Navegando por Assunto "Glycoside hydrolases"

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    Oxidative cleavage of polysaccharides by a termite-derived superoxide dismutase boosts the degradation of biomass by glycoside hydrolases
    (Royal Society of Chemistry) Cairo, João Paulo L. Franco; Mandelli, Fernanda; Tramontina, Robson; Cannella, David; Paradisi, Alessandro; Ciano, Luisa; Ferreira, Marcel R.; Liberato, Marcelo V.; Brenelli, Lívia B.; Gonçalves, Thiago A.; Rodrigues, Gisele N.; Alvarez, Thabata M.; Mofatto, Luciana S.; Carazzolle, Marcelo F.; Pradella, Jose Geraldo da Cruz; Leme, Adriana F. Paes; Leonardo, Ana M. Costa; Neto, Mário Oliveira; Damasio, André; Davies, Gideon J.; Felby, Claus; Walton, Paul H.; Squina, Fabio M.
    Wood-feeding termites effectively degrade plant biomass through enzymatic degradation. Despite their high efficiencies, however, individual glycoside hydrolases isolated from termites and their symbionts exhibit anomalously low effectiveness in lignocellulose degradation, suggesting hereto unknown enzymatic activities in their digestome. Herein, we demonstrate that an ancient redox-active enzyme encoded by the lower termite Coptotermes gestroi, a Cu/Zn superoxide dismutase (CgSOD-1), plays a previously unknown role in plant biomass degradation. We show that CgSOD-1 transcripts and peptides are up-regulated in response to an increased level of lignocellulose recalcitrance and that CgSOD-1 localizes in the lumen of the fore- and midguts of C. gestroi together with termite main cellulase, CgEG-1-GH9. CgSOD-1 boosts the saccharification of polysaccharides by CgEG-1-GH9. We show that the boosting effect of CgSOD-1 involves an oxidative mechanism of action in which CgSOD-1 generates reactive oxygen species that subsequently cleave the polysaccharide. SOD-type enzymes constitute a new addition to the growing family of oxidases, ones which are up-regulated when exposed to recalcitrant polysaccharides, and that are used by Nature for biomass degradation.
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    Replacement of the carbon catabolite regulator (cre1) and fed-batch cultivation as strategies to enhance cellulase production in Trichoderma harzianum
    (Elsevier) Delabona, Priscila da Silva; Lima, Deise Juliana; Codima, Carla Aloia; Ramoni, Jonas; Gelain, Lucas; Melo, Vandierly Sampaio de; Farinas, Cristiane Sanchez; Pradella, José Geraldo da Cruz; Seiboth, Bernhard
    This work focused on mitigating carbon catabolic repression (CCR) and increasing cellulase production in Trichoderma harzianum based on the cre1 deletion. The CRE1 protein (encoded by cre1) has been described as a cellulase transcriptional repressor in various cellulotic fungi, but has not been investigated in T. harzianum. We constructed ∆cre1 T. harzianum by replacing the cre1 gene with the amdS gene from Aspergillus nidulans. Quantitative PCR analysis of some Cazymes genes showed that CRE1 acts positively on gh61, bgl1 and xyn2. The fed-batch strategy using hydrothermal sugarcane bagasse by the ∆cre1_Th15 produced a constant rate of FPase under glucose influence, suggesting that the knockout of the carbon catabolite regulator improved the glycoside hydrolases (FPase 1.96 ± 0.32 IU/mL; β-glucosidase 5.67 ± 0.28 IU/mL and xylanase 327. 26 ± 14.25 IU/mL), so that this strain can be used for biorefinery purposes.