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1.
Water Sci Technol ; 84(3): 656-666, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34388125

RESUMO

This study compares the H2 production from glucose, xylose, and acidic hydrolysates of Agave tequilana bagasse as substrates. The fermentation was performed in a granular sludge reactor operated in two phases: (1) model substrates (glucose and xylose) and (2) acidic hydrolysates at 35 °C, pH 4.5 and a hydraulic retention time of 5.5 h with glucose (10 g L-1) and xylose (12 g L-1). A sequencing batch reactor was used to acclimate the biomass between the glucose and xylose continuous fermentation (with a mixture of xylose-glucose) and acidic hydrolysates. During the discontinuous acclimating step, the xylose/glucose ratio increment negatively affected the H2 productivity. Although the continuous H2 production with xylose was negligible, the co-fermentation with glucose (88-12%) allowed H2 productivity of 2,889 ± 502 mL H2 L-1d-1. An acidic hydrolysate concentration of 3.3 gcarbohydrate L-1 showed a three-fold higher H2 productivity than with a concentration of 10 g L-1. The results indicated that xylose, as the only substrate, was challenging to metabolize by the inoculum, and its mixture with glucose improved the H2 productivity. Therefore, the low H2 productivity with hydrolysates could be related to the presence of xylose.


Assuntos
Agave , Xilose , Agave/metabolismo , Celulose/metabolismo , Fermentação , Glucose
2.
Plant Mol Biol ; 106(6): 533-554, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34263437

RESUMO

KEY MESSAGE: The role of central carbon metabolism in the synthesis and emission of scent volatiles in tuberose flowers was revealed through measurement of changes in transcripts and metabolites levels. Tuberose or Agave amica (Medikus) Thiede & Govaerts is a widely cultivated ornamental plant in several subtropical countries. Little is known about metabolite networking involved in biosynthesis of specialized metabolites utilizing primary metabolites. In this study, metabolite profiling and gene expression analyses were carried out from six stages of maturation throughout floral lifespan. Multivariate analysis indicated distinction between early and late maturation stages. Further, the roles of sugars viz. sucrose, glucose and fructose in synthesis, glycosylation and emission of floral scent volatiles were studied. Transcript levels of an ABC G family transporter (picked up from the floral transcriptome) was in synchronization with terpene volatiles emission during the anthesis stage. A diversion from phenylpropanoid/benzenoid to flavonoid metabolism was observed as flowers mature. Further, it was suggested that this metabolic shift could be mediated by isoforms of 4-Coumarate-CoA ligase along with Myb308 transcription factor. Maximum glycosylation of floral scent volatiles was shown to occur at the late mature stage when emission declined, facilitating both storage and export from the floral tissues. Thus, this study provides an insight into floral scent volatiles synthesis, storage and emission by measuring changes at transcripts and metabolites levels in tuberose throughout floral lifespan.


Assuntos
Agave/genética , Flores/genética , Regulação da Expressão Gênica de Plantas , Odorantes/análise , Transcriptoma , Compostos Orgânicos Voláteis/metabolismo , Agave/crescimento & desenvolvimento , Agave/metabolismo , Cromatografia Líquida de Alta Pressão/métodos , Flavonoides/análise , Flores/crescimento & desenvolvimento , Flores/metabolismo , Cromatografia Gasosa-Espectrometria de Massas/métodos , Perfilação da Expressão Gênica/métodos , Hidroxibenzoatos/análise , RNA-Seq/métodos
3.
Plant Sci ; 305: 110748, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33691954

RESUMO

Agave lechuguilla is one of the most abundant species in arid and semiarid regions of Mexico, and is used to extract fiber. However, 85 % of the harvested plant material is discarded. Previous bioprospecting studies of the waste biomass suggest the presence of bioactive compounds, although the extraction process limited metabolite characterization. This work achieved flavonoid profiling of A. lechuguilla in both processed and non-processed leaf tissues using transcriptomic analysis. Functional annotation of the first de novo transcriptome of A. lechuguilla (255.7 Mbp) allowed identifying genes coding for 33 enzymes and 8 transcription factors involved in flavonoid biosynthesis. The flavonoid metabolic pathway was mostly elucidated by HPLC-MS/MS screening of alcoholic extracts. Key genes of flavonoid synthesis were higher expressed in processed leaf tissues than in non-processed leaves, suggesting a high content of flavonoids and glycoside derivatives in the waste biomass. Targeted HPLC-UV-MS analyses confirmed the concentration of isorhamnetin (1251.96 µg), flavanone (291.51 µg), hesperidin (34.23 µg), delphinidin (24.23 µg), quercetin (15.57 µg), kaempferol (13.71 µg), cyanidin (12.32 µg), apigenin (9.70 µg) and catechin (7.91 µg) per gram of dry residue. Transcriptomic and biochemical profiling concur in the potential of lechuguilla by-products with a wide range of applications in agriculture, feed, food, cosmetics, and pharmaceutical industries.


Assuntos
Agave/química , Agave/genética , Agave/metabolismo , Biomassa , Flavonoides/metabolismo , Extratos Vegetais/química , Resíduos/análise , Perfilação da Expressão Gênica , México
4.
Int J Biol Macromol ; 175: 199-208, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33548315

RESUMO

Lignocellulosic wastes may provide a means to economize polyhydroxybutyrate (PHB) production. This study has proposed the use of Agave durangensis leaves obtained from the artisanal mezcal industry as a novel substrate for this aim. Results revealed an increase in PHB biosynthesis (0.32 g/L) and improvement in %PHB (16.79-19.51%) by Bacillus cereus 4N when A. durangensis leaves used as carbon source were physically pre-treated by ultrasound for 30 min (ADL + US30') and thermally pre-treated (ADL + Q). Chemical analyses and SEM studies revealed compositional and morphological changes when A. durangensis leaves were physically pre-treated. Also, elemental analysis of growth media showed that carbon/nitrogen ratios of 14-21, and low nitrogen, hydrogen, and protein content were well-suited for PHB biosynthesis. Confocal microscopy revealed morphological changes in the bacterial cell and carbonosome structure under the influence of different substrates. Finally, Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) analyses showed that homopolymeric PHB with a high thermal-resistance (271.94-272.89 °C) was produced. Therefore, the present study demonstrates the potential use of physically pre-treated A. durangensis leaves to produce PHB. These results promote the development of a circular economy in Mexico, where lignocellulosic wastes can be employed to produce value-added biotechnological products.


Assuntos
Agave/metabolismo , Bacillus cereus/metabolismo , Hidroxibutiratos/química , Agave/microbiologia , Bacillus cereus/crescimento & desenvolvimento , Biotecnologia , Calorimetria/métodos , Carbono/metabolismo , Fermentação , Hidrogênio/metabolismo , Nitrogênio/metabolismo , Folhas de Planta/metabolismo , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Resíduos/economia
5.
Plant Cell Environ ; 44(1): 34-48, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33073369

RESUMO

Crassulacean acid metabolism (CAM) crops are important agricultural commodities in water-limited environments across the globe, yet modelling of CAM productivity lacks the sophistication of widely used C3 and C4 crop models, in part due to the complex responses of the CAM cycle to environmental conditions. This work builds on recent advances in CAM modelling to provide a framework for estimating CAM biomass yield and water use efficiency from basic principles. These advances, which integrate the CAM circadian rhythm with established models of carbon fixation, stomatal conductance and the soil-plant-atmosphere continuum, are coupled to models of light attenuation, plant respiration and biomass partitioning. Resulting biomass yield and transpiration for Opuntia ficus-indica and Agave tequilana are validated against field data and compared with predictions of CAM productivity obtained using the empirically based environmental productivity index. By representing regulation of the circadian state as a nonlinear oscillator, the modelling approach captures the diurnal dynamics of CAM stomatal conductance, allowing the prediction of CAM transpiration and water use efficiency for the first time at the plot scale. This approach may improve estimates of CAM productivity under light-limiting conditions when compared with previous methods.


Assuntos
Metabolismo Ácido das Crassuláceas , Água , Agave/metabolismo , Biomassa , Carbono/metabolismo , Dinâmica não Linear , Opuntia/metabolismo , Fotossíntese , Transpiração Vegetal , Água/metabolismo
6.
Steroids ; 160: 108648, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32298660

RESUMO

Agave plants are popular for their myriad applications in traditional medicine attributed to their reported anti-inflammatory, immunomodulatory, cytotoxic and antifungal activities. The aim of this study was to examine the anti-inflammatory, immunomodulatory and ulceroprotective activity of Agave species in relation to their metabolite fingerprint via a metabolome based ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) approach coupled to chemometrics. The metabolomic differences among five examined Agave leaves viz. Agave americana L., A. americana var. marginata Trel, A. angustifolia Haw. cv. marginata, A. desmettiana Jacobi, A. pygmaea Gentry were determined via a total of 56 annotated metabolites. Identification based on MSn and UV spectra revealed 25 steroidal saponins and sapogenins, 6 flavonoids, 2 homoisoflavonoids, 7 phenolic acids, 6 fatty acids and 3 fatty acid amides, some of which are reported for the first time in Agave. Metabolites heterogeneity was assessed among leaf taxa via multivariate data analyses for samples classification, showing that saponins is the major metabolite contributing to their classification. The carrageenan induced acute inflammatory rat model was used to assess the anti-inflammatory activity of Agave extracts via monitoring of blood cytokine levels. Additionally, their effects on ethanol-induced gastric ulcer in rats were evaluated. A. pygmaea showed the most significant anti-inflammatory and immunomodulatory activity, while A. angustifolia var. marginata possessed the highest ulceroprotective activity, which could be attributable to the high abundance of various saponins and homoisoflavonoids in those taxa.


Assuntos
Anti-Inflamatórios/farmacologia , Antiulcerosos/farmacologia , Fatores Imunológicos/farmacologia , Isoflavonas/farmacologia , Extratos Vegetais/farmacologia , Saponinas/farmacologia , Agave/química , Agave/metabolismo , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/metabolismo , Antiulcerosos/química , Antiulcerosos/metabolismo , Carragenina , Cromatografia Líquida de Alta Pressão , Modelos Animais de Doenças , Etanol , Feminino , Fatores Imunológicos/química , Fatores Imunológicos/metabolismo , Imunomodulação/efeitos dos fármacos , Inflamação/induzido quimicamente , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Isoflavonas/química , Isoflavonas/metabolismo , Masculino , Metabolômica , Camundongos , Estrutura Molecular , Extratos Vegetais/química , Extratos Vegetais/metabolismo , Folhas de Planta/química , Folhas de Planta/metabolismo , Ratos , Ratos Wistar , Saponinas/química , Saponinas/metabolismo , Espectrometria de Massas por Ionização por Electrospray , Úlcera Gástrica/induzido quimicamente , Úlcera Gástrica/tratamento farmacológico , Úlcera Gástrica/metabolismo
7.
Sci Rep ; 10(1): 3860, 2020 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-32123284

RESUMO

Auxins are one of the most important and studied phytohormones in nature. Auxin signaling and perception take place in the cytosol, where the auxin is sensed. Then, in the nucleus, the auxin response factors (ARF) promote the expression of early-response genes. It is well known that not all plants respond to the same amount and type of auxins and that the response can be very different even among plants of the same species, as we present here. Here we investigate the behavior of ARF in response to various auxins in Agave angustifolia Haw., A. fourcroydes Lem. and A. tequilana Weber var. Azul. By screening the available database of A. tequilana genes, we have identified 32 ARF genes with high sequence identity in the conserved domains, grouped into three main clades. A phylogenetic tree was inferred from alignments of the 32 Agave ARF protein sequences and the evolutionary relationship with other species was analyzed. AteqARF 4, 15, 21, and 29 were selected as a representative diverse sample coming from each of the different subclades that comprise the two main clades of the inferred phylogenetic reconstruction. These ARFs showed differential species-specific expression patterns in the presence of indole-3-acetic acid (IAA) and 2,4-dichlorophenoxyacetic acid (2,4-D). Interestingly, A. angustifolia showed different phenotypes in the presence and absence of auxins. In the absence of auxin, A. angustifolia produces roots, while shoots are developed in the presence of IAA. However, in the presence of 2,4-D, the plant meristem converts into callus. According to our results, it is likely that AteqARF15 participates in this outcome.


Assuntos
Agave/metabolismo , Bases de Dados de Ácidos Nucleicos , Regulação da Expressão Gênica de Plantas , Ácidos Indolacéticos/metabolismo , Proteínas de Plantas/biossíntese , Fatores de Transcrição/biossíntese , Agave/genética , Proteínas de Plantas/genética , Especificidade da Espécie , Fatores de Transcrição/genética
8.
Sci Rep ; 10(1): 1404, 2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31996722

RESUMO

While terahertz imaging has been used before for the determination of water content in vegetative tissue, most studies have either presented measurements of the temporal evolution of water content at a single-point of the plant or have presented two-dimensional images of leaves, demonstrating the potential of the technique, but relatively little of such information has been used to support biologically relevant conclusions. In this article we introduce terahertz time-domain spectroscopic imaging as a technique for the determination of the three-dimensional distribution of water in succulent plant tissues. We present the first three-dimensional water mapping of an agave leaf, which demonstrates an unprecedented capability to study the water retention mechanisms within succulent plants. We found that agave leaves are composed of a low-hydration outer tissue layer, defined by the outermost layer of vascular tissue that surrounds a high-hydration tissue, the carbohydrate rich hydrenchyma. The findings are supported by histological images and the correlation between the water content and carbohydrate presence is consistent with recently published findings of a remarkably large hydration shell associated with agave fructans.


Assuntos
Agave/química , Imageamento Tridimensional , Folhas de Planta/química , Imagem Terahertz/métodos , Água/análise , Aclimatação , Agave/metabolismo , Secas , Frutanos/metabolismo , Folhas de Planta/metabolismo , Espectroscopia Terahertz/métodos , Água/metabolismo
9.
J Sci Food Agric ; 99(14): 6307-6314, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31260113

RESUMO

BACKGROUND: Pulque bread is a traditional Mexican product obtained by fermentation using microflora present only in pulque. In this study, the possibility of creating a pulque microbial consortium under laboratory conditions and its applications were evaluated. A laboratory-made consortium was compared with a consortium originating in Mexico in bread and pulque production. They were tested in various growth medium systems: pulque made from agave sap and malt extract, Mexican wheat and rye pulque bread, and European wheat and rye bread. RESULTS: Depending on the growth medium, consortiums showed differing influence on many factors, such as specific volume, weight loss after baking, soluble proteins, and crust and crumb color. Indigenous starters increased sensorial acceptance of pulque and Mexican rye bread, decreased pH, and increased titratable acidity of the breads at the highest level whereas laboratory consortia improved sensory acceptance of wheat breads. The laboratory-prepared starter in some cases improved antiradical activity. All pulques received similar consumer evaluations. However, malt pulque was the least appreciated beverage. CONCLUSION: The results show the possibility of creating a pulque microbial consortium under laboratory conditions. Depending on the flour type and the breadmaking technique, the use of a particular microbial consortium allowed modification of certain physicochemical parameters. In conclusion, it is feasible to modify bread parameters to obtain features corresponding to consumer demands by using an appropriate microflora, pulque, or flour type. Moreover, this research describes, for the first time, the use of rye malt for pulque and rye flour for pulque bread preparation as raw materials. © 2019 Society of Chemical Industry.


Assuntos
Bactérias/metabolismo , Pão/microbiologia , Consórcios Microbianos , Agave/metabolismo , Agave/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Pão/análise , Fermentação , Farinha/análise , Farinha/microbiologia , Manipulação de Alimentos , Humanos , México , Secale/metabolismo , Secale/microbiologia , Paladar , Triticum/metabolismo , Triticum/microbiologia
10.
J Sci Food Agric ; 99(14): 6601-6607, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31347166

RESUMO

BACKGROUND: Phosphate-solubilizing bacteria (PSB) can be an environment-friendly strategy to improve crop production in low-phosphorus (P) or P-deficient soils. The effect of indigenous mixed inocula of PSB on Agave angustifolia Haw. growth was assessed. The four treatments evaluated were T1 (Pseudomonas luteola + Enterobacter sp.), T2 (Pseudomonas luteola + Bacillus sp.), T3 (Pseudomonas luteola + Acinetobacter sp.), and T4 (control); each was replicated 25 times using a completely randomized design during 12 months under rain-fed conditions. Additionally, P solubilization in vitro of the mixed inocula with three different sources of inorganic P was tested. RESULTS: The mixed inocula were able to solubilize more P from tricalcium phosphate Ca3 (PO4 )2 than from aluminum phosphate (AlPO4 ) and iron phosphate (FePO4 ). Relative to the control, T2 increased plant height by 22.9%, leaf dry weight by 391.4%, plant stem diameter by 49.6%, and root dry weight by 193.9%. The stem solid soluble content increased 50.0% with T1. Plant-available soil P increased 94.6% with T3 and 77.3% with T1. Soil alkaline phosphatase activity increased 85.9% with T1. CONCLUSION: T2 was the mixed inoculum that most improved Agave angustifolia plant growth. The indigenous mixed inocula of PSB evaluated appears to be a practical and efficient option for promoting field growth of Agave angustifolia plants. However, further research is necessary to achieve a deeper understanding of the relationships between different PSB species and their effects on agave, which may reveal some of the mechanisms of the synergistic interactions that are involved in the promotion of plant growth. © 2019 Society of Chemical Industry.


Assuntos
Acinetobacter/metabolismo , Agave/crescimento & desenvolvimento , Agave/microbiologia , Inoculantes Agrícolas/metabolismo , Bacillus/metabolismo , Enterobacter/metabolismo , Fosfatos/metabolismo , Pseudomonas/metabolismo , Agave/metabolismo , Fosfatos/química , Microbiologia do Solo , Solubilidade
11.
BMC Genomics ; 20(1): 473, 2019 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-31182030

RESUMO

BACKGROUND: Reliable indicators for the onset of flowering are not available for most perennial monocarpic species, representing a drawback for crops such as bamboo, agave and banana. The ability to predict and control the transition to the reproductive stage in A. tequilana would represent an advantage for field management of agaves for tequila production and for the development of a laboratory model for agave species. RESULTS: Consistent morphological features could not be determined for the vegetative to reproductive transition in A. tequilana. However, changes in carbohydrate metabolism where sucrose decreased and fructans of higher degree of polymerization increased in leaves before and after the vegetative to reproductive transition were observed. At the molecular level, transcriptome analysis from leaf and shoot apical meristem tissue of A. tequilana plants from different developmental stages identified OASES as the most effective assembly program and revealed evidence for incomplete transcript processing in the highly redundant assembly obtained. Gene ontology analysis uncovered enrichment for terms associated with carbohydrate and hormone metabolism and detailed analysis of expression patterns for individual genes revealed roles for specific Flowering locus T (florigen), MADS box proteins, gibberellins and fructans in the transition to flowering. CONCLUSIONS: Based on the data obtained, a preliminary model was developed to describe the regulatory mechanisms underlying the initiation of flowering in A. tequilana. Identification of specific promoter and repressor Flowering Locus T and MADS box genes facilitates functional analysis and the development of strategies to modulate the vegetative to reproductive transition in A. tequilana.


Assuntos
Agave/crescimento & desenvolvimento , Agave/genética , Agave/anatomia & histologia , Agave/metabolismo , Florígeno/metabolismo , Flores/crescimento & desenvolvimento , Frutanos/metabolismo , Giberelinas/metabolismo , Proteínas de Domínio MADS/genética , Família Multigênica , Folhas de Planta/química , Folhas de Planta/metabolismo , Proteínas de Plantas/genética , Processamento Pós-Transcricional do RNA , RNA Mensageiro/metabolismo , RNA-Seq , Açúcares/análise , Transcriptoma
12.
Food Chem ; 291: 94-100, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31006476

RESUMO

We present a study of the hydration shells of some carbohydrate polymers of commercial and biological importance, namely, agave fructans, inulin, and maltodextrin, employing terahertz time-domain spectroscopy and differential scanning calorimetry. We observe that the hydration numbers calculated using terahertz spectroscopy are marginally higher than those of the calorimetric values. We attribute this discrepancy to the definition of hydration number, which in a way correlates with the physical process used to quantify it. The aqueous solutions show a non-proportional increase in the absorption coefficient and the hydration number, with a decrease in the carbohydrate concentration. We demonstrate that this behavior is consistent with the "chaotropic" or "structure breaking" model of the hydration shell around the carbohydrates. In addition, the study reveals that agave fructans and inulin have good hydration ability. Given the high glass transition temperature and good hydration ability, these carbohydrates may behave as good bio-protectants and hydrating additives for food and beverages.


Assuntos
Carboidratos/química , Polímeros/química , Agave/química , Agave/metabolismo , Varredura Diferencial de Calorimetria , Frutanos/análise , Frutanos/química , Luz , Polissacarídeos/química , Espectroscopia Terahertz
13.
Protoplasma ; 256(4): 1079-1092, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30923921

RESUMO

Calcium is a secondary messenger that regulates and coordinates the cellular responses to environmental cues. Despite calcium being a key player during fertilization in plants, little is known about its role during the development of the endosperm. For this reason, the distribution, abundance, and dynamics of cytosolic calcium during the first stages of endosperm development of Agave tequilana and Agave salmiana were analyzed. Cytosolic calcium and actin filaments detected in the embryo sacs of Agave tequilana and A. salmiana revealed that they play an important role during the division and nuclear migration of the endosperm. After fertilization, a relatively high concentration of cytosolic calcium was located in the primary nucleus of the endosperm, as well as around migrating nuclei during the development of the endosperm. Cytosolic calcium participates actively during the first mitosis of the endosperm mother cell and interacts with the actin filaments that generate the motor forces during the migration of the nuclei through the large cytoplasm of the central cell.


Assuntos
Agave/crescimento & desenvolvimento , Cálcio/metabolismo , Citosol/metabolismo , Endosperma/crescimento & desenvolvimento , Citoesqueleto de Actina/metabolismo , Agave/citologia , Agave/metabolismo , Endosperma/citologia , Endosperma/metabolismo , Mitose , Células Vegetais/metabolismo
14.
Bioresour Technol ; 283: 251-260, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30913433

RESUMO

Continuous hydrogen (H2) production from individual (Stonezyme, IH) and binary (Celluclast-Viscozyme, BH) enzymatic hydrolysates of agave bagasse was evaluated in continuous stirred-tank reactors (CSTR) and trickling bed reactors (TBR). The volumetric H2 production rates (VHPR) in CSTR were 13 and 2.25 L H2/L-d with BH and IH, respectively. Meanwhile, VHPR of 5.76 and 2.0 L H2/L-d were obtained in the TBR configuration using BH and IH, respectively. Differences on VHPR between reactors could be explained by substrate availability, which is intrinsic to the growth mode of each reactor configuration; while differences of VHPR between hydrolysates were possibly related to the composition of enzymatic hydrolysates. Furthermore, homoacetogenesis was strongly influenced by H2 and substrate transfer conditions. Considering VHPR, H2 yields, and costs of hydrolysis, hydrogen production from binary hydrolysates of agave bagasse was identified as the most promising alternative evaluated with scale-up potential for the production of energy biofuels.


Assuntos
Agave/metabolismo , Biofilmes , Celulose/metabolismo , Hidrogênio/metabolismo , Biocombustíveis , Fermentação , Hidrólise
15.
J Appl Microbiol ; 126(5): 1618-1630, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30803104

RESUMO

AIMS: The purpose of this study was to apply cDNA approach for the characterization of active prokaryotic community to understand microbial scenarios and performance of an AnSBR digester fed with acid hydrolysates of Agave tequilana var. azul bagasse (ATAB). METHODS AND RESULTS: The digester was implemented for methane production under organic loading rate (OLR) disturbances to correlate physicochemical variables with changes in abundance, diversity and population dynamics of active Bacteria and Archaea by principal components analysis (PCA). Results indicated that methane yield increased as well as active syntrophic relationships for interspecies hydrogen/formate (Anaerolinaceae-Methanobacterium beijingense) and acetate (Anaerolinaceae-Methanosaeta concilii) transfers at 8 g-COD l-1  day-1 . However, methane yield was negatively affected at 16 g-COD l-1  day-1 due to the competition for acetate by active Desulfovibrio marrakechensis and volatile fatty acids inhibition. CONCLUSIONS: Microbial scenarios obtained by PCA correlations indicated that methane production from acid hydrolysates of ATAB was feasible at 8 g-COD l-1  day-1 . The digester operation at higher OLR only favoured methanogenesis by the hydrogenotrophic pathway. SIGNIFICANCE AND IMPACT OF THE STUDY: Only cDNA analysis showed Archaea population dynamics, exhibiting high correlation with physicochemical variables towards the understanding of the methanogenic digester performance during OLR disturbances.


Assuntos
Agave , Archaea/metabolismo , Bactérias/metabolismo , Reatores Biológicos/microbiologia , Metano , Agave/química , Agave/metabolismo , Metano/análise , Metano/metabolismo
16.
Bioresour Technol ; 276: 74-80, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30611089

RESUMO

The aim of this work was to compare the biohydrogen production potential of undetoxified and detoxified acid hydrolysates from A. tequilana bagasse. Detoxification was carried out with activated carbon at different concentrations and pH values. Results indicated that pH was not a significant variable, while the lowest evaluated concentration of activated carbon (1% p/v) significantly promoted the highest removal of acetic acid (89%) with minimal losses of fermentable sugars. Regarding dark fermentation experiments, central composite designs were used to optimize COD and pH variables for both substrates, undetoxified and detoxified hydrolysates (activated carbon 1% p/v and pH 0.6). At optimal conditions, the detoxified hydrolysate produced 33% more biohydrogen than the undetoxified one. Hydrogen molar yields were 1.71 and 1.23 mol H2/molsugar, respectively. This improvement was correlated to changes in metabolic byproducts, since the detoxified hydrolysate produced only acetic and butyric acids, while lactic acid was detected in the undetoxified hydrolysate.


Assuntos
Ácidos/química , Agave/metabolismo , Celulose/metabolismo , Hidrogênio/metabolismo , Ácido Acético/metabolismo , Fermentação , Hidrólise , Inativação Metabólica
17.
Bioresour Technol ; 275: 410-415, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30605828

RESUMO

In this work, three Clostridium strains were tested for butanol production from Agave lechuguilla hydrolysates to select one for co-culturing. The agave hydrolysates medium was supplemented with nutrients and reducing agents to promote anaerobiosis. Clostridium acetobutylicum ATCC 824 had the highest butanol production (6.04 g/L) and was selected for further analyses. In the co-culture process, Bacillus subtilis CDBB 555 was used to deplete oxygen and achieve anaerobic conditions required for butanol production. The co-culture was prepared with C. acetobutylicum and B. subtilis without anaerobic pretreatment. Butanol production in co-culture from agave hydrolysates was compared with experiments using synthetic medium with glucose and a pure culture of C. acetobutylicum. The maximum butanol concentration obtained was 8.28 g/L in the co-cultured hydrolysate medium. Results obtained in the present work demonstrated that agave hydrolysates have the potential for butanol production using a co-culture of B. subtilis and C. acetobutylicum without anaerobic pretreatment.


Assuntos
Agave/metabolismo , Bacillus subtilis/metabolismo , Butanóis/metabolismo , Clostridium acetobutylicum/metabolismo , Anaerobiose , Técnicas de Cocultura , Fermentação
18.
Sci Rep ; 9(1): 396, 2019 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-30674899

RESUMO

Agave, monocotyledonous succulent plants, is endemic to arid regions of North America, exhibiting exceptional tolerance to their xeric environments. They employ various strategies to overcome environmental constraints, such as crassulacean acid metabolism, wax depositions, and protective leaf morphology. Genomic resources of Agave species have received little attention irrespective of their cultural, economic and ecological importance, which so far prevented the understanding of the molecular bases underlying their adaptations to the arid environment. In this study, we aimed to elucidate molecular mechanism(s) using transcriptome sequencing of A. sisalana. A de novo approach was applied to assemble paired-end reads. The expression study unveiled 3,095 differentially expressed unigenes between well-irrigated and drought-stressed leaf samples. Gene ontology and KEGG analysis specified a significant number of abiotic stress responsive genes and pathways involved in processes like hormonal responses, antioxidant activity, response to stress stimuli, wax biosynthesis, and ROS metabolism. We also identified transcripts belonging to several families harboring important drought-responsive genes. Our study provides the first insight into the genomic structure of A. sisalana underlying adaptations to drought stress, thus providing diverse genetic resources for drought tolerance breeding research.


Assuntos
Agave , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Estresse Fisiológico , Transcriptoma , Agave/genética , Agave/metabolismo , Desidratação/genética , Desidratação/metabolismo
19.
Bioresour Technol ; 272: 26-33, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30308404

RESUMO

To develop a cost-effective, time-saving and efficient saccharification system for converting biomass into mono-/oligo-saccharides for production of bioethanol or other biochemicals, a relatively low recalcitrant and widely available biomass Agave americana was selected as feedstock. During the investigation of efficient enzyme cocktail, pectinase, which usually is neglect for biomass saccharification, was confirmed that it dramatically improves the saccharification of agave biomass. A production-friendly fungal strain of Aspergillus niger Gyx086 was employed for low-cost enzyme cocktails production using wheat straw as substance. The enzyme cocktail which was with hyperactive pectinase activity of 6.29 ±â€¯0.42 U/ml could efficiently saccharify un-pretreated agave biomasses. As a result, under a mild condition at 35 °C in less than 72 h, most of the polysaccharides were completely converted into reducing sugar. The low-cost, process-simplified, and efficient biotechnology should stimulate the development of agave as feedstock for green energy and bio-based products production.


Assuntos
Agave/metabolismo , Aspergillus niger/enzimologia , Biomassa , Hidrólise , Poligalacturonase/metabolismo
20.
Plant Cell Environ ; 42(4): 1368-1380, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30378133

RESUMO

The plant microbiota can affect host fitness via the emission of microbial volatile organic compounds (mVOCs) that influence growth and development. However, evidence of these molecules and their effects in plants from arid ecosystems is limited. We screened the mVOCs produced by 40 core and representative members of the microbiome of agaves and cacti in their interaction with Arabidopsis thaliana and Nicotiana benthamiana. We used SPME-GC-MS to characterize the chemical diversity of mVOCs and tested the effects of selected compounds on growth and development of model and host plants. Our study revealed that approximately 90% of the bacterial strains promoted plant growth both in A. thaliana and N. benthamiana. Bacterial VOCs were mainly composed of esters, alcohols, and S-containing compounds with 25% of them not previously characterized. Remarkably, ethyl isovalerate, isoamyl acetate, 3-methyl-1-butanol, benzyl alcohol, 2-phenylethyl alcohol, and 3-(methylthio)-1-propanol, and some of their mixtures, displayed beneficial effects in A. thaliana and also improved growth and development of Agave tequilana and Agave salmiana in just 60 days. Volatiles produced by bacteria isolated from agaves and cacti are promising molecules for the sustainable production of crops in arid and semi-arid regions.


Assuntos
Agave/metabolismo , Arabidopsis/metabolismo , Microbiota , Tabaco/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Agave/crescimento & desenvolvimento , Agave/microbiologia , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/microbiologia , Clorofila/metabolismo , Clima Desértico , Cromatografia Gasosa-Espectrometria de Massas , Raízes de Plantas/crescimento & desenvolvimento , Brotos de Planta/crescimento & desenvolvimento , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Plântula/microbiologia , Tabaco/crescimento & desenvolvimento , Tabaco/microbiologia
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