A carregar...
Projeto de investigação
Enhancing storage stability of vaccines and bacteriophages using Natural Deep Eutectic Solvents
Financiador
Autores
Publicações
Supercritical CO2 assisted impregnation of ibuprofen on medium-chain-length polyhydroxyalkanoates (mcl-PHA)
Publication . Meneses, Liane; Craveiro, Rita; Jesus, Ana Rita; Reis, Maria A. M.; Freitas, Filomena; Paiva, Alexandre; DQ - Departamento de Química; LAQV@REQUIMTE; UCIBIO - Applied Molecular Biosciences Unit; MDPI - Multidisciplinary Digital Publishing Institute
In this work, we propose the utilization of scCO2 to impregnate ibuprofen into the mcl- PHA matrix produced by Pseudomonas chlororaphis subs. aurantiaca (DSM 19603). The biopolymer has adhesive properties, is biocompatible and has a melting temperature of 45 °C. Several conditions, namely, pressure (15 and 20 MPa) and impregnation time (30 min, 1 h and 3 h) were tested. The highest ibuprofen content (90.8 ± 6.5 mg of ibuprofen/gPHA) was obtained at 20 MPa and 40 °C, for 1 h, with an impregnation rate of 89 mg/(g.h). The processed mcl-PHA samples suffered a plasticization, as shown by the decrease of 6.5 °C in the Tg, at 20 MPa. The polymer’s crystallinity was also affected concomitantly with the matrices’ ibuprofen content. For all the impregnation conditions tested the release of ibuprofen from the biopolymer followed a type II release profile. This study has demonstrated that the mcl-PHA produced by P. chlororaphis has a great potential for the development of novel topical drug delivery systems.
Subcritical Water as a Pre-Treatment of Mixed Microbial Biomass for the Extraction of Polyhydroxyalkanoates
Publication . Meneses, Liane; Esmail, Asiyah; Matos, Mariana; Sevrin, Chantal; Grandfils, Christian; Barreiros, Susana; Reis, Maria A. M.; Freitas, Filomena; Paiva, Alexandre; DQ - Departamento de Química; LAQV@REQUIMTE; UCIBIO - Applied Molecular Biosciences Unit; MDPI AG
Polyhydroxyalkanoate (PHA) recovery from microbial cells relies on either solvent extraction (usually using halogenated solvents) and/or digestion of the non-PHA cell mass (NPCM) by the action of chemicals (e.g., hypochlorite) that raise environmental and health hazards. A greener alternative for PHA recovery, subcritical water (SBW), was evaluated as a method for the dissolution of the NPCM of a mixed microbial culture (MMC) biomass. A temperature of 150 degrees C was found as a compromise to reach NPCM solubilization while mostly preventing the degradation of the biopolymer during the procedure. Such conditions yielded a polymer with a purity of 77%. PHA purity was further improved by combining the SBW treatment with hypochlorite digestion, in which a significantly lower hypochlorite concentration (0.1%, v/v) was sufficient to achieve an overall polymer purity of 80%. During the procedure, the biopolymer suffered some depolymerization, as evidenced by the lower molecular weight (M-w) and higher polydispersity of the extracted samples. Although such changes in the biopolymer's molecular mass distribution impact its mechanical properties, impairing its utilization in most conventional plastic uses, the obtained PHA can find use in several applications, for example as additives or for the preparation of graft or block co-polymers, in which low-M-w oligomers are sought.
Improving the activity of horseradish peroxidase in betaine-based natural deep eutectic systems
Publication . Meneses, Liane; Gajardo-Parra, Nicolás F.; Cea-Klapp, Esteban; Garrido, José Matías; Held, Christoph; Duarte, Ana Rita; Paiva, Alexandre; DQ - Departamento de Química; LAQV@REQUIMTE; RSC - Royal Society of Chemistry
In this work, the activity of horseradish peroxidase (HRP) in betaine-based natural deep eutectic systems (NADESs) was measured and studied by molecular simulations. Focus was laid on enzymatic activity in the NADESs under thermal stress as well as under the influence of water. Furthermore, the structure of HRP under these different conditions was measured by circular dichroism (CD). As a result, HRP remains enzymatically active in all NADESs upon incubation for 24 h at 37 °C and 60 °C and after 4 h at 80 °C, especially when incubated in a NADES composed of betaine, trehalose, glycerol, and water, in a molar ratio of 2 : 1 : 3 : 5. The CD studies have shown that high activity is obtained in the systems that promoted higher α-helix contents. The molecular simulations showed that using a NADES instead of buffer solvent reduces HRP flexibility, and we found that enzymatic activity correlates with Gibbs energy of solvation of HRP. Finally, hydrophobic hydration interactions govern the stabilization mechanism of the HRP folded state as shown by a drastic enzymatic activity drop upon 5 wt% water addition using a betaine: glycerol NADES as solvent.
Unidades organizacionais
Descrição
Palavras-chave
Contribuidores
Financiadores
Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
OE
Número da atribuição
SFRH/BD/148510/2019