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1.
Food Chem ; 368: 130822, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34411853

RESUMO

Lei bamboo (Phyllostachys violascens) shoots are delicious food in Asia. Here, the molecular basis of lignification in postharvest Lei bamboo shoots under low temperature (LT) is revealed by transcriptomic and metabolomics analyses for the first time. We identified substantial accumulations of jasmonates (JAs) and major lignin biosynthesis precursors (coumarin, trans-4-coumaric acid, trans-ferulic acid and L-phenylalanine). Transcriptome analysis indicated that some regulatory genes were significantly differentially expressed, and the expression patterns of them were highly consistent with the changes in the key lignin precursors or JA profiles. Co-expression analysis showed that the LT responsive genes PvCRPK-4/-5, PvICE2-1/2, PvDREB2B might form a network module with the lignin (PvC3H-2/3, PvC4H-2/4, PvCAD-1/2/3/4, etc.) or JA biosynthesis genes (PvOPR2, PvJAZ-4 and PvPEX5, etc.), indicating a LT-lignification or LT-JA-lignification regulatory pathway in Lei bamboo shoots. Above all, our findings provide new an insight into the LT-associated lignification in postharvest bamboo shoots.


Assuntos
Redes Reguladoras de Genes , Transcriptoma , Regulação da Expressão Gênica de Plantas , Lignina/metabolismo , Metabolômica , Temperatura
2.
Phys Chem Chem Phys ; 23(37): 20919-20935, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34541592

RESUMO

Computational studies on the pyrolysis of lignin using electronic structure methods have been largely limited to dimeric or trimeric models. In the current work we have modeled a lignin oligomer consisting of 10 syringyl units linked through 9 ß-O-4' bonds. A lignin model of this size is potentially more representative of the polymer in angiosperms; therefore, we used this representative model to examine the behavior of hardwood lignin during the initial steps of pyrolysis. Using this oligomer, the present work aims to determine if and how the reaction enthalpies of bond cleavage vary with positions within the chain. To accomplish this, we utilized a composite method using molecular mechanics based conformational sampling and quantum mechanically based density functional theory (DFT) calculations. Our key results show marked differences in bond dissociation enthalpies (BDE) with the position. In addition, we calculated standard thermodynamic properties, including enthalpy of formation, heat capacity, entropy, and Gibbs free energy for a wide range of temperatures from 25 K to 1000 K. The prediction of these thermodynamic properties and the reaction enthalpies will benefit further computational studies and cross-validation with pyrolysis experiments. Overall, the results demonstrate the utility of a better understanding of lignin pyrolysis for its effective valorization.


Assuntos
Lignina/química , Celulose/química , Celulose/metabolismo , Teoria da Densidade Funcional , Lignina/metabolismo , Conformação Molecular , Pressão , Pirólise , Temperatura , Termodinâmica
3.
J Environ Manage ; 300: 113684, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34509817

RESUMO

Biomethanation potential of lignin rich residue (LRR) obtained from lignocellulosic ethanol fermentation was evaluated after subjecting to microbe assisted pretreatment using selectively enriched lignin depolymerizing consortia (LDC). The efficiency of LDC in lignin depolymerization was established using alkali and dealkali lignins (AL and DL) along with LRR as feedstocks. Microbial growth on media having lignin as sole carbon source, activity of lignin depolymerizing enzymes, viz., lignin peroxidase and laccase, ability of culture to decolorize the lignin mimicking dyes like methylene blue and ramezol brilliant blue, were considered to confirm the efficiency of enriched mixed culture. Microbial treatment using LDC showed significant positive impact on lignin breakdown irrespective of the substrate (LRR, 46.33%; AL, 31.37%; DL, 34.20%). The hydrolysate of LRR obtained from microbial pretreatment showed higher biogas yield (424 ml/g VS) owing to the efficiency of lignin depolymerization and availability of readily available biodegradable components in residual lignin from previous processing. Depolymerization of commercial lignins also produced a good amount of biogas (302-324 ml/g VS) after pretreatment with LDC. Overall, an additional energy conversion efficiency of about 11.75 kJ/g VS was obtained by valorizing the residual lignin through integrating biomethanation technology to ethanol fermentation. Outcome of this study indicated the feasibility of using lignin rich residue generated from the second generation cellulosic bioethanol plants as a potential feedstock to meet the current gaseous fuel demands. This integration also helps in closing the biomass based biorefinery loop and also promotes the circular economy.


Assuntos
Biocombustíveis , Lignina , Biomassa , Fermentação , Gases , Lignina/metabolismo
4.
Bioresour Technol ; 340: 125709, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34375790

RESUMO

The characterized microbial consortium can efficiently degrade rice straw to produce acetic and butyric acids in high yields. The rice straw lost 86.9% in weight and degradation rates of hemicellulose, cellulose, and lignin attained were 97.1%, 86.4% and 70.3% within 12 days, respectively. During biodegradation via fermentation of rice straw, average concentrations of acetic and butyric acids reached 1570 mg/L and 1270 mg/L, accounting for 47.2% and 35.4% of the total volatile fatty acids, respectively. The consortium mainly composed of Prevotella, Cellulosilyticum, Pseudomonas, Clostridium and Ruminococcaceae, etc. Metagenomic analyses indicated that glycoside hydrolases (GHs) were the largest enzyme group with a relative abundance of 54.5%. Various lignocellulose degrading enzymes were identified in the top 30 abundant GHs, and were primarily distributed in the dominant genera (Prevotella, Cellulosilyticum and Clostridium). These results provide a new route for the commercial recycling of rice straw to produce organic acids.


Assuntos
Consórcios Microbianos , Oryza , Butiratos , DNA Ribossômico , Fermentação , Lignina/metabolismo , Metagenoma , Oryza/metabolismo
5.
Plant Physiol Biochem ; 167: 245-256, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34385003

RESUMO

Plant class III peroxidases (CIII Prxs) are involved in numerous essential plant life processes, such as plant development and differentiation, lignification and seed germination, and defence against pathogens. However, there is limited information about the structure-function relationships of Prxs in carrots. This study identified 75 carrot peroxidases (DcPrxs) and classified them into seven subgroups based on phylogenetic analysis. Gene structure analysis revealed that these DcPrxs had between one and eight introns, while conserved motif analysis showed a typical motif composition and arrangement for CIII Prx. In addition, eighteen tandem duplication events, but only eight segmental duplications, were identified among these DcPrxs, indicating that tandem duplication was the main contributor to the expansion of this gene family. Histochemical analyses showed that lignin was mainly localised in the cell walls of xylem, and Prx activity was determined in the epidermal region of taproots. The xylem always showed higher lignin concentration and lower Prx activity compared to the phloem in the taproots of both carrot cultivars. Combining these observations with RNA sequencing, some Prx genes were identified as candidate genes related to lignification and pigmentation. Three peroxidases (DcPrx30, DcPrx32, DcPrx62) were upregulated in the phloem of both genotypes. Carrot taproots are an attractive resource for natural food colourants and this study elucidated genome-wide insights of Prx for the first time, developing hypotheses concerning their involvement with lignin and anthocyanin in purple carrots. The findings provide an essential foundation for further studies of Prx genes in carrot, especially on pigmentation and lignification mechanisms.


Assuntos
Antocianinas/metabolismo , Daucus carota , Lignina , Peroxidase , Daucus carota/enzimologia , Daucus carota/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Lignina/metabolismo , Família Multigênica , Peroxidase/genética , Peroxidase/metabolismo , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
6.
J Environ Manage ; 298: 113539, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34426215

RESUMO

Lignocellulosic energy crops are promising feedstocks for producing renewable fuels, such as methane, that can replace diminishing fossil fuels. However, there is a major handicap in using lignocellulosic sources to produce biofuels, which is their low biodegradability. In this study, the application and the optimization of a lignocellulose pretreatment process, named alkaline hydrogen peroxide, was investigated for the enhancement of methane production from the energy crop switchgrass. Four independent process variables, solid content (3-7%), reaction temperature (50-100 °C), H2O2 concentration (1-3%), and reaction time (6-24 h), and three response variables, soluble reducing sugar, soluble chemical oxygen demand, and biochemical methane potential were used in process optimization and modeling. The optimization was performed by two different approaches as maximum methane production and cost minimization. The optimum conditions for the highest methane production were found as 6.65 wt% solid content, 50.6 °C reaction temperature, 2.94 wt% H2O2 concentration, and 16.05 h reaction time. The conditions providing the lowest cost were 6.43 wt% solid content, 50 °C reaction temperature, 1.83 wt% H2O2 concentration, and 6.78 h reaction time. For maximum methane production and cost minimization, specific methane yields of 338.52 mL CH4/g VS and 291.34 mL CH4/g VS were predicted with 62.4 % and 39.8 % enhancements compared to untreated switchgrass, respectively. Finally, it was found that the predicted methane production for the maximum methane production represents 77 % of the theoretical methane yield and 82.22 % energy recovery.


Assuntos
Peróxido de Hidrogênio , Lignina , Anaerobiose , Biocombustíveis , Biomassa , Lignina/metabolismo , Metano
7.
Bioresour Technol ; 341: 125815, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34454234

RESUMO

To solve the central problems caused by traditional composting treatments, such as long-time consumption and poor regulation effects, this study used three fermentation methods and four enzymes to develop rapid and directional regulation methods to convert wheat straw into a suitable substrate. The results showed that the mixed anaerobic method led to better pH (4.39-5.75) and EC values (1.27-1.89 mS/cm) in the straw substrates, while the aerobic method retained more nutrients and increased lignin and cellulose contents by 5.07-8.04% and 1.52-3.32%. The cellulase mixed with hemicellulase or laccase treatments all increased the crystallinity by 0.45-7.23%. The TG/DTG results showed that all treatments decreased the initial straw glass transition temperature, particularly when using the mixed anaerobic method, with decreases of 10.63-25.48 °C. Overall, mixed anaerobic fermentation and multiple enzymes, including cellulase, have been suggested as alternative biological modification methods for straw substrates.


Assuntos
Celulase , Triticum , Celulase/metabolismo , Fermentação , Lignina/metabolismo , Solo , Triticum/metabolismo
8.
J Agric Food Chem ; 69(35): 10069-10081, 2021 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-34410120

RESUMO

Many studies have shown that phenolic compounds such as lignin and flavonoids enhance plant resistance. Tea plants are rich in flavonoid compounds. Whether these compounds are related to tea plant resistance is unclear. In this study, an interesting conclusion was drawn on the basis of experimental results: in response to abiotic stress (except for sucrose treatment), gene expression was increased in the phenylpropanoid and lignin pathways and was reduced in the flavonoid pathway in tea plants. CsHCTs, the genes located at the branch point of the lignin and flavonoid pathways, are most suitable for regulating the ratio of carbon flow in the lignin pathway and flavonoid synthesis. Enzymatic and genetic modification experiments proved that CsHCTs encode hydroxycinnamoyl-coenzyme A:shikimate/quinate hydroxycinnamoyl transferase in vitro and in vivo. Furthermore, the genetic modification results showed that the contents of phenolic acids and lignin were increased in tobacco and Arabidopsis plants overexpressing CsHCTs, whereas the content of flavonol glycosides was decreased. Both types of transgenic plants showed resistance to many abiotic stresses and bacterial infections. We speculate that CsHCTs participate in regulation of the metabolic flow of carbon from the flavonoid pathway to the chlorogenic acid, caffeoylshikimic acid, and lignin pathways to increase resistance to biotic and abiotic stresses.


Assuntos
Arabidopsis , Camellia sinensis , Arabidopsis/genética , Arabidopsis/metabolismo , Camellia sinensis/metabolismo , Regulação da Expressão Gênica de Plantas , Lignina/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Estresse Fisiológico , Chá
9.
Physiol Plant ; 173(3): 961-977, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34237150

RESUMO

Paeonia is recognized globally due to its ornamental value. However, the mechanisms behind the formation of distinct levels of lignification in Paeonia stems remain largely unknown. In this study, we selected three representative Paeonia species, namely P. ostii (shrub), P. lactiflora (herb), and P. × 'Hexie' (semi-shrub), to evaluate and contrast their respective anatomical structure, phytochemical composition and transcriptomic profile. Our results showed that the degree of lignin deposition on the cell wall, along with the total amount of lignin and its monomers (especially G-lignin) were higher in P. ostii stems compared to the other two species at almost all development stages except 80 days after flowering. Furthermore, we estimated a total number of unigenes of 60,238 in P. ostii, 43,563 in P. × 'Hexie', and 40,212 in P. lactiflora from stem transcriptome. We then built a co-expression network of 25 transcription factors and 21 enzyme genes involved in lignin biosynthesis and identified nine key candidate genes. The expression patterns of these genes were positively correlated with the transcription levels of PAL, C4H, 4CL2, CCR, and COMT, as well as lignin content. Moreover, the highest relative expression levels of CCR, 4CL2, and C4H were found in P. ostii. This study provides an explanation for the observed differences in lignification between woody and herbaceous Paeonia stems, and constitutes a novel reference for molecular studies of stem-specific lignification process and lignin biosynthesis that can impact the ornamental industry.


Assuntos
Paeonia , Parede Celular/genética , Parede Celular/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Lignina/metabolismo , Paeonia/genética , Paeonia/metabolismo , Transcriptoma/genética
10.
Microb Biotechnol ; 14(5): 2140-2151, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34310858

RESUMO

Fungal laccases are attracting enzymes for sustainable valorization of biorefinery lignins. To improve the lignin oxidation capacity of two previously characterized laccase isoenzymes from the white-rot fungus Obba rivulosa, we mutated their substrate-binding site at T1. As a result, the pH optimum of the recombinantly produced laccase variant rOrLcc2-D206N shifted by three units towards neutral pH. O. rivulosa laccase variants with redox mediators oxidized both the dimeric lignin model compound and biorefinery poplar lignin. Significant structural changes, such as selective benzylic α-oxidation, were detected by nuclear magnetic resonance analysis, although no polymerization of lignin was observed by gel permeation chromatography. This suggests that especially rOrLcc2-D206N is a promising candidate for lignin-related applications.


Assuntos
Lacase , Polyporales , Fungos/metabolismo , Lacase/genética , Lacase/metabolismo , Lignina/metabolismo , Oxirredução , Polyporales/metabolismo
11.
Bioresour Technol ; 340: 125632, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34332440

RESUMO

Dairy manure subjected to four pretreatments (acid, alkaline, sulfite (SPORL), alkaline hydrogen peroxide (AHP)) at high chemical dosages (termed severe conditions) were evaluated for enhancements in biogas production and inhibitory effects due to concomitant generation of furan byproducts. All four pretreatments enhanced solubilization of carbohydrates, but only alkaline and AHP resulted in higher methane yield (356 and 333 mL/g-VS, respectively) relative to moderate pretreatment conditions (311 and 261 mL/g-VS, respectively). Methane yield of severe-SPORL pretreatment (233 mL/g-VS) was greater than that of untreated manure (116 mL/g-VS), but lower than that of moderate-SPORL (353 mL/g-VS). Severe-acid pretreatment showed early termination in biogas production likely due to inhibitory effects of furfural and 5-hydroxymethyl furfural. Both experimental data and kinetic modeling indicated that severe-acid pretreatment led to degradation of carbohydrates to furfural, which reduced biogas production due to direct toxicity rather than competitive inhibitory effects. Pretreatment conditions (severity and byproduct levels) for dairy manure biomass may be optimized based on the current findings.


Assuntos
Lignina , Esterco , Anaerobiose , Biocombustíveis , Lignina/metabolismo , Metano
12.
Int J Mol Sci ; 22(14)2021 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-34299234

RESUMO

Brassinosteroids (BRs) are known to be essential regulators for wood formation in herbaceous plants and poplar, but their roles in secondary growth and xylem development are still not well-defined, especially in pines. Here, we treated Pinus massoniana seedlings with different concentrations of exogenous BRs, and assayed the effects on plant growth, xylem development, endogenous phytohormone contents and gene expression within stems. Application of exogenous BR resulted in improving development of xylem more than phloem, and promoting xylem development in a dosage-dependent manner in a certain concentration rage. Endogenous hormone determination showed that BR may interact with other phytohormones in regulating xylem development. RNA-seq analysis revealed that some conventional phenylpropanoid biosynthesis- or lignin synthesis-related genes were downregulated, but the lignin content was elevated, suggesting that new lignin synthesis pathways or other cell wall components should be activated by BR treatment in P. massoniana. The results presented here reveal the foundational role of BRs in regulating plant secondary growth, and provide the basis for understanding molecular mechanisms of xylem development in P. massoniana.


Assuntos
Brassinosteroides/farmacologia , Pinus/metabolismo , Xilema/metabolismo , Brassinosteroides/metabolismo , Parede Celular/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Lignina/metabolismo , Floema/efeitos dos fármacos , Floema/metabolismo , Pinus/crescimento & desenvolvimento , Reguladores de Crescimento de Plantas/metabolismo , Reguladores de Crescimento de Plantas/farmacologia , Proteínas de Plantas/genética , Plântula/crescimento & desenvolvimento , Plântula/metabolismo , Madeira/genética , Xilema/efeitos dos fármacos , Xilema/crescimento & desenvolvimento
13.
Int J Mol Sci ; 22(12)2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34207287

RESUMO

Gastrodia elata is a well-known medicinal and heterotrophic orchid. Its germination, limited by the impermeability of seed coat lignin and inhibition by abscisic acid (ABA), is triggered by symbiosis with fungi such as Mycena spp. However, the molecular mechanisms of lignin degradation by Mycena and ABA biosynthesis and signaling in G. elata remain unclear. In order to gain insights into these two processes, this study analyzed the transcriptomes of these organisms during their dynamic symbiosis. Among the 25 lignin-modifying enzyme genes in Mycena, two ligninolytic class II peroxidases and two laccases were significantly upregulated, most likely enabling Mycena hyphae to break through the lignin seed coats of G. elata. Genes related to reduced virulence and loss of pathogenicity in Mycena accounted for more than half of annotated genes, presumably contributing to symbiosis. After coculture, upregulated genes outnumbered downregulated genes in G. elata seeds, suggesting slightly increased biological activity, while Mycena hyphae had fewer upregulated than downregulated genes, indicating decreased biological activity. ABA biosynthesis in G. elata was reduced by the downregulated expression of 9-cis-epoxycarotenoid dioxygenase (NCED-2), and ABA signaling was blocked by the downregulated expression of a receptor protein (PYL12-like). This is the first report to describe the role of NCED-2 and PYL12-like in breaking G. elata seed dormancy by reducing the synthesis and blocking the signaling of the germination inhibitor ABA. This study provides a theoretical basis for screening germination fungi to identify effective symbionts and for reducing ABA inhibition of G. elata seed germination.


Assuntos
Ácido Abscísico/metabolismo , Agaricales/patogenicidade , Proteínas Fúngicas/genética , Gastrodia/microbiologia , Lignina/metabolismo , Proteínas de Plantas/genética , Agaricales/genética , Agaricales/metabolismo , Dioxigenases/genética , Dioxigenases/metabolismo , Proteínas Fúngicas/metabolismo , Gastrodia/genética , Gastrodia/crescimento & desenvolvimento , Gastrodia/metabolismo , Germinação , Lacase/genética , Lacase/metabolismo , Lignina/genética , Peroxidases/genética , Peroxidases/metabolismo , Proteínas de Plantas/metabolismo , Simbiose , Transcriptoma
14.
Commun Biol ; 4(1): 871, 2021 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-34267314

RESUMO

Fungal biotechnology is set to play a keystone role in the emerging bioeconomy, notably to address pollution issues arising from human activities. Because they preserve biological diversity, Biological Resource Centres are considered as critical infrastructures to support the development of biotechnological solutions. Here, we report the first large-scale phenotyping of more than 1,000 fungal strains with evaluation of their growth and degradation potential towards five industrial, human-designed and recalcitrant compounds, including two synthetic dyes, two lignocellulose-derived compounds and a synthetic plastic polymer. We draw a functional map over the phylogenetic diversity of Basidiomycota and Ascomycota, to guide the selection of fungal taxa to be tested for dedicated biotechnological applications. We evidence a functional diversity at all taxonomic ranks, including between strains of a same species. Beyond demonstrating the tremendous potential of filamentous fungi, our results pave the avenue for further functional exploration to solve the ever-growing issue of ecosystems pollution.


Assuntos
Biotecnologia/métodos , Corantes/metabolismo , Fungos/metabolismo , Microbiologia Industrial/métodos , Lignina/metabolismo , Plásticos/metabolismo , Ascomicetos/classificação , Ascomicetos/genética , Ascomicetos/metabolismo , Basidiomycota/classificação , Basidiomycota/genética , Basidiomycota/metabolismo , Fungos/classificação , Fungos/genética , Variação Genética , Geografia , Humanos , Fenótipo , Filogenia , Especificidade da Espécie
15.
Bioresour Technol ; 339: 125596, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34298246

RESUMO

Dewaxing effects on the pretreatment, saccharification and fermentation are rarely reported due to the low abundance of wax in lignocellulose. This study aimed to investigate the effect of wax removal on saccharification and ethanol yield from lignocellulose by using Rice straw (RS), Napier grass (NG), and sugarcane bagasse (SB). The wax contents of 0.56%, 1.7%, and 0.6% were obtained from RS, NG and SB after the wax extraction, respectively. The alkaline pretreatment was applied in combination with dewaxing to decipher the synergistic effect of these treatments. Dewaxing and alkaline pretreatment of lignocellulosic biomass showed changes in the plant compositions. Removal of wax from RS, NG and SB showed significant changes in the surface morphology and functional groups. A higher yield of sugars and ethanol was observed in dewaxed and alkaline pretreated samples. The ethanol yields of 75.4%, 89.85%, and 74% from RS, NG, and SB were obtained after fermentation, respectively.


Assuntos
Etanol , Lignina , Biomassa , Fermentação , Hidrólise , Lignina/metabolismo
16.
Bioresour Technol ; 338: 125521, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34273631

RESUMO

This study aims to explore distinct bacterial strains from wood-feeding termites and to construct novel bacterial consortium for improving the methane yield during anaerobic digestion by degrading birchwood sawdust (BSD) and removing creosote (CRO) compounds simultaneously. A novel bacterial consortium CTB-4 which stands for the molecularly identified species Burkholderia sp., Xanthomonas sp., Shewanella sp., and Pseudomonas mosselii was successfully developed. The CTB-4 consortium showed high efficiency in the removal of naphthalene and phenol. It also revealed reduction in lignin, hemicellulose, and cellulose by 19.4, 52.5, and 76.8%, respectively. The main metabolites after the CRO degradation were acetic acid, succinate, pyruvate, and acetaldehyde. Pretreatment of treated BSD mixed with CRO enhanced the total methane yield (162 L/kg VS) by 82.7% and biomass reduction by 54.7% compared to the untreated substrate. CRO showed a toxicity decrease of >90%, suggesting the efficiency of constructed bacterial consortia in bioremediation and biofuel production.


Assuntos
Isópteros , Madeira , Anaerobiose , Animais , Bactérias/genética , Bactérias/metabolismo , Biodegradação Ambiental , Biocombustíveis/análise , Creosoto , Lignina/metabolismo , Metano , Consórcios Microbianos , Pseudomonas , Madeira/química
17.
J Plant Physiol ; 263: 153462, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34225178

RESUMO

Bacillus subtilis is one of the non-pathogenic beneficial bacteria that promote plant growth and stress tolerance. In the present study, we revealed that seed priming with endophytic B. subtilis (strains 10-4, 26D) improved Phaseolus vulgaris L. (common bean) seed germination and plant growth under both saline and non-saline conditions. 10-4 and 26D decreased oxidative and osmotic damage to the plant cells since bacterial inoculations reduced lipid peroxidation and proline accumulation in plants under salinity. 26D and especially 10-4 preserved different elevated levels of chlorophyll (Chl) a and Chl b in bean leaves under salinity, while carotenoids (Car) increased only by 10-4 and slightly decreased by 26D. Under normal conditions, 10-4 and 26D did not affect Chl a and Car concentrations, while Chl b decreased in the same plants. Under non-saline and especially saline conditions, 10-4 and 26D significantly increased lignin accumulation in plant roots and the highest lignin content along with better growth and oxidative damages reduction was observed after 10-4 inoculation under salinity, indicating a major role of B. subtilis-induced strengthening the root cell walls in the implementation protective effect of studied bacteria on plants. Therefore, B. subtilis 10-4 and 26D exerts protective effects on the growth of common bean plants under salinity by regulating plant defense mechanisms and the major role in tolerance development may contribute through the activation by B. subtilis lignin deposition in roots. The obtained data also indicates a strain-dependent efficiency of endophytic B. subtilis since strains 10-4 and 26D differently improved growth attributes and modulates cellular response reactions of the same common bean plants both under normal and salinity conditions, that generates interest for further investigations in this direction.


Assuntos
Bacillus subtilis/patogenicidade , Germinação/fisiologia , Lignina/metabolismo , Phaseolus/crescimento & desenvolvimento , Phaseolus/microbiologia , Desenvolvimento Vegetal/fisiologia , Raízes de Plantas/metabolismo , Produtos Agrícolas/crescimento & desenvolvimento , Produtos Agrícolas/microbiologia , Endófitos/patogenicidade , Estresse Oxidativo/fisiologia , Federação Russa , Salinidade , Tolerância ao Sal/fisiologia , Estresse Fisiológico/fisiologia
18.
Bioresour Technol ; 337: 125487, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34320766

RESUMO

A Saccharomyces cerevisiae strain CCW12OE was constructed by overexpressing CCW12 in a previously reported strain WXY70 harboring six xylose utilization genes. CCW12OE produced an optimal ethanol yield of 98.8% theoretical value within 48 h in a simulated corn stover hydrolysate. CCW12OEwas comprehensively evaluated for ethanol production in Miscanthus, maize and corncob hydrolysates, among which a 96.1% theoretical value was achieved within 12 h in corncob hydrolysates. Under normal growth conditions, CCW12OE did not display altered cell morphology; however, in the presence of acetate, CCW12OE maintained relatively intact cell structure and increased cell wall thickness by nearly 50%, while WXY70 had abnormal cell morphology and reduced cell wall thickness by nearly 50%. Besides, CCW12OE had higher fermentation capacity than that of WXY70 in undetoxified and detoxified hydrolysates with both aerobic and anaerobic conditions, demonstrating that CCW12 overexpression alone exhibits improved stress resistance and better fermentation performance.


Assuntos
Etanol , Saccharomyces cerevisiae , Fermentação , Lignina/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Xilose
19.
Fungal Biol ; 125(7): 560-575, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34140152

RESUMO

The increased availability and production of lignocellulosic agroindustrial wastes has originated proposals for their use as raw material to obtain biofuels (ethanol and biodiesel) or derived products. However, for biomass generated from lignocellulosic residues to be successfully degraded, in most cases it requires a physical (thermal), chemical, or enzymatic pretreatment before the application of microbial or enzymatic fermentation technologies (biocatalysis). In the context of enzymatic technologies, fungi have demonstrated to produce enzymes capable of degrading polysaccharides like cellulose, hemicelluloses and pectin. Because of this ability for degrading lignocellulosic material, researchers are making efforts to isolate and identify fungal enzymes that could have a better activity for the degradation of plant cell walls and agroindustrial biomass. We performed an in silico analysis of alpha-glucoronidase in 82 accessions of the genus Aspergillus. The constructed dendrograms of amino acid sequences defined the formation of 6 groups (I, II, III, IV, V, and VI), which demonstrates the high diversity of the enzyme. Despite this ample divergence between enzyme groups, our 3D structure modeling showed both conservation and differences in amino acid residues participating in enzyme-substrate binding, which indicates the possibility that some enzymes are functionally specialized for the specific degradation of a substrate depending on the genetics of each species in the genus and the condition of the habitat where they evolved. The identification of alpha-glucuronidase isoenzymes would allow future use of genetic engineering and biocatalysis technologies aimed at specific production of the enzyme for its use in biotransformation.


Assuntos
Aspergillus , Glicosídeo Hidrolases , Aspergillus/classificação , Aspergillus/enzimologia , Aspergillus/genética , Fermentação , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Glicosídeo Hidrolases/genética , Lignina/metabolismo , Filogenia , Ligação Proteica
20.
J Hazard Mater ; 418: 126091, 2021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34118544

RESUMO

Lignocellulosic biomass represents an unlimited and ubiquitous energy source, which can effectively address current global challenges, including climate change, greenhouse gas emissions, and increased energy demand. However, lignocellulose recalcitrance hinders microbial degradation, especially in case of contaminated materials such as creosote (CRO)-treated wood, which necessitates appropriate processing in order to eliminate pollution. This study might be the first to explore a novel bacterial consortium SST-4, for decomposing birchwood sawdust, capable of concurrently degrading lignocellulose and CRO compounds. Afterwards, SST-4 which stands for molecularly identified bacterial strains Acinetobacter calcoaceticus BSW-11, Shewanella putrefaciens BSW-18, Bacillus cereus BSW-23, and Novosphingobium taihuense BSW-25 was evaluated in terms of biological sawdust pre-treatment, resulting in effective lignocellulose degradation and 100% removal of phenol and naphthalene. Subsequently, the maximum biogas production observed was 18.7 L/kg VS, while cumulative methane production was 162.8 L/kg VS, compared to 88.5 without microbial pre-treatment. The cumulative energy production from AD-I and AD-II through biomethanation was calculated as 3177.1 and 5843.6 KJ/kg, respectively. The pretreatment process exhibited a significant increase in the energy yield by 83.9%. Lastly, effective CRO detoxification was achieved with EC50 values exceeding 90%, showing the potential for an integrated process of effective contaminated wood management and bioenergy production.


Assuntos
Consórcios Microbianos , Sphingomonadaceae , Anaerobiose , Biocombustíveis/análise , Biomassa , Creosoto , Lignina/metabolismo , Metano , Sphingomonadaceae/metabolismo , Madeira/química
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