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1.
Int J Mol Sci ; 23(21)2022 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-36362138

RESUMEN

Xylooligosaccharides (XOS) are widely used in the food industry as prebiotic components. XOS with high purity are required for practical prebiotic function and other biological benefits, such as antioxidant and inflammatory properties. In this work, we immobilized the recombinant endo-1,4-ß-xylanase of Malbranchea pulchella (MpXyn10) in various chemical supports and evaluated its potential to produce xylooligosaccharides (XOS) from hydrothermal liquor of eucalyptus wood chips. Values >90% of immobilization yields were achieved from amino-activated supports for 120 min. The highest recovery values were found on Purolite (142%) and MANAE-MpXyn10 (137%) derivatives, which maintained more than 90% residual activity for 24 h at 70 °C, while the free-MpXyn10 maintained only 11%. In addition, active MpXyn10 derivatives were stable in the range of pH 4.0−6.0 and the presence of the furfural and HMF compounds. MpXyn10 derivatives were tested to produce XOS from xylan of various sources. Maximum values were observed for birchwood xylan at 8.6 mg mL−1 and wheat arabinoxylan at 8.9 mg mL−1, using Purolite-MpXyn10. Its derivative was also successfully applied in the hydrolysis of soluble xylan present in hydrothermal liquor, with 0.9 mg mL−1 of XOS after 3 h at 50 °C. This derivative maintained more than 80% XOS yield after six cycles of the assay. The results obtained provide a basis for the application of immobilized MpXyn10 to produce XOS with high purity and other high-value-added products in the lignocellulosic biorefinery field.


Asunto(s)
Eucalyptus , Xilanos , Madera , Glucuronatos , Oligosacáridos/química , Endo-1,4-beta Xilanasas , Prebióticos , Hidrólisis
2.
J Exp Bot ; 70(2): 497-506, 2019 01 07.
Artículo en Inglés | MEDLINE | ID: mdl-30605523

RESUMEN

The development of lysigenous aerenchyma starts with cell expansion and degradation of pectin from the middle lamella, leading to cell wall modification, and culminating with cell separation. Here we report that nutritional starvation of sugarcane induced gene expression along sections of the first 5 cm of the root and between treatments. We selected two candidate genes: a RAV transcription factor, from the ethylene response factors superfamily, and an endopolygalacturonase (EPG), a glycosyl hydrolase related to homogalacturonan hydrolysis from the middle lamella. epg1 and rav1 transcriptional patterns suggest they are essential genes at the initial steps of pectin degradation during aerenchyma development in sugarcane. Due to the high complexity of the sugarcane genome, rav1 and epg1 were sequenced from 17 bacterial artificial chromosome clones containing hom(e)ologous genomic regions, and the sequences were compared with those of Sorghum bicolor. We used one hom(e)olog sequence from each gene for transactivation assays in tobacco. rav1 was shown to bind to the epg1 promoter, repressing ß-glucuronidase activity. RAV repression upon epg1 transcription is the first reported link between ethylene regulation and pectin hydrolysis during aerenchyma formation. Our findings may help to elucidate cell wall degradation in sugarcane and therefore contribute to second-generation bioethanol production.


Asunto(s)
Pared Celular/metabolismo , Poligalacturonasa/metabolismo , Saccharum/enzimología , Factores de Transcripción/metabolismo , Proteínas de Plantas/metabolismo , Saccharum/genética , Saccharum/crecimiento & desarrollo
3.
Ann Bot ; 124(4): 553-566, 2019 10 29.
Artículo en Inglés | MEDLINE | ID: mdl-30137291

RESUMEN

BACKGROUND AND AIMS: The cultivation of dedicated biomass crops, including miscanthus, on marginal land provides a promising approach to the reduction of dependency on fossil fuels. However, little is known about the impact of environmental stresses often experienced on lower-grade agricultural land on cell-wall quality traits in miscanthus biomass crops. In this study, three different miscanthus genotypes were exposed to drought stress and nutrient stress, both separately and in combination, with the aim of evaluating their impact on plant growth and cell-wall properties. METHODS: Automated imaging facilities at the National Plant Phenomics Centre (NPPC-Aberystwyth) were used for dynamic phenotyping to identify plant responses to separate and combinatorial stresses. Harvested leaf and stem samples of the three miscanthus genotypes (Miscanthus sinensis, Miscanthus sacchariflorus and Miscanthus × giganteus) were separately subjected to saccharification assays, to measure sugar release, and cell-wall composition analyses. KEY RESULTS: Phenotyping showed that the M. sacchariflorus genotype Sac-5 and particularly the M. sinensis genotype Sin-11 coped better than the M. × giganteus genotype Gig-311 with drought stress when grown in nutrient-poor compost. Sugar release by enzymatic hydrolysis, used as a biomass quality measure, was significantly affected by the different environmental conditions in a stress-, genotype- and organ-dependent manner. A combination of abundant water and low nutrients resulted in the highest sugar release from leaves, while for stems this was generally associated with the combination of drought and nutrient-rich conditions. Cell-wall composition analyses suggest that changes in fine structure of cell-wall polysaccharides, including heteroxylans and pectins, possibly in association with lignin, contribute to the observed differences in cell-wall biomass sugar release. CONCLUSIONS: The results highlight the importance of the assessment of miscanthus biomass quality measures in addition to biomass yield determinations and the requirement for selecting suitable miscanthus genotypes for different environmental conditions.


Asunto(s)
Sequías , Poaceae , Biomasa , Lignina , Nutrientes
4.
Ann Bot ; 124(6): 1067-1089, 2019 11 27.
Artículo en Inglés | MEDLINE | ID: mdl-31190078

RESUMEN

BACKGROUND AND AIMS: Cell wall disassembly occurs naturally in plants by the action of several glycosyl-hydrolases during different developmental processes such as lysigenous and constitutive aerenchyma formation in sugarcane roots. Wall degradation has been reported in aerenchyma development in different species, but little is known about the action of glycosyl-hydrolases in this process. METHODS: In this work, gene expression, protein levels and enzymatic activity of cell wall hydrolases were assessed. Since aerenchyma formation is constitutive in sugarcane roots, they were assessed in segments corresponding to the first 5 cm from the root tip where aerenchyma develops. KEY RESULTS: Our results indicate that the wall degradation starts with a partial attack on pectins (by acetyl esterases, endopolygalacturonases, ß-galactosidases and α-arabinofuranosidases) followed by the action of ß-glucan-/callose-hydrolysing enzymes. At the same time, there are modifications in arabinoxylan (by α-arabinofuranosidases), xyloglucan (by XTH), xyloglucan-cellulose interactions (by expansins) and partial hydrolysis of cellulose. Saccharification revealed that access to the cell wall varies among segments, consistent with an increase in recalcitrance and composite formation during aerenchyma development. CONCLUSION: Our findings corroborate the hypothesis that hydrolases are synchronically synthesized, leading to cell wall modifications that are modulated by the fine structure of cell wall polymers during aerenchyma formation in the cortex of sugarcane roots.


Asunto(s)
Saccharum , Pared Celular , Hidrolasas , Meristema , Raíces de Plantas
5.
Plant Physiol ; 169(3): 1755-65, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26336093

RESUMEN

Projections indicate an elevation of the atmospheric CO2 concentration ([CO2]) concomitant with an intensification of drought for this century, increasing the challenges to food security. On the one hand, drought is a main environmental factor responsible for decreasing crop productivity and grain quality, especially when occurring during the grain-filling stage. On the other hand, elevated [CO2] is predicted to mitigate some of the negative effects of drought. Sorghum (Sorghum bicolor) is a C4 grass that has important economical and nutritional values in many parts of the world. Although the impact of elevated [CO2] and drought in photosynthesis and growth has been well documented for sorghum, the effects of the combination of these two environmental factors on plant metabolism have yet to be determined. To address this question, sorghum plants (cv BRS 330) were grown and monitored at ambient (400 µmol mol(-1)) or elevated (800 µmol mol(-1)) [CO2] for 120 d and subjected to drought during the grain-filling stage. Leaf photosynthesis, respiration, and stomatal conductance were measured at 90 and 120 d after planting, and plant organs (leaves, culm, roots, prop roots, and grains) were harvested. Finally, biochemical composition and intracellular metabolites were assessed for each organ. As expected, elevated [CO2] reduced the stomatal conductance, which preserved soil moisture and plant fitness under drought. Interestingly, the whole-plant metabolism was adjusted and protein content in grains was improved by 60% in sorghum grown under elevated [CO2].


Asunto(s)
Dióxido de Carbono/metabolismo , Metaboloma , Sorghum/fisiología , Sequías , Grano Comestible , Fotosíntesis/fisiología , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/fisiología , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/crecimiento & desarrollo , Raíces de Plantas/fisiología , Transpiración de Plantas/fisiología , Sorghum/efectos de los fármacos , Sorghum/crecimiento & desarrollo
6.
J Exp Bot ; 66(14): 4133-43, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25922489

RESUMEN

Cell-wall recalcitrance to hydrolysis still represents one of the major bottlenecks for second-generation bioethanol production. This occurs despite the development of pre-treatments, the prospect of new enzymes, and the production of transgenic plants with less-recalcitrant cell walls. Recalcitrance, which is the intrinsic resistance to breakdown imposed by polymer assembly, is the result of inherent limitations in its three domains. These consist of: (i) porosity, associated with a pectin matrix impairing trafficking through the wall; (ii) the glycomic code, which refers to the fine-structural emergent complexity of cell-wall polymers that are unique to cells, tissues, and species; and (iii) cellulose crystallinity, which refers to the organization in micro- and/or macrofibrils. One way to circumvent recalcitrance could be by following cell-wall hydrolysis strategies underlying plant endogenous mechanisms that are optimized to precisely modify cell walls in planta. Thus, the cell-wall degradation that occurs during fruit ripening, abscission, storage cell-wall mobilization, and aerenchyma formation are reviewed in order to highlight how plants deal with recalcitrance and which are the routes to couple prospective enzymes and cocktail designs with cell-wall features. The manipulation of key enzyme levels in planta can help achieving biologically pre-treated walls (i.e. less recalcitrant) before plants are harvested for bioethanol production. This may be helpful in decreasing the costs associated with producing bioethanol from biomass.


Asunto(s)
Biomasa , Metabolismo de los Hidratos de Carbono , Pared Celular/metabolismo , Plantas/metabolismo
7.
J Exp Bot ; 66(14): 4351-65, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-25908240

RESUMEN

The production of bioenergy from grasses has been developing quickly during the last decade, with Miscanthus being among the most important choices for production of bioethanol. However, one of the key barriers to producing bioethanol is the lack of information about cell wall structure. Cell walls are thought to display compositional differences that lead to emergence of a very high level of complexity, resulting in great diversity in cell wall architectures. In this work, a set of different techniques was used to access the complexity of cell walls of different genotypes of Miscanthus sinensis in order to understand how they interfere with saccharification efficiency. Three genotypes of M. sinensis displaying different patterns of correlation between lignin content and saccharification efficiency were subjected to cell wall analysis by quantitative/qualitative analytical techniques such as monosaccharide composition, oligosaccharide profiling, and glycome profiling. When saccharification efficiency was correlated negatively with lignin, the structural features of arabinoxylan and xyloglucan were found to contribute positively to hydrolysis. In the absence of such correlation, different types of pectins, and some mannans contributed to saccharification efficiency. Different genotypes of M. sinensis were shown to display distinct interactions among their cell wall components, which seem to influence cell wall hydrolysis.


Asunto(s)
Conformación de Carbohidratos , Pared Celular/metabolismo , Poaceae/metabolismo , Genotipo , Poaceae/genética
8.
Biochim Biophys Acta ; 1824(3): 461-7, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22230786

RESUMEN

Xyloglucan is a major structural polysaccharide of the primary (growing) cell wall of higher plants. It consists of a cellulosic backbone (beta-1,4-linked glucosyl residues) that is frequently substituted with side chains. This report describes Aspergillus nidulans strain A773 recombinant secretion of a dimeric xyloglucan-specific endo-ß-1,4-glucanohydrolase (XegA) cloned from Aspergillus niveus. The ORF of the A. niveus xegA gene is comprised of 714 nucleotides, and encodes a 238 amino acid protein with a calculated molecular weight of 23.5kDa and isoelectric point of 4.38. The optimal pH and temperature were 6.0 and 60°C, respectively. XegA generated a xyloglucan-oligosaccharides (XGOs) pattern similar to that observed for cellulases from family GH12, i.e., demonstrating that its mode of action includes hydrolysis of the glycosidic linkages between glucosyl residues that are not branched with xylose. In contrast to commercial lichenase, mixed linkage beta-glucan (lichenan) was not digested by XegA, indicating that the enzyme did not cleave glucan ß-1,3 or ß-1,6 bonds. The far-UV CD spectrum of the purified enzyme indicated a protein rich in ß-sheet structures as expected for GH12 xyloglucanases. Thermal unfolding studies displayed two transitions with mid-point temperatures of 51.3°C and 81.3°C respectively, and dynamic light scattering studies indicated that the first transition involves a change in oligomeric state from a dimeric to a monomeric form. Since the enzyme is a predominantly a monomer at 60°C, the enzymatic assays demonstrated that XegA is more active in its monomeric state.


Asunto(s)
Aspergillus/química , Pared Celular/química , Celulasa/química , Proteínas Fúngicas/química , Glucanos/química , Xilanos/química , Secuencia de Aminoácidos , Aspergillus/enzimología , Aspergillus nidulans/genética , Pared Celular/enzimología , Celulasa/genética , Celulasa/metabolismo , Dicroismo Circular , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Glucanos/metabolismo , Glicósido Hidrolasas/química , Glicósido Hidrolasas/metabolismo , Concentración de Iones de Hidrógeno , Punto Isoeléctrico , Cinética , Luz , Datos de Secuencia Molecular , Peso Molecular , Multimerización de Proteína , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Dispersión de Radiación , Especificidad por Sustrato , Temperatura , Xilanos/metabolismo
9.
FEMS Yeast Res ; 13(3): 277-90, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-23360418

RESUMEN

Brazil played a pioneering role in the global establishment of the sugarcane bioethanol industry. The bioethanol fermentation process currently used in Brazil is unique due to the acid wash and recycling of yeast cells. Two, industrially adopted, wild yeast strains, CAT-1 and PE-2, have become the most widely used in Brazil. How these strains respond to the unique fermentation process is poorly understood. The improved performance of CAT-1 and PE-2 is hypothesised to be related to enhanced stress tolerance. This study presents a genome-wide analysis of the CAT-1 and PE-2 transcriptomes during a small-scale fermentation process that mimicked the industrial conditions. The common and unique transcriptional responses of the two strains to the Brazilian fermentation process were identified. Environmental stress response genes were up-regulated postfermenter feeding, demonstrating the impact of the prior acid wash and high glucose environment. Cell wall and oxidative stress tolerance were subsequently demonstrated to be enhanced for the industrial strains. Conversely, numerous genes involved in protein synthesis were down-regulated at the end of fermentation revealing the later impact of ethanol-induced stress. Subsequently, the industrial strains demonstrated a greater tolerance of ethanol and the disruption of endoplasmic reticulum homoeostasis. This increased ethanol tolerance was finally correlated with an increased unfolded protein response and increased HAC1 splicing.


Asunto(s)
Perfilación de la Expresión Génica , Microbiología Industrial , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Saccharum/metabolismo , Brasil , Etanol/metabolismo , Fermentación , Saccharomyces cerevisiae/aislamiento & purificación
11.
Front Plant Sci ; 14: 1208888, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37528985

RESUMEN

Pectic polysaccharides containing apiose, xylose, and uronic acids are excellent candidates for boron fixation. Duckweeds are the fastest-growing angiosperms that can absorb diverse metals and contaminants from water and have high pectin content in their cell walls. Therefore, these plants can be considered excellent boron (B) accumulators. This work aimed to investigate the relationship between B assimilation capacity with apiose content in the cell wall of Spirodela polyrhiza subjected to different boric acid concentrations. Plants were grown for 7 and 10 days in ½ Schenck-Hildebrandt media supplemented with 0 to 56 mg B.L-1, the non-structural and structural carbohydrates, and related genes were evaluated. The results showed that B altered the morphology and carbohydrate composition of this species during plant development. The optimum B concentration (1.8 mg B.L-1) led to the highest relative growth and biomass accumulation, reduced starch, and high pectin and apiose contents, together with increased expression of UDP-apiose/UDP-xylose synthase (AXS) and 1,4-α-galacturonosyltransferase (GAUT). The toxic state (28 and 56 mg B.L-1) increased the hexose contents in the cell wall with a concomitant reduction of pectins, apiose, and growth. The pectin content of S. polyrhiza was strongly associated with its growth capacity and regulation of B content within the cells, which have AXS as an important regulator. These findings suggest that duckweeds are suitable for B remediation, and their biomass can be used for bioenergy production.

12.
Curr Res Food Sci ; 5: 102-106, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35024623

RESUMEN

The popping expansion is a characteristic that is positively related with the quality of popcorn. A positive correlation between the volume of expansion and the thickness of the pericarp, and between the proportion of the opaque/shiny endosperm and the grain weight and volume, were postulated. However, there are no reports in the literature that address the importance of cell wall components in the popping expansion. Here, we investigate the biochemical composition of the pericarp cell walls of three inbred lines of popcorn with different popping expansion. Inbred lines GP12 (expansion volume >40 mL g-1), P11 (expansion volume 30 mL g-1) and P16 (expansion volume 14 mL g-1) were used for the analysis and quantification of monosaccharides by HPAEC-PAD, and ferulic and p-coumaric acids and lignin by HPLC. Our hypothesis is that the biochemical composition of the pericarp cell walls may be related to greater or lesser popping expansion. Our data suggest that the lignin content and composition contribute to popping expansion. The highest concentration of lignin (129.74 µg mg-1; 12.97%) was detected in the pericarp cell wall of the GP12 inbred line with extremely high popping expansion, and the lowest concentration (113.52 µg mg-1; 11.35%) was observed in the P16 inbred line with low popping expansion. These findings may contribute to indicating the quantitative trait locus for breeding programs and to developing other methods to improve the popping expansion of popcorn.

13.
Appl Microbiol Biotechnol ; 91(5): 1267-75, 2011 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-21735264

RESUMEN

Bioethanol (fuel alcohol) has been produced by industrial alcoholic fermentation processes in Brazil since the beginning of the twentieth century. Currently, 432 mills and distilleries crush about 625 million tons of sugarcane per crop, producing about 27 billion liters of ethanol and 38.7 million tons of sugar. The production of bioethanol from sugarcane represents a major large-scale technology capable of producing biofuel efficiently and economically, providing viable substitutes to gasoline. The combination of immobilization of CO2 by sugarcane crops by photosynthesis into biomass together with alcoholic fermentation of this biomass has allowed production of a clean and high-quality liquid fuel that contains 93% of the original energy found in sugar. Over the last 30 years, several innovations have been introduced to Brazilian alcohol distilleries resulting in the improvement of plant efficiency and economic competitiveness. Currently, the main scientific challenges are to develop new technologies for bioethanol production from first and second generation feedstocks that exhibit positive energy balances and appropriately meet environmental sustainability criteria. This review focuses on these aspects and provides special emphasis on the selection of new yeast strains, genetic breeding, and recombinant DNA technology, as applied to bioethanol production processes.


Asunto(s)
Biocombustibles/microbiología , Etanol/metabolismo , Microbiología Industrial , Saccharomyces cerevisiae/metabolismo , Saccharum/microbiología , Brasil , Microbiología Industrial/tendencias , Saccharomyces cerevisiae/genética , Saccharum/metabolismo
14.
An Acad Bras Cienc ; 83(2): 523-31, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21670876

RESUMEN

Contents of proteins, carbohydrates and oil of seeds of 57 individuals of Vochysiaceae, involving one species of Callisthene, six of Qualea, one of Salvertia and eight of Vochysia were determined. The main nutritional reserves of Vochysiaceae seeds are proteins (20% in average) and oils (21. 6%). Mean of carbohydrate contents was 5. 8%. Callisthene showed the lowest protein content (16. 9%), while Q. cordata was the species with the highest content (30% in average). The contents of ethanol soluble carbohydrates were much higher than those of water soluble carbohydrates. Oil contents lay above 20% for most species (30. 4% in V. pygmaea and V. pyramidalis seeds). The predominant fatty acids are lauric (Q. grandiflora), oleic (Qualea and Salvertia) or acids with longer carbon chains (Salvertia and a group of Vochysia species). The distribution of Vochysiaceae fatty acids suggests for seeds of some species an exploitation as food sources (predominance of oleic acid), for other species an alternative to cocoa butter (high contents or predominance of stearic acid) or the production of lubricants, surfactants, detergents, cosmetics and plastic (predominance of acids with C(20) or C(22) chains) or biodiesel (predominance of monounsaturated acids). The possibility of exploitation of Vochysiaceae products in a cultivation regimen and in extractive reserves is discussed.


Asunto(s)
Carbohidratos de la Dieta/análisis , Grasas de la Dieta/análisis , Ácidos Grasos/análisis , Magnoliopsida/química , Aceites de Plantas/análisis , Proteínas de Plantas/análisis , Semillas/química , Economía , Magnoliopsida/clasificación
15.
Front Plant Sci ; 12: 652168, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34335640

RESUMEN

Cellulosic ethanol is an alternative for increasing the amount of bioethanol production in the world. In Brazil, sugarcane leads the bioethanol production, and to improve its yield, besides bagasse, sugarcane straw is a possible feedstock. However, the process that leads to cell wall disassembly under field conditions is unknown, and understanding how this happens can improve sugarcane biorefinery and soil quality. In the present work, we aimed at studying how sugarcane straw is degraded in the field after 3, 6, 9, and 12 months. Non-structural and structural carbohydrates, lignin content, ash, and cellulose crystallinity were analyzed. The cell wall composition was determined by cell wall fractionation and determination of monosaccharide composition. Non-structural carbohydrates degraded quickly during the first 3 months in the field. Pectins and lignin remained in the plant waste for up to 12 months, while the hemicelluloses and cellulose decreased 7.4 and 12.4%, respectively. Changes in monosaccharide compositions indicated solubilization of arabinoxylan (xylose and arabinose) and ß-glucans (ß-1,3 1,4 glucan; after 3 months) followed by degradation of cellulose (after 6 months). Despite cellulose reduction, the xylose:glucose ratio increased, suggesting that glucose is consumed faster than xylose. The degradation and solubilization of the cell wall polysaccharides concomitantly increased the level of compounds related to recalcitrance, which led to a reduction in saccharification and an increase in minerals and ash contents. Cellulose crystallinity changed little, with evidence of silica at the latter stages, indicating mineralization of the material. Our data suggest that for better soil mineralization, sugarcane straw must stay in the field for over 1 year. Alternatively, for bioenergy purposes, straw should be used in less than 3 months.

16.
Biotechnol Rep (Amst) ; 30: e00618, 2021 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-33981591

RESUMEN

ß-Glucosidases are a limiting factor in the conversion of cellulose to glucose for the subsequent ethanol production. Here, ß-glucosidase production by Malbranchea pulchella was optimized using Composite Central Designs and Response Surface Methodologies from a medium designed. The coefficient of determination (R2 ) was 0.9960, F-value was very high, and the lack of fit was found to be non-significant. This indicates a statistic valid and predictive result. M. pulchella enzymatic extract was successfully tested as an enzymatic cocktail in a mixture design using sugarcane bagasse, soybean hull and barley bagasse. We proved that the optimization of the ß-glucosidase production and the application in hydrolysis using unexpansive biomass and agricultural wastes can be accomplished by means of statistical methodologies. The strategy presented here can be useful for the improvement of enzyme production and the hydrolysis process, arising as an alternative for bioeconomy.

17.
Nat Commun ; 12(1): 4049, 2021 06 30.
Artículo en Inglés | MEDLINE | ID: mdl-34193873

RESUMEN

Xyloglucans are highly substituted and recalcitrant polysaccharides found in the primary cell walls of vascular plants, acting as a barrier against pathogens. Here, we reveal that the diverse and economically relevant Xanthomonas bacteria are endowed with a xyloglucan depolymerization machinery that is linked to pathogenesis. Using the citrus canker pathogen as a model organism, we show that this system encompasses distinctive glycoside hydrolases, a modular xyloglucan acetylesterase and specific membrane transporters, demonstrating that plant-associated bacteria employ distinct molecular strategies from commensal gut bacteria to cope with xyloglucans. Notably, the sugars released by this system elicit the expression of several key virulence factors, including the type III secretion system, a membrane-embedded apparatus to deliver effector proteins into the host cells. Together, these findings shed light on the molecular mechanisms underpinning the intricate enzymatic machinery of Xanthomonas to depolymerize xyloglucans and uncover a role for this system in signaling pathways driving pathogenesis.


Asunto(s)
Pared Celular/metabolismo , Citrus/microbiología , Glucanos/metabolismo , Glicósido Hidrolasas/metabolismo , Factores de Virulencia/genética , Xanthomonas/metabolismo , Xilanos/metabolismo , Proteínas Bacterianas/metabolismo , Enfermedades de las Plantas/genética , Enfermedades de las Plantas/microbiología , Activación Transcripcional , Sistemas de Secreción Tipo III/metabolismo , Factores de Virulencia/metabolismo , Xanthomonas/genética , Xanthomonas/patogenicidad
18.
Sci Rep ; 10(1): 6998, 2020 04 24.
Artículo en Inglés | MEDLINE | ID: mdl-32332833

RESUMEN

ß-glucosidases catalyze the hydrolysis ß-1,4, ß-1,3 and ß-1,6 glucosidic linkages from non-reducing end of short chain oligosaccharides, alkyl and aryl ß-D-glucosides and disaccharides. They catalyze the rate-limiting reaction in the conversion of cellobiose to glucose in the saccharification of cellulose for second-generation ethanol production, and due to this important role the search for glucose tolerant enzymes is of biochemical and biotechnological importance. In this study we characterize a family 3 glycosyl hydrolase (GH3) ß-glucosidase (Bgl) produced by Malbranchea pulchella (MpBgl3) grown on cellobiose as the sole carbon source. Kinetic characterization revealed that the MpBgl3 was highly tolerant to glucose, which is in contrast to many Bgls that are completely inhibited by glucose. A 3D model of MpBgl3 was generated by molecular modeling and used for the evaluation of structural differences with a Bgl3 that is inhibited by glucose. Taken together, our results provide new clues to understand the glucose tolerance in GH3 ß-glucosidases.


Asunto(s)
Celobiosa/metabolismo , Glucosa/metabolismo , Onygenales/metabolismo , beta-Glucosidasa/metabolismo , Carbono/metabolismo , Celulosa/metabolismo , Hidrólisis , Onygenales/enzimología
19.
Int J Biol Macromol ; 136: 1133-1141, 2019 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-31220494

RESUMEN

ß-glucosidases (BGLs) hydrolyze short-chain cellulooligosaccharides. Some BGLs can hydrolyze anthocyanins and be applied in the clarification process of food industries, especially grape juice and wine. Enzyme immobilization is a valuable tool to increase enzyme stabilization. In this work, Malbranchea pulchella BGL was immobilized on Monoaminoethyl-N-ethyl-agarose ionic support, MANAE-agarose, and Concanavalin A-Sepharose affinity support, Con-A-Sepharose. The formed biocatalysts, denominated BLG-MANAE and BLG-ConA, were applied in the grape juice and red wine clarification. BGL-MANAE and BGL-ConA hyperactivated M. pulchella BGL 10- and 3-fold, respectively. Both biocatalysts showed at least 70% activity at pH range 2-11, until 24 h incubation. BGL-MANAE and BGL-ConA showed activity of 60% and 100%, respectively, at 50 °C, up to 24 h. Both biocatalysts were efficiently reused 20-fold. They were stable in the presence of up to 0.1 M glucose for 24 h incubation, and with 5%, 10% and 15% ethanol kept up to 70% activity. BGL-MANAE biocatalyst was 11% and 25% more efficient than BGL-ConA in clarification of concentrate and diluted wines, respectively. Likewise, BGL-MANAE biocatalysts were 14% and 33% more efficient than the BGL-ConA in clarification of diluted and concentrated juices, respectively. Therefore, the BGL-MANAE biocatalyst was especially effective in red wine and grape juice clarification.


Asunto(s)
Antocianinas/metabolismo , Ascomicetos/enzimología , Jugos de Frutas y Vegetales/análisis , Sefarosa/análogos & derivados , Vitis/química , Vino/análisis , beta-Glucosidasa/metabolismo , Biocatálisis , Activación Enzimática , Estabilidad de Enzimas , Enzimas Inmovilizadas/antagonistas & inhibidores , Enzimas Inmovilizadas/química , Enzimas Inmovilizadas/metabolismo , Glucosa/farmacología , Concentración de Iones de Hidrógeno , Hidrólisis , Sefarosa/química , Temperatura , beta-Glucosidasa/antagonistas & inhibidores , beta-Glucosidasa/química
20.
Biosystems ; 164: 112-120, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-28993247

RESUMEN

The extracellular matrices (ECMs) of living organisms are compartments responsible for maintenance of cell shape, cell adhesion, and cell communication. They are also involved in cell signaling and defense against the attack of pathogens. The plant cell walls have been recently defined as encoded structures that combine polysaccharides with other encoded structures (proteins and phenolic compounds). The term Glycomic Code has been used to define the set of mechanisms that generate cell wall architecture (the combination of polymers of different types) and biological function. Here, the composition of the extracellular matrices of archaea, bacteria, animals, fungi, algae, and plants was compared to understand how the Glycomic Code of these different organisms operate to produce polysaccharides and therefore how the Glycomic Code may have evolved in nature. It was found that the heterotrophs display EMC polysaccharides containing aminosugars (nitrogen-based polysaccharides) whereas the photosynthetic organisms have cellulose-based walls, with polymers that hardly present aminosugars in its composition. Another subgroup is of the organisms containing EMCs with sulfated polysaccharides (animals and red algae). The main hemicellulose found in plants (xyloglucan) is used as a case study along with other seed cell wall storage polysaccharides of plants to exemplify the evolution of the Glycomic Code in plants. Overall, the trends observed in this work shows for the first time how the Glycomic Code in ECMs of living organisms may have evolved and diversified in nature.


Asunto(s)
Evolución Molecular , Matriz Extracelular/metabolismo , Código Genético/fisiología , Glicómica/tendencias , Animales , Pared Celular/genética , Pared Celular/metabolismo , Matriz Extracelular/genética , Glicómica/métodos , Humanos
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