para procesos de captura/rexeneración de co2

Traballo Fin de Máster en Enxeñaría Química e Bioprocesos. Curso 2014-2015No presente Traballo Fin de Máster realizouse un estudo sobre o proceso de captura/rexeneración de dióxido de carbono (CO2) por absorción en distintos disolventes químicos non empregados comunmente a nivel industrial. Establecéronse comparacións entre o uso de N,N‑Dimetiletilendiamina (DMEN) e o uso dunha mestura de etanolamina (MEA) e N,N-Dimetiletanolamina (DMEA) no proceso de absorción de CO2, podendo así analizar a influenza da composición do disolvente, tendo en conta que estes compostos aportan a mesma concentración dos mesmos grupos amino. Asemade establecéronse comparacións entre o uso dunha mestura de MEA e DMEA cunha relación equimolar de ambos compostos fronte a unha mestura cun 83.3% dos grupos amino procedentes de MEA. Os diferentes mecanismos de absorción de CO2 determináronse empregando a espectroscopía de resonancia magnética nuclear de hidróxeno e carbono para determinar as especies presentes no medio ao longo do tempo. A maiores, realizáronse experimentos de captura/rexeneración de CO2 en continuo que permitiron analizar o proceso completo e identificar a capacidade de rexeneración dos disolventes estudados, así coma a posible existencia de degradación do disolvente

Laccase Activity as an Essential Factor in the Oligomerization of Rutin

The enzyme-mediated polymerization of bioactive phenolic compounds, such as the flavonoid rutin, has gained interest due to the enhanced physico-chemical and biological properties of the products, which increases their potential application as a nutraceutical. In this work, the influence of enzyme activity on rutin oligomerization was evaluated in reactions with low (1000 U/L) and high (10,000 U/L) initial laccase activities. For both reactions, high molecular weight oligomer fractions showed better properties compared to lower weight oligomers. Products of the reaction with low laccase activity exhibited thermal stability and antioxidant potential similar to control reaction, but led to higher inhibitory activity of xanthine oxidase and apparent aqueous solubility. Oligomers obtained in the reaction with high laccase activity showed better apparent aqueous solubility but decreased biological activities and stability. Their low antioxidant activity was correlated with a decreased phenolic content, which could be attributed to the formation of several bonds between rutin molecules

Comprehensive investigation of the enzymatic oligomerization of esculin by laccase in ethanol : water mixtures

The enzymatic polymerization of phenolic compounds arouses increasing interest due to the production of derivatives with improved biological activity. The reaction yield, the molecular mass, the structure and the properties of synthesized polymers can be controlled by the reaction conditions such as solvent and type of enzyme and substrate. In this study, the oxidative oligomerization of esculin by laccase from Trametes versicolor was performed in the presence of ethanol, a biocompatible co-solvent for food and nutraceutical applications. The formation of a precipitate was associated with the oligomerization reaction except for the medium with 50% (v/v) ethanol, due to the low reaction yield. The evaluation of antioxidant activity of the monomer and products showed that the pellet fraction from the reaction with esculin at 2 g L−1 in acetate buffer led to the highest activities. The presence of esculin oligomers was confirmed by MALDI-TOF analysis, which identified a repetition unit of 338 Da with a degree of polymerization up to 9 as well as other oligomers, mainly in the pellet fraction, with a repetition unit of 176 Da which are attributed to be esculetin oligomers. Additionally, size exclusion chromatography (SEC) and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the products.This work was financially supported by the Spanish Ministry of Economy and Competitiveness (CTQ2014-58879-JIN). Authors belong to the Galician Competitive Research Group GRC 2013-032 and to the strategic group CRETUS (AGRUP2015/02). All these programmes are co-funded by FEDER. B. G. thanks the Spanish Ministry of Economy and Competitiveness for her postdoctoral fellowship (Grant reference FPDI-2013-17341)S