Goncalves TA

References (2)

Title : The secretome of two representative lignocellulose-decay basidiomycetes growing on sugarcane bagasse solid-state cultures - Valadares_2019_Enzyme.Microb.Technol_130_109370
Author(s) : Valadares F , Goncalves TA , Damasio A , Milagres AM , Squina FM , Segato F , Ferraz A
Ref : Enzyme Microb Technol , 130 :109370 , 2019
Abstract : Secretome evaluations of lignocellulose-decay basidiomycetes can reveal new enzymes in selected fungal species that degrade specific substrates. Proteins discovered in such studies can support biorefinery development. Brown-rot (Gloeophyllum trabeum) and white-rot (Pleurotus ostreatus) fungi growing in sugarcane bagasse solid-state cultures produced 119 and 63 different extracellular proteins, respectively. Several of the identified enzymes are suitable for in vitro biomass conversion, including a range of cellulases (endoglucanases, cellobiohydrolases and beta-glucosidases), hemicellulases (endoxylanases, alpha-arabinofuranosidases, alpha-glucuronidases and acetylxylan esterases) and carbohydrate-active auxiliary proteins, such as AA9 lytic polysaccharide monooxygenase, AA1 laccase and AA2 versatile peroxidase. Extracellular oxalate decarboxylase was also detected in both fungal species, exclusively in media containing sugarcane bagasse. Interestingly, intracellular AA6 quinone oxidoreductases were also exclusively produced under sugarcane bagasse induction in both fungi. These enzymes promote quinone redox cycling, which is used to produce Fenton's reagents by lignocellulose-decay fungi. Hitherto undiscovered hypothetical proteins that are predicted in lignocellulose-decay fungi genomes appeared in high relative abundance in the cultures containing sugarcane bagasse, which suggests undisclosed, new biochemical mechanisms that are used by lignocellulose-decay fungi to degrade sugarcane biomass. In general, lignocellulose-decay fungi produce a number of canonical hydrolases, as well as some newly observed enzymes, that are suitable for in vitro biomass digestion in a biorefinery context.
ESTHER : Valadares_2019_Enzyme.Microb.Technol_130_109370
PubMedSearch : Valadares_2019_Enzyme.Microb.Technol_130_109370
PubMedID: 31421724

Title : Characterization and Low-Resolution Structure of an Extremely Thermostable Esterase of Potential Biotechnological Interest from Pyrococcus furiosus - Mandelli_2016_Mol.Biotechnol_58_757
Author(s) : Mandelli F , Goncalves TA , Gandin CA , Oliveira AC , Oliveira Neto M , Squina FM
Ref : Mol Biotechnol , 58 :757 , 2016
Abstract : Enzymes isolated from extremophiles often exhibit superior performance and potential industrial applications. There are several advantages performing biocatalysis at elevated temperatures, including enhanced reaction rates, increased substrate solubility and decreased risks of contamination. Furthermore, thermophilic enzymes usually exhibit high resistance against many organic solvents and detergents, and are also more resistant to proteolytic attack. In this study, we subcloned and characterized an esterase from the hyperthermophilic archaeon Pyrococcus furiosus (Pf_Est) that exhibits optimal activity around 80 degrees C using naphthol-derived substrates and p-nitrophenyl palmitate (pNPP). According to the circular dichroism spectra, the secondary structure of P. furiosus esterase, which is predominantly formed by a beta-sheet structure, is very stable, even after incubation at 120 degrees C. We performed SAXS to determine the low-resolution structure of Pf_Est, which is monomeric in solution at 80 degrees C and has a molecular weight of 28 kDa. The Km and V max values for this esterase acting on pNPP were 0.53 mmol/L and 6.5 x 10-3 U, respectively. Pf_Est was most active in the immiscible solvents and retained more than 50 % in miscible solvents. Moreover, Pf_Est possesses transesterification capacity, presenting better results when isobutanol was used as an acyl acceptor (2.69 +/- 0.14 x 10-2 mumol/min mg) and the highest hydrolytic activity toward olive oil among different types of oils testes in this study. Collectively, these biophysical and catalytic properties are of interest for several biotechnological applications that require harsh conditions, including high temperature and the presence of organic solvents.
ESTHER : Mandelli_2016_Mol.Biotechnol_58_757
PubMedSearch : Mandelli_2016_Mol.Biotechnol_58_757
PubMedID: 27665110
Gene_locus related to this paper: pyrfu-PF1108