Person: García Martín, Alberto
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First Name
Alberto
Last Name
García Martín
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Ingeniería Química y de Materiales
Area
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5 results
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Item Kinetically controlled acylation of 6-APA catalyzed by penicillin acylase from Streptomyces lavendulae: effect of reaction conditions in the enzymatic synthesis of penicillin V(Biocatalysis and Biotransformation, 2019) Hormigo, Daniel; López Conejo, María Teresa; Serrano Aguirre, Lara; García Martín, Alberto; Saborido Modia, Ana; De La Mata Riesco, Mª Isabel; Arroyo Sánchez, MiguelEnzymatic synthesis of penicillin V (penV) by acylation of 6-aminopenicillanic acid (6-APA) was carried out using methyl phenoxyacetate (MPOA) as activated acyl donor and soluble penicillin acylase from Streptomyces lavendulae (SlPVA) as biocatalyst. The effect of different reaction conditions on penV synthesis was investigated, such as enzyme concentration, pH, molar ratio of 6-APA to MPOA, as well as presence of DMSO as water-miscible co-solvent at different concentrations. Time-course profiles of all reactions followed the typical pattern of kinetically controlled synthesis (KCS) of β-lactam antibiotics: penV concentration reached a maximum (highest yield or Ymax) and then decreased gradually. Such maximum was higher at pH 7.0, observing that final penV concentration was abruptly reduced when basic pH values were employed in the reaction. Under the selected conditions (100 mM Tris/HCl buffer pH 7.0, 30 °C, 2.7% (v/v) DMSO, 20 mM MPOA, 0.3 UI/ml of SlPVA), Ymax was enhanced by increasing the substrate molar ratio (6-APA to MPOA) up to 5, reaching a maximum of 94.5% and a S/H value of 16.4 (ratio of synthetic activity to hydrolytic activity). As a consequence, the use of an excess of 6-APA as nucleophile has allowed us to obtain some of the highest Ymax and S/H values among those reported in literature for KCS of β-lactam antibiotics. Although many penicillin G acylases (PGAs) have been described in kinetically controlled acylations, SlPVA should be considered as a different enzyme in the biocatalytic tool-box for novel potential synthetic processes, mainly due to its different substrate specificity compared to PGAs.Item Extraction of Antioxidants from Grape and Apple Pomace: Solvent Selection and Process Kinetics(Applied Sciences, 2022) Garcia Montalvo, Jorge; García Martín, Alberto; Ibañez Bujan, Jon; Santos Mazorra, Victoria Eugenia; Yustos Cuesta, Pedro; Bolívar Bolívar, Juan Manuel; Ladero Galán, MiguelPolyphenols have become a research target due to their antioxidant, anti-inflammatory and antimicrobial activity. Obtention via extraction from natural sources includes the revalorization of food wastes such as grape pomace (GP) or apple pomace (AP). In this work, GP and AP were submitted to a liquid–solid extraction using different solvents of industrial interest. Process kinetics were studied measuring the total phenolic content (TPC) and antioxidant capacity (AC), while the extraction liquor composition was analyzed employing chromatographic methods. Extraction processes using water-solvent mixtures stood out as the better options, with a particular preference for water 30%–ethanol 70% (v/v) at 90 °C, a mixture that quickly extracts up to 68.46 mg GAE/gds (Gallic Acid Equivalent per gram dry solid) and 122.67 TEAC/gds (TROLOX equivalent antioxidant capacity per gram dry solid) in case of GP, while ethylene water 10%–ethylene glycol 90% (v/v) at 70 °C allows to reach 27.19 mg GAE/gds and 27.45 TEAC/gds, in the case of AP. These extraction processes can be well-described by a second-order kinetic model that includes a solubility-related parameter for the first and fast-washing and two parameters for the slow mass transfer controlled second extraction phase. AP liquors were found to be rich in quercetin with different sugar moieties and GP extracts highlighted flavonols, cinnamic acids, and anthocyanins. Therefore, using identical extraction conditions for AP and GP and a comparative kinetic analysis of TPC and AC results for the first time, we concluded that ethanol/water mixtures are adequate solvents for polyphenols extraction due to their high efficiency and environmentally benign nature.Item Pectooligosaccharides rich in galacturonic acid produced from Orange Processing Waste by autohydrolysis: Process optimization and kinetic analysis(Bioresource Technology Reports, 2023) Pablo Comendador Morales; García Martín, Alberto; Ladero Galán, MiguelPectooligosaccharides (POS) are notorious for their prebiotics and elicitor activities. In this work, we have optimized the autohydrolysis of Orange Processing Waste (OPW) to obtain POS fractions via a Taguchi approach, maximizing homogalacturonan oligosaccharides yield by considering several process variables: particle diameter, stirring speed, liquid-solid ratio and time, determining that only time had a significant effect in the studied range. 19.38 % w/w POS yield from OPW was obtained in optima conditions. After ensuring no limitation due to mass transfer, the kinetic analysis assumed that homogalacturonan was converted into high, medium and low molecular weight oligosaccharides, and galacturonic acid. Moreover, we considered that there is one pseudohomogeneous reaction type combined with three irreversible, elemental, of pseudo first global order (first order with respect to the reagent which is hydrolysed) reactions in series. The model successfully reproduced experimental data at constant temperature (150 ◦C–180 ◦C) and pH (3.73).Item Biochemical properties and biotechnological applications of microbial enzymes involved in the degradation of polyester-type plastics(BBA - Biochimica et Biophysica Acta, 2019) Urbanek, Aneta K.; Mirończuk, Aleksandra M.; García Martín, Alberto; Saborido Modia, Ana; De La Mata Riesco, Mª Isabel; Arroyo Sánchez, MiguelApplication of polyester-degrading enzymes should be considered as an eco-friendly alternative to chemical recycling due to the huge plastic waste disposal nowadays. Many hydrolases from several fungi and bacteria have been discovered and successfully evaluated for their activity towards different aliphatic polyesters (PHA, PBS, PBSA, PCL, PLA), aromatic polyesters (PET, PBT, PMT) as well as their co-polyesters (PBST, PBAT, PBSTIL). This revision gives an up-to-date overview on the main biochemical features and biotechnological applications of those reported enzymes which are able to degrade polyester-based plastics, including different microbial polyester depolymerases, esterases, cutinase-like enzymes and lipases. Summarized information includes available protein sequences with the corresponding accession numbers deposited in NCBI server, 3D resolved structures, and data about optimal conditions for enzymatic activity and stability of many of these microbial enzymes that would be helpful for researchers in this topic. Although screening and identification of new native polyester hydrolases from microbial sources is undeniable according to literature, we briefly highlight the importance of the design of improved enzymes towards recalcitrant aromatic polyesters through different approaches that include site-directed mutagenesis and surface protein engineering.Item Fumaric Acid Production by R. arrhizus NRRL 1526 Using Apple Pomace Enzymatic Hydrolysates: Kinetic Modelling(Processes, 2022) Martín Domínguez, Víctor; García Montalvo, Jorge; García Martín, Alberto; Ladero Galán, Miguel; Santos Mazorra, Victoria EugeniaFumaric acid is one of the most promising biorefinery platform chemicals, fruit residues being a very suitable raw material for its production in second generation biorefineries. In particular, apple pomace is a plentiful residue from the apple juice industry, with apple being the second largest fruit crop in the world, with a production that increased from 46 to 86 Mtons in the 1994–2021 period. With a global apple juice production of more than 4.5 Mtons, a similar amount of apple pomace is produced yearly. In this work, apple pomace hydrolysate has been obtained by enzymatic hydrolysis and further characterized for its content in sugars, phenolics and nitrogen using different analytic methods, based on HPLC and colorimetric techniques. Previous to the use of this hydrolysate (APH), we studied if the addition of fructose to the usual glucose-rich broth could lead to high fumaric acid yields, titers and productivities. Afterwards, APH fermentation was performed and improved using different nitrogen initial amounts, obtaining production yields (0.32 gFumaric acid/gconsumed sugar) similar to those obtained with synthetic media (0.38 gFumaric acid/gconsumed sugar). Kinetic modelling was employed to evaluate, explain, and understand the experimental values and trends of relevant components in the fermentation broth as functions of the bioprocess time, proposing a suitable reaction scheme and a non-structured, non-segregated kinetic model based on it.