06 April, 2022
Elimination of D-Glucose in carbohydrate syrups published in ACS Food Science & Technology
04 February, 2022
The molecular machinery behind processive fungal chitinases
Ref.: “Structural inspection and protein motions modelling of a fungal glycoside hydrolase family 18 chitinase by crystallography depicts dynamic enzymatic mechanism”. E. Jiménez-Ortega, P.E. Kidibule, M. Fernández-Lobato, J. Sanz-Aparicio. Computational and Structural Biotechnology Journal 19, 5466-5478 (2021) http://doi.org/10.1016/j.csbj.2021.09.027
30 September, 2021
Thesis on exopolisaccharides producing microorganisms
09 September, 2021
Characterization of a GH10 xylanase active at extreme conditions
We carried out a comprehensive bioinformatics study of the GH10 family searching for enzymes able to replace the use of highly pollutant chemicals in the pulp and paper industry, . The phylogenetic analysis allowed the construction of a radial cladogram in which protein sequences putatively ascribed as thermophilic and alkaliphilic appeared grouped in a well-defined region of the cladogram, designated TAK Cluster. One among five TAK sequences selected for experimental analysis (Xyn11) showed extraordinary xylanolytic activity under simultaneous conditions of high temperature (90 °C) and alkalinity (pH 10.5). Addition of a carbohydrate binding domain (CBM2) at the C-terminus of the protein sequence further improved the activity of the enzyme at high pH. Xyn11 structure, which has been solved at 1.8 Å resolution by X-ray crystallography, reveals an unusually high number of hydrophobic, ionic and hydrogen bond atomic interactions that could account for the enzyme’s extremophilic nature.
Ref.: "Phylogenetic, functional and structural characterization of a GH10 xylanase active at extreme conditions of temperature and alkalinity". D.Talens-Perales, E. Jiménez-Ortega, P. Sánchez-Torres, J.Sanz-Aparicio, J. Polaina. RSC Advances, 19, 2676-2686 (2021) https://doi.org/10.1016/j.csbj.2021.05.004
12 July, 2021
Enzymatic synthesis of novel fructosylated compounds
The β-fructofuranosidase from the yeast Schwanniomyces occidentalis (Ffase) produces potential prebiotic fructooligosaccharides (FOS) by self-transfructosylation of sucrose, being one of the highest known producers of 6-kestose. The use of Green Solvents (GS) in biocatalysis has emerged as a sustainable alternative to conventional organic media for improving product yields and generating new molecules. In this work, the Ffase hydrolytic and transfructosylating activity was analysed using different GS, including biosolvents and ionic liquids. Among them, 11 were compatible for the net synthesis of FOS. Besides, two glycerol derivatives improved the yield of total FOS. Interestingly, polyols ethylene glycol and glycerol were found to be efficient alternative fructosyl-acceptors, both substantially decreasing the sucrose fructosylation. The main transfer product of the reaction with glycerol was a 62 g L−1isomeric mixture of 1-O and 2-O-β-d-fructofuranosylglycerol, representing 95% of all chemicals generated by transfructosylation. Unexpectedly, the non-terminal 2-Ofructo-conjugate was the major molecule catalysed during the process, while the 1-Oisomer was the minor one. This fact made Ffase the first known enzyme from yeast showing this catalytic ability. Thus, novel fructosylated compounds with potential applications in food, cosmetics, and pharmaceutical fields have been obtained in this work, increasing the biotechnological interest of Ffase with innocuous GS.
Ref.:"Enzymatic synthesis of novel fructosylated compounds by Ffase from Schwanniomyces occidentalisin green solvents".David Piedrabuena, Ángel Rumbero, Elísabet Pires, Alejandro Leal-Duaso ,Concepción Civera, María Fernández-Lobato and Maria J. Hernaiz . RSC Advances, 11, 39, 24312-24319 (2021), doi: 10.1039/d1ra01391b
30 April, 2021
Enzymatic Synthesis of Phloretin α‐Glucosides
Glycosylation of polyphenols may increase their aqueous solubility, stability, bioavailability and pharmacological activity. Herein, we used a mutant of sucrose phosphorylase from Thermoanaerobacterium thermosaccharolyticum engineered to accept large polyphenols (variant TtSPP_R134A) to produce phloretin glucosides. The selective formation of a monoglucoside or a diglucoside can be kinetically controlled. MS and 2D-NMR determined that the monoglucoside was phloretin 4’-O-α-D-glucopyranoside and the diglucoside phloretin-4’-O-[α-D-glucopyranosyl-(1→3)-O-α-D-glucopyranoside], a novel compound. The molecular features that determine the specificity of this enzyme for 4’-OH phenolic group were analysed by induced-fit docking analysis of each putative derivative, using the crystal structure of TtSPP and changing the mutated residue. The mono- and diglucoside were, respectively, 71- and 1200-fold more soluble in water than phloretin at room temperature. Since phloretin attracts a great interest in dermocosmetic applications, we analyzed the percutaneous absorption of glucosides and the aglycon employing a pig skin model. Although the three compounds were detected in all skin layers (except the fluid receptor), the diglucoside was present mainly on superficial layers.
Ref: "Enzymatic Synthesis of Phloretin α‐Glucosides using a Sucrose Phosphorylase Mutant and its Effect on Solubility, Antioxidant Properties and Skin Absorption. Advanced Synthesis & Catalysis". J.L. Gonzalez-Alfonso, Z. Ubiparip, E. Jimenez-Ortega, A. Poveda, C. Alonso, L. Coderch, J. Jimenez-Barbero, J. Sanz-Aparicio, A. Ballesteros, T. Desmet, F.J. Plou. (2021). Volume363, Issue12, Pages 3079-3089 https://doi.org/10.1002/adsc.202100201
31 March, 2021
New insights into the molecular mechanism behind mannitol and erythritol fructosylation
The β-fructofuranosidase from Schwanniomyces occidentalis (Ffase) is a useful biotechnological tool for the fructosylation of different acceptors to produce fructooligosaccharides (FOS) and fructo-conjugates. In this work, the structural determinants of Ffase involved in the transfructosylating reaction of the alditols mannitol and erythritol have been studied in detail. Complexes with fructosyl-erythritol or sucrose were analyzed by crystallography and the effect of mutational changes in positions Gln-176, Gln-228, and Asn-254 studied to explore their role in modulating this biocatalytic process. Interestingly, N254T variant enhanced the wild-type protein production of fructosyl-erythritol and FOS by 30% and 48%, respectively. Moreover, it produced neokestose, which represented 27% of total FOS, and yielded 31.8 g l−1 blastose by using glucose as exclusive fructosyl-acceptor. Noteworthy, N254D and Q176E replacements turned the specificity of Ffase transferase activity towards the synthesis of the fructosylated polyols at the expense of FOS production, but without increasing the total reaction efficiency. The results presented here highlight the relevance of the pair Gln-228/Asn-254 for Ffase donor-sucrose binding and opens new windows of opportunity for optimizing the generation of fructosyl-derivatives by this enzyme enhancing its biotechnological applicability.
02 February, 2021
Production and characterization of chitooligosaccharides
04 December, 2020
Use of a β-galactosidase from Pantoea anthophila to produce galactooligosaccharides from a byproduct of the dairy industry
Ref.:"Synthesis of β(1 → 3) and β(1 → 6) galactooligosaccharides from lactose and whey using a recombinant β-galactosidase from Pantoea anthophila" Claudia V.Yañez-Ñeco, Fadia V.Cervantes, LorenaAmaya-Delgado, Antonio O.Ballesteros, Francisco J.Plou, Javier Arrizon. Electronic Journal of Biotechnology, Volume 49, January 2021, Pages 14-21. https://doi.org/10.1016/j.ejbt.2020.10.004
11 July, 2020
Molecular characterization and heterologous expression of two α-glucosidases from Metschnikowia spp
α-Glucosidases are widely distributed enzymes with a varied substrate specificity that are traditionally used in biotechnological industries based on oligo- and polysaccharides as starting materials. According to amino acid sequence homology, α-glucosidases are included into two major families, GH13 and GH31. The members of family GH13 contain several α-glucosidases with confirmed hydrolytic activity on sucrose. Previously, a sucrose splitting activity from the nectar colonizing yeast Metschnikowia reukaufii which produced rare sugars with α-(1→1), α-(1→3) and α-(1→6) glycosidic linkages from sucrose was described.
In this study, genes codifying for α-glucosidases from the nectaries yeast M. gruessii and M. reukaufii were characterised and heterologously expressed in Escherichia coli for the first time. Recombinant proteins (Mg-αGlu and Mr-αGlu) were purified and biochemically analysed. Both enzymes mainly displayed hydrolytic activity towards sucrose, maltose and p-nitrophenyl-α-D-glucopyranoside. Structural analysis of these proteins allowed the identification of common features from the α-amylase family, in particular from glycoside hydrolases that belong to family GH13. The three acidic residues comprising the catalytic triad were identified and their relevance for the protein hydrolytic mechanism confirmed by site-directed mutagenesis. Recombinant enzymes produced oligosaccharides naturally present in honey employing sucrose as initial substrate and gave rise to mixtures with the same products profile (isomelezitose, trehalulose, erlose, melezitose, theanderose and esculose) previously obtained with M. reukaufii cell extracts. Furthermore, the same enzymatic activity was detected with its orthologous Mg-αGlu from M. gruessii. Interestingly, the isomelezitose amounts obtained in reactions mediated by the recombinant proteins, ~ 170 g/L, were the highest reported so far.