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1.
Food Chem ; 336: 127636, 2021 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32805513

RESUMO

Deposition of both lignin and cellulose accompanied by juice sac granulation is widespread in harvested citrus fruit. Hence, measures to suppress postharvest granulation of 'Majiayou' pummelo is of great importance. The fruit was treated with 1.5% chitosan and then stored at room temperature (20 ± 2 °C) for 150 d. As compared to the control fruits, chitosan coating significantly suppressed granulation index and maintained good quality. Chitosan coating inhibited lignification by suppressing the activities and expression levels of lignin synthesis-related enzymes (PAL, CAD and POD). By contrast, chitosan treatment enhanced the activities and expression levels of cell wall degrading enzymes, including PME, PG, Cx, XTH and ß-Gal, which might contribute to the decrease in cellulose. In a nutshell, chitosan coating can effectively suppress juice sac granulation and fruit senescence of pummelo fruits, and play a crucial role in maintaining the cell wall modification.


Assuntos
Parede Celular/efeitos dos fármacos , Quitosana/farmacologia , Citrus/efeitos dos fármacos , Armazenamento de Alimentos , Frutas/efeitos dos fármacos , Parede Celular/química , Parede Celular/metabolismo , Celulose/metabolismo , Citrus/metabolismo , Enzimas/genética , Enzimas/metabolismo , Conservantes de Alimentos/farmacologia , Frutas/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Lignina/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Análise de Componente Principal , Temperatura
2.
Biointerphases ; 15(5): 051008, 2020 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-33105999

RESUMO

A prominent feature of coronaviruses is the presence of a large glycoprotein spike protruding from a lipidic membrane. This glycoprotein spike determines the interaction of coronaviruses with the environment and the host. In this paper, we perform all atomic molecular dynamics simulations of the interaction between the SARS-CoV-2 trimeric glycoprotein spike and surfaces of materials. We considered a material with high hydrogen bonding capacity (cellulose) and a material capable of strong hydrophobic interactions (graphite). Initially, the spike adsorbs to both surfaces through essentially the same residues belonging to the receptor binding subunit of its three monomers. Adsorption onto cellulose stabilizes in this configuration, with the help of a large number of hydrogen bonds developed between cellulose and the three receptor-binding domains of the glycoprotein spike. In the case of adsorption onto graphite, the initial adsorption configuration is not stable and the surface induces a substantial deformation of the glycoprotein spike with a large number of adsorbed residues not pertaining to the binding subunits of the spike monomers.


Assuntos
Betacoronavirus/metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo , Adsorção , Betacoronavirus/isolamento & purificação , Sítios de Ligação , Celulose/química , Celulose/metabolismo , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Grafite/química , Grafite/metabolismo , Humanos , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Simulação de Dinâmica Molecular , Pandemias , Pneumonia Viral/patologia , Pneumonia Viral/virologia , Ligação Proteica , Glicoproteína da Espícula de Coronavírus/química , Propriedades de Superfície
3.
Bioresour Technol ; 318: 124217, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33096440

RESUMO

Myxobacteria are soil microorganisms with the ability to break down biological macromolecules due to the secretion of a large number of extracellular enzymes, but there has been no research report on myxobacterial lytic polysaccharide monooxygenases (LPMOs). In this study, two LPMO10s, ViLPMO10A and ViLPMO10B, from myxobacterium Vitiosangium sp. GDMCC 1.1324 were characterized. Of which, ViLPMO10B is a C1-oxidizing cellulose-active LPMO. Moreover, ViLPMO10B could decrease the degree of polymerization of crop straws cellulose and synergize with commercial cellulase to promote the saccharification. When the weight ratio of commercial cellulase to ViLPMO10B was 9:1, the conversion efficiency of corn stalk, sugarcane bagasse, and rice straw into reducing sugar was improved by 17%, 16%, and 22%, respectively, compared with commercial cellulase without ViLPMO10B. These results indicate that ViLPMO10B has the potential to be a component of a high-efficient cellulase cocktail and has application value in the saccharification of agricultural residual biomasses.


Assuntos
Celulase , Myxococcales , Biomassa , Celulase/metabolismo , Celulose/metabolismo , Produtos Agrícolas/metabolismo , Hidrólise , Myxococcales/metabolismo , Oxirredução
4.
Nat Commun ; 11(1): 4897, 2020 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-32994415

RESUMO

Soil microbial respiration is an important source of uncertainty in projecting future climate and carbon (C) cycle feedbacks. However, its feedbacks to climate warming and underlying microbial mechanisms are still poorly understood. Here we show that the temperature sensitivity of soil microbial respiration (Q10) in a temperate grassland ecosystem persistently decreases by 12.0 ± 3.7% across 7 years of warming. Also, the shifts of microbial communities play critical roles in regulating thermal adaptation of soil respiration. Incorporating microbial functional gene abundance data into a microbially-enabled ecosystem model significantly improves the modeling performance of soil microbial respiration by 5-19%, and reduces model parametric uncertainty by 55-71%. In addition, modeling analyses show that the microbial thermal adaptation can lead to considerably less heterotrophic respiration (11.6 ± 7.5%), and hence less soil C loss. If such microbially mediated dampening effects occur generally across different spatial and temporal scales, the potential positive feedback of soil microbial respiration in response to climate warming may be less than previously predicted.


Assuntos
Carbono/análise , Metagenoma/genética , Microbiota/fisiologia , Microbiologia do Solo , Solo/química , Aclimatação/genética , Archaea/genética , Archaea/isolamento & purificação , Archaea/metabolismo , Bactérias/genética , Bactérias/isolamento & purificação , Bactérias/metabolismo , Carbono/metabolismo , Ciclo do Carbono , Celulose/metabolismo , DNA Ambiental/genética , DNA Ambiental/isolamento & purificação , Fungos/genética , Fungos/isolamento & purificação , Fungos/metabolismo , Aquecimento Global , Pradaria , Temperatura Alta/efeitos adversos , Metagenômica , Modelos Genéticos , Raízes de Plantas/química , Poaceae/química
5.
PLoS One ; 15(8): e0226235, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32797046

RESUMO

Plant-derived fuels and chemicals from renewable biomass have significant potential to replace reliance on petroleum and improve global carbon balance. However, plant biomass contains significant fractions of oligosaccharides that are not usable natively by many industrial microorganisms, including Escherichia coli, Saccharomyces cerevisiae, and Zymomonas mobilis. Even after chemical or enzymatic hydrolysis, some carbohydrate remains as non-metabolizable oligosaccharides (e.g., cellobiose or longer cellulose-derived oligomers), thus reducing the efficiency of conversion to useful products. To begin to address this problem for Z. mobilis, we engineered a strain (Z. mobilis GH3) that expresses a glycosyl hydrolase (GH) with ß-glucosidase activity from a related α-proteobacterial species, Caulobacter crescentus, and subjected it to an adaptation in cellobiose medium. Growth on cellobiose was achieved after a prolonged lag phase in cellobiose medium that induced changes in gene expression and cell composition, including increased expression and extracellular release of GH. These changes were reversible upon growth in glucose-containing medium, meaning they did not result from genetic mutation but could be retained upon transfer of cells to fresh cellobiose medium. After adaptation to cellobiose, our GH-expressing strain was able to convert about 50% of cellobiose to glucose within 24 h and use it for growth and ethanol production. Alternatively, pre-growth of Z. mobilis GH3 in sucrose medium enabled immediate growth on cellobiose. Proteomic analysis of cellobiose- and sucrose-adapted strains revealed upregulation of secretion-, transport-, and outer membrane-related proteins, which may aid release or surface display of GHs, entry of cellobiose into the periplasm, or both. Our two key findings are that Z. mobilis can be reprogrammed to grow on cellobiose as a sole carbon source and that this reprogramming is related to a natural response of Z. mobilis to sucrose that promotes sucrase production.


Assuntos
Celobiose/metabolismo , Zymomonas/crescimento & desenvolvimento , Zymomonas/metabolismo , Adaptação Fisiológica/fisiologia , Biomassa , Reprogramação Celular/genética , Reprogramação Celular/fisiologia , Celulose/metabolismo , Expressão Gênica/genética , Glucose/metabolismo , Hidrolases/metabolismo , Proteômica , Sacarase/metabolismo , Sacarose/metabolismo , Zymomonas/genética , beta-Glucosidase/metabolismo
6.
Proc Natl Acad Sci U S A ; 117(33): 19896-19903, 2020 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-32747547

RESUMO

Cellulose is the most abundant biomass on Earth, and many microorganisms depend on it as a source of energy. It consists mainly of crystalline and amorphous regions, and natural degradation of the crystalline part is highly dependent on the degree of processivity of the degrading enzymes (i.e., the extent of continuous hydrolysis without detachment from the substrate cellulose). Here, we report high-speed atomic force microscopic (HS-AFM) observations of the movement of four types of cellulases derived from the cellulolytic bacteria Cellulomonas fimi on various insoluble cellulose substrates. The HS-AFM images clearly demonstrated that two of them (CfCel6B and CfCel48A) slide on crystalline cellulose. The direction of processive movement of CfCel6B is from the nonreducing to the reducing end of the substrate, which is opposite that of processive cellulase Cel7A of the fungus Trichoderma reesei (TrCel7A), whose movement was first observed by this technique, while CfCel48A moves in the same direction as TrCel7A. When CfCel6B and TrCel7A were mixed on the same substrate, "traffic accidents" were observed, in which the two cellulases blocked each other's progress. The processivity of CfCel6B was similar to those of fungal family 7 cellulases but considerably higher than those of fungal family 6 cellulases. The results indicate that bacteria utilize family 6 cellulases as high-processivity enzymes for efficient degradation of crystalline cellulose, whereas family 7 enzymes have the same function in fungi. This is consistent with the idea of convergent evolution of processive cellulases in fungi and bacteria to achieve similar functionality using different protein foldings.


Assuntos
Proteínas de Bactérias/química , Celulases/química , Cellulomonas/enzimologia , Proteínas Fúngicas/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biocatálise , Evolução Biológica , Celulases/genética , Celulases/metabolismo , Cellulomonas/química , Cellulomonas/genética , Cellulomonas/metabolismo , Celulose/química , Celulose/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Cinética , Microscopia de Força Atômica
7.
Arch Insect Biochem Physiol ; 105(2): e21730, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32737998

RESUMO

The cotton boll weevil, Anthonomus grandis, is a major pest of cotton crops in South America. In this work, partial biochemical characterizations of (hemi) cellulases and pectinases activities in the digestive system (head- and gut- extracts) of A. grandis were evaluated. Gut extract section from third instar larvae exhibited endoglucanase, xylanase, ß-glucosidase, and pectinase activities. The endoglucanase and xylanase activities were localized in the foregut, whereas ß-glucosidase activity was mainly detected in the hindgut. In addition, no difference in pectinase activity was observed across the gut sections. Thus, A. grandis digestive system is a potentially interesting reservoir for further lignocellulolytic enzymes research.


Assuntos
Sistema Digestório/enzimologia , Gorgulhos/enzimologia , Animais , Líquidos Corporais/enzimologia , Celulases/química , Celulose/metabolismo , Sistema Digestório/crescimento & desenvolvimento , Cabeça , Larva/enzimologia , Larva/crescimento & desenvolvimento , Poligalacturonase/química , Gorgulhos/crescimento & desenvolvimento
8.
Proc Natl Acad Sci U S A ; 117(36): 21968-21977, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32839342

RESUMO

Biofuel and bioenergy systems are integral to most climate stabilization scenarios for displacement of transport sector fossil fuel use and for producing negative emissions via carbon capture and storage (CCS). However, the net greenhouse gas mitigation benefit of such pathways is controversial due to concerns around ecosystem carbon losses from land use change and foregone sequestration benefits from alternative land uses. Here, we couple bottom-up ecosystem simulation with models of cellulosic biofuel production and CCS in order to track ecosystem and supply chain carbon flows for current and future biofuel systems, with comparison to competing land-based biological mitigation schemes. Analyzing three contrasting US case study sites, we show that on land transitioning out of crops or pasture, switchgrass cultivation for cellulosic ethanol production has per-hectare mitigation potential comparable to reforestation and severalfold greater than grassland restoration. In contrast, harvesting and converting existing secondary forest at those sites incurs large initial carbon debt requiring long payback periods. We also highlight how plausible future improvements in energy crop yields and biorefining technology together with CCS would achieve mitigation potential 4 and 15 times greater than forest and grassland restoration, respectively. Finally, we show that recent estimates of induced land use change are small relative to the opportunities for improving system performance that we quantify here. While climate and other ecosystem service benefits cannot be taken for granted from cellulosic biofuel deployment, our scenarios illustrate how conventional and carbon-negative biofuel systems could make a near-term, robust, and distinctive contribution to the climate challenge.


Assuntos
Biocombustíveis/análise , Carbono/análise , Gases de Efeito Estufa/análise , Biocombustíveis/efeitos adversos , Biotecnologia , Carbono/metabolismo , Celulose/química , Celulose/metabolismo , Produtos Agrícolas/química , Produtos Agrícolas/metabolismo , Ecossistema , Etanol/metabolismo , Gases de Efeito Estufa/efeitos adversos
9.
Plant Mol Biol ; 104(3): 249-261, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32715397

RESUMO

Secondary cell wall not only provides rigidity and mechanical resistance to plants, but also has a large impact on plant growth and adaptation to environments. Biosynthesis of secondary cell wall is regulated by a complicated signaling transduction network; however, it is still unclear how the transcriptional regulation of secondary cell wall biosynthesis works at the molecular level. Here, we report in rice that OVATE family proteins 6 (OsOFP6) is a positive regulator in modulating expression of the genes related to biosynthesis of the secondary cell wall. Transgenic plants with knock-down of OsOFP6 by RNA interference showed increased leaf angle, which resulted from the thinner secondary cell wall with reduced amounts of cellulose and lignin, whilst overexpression of OsOFP6 in rice led to the thinker secondary cell wall with increased lignin content. Protein-protein interaction analysis revealed that OsOFP6 interacts with Oryza sativa homeobox 15 (OSH15), a class I KNOX protein. The interaction of OsOFP6 and OSH15 enhanced the transcriptional activity of OSH15 which binds to the promoter of OsIRX9 (Oryza sativa IRREGULAR XYLEM 9). Taken together, our study provides insights into the function of OsOFP6 in regulating leaf angle and the control of biosynthesis of secondary cell wall.


Assuntos
Parede Celular/metabolismo , Oryza/metabolismo , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Proteínas Repressoras/metabolismo , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Parede Celular/ultraestrutura , Celulose/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Homeodomínio/metabolismo , Lignina/metabolismo , Oryza/genética , Folhas de Planta/anatomia & histologia , Folhas de Planta/citologia , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas/genética , Regiões Promotoras Genéticas , Domínios e Motivos de Interação entre Proteínas , Interferência de RNA , Proteínas Repressoras/genética , Fatores de Transcrição/genética , Xilema/metabolismo
10.
PLoS One ; 15(7): e0236518, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32702033

RESUMO

Thermophilic microorganisms and their enzymes have been utilized in various industrial applications. In this work, we isolated and characterized thermophilic anaerobic bacteria with the cellulose and hemicellulose degrading activities from a tropical dry deciduous forest in northern Thailand. Out of 502 isolated thermophilic anaerobic soil bacteria, 6 isolates, identified as Thermoanaerobacterium sp., displayed an ability to utilize a wide range of oligosaccharides and lignocellulosic substrates. The isolates exhibited significant cellulase and xylanase activities at high temperature (65°C). Among all isolates, Thermoanaerobacterium sp. strain R63 exhibited remarkable hydrolytic properties with the highest cellulase and xylanase activities at 1.15 U/mg and 6.17 U/mg, respectively. Extracellular extract of Thermoanaerobacterium sp. strain R63 was thermostable with an optimal temperature at 65°C and could exhibit enzymatic activities on pH range 5.0-9.0. Our findings suggest promising applications of these thermoanaerobic bacteria and their potent enzymes for industrial purposes.


Assuntos
Celulose/metabolismo , Polissacarídeos/metabolismo , Microbiologia do Solo , Thermoanaerobacterium/metabolismo , Proteínas de Bactérias/metabolismo , Biomassa , Celulase/metabolismo , Endo-1,4-beta-Xilanases/metabolismo , Estabilidade Enzimática , Temperatura Alta , Concentração de Íons de Hidrogênio , Filogenia , Especificidade por Substrato , Thermoanaerobacterium/classificação , Thermoanaerobacterium/enzimologia , Thermoanaerobacterium/isolamento & purificação
11.
Food Chem ; 332: 127416, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32619946

RESUMO

Water bamboo shoots quickly deteriorate after harvest as a result of rapid lignification and softening. Nitric oxide (NO) has been used to extend the postharvest life of several other vegetables. Here, we examined the effect of NO on the storage of water bamboo shoots at 4℃ for 28 days. Without NO, fresh weight and firmness decreased quickly, while the cellulose and lignin contents increased sharply during storage. NO treatment delayed softening by maintaining the integrity of the cell wall and inhibiting the degradation of protopectin and the expressions of pectin methylesterase and polygalacturonase. NO treatment also delayed cellulose synthesis by increasing cellulase activity. NO treatment decreased the synthesis of lignin by inhibiting the activities of phenylalanine ammonia-lyase, cinnamyl alcohol dehydrogenase, laccase and peroxidase. These results indicate that NO treatment is effective at suppressing the softening and lignification of water bamboo shoots during postharvest storage.


Assuntos
Armazenamento de Alimentos/métodos , Óxido Nítrico/farmacologia , Poaceae/efeitos dos fármacos , Hidrolases de Éster Carboxílico/metabolismo , Parede Celular/efeitos dos fármacos , Parede Celular/ultraestrutura , Celulase/metabolismo , Celulose/metabolismo , Temperatura Baixa , Lignina/metabolismo , Microscopia Eletrônica de Varredura , Brotos de Planta/efeitos dos fármacos , Brotos de Planta/metabolismo , Poaceae/metabolismo , Poligalacturonase/metabolismo
12.
Arch Microbiol ; 202(9): 2591-2597, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32607725

RESUMO

To date, the genus Parvularcula consists of 6 species and no potential application of this genus was reported. Current study presents the genome sequence of Parvularcula flava strain NH6-79 T and its cellulolytic enzyme analysis. The assembled draft genome of strain NH6-79 T consists of 9 contigs and 7 scaffolds with 3.68 Mbp in size and GC content of 59.87%. From a total of 3,465 genes predicted, 96 of them are annotated as glycoside hydrolases (GHs). Within these GHs, 20 encoded genes are related to cellulosic biomass degradation, including 12 endoglucanases (5 GH10, 4 GH5, and 3 GH51), 2 exoglucanases (GH9) and 6 ß-glucosidases (GH3). In addition, highest relative enzyme activities (endoglucanase, exoglucanase, and ß-glucosidase) were observed at 27th hour when the strain was cultured in the carboxymethyl cellulose/Avicel®-containing medium for 45 h. The combination of genome analysis with experimental studies indicated the ability of strain NH6-79 T to produce extracellular endoglucanase, exoglucanase, and ß-glucosidase. These findings suggest the potential of Parvularcula flava strain NH6-79 T in cellulose-containing biomass degradation and that the strain could be used in cellulosic biorefining process.


Assuntos
Alphaproteobacteria/enzimologia , Alphaproteobacteria/genética , Genoma Bacteriano/genética , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Composição de Bases , Biomassa , Celulase/genética , Celulase/metabolismo , Celulose/metabolismo , beta-Glucosidase/genética , beta-Glucosidase/metabolismo
13.
J Vis Exp ; (159)2020 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-32510485

RESUMO

Understanding cell and tissue level regulation of growth and morphogenesis has been at the forefront of biological research for many decades. Advances in molecular and imaging technologies allowed us to gain insights into how biochemical signals influence morphogenetic events. However, it is increasingly evident that apart from biochemical signals, mechanical cues also impact several aspects of cell and tissue growth. The Arabidopsis shoot apical meristem (SAM) is a dome-shaped structure responsible for the generation of all aboveground organs. The organization of the cortical microtubule cytoskeleton that mediates apoplastic cellulose deposition in plant cells is spatially distinct. Visualization and quantitative assessment of patterns of cortical microtubules are necessary for understanding the biophysical nature of cells at the SAM, as cellulose is the stiffest component of the plant cell wall. The stereotypical form of cortical microtubule organization is also a consequence of tissue-wide physical forces existing at the SAM. Perturbation of these physical forces and subsequent monitoring of cortical microtubule organization allows for the identification of candidate proteins involved in mediating mechano-perception and transduction. Here we describe a protocol that helps investigate such processes.


Assuntos
Arabidopsis/citologia , Citoesqueleto/metabolismo , Fenômenos Mecânicos , Microtúbulos/metabolismo , Imagem Molecular , Arabidopsis/crescimento & desenvolvimento , Fenômenos Biomecânicos , Sobrevivência Celular , Parede Celular/metabolismo , Celulose/metabolismo , Meristema/citologia , Meristema/crescimento & desenvolvimento , Morfogênese
14.
World J Microbiol Biotechnol ; 36(5): 73, 2020 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-32385754

RESUMO

Liometopum apiculatum is a species of ants widely distributed in arid and semi-arid ecosystems where there is a relative food shortage compared with tropical ecosystems. L. apiculatum has established an ecological balance involving symbiotic interactions, which have allowed them to survive through mechanisms that are still unknown. Therefore, the aim of this study was to explore the metabolic potential of isolated bacteria from L. apiculatum using enzymatic activity assay and substrate assimilation. Results revealed a complex bacteria consortium belonging to Proteobacteria, Firmicutes, and Actinobacteria phylum. Most of the isolated bacteria showed activities associated with biopolymers degradation, from them Exiguobacterium and B. simplex showed the highest amylolytic activity (27 U/mg protein), while A. johnsonii and B. pumulis showed the highest cellulolytic and xylanolytic activities (1 and 2.9 U/mg protein, respectively). By other hand, some microorganisms such as S. ficaria, E. asburiae, P. agglomerans, A. johnsonii, S. rubidaea, S. marcescens, S. warneri, and M. hydrocarbonoxydans were able to grow up to 1000 mg/L of phthalates esters. These results not only revealed the important contribution of the symbionts in L apiculatum ants feeding habits, but also have shown a promising source of enzymes with potential biotechnological applications such as lignocellulosic biomass hydrolysis and bioremediation processes.


Assuntos
Formigas/microbiologia , Bactérias/isolamento & purificação , Bactérias/metabolismo , Biodegradação Ambiental , Microbiota/fisiologia , Animais , Bactérias/classificação , Bactérias/enzimologia , Biomassa , Celulose/metabolismo , Hábitos , Hidrólise , Larva/microbiologia , Lignina/metabolismo , Polissacarídeos/metabolismo , Simbiose , Xilanos/metabolismo
15.
Artigo em Inglês | MEDLINE | ID: mdl-32458727

RESUMO

Waste-activated sludge (WAS) with trace organic pollutants, e.g., polycyclic aromatic hydrocarbons (PAHs), has become an environmental concern. Anaerobic technology is a feasible option for WAS treatment due to its advantages of low-energy consumption and high-energy recovery compared to aerobic technology, but it still has many shortcomings, such as low biogas production and a low organic pollutant removal efficiency. Thus, this study investigated the effects of cellulose on PAHs degradation and microbial community structure variation during anaerobic digestion of sewage sludge. Four semicontinuous experiments were set by adding cellulose to sewage sludge based on the volatile solids (VS) concentration. The proportions of sludge VS to cellulose VS were 1:0 (CK), 1:0.2, 1:0.5 and 1:1. The results showed the following: (1) The biodegradation of 2-ring, 3-ring and 4-ring PAHs was enhanced by cellulose addition, with total PAHs removal efficiencies of 14.82%, 20.75% and 19.35%, respectively. (2) The abundance of bacteria that could degrade PAHs, such as Chloroflexi, Bacteroidetes, Aminicenantes, Planctomycetes and Spirochaeta, was obviously increased by cellulose addition. (3) The abundance of Methanosaeta during sludge anaerobic digestion was apparently increased by cellulose addition. Methanobacterium and Methanolinea appeared after cellulose addition, while they were not observed in the blank experiment.


Assuntos
Celulose/farmacologia , Microbiota/efeitos dos fármacos , Hidrocarbonetos Policíclicos Aromáticos/análise , Esgotos , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Anaerobiose , Biodegradação Ambiental , Biocombustíveis/análise , Celulose/metabolismo , Esgotos/química , Esgotos/microbiologia
16.
Nat Chem Biol ; 16(7): 740-748, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32424305

RESUMO

Glycosylation is one of the most prevalent molecular modifications in nature. Single or multiple sugars can decorate a wide range of acceptors from proteins to lipids, cell wall glycans and small molecules, dramatically affecting their activity. Here, we discovered that by 'hijacking' an enzyme of the cellulose synthesis machinery involved in cell wall assembly, plants evolved cellulose synthase-like enzymes (Csls) and acquired the capacity to glucuronidate specialized metabolites, that is, triterpenoid saponins. Apparently, endoplasmic reticulum-membrane localization of Csls and of other pathway proteins was part of evolving a new glycosyltransferase function, as plant metabolite glycosyltransferases typically act in the cytosol. Discovery of glucuronic acid transferases across several plant orders uncovered the long-pursued enzymatic reaction in the production of a low-calorie sweetener from licorice roots. Our work opens the way for engineering potent saponins through microbial fermentation and plant-based systems.


Assuntos
Regulação da Expressão Gênica de Plantas , Glucosiltransferases/genética , Glicosiltransferases/genética , Proteínas de Plantas/genética , Saponinas/biossíntese , Spinacia oleracea/metabolismo , Terpenos/metabolismo , Beta vulgaris/genética , Beta vulgaris/metabolismo , Membrana Celular/metabolismo , Parede Celular/metabolismo , Celulose/metabolismo , Retículo Endoplasmático/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Glucosiltransferases/metabolismo , Ácido Glucurônico/metabolismo , Glicosilação , Glicosiltransferases/metabolismo , Glycyrrhiza/genética , Glycyrrhiza/metabolismo , Células Vegetais/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Spinacia oleracea/genética
17.
Appl Environ Microbiol ; 86(15)2020 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-32471912

RESUMO

Filamentous fungi are intensively used for producing industrial enzymes, including lignocellulases. Employing insoluble cellulose to induce the production of lignocellulases causes some drawbacks, e.g., a complex fermentation operation, which can be overcome by using soluble inducers such as cellobiose. Here, a triple ß-glucosidase mutant of Neurospora crassa, which prevents rapid turnover of cellobiose and thus allows the disaccharide to induce lignocellulases, was applied to profile the proteome responses to cellobiose and cellulose (Avicel). Our results revealed a shared proteomic response to cellobiose and Avicel, whose elements included lignocellulases and cellulolytic product transporters. While the cellulolytic proteins showed a correlated increase in protein and mRNA levels, only a moderate correlation was observed on a proteomic scale between protein and mRNA levels (R 2 = 0.31). Ribosome biogenesis and rRNA processing were significantly overrepresented in the protein set with increased protein but unchanged mRNA abundances in response to Avicel. Ribosome biogenesis, as well as protein processing and protein export, was also enriched in the protein set that showed increased abundance in response to cellobiose. NCU05895, a homolog of yeast CWH43, is potentially involved in transferring a glycosylphosphatidylinositol (GPI) anchor to nascent proteins. This protein showed increased abundance but no significant change in mRNA levels. Disruption of CWH43 resulted in a significant decrease in cellulase activities and secreted protein levels in cultures grown on Avicel, suggesting a positive regulatory role for CWH43 in cellulase production. The findings should have an impact on a systems engineering approach for strain improvement for the production of lignocellulases.IMPORTANCE Lignocellulases are important industrial enzymes for sustainable production of biofuels and bio-products. Insoluble cellulose has been commonly used to induce the production of lignocellulases in filamentous fungi, which causes a difficult fermentation operation and enzyme loss due to adsorption to cellulose. The disadvantages can be overcome by using soluble inducers, such as the disaccharide cellobiose. Quantitative proteome profiling of the model filamentous fungus Neurospora crassa revealed cellobiose-dependent pathways for cellulase production, including protein processing and export. A protein (CWH43) potentially involved in protein processing was found to be a positive regulator of lignocellulase production. The cellobiose-dependent mechanisms provide new opportunities to improve the production of lignocellulases in filamentous fungi.


Assuntos
Celobiose/metabolismo , Proteínas Fúngicas/metabolismo , Neurospora crassa/metabolismo , Proteoma/metabolismo , beta-Glucosidase/genética , Biocombustíveis/microbiologia , Celulose/metabolismo , Proteínas Fúngicas/genética , Neurospora crassa/enzimologia , Neurospora crassa/genética , Proteoma/genética , beta-Glucosidase/deficiência
18.
J Phys Chem Lett ; 11(10): 3987-3992, 2020 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-32352790

RESUMO

A distinct interaction pattern of lytic polysaccharide monooxygenases (LPMOs) with their insoluble substrate, cellulose, was revealed through the combination of computational and biochemical approaches. The results indicated that the enzymes can stably bind on the flat hydrophobic surface of cellulose via the interactions of the key residues located in the axis across the conserved distal tyrosine residue and copper ion with two adjacent cellulose chains. Further studies on the correlation of substrate binding and H2O2 accumulation suggested that LPMOs involved in the productive binding on the insoluble polysaccharides not only fail to accumulate H2O2 but also consume the H2O2 produced by the unbound molecules under the lab condition. This was further substantiated by quantum-mechanical calculations. These findings broadened our knowledge of the interaction between enzymes and insoluble substrates and deepened our understanding of the role that H2O2 plays in LPMO activity.


Assuntos
Celulose/química , Teoria da Densidade Funcional , Oxigenases de Função Mista/química , Polissacarídeos/química , Celulose/metabolismo , Peróxido de Hidrogênio/química , Peróxido de Hidrogênio/metabolismo , Oxigenases de Função Mista/metabolismo , Modelos Moleculares , Polissacarídeos/metabolismo
19.
Zhongguo Zhong Yao Za Zhi ; 45(3): 472-477, 2020 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-32237502

RESUMO

The phenomenon that waste of fungus-growing materials in the planting process of Gastrodia elata is very common. It has been proved by practice that the used fungus-growing materials planted with G. elata can be used to plant Phallus impudicus. But the mechanism is unclear. In this study, we compared the different infested-capacity of Armillaria gallica and Phallus impudicus by morphological anatomy of the used fungus-growing materials. We also compared the differences on the two fungi consumed the main contents of fungus-growing materials, cellulose, lignin and hemicellulose, by using nitric acid-95% ethanol method, sulfuric acid method and tetrabromide method respectively, so that to explore the mechanism of A. gallica and P. impudicus recycle the fungus-growing materials, and to provide scientific basis for recycling the used fungus-growing materials of G. elata. The results showed that A. gallica had a strong ability to invade some parts outside the vascular cambium, but it had a weak ability to invade some parts inside the vascular cambium, while P. impudicus had a strong ability to invade the same parts. The contents of lignin and cellulose, which from inside and outside the vascular cambium of fungus-growing materials were significantly different. In the parts of outside the vascular cambium of fungus-growing materials, A. gallica degraded more lignin and cellulose, while P. impudicus degraded more hemicellulose. In the parts of inside the vascular cambium of fungus-growing materials, A. gallica degraded more cellulose, while P. impudicus degraded more hemicellulose. The present results suggested that A. gallica and P. impudicus made differential utilization of the carbon source in the fungus-growing materials to realize that P. impudicus recycle the used fungus-growing materials of G. elata. A. gallica used lignin and cellulose as the main carbon source, while P. impudicus used hemicellulose as the main carbon source.


Assuntos
Agaricales/crescimento & desenvolvimento , Armillaria/crescimento & desenvolvimento , Celulose/metabolismo , Lignina/metabolismo , Polissacarídeos/metabolismo
20.
Nat Commun ; 11(1): 1937, 2020 04 22.
Artigo em Inglês | MEDLINE | ID: mdl-32321909

RESUMO

The fiber in corn kernels, currently unutilized in the corn to ethanol process, represents an opportunity for introduction of cellulose conversion technology. We report here that Clostridium thermocellum can solubilize over 90% of the carbohydrate in autoclaved corn fiber, including its hemicellulose component glucuronoarabinoxylan (GAX). However, Thermoanaerobacterium thermosaccharolyticum or several other described hemicellulose-fermenting thermophilic bacteria can only partially utilize this GAX. We describe the isolation of a previously undescribed organism, Herbinix spp. strain LL1355, from a thermophilic microbiome that can consume 85% of the recalcitrant GAX. We sequence its genome, and based on structural analysis of the GAX, identify six enzymes that hydrolyze GAX linkages. Combinations of up to four enzymes are successfully expressed in T. thermosaccharolyticum. Supplementation with these enzymes allows T. thermosaccharolyticum to consume 78% of the GAX compared to 53% by the parent strain and increases ethanol yield from corn fiber by 24%.


Assuntos
Clostridiales/metabolismo , Técnicas de Cocultura/métodos , Etanol/metabolismo , Microbiologia Industrial/métodos , Thermoanaerobacterium/metabolismo , Zea mays/microbiologia , Celulose/metabolismo , Clostridiales/genética , Fermentação , Temperatura Alta , Thermoanaerobacterium/genética , Xilanos/metabolismo , Zea mays/metabolismo
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