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1.
Waste Manag ; 118: 45-54, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32889233

RESUMO

Co-processing of lignocellulosic wastes, e.g., garden and paper wastes, and the organic matters fraction of municipal solid waste (OMSW) in an integrated bioprocess is a possible approach to realize the potential of wastes for biobutanol production. Dilute acid pretreatment is a multi-functional stage for breaking the recalcitrant lignocellulose's structure, hydrolyzing hemicellulose, and hydrolyzing/solubilizing starch, leading to a pretreated solid and a rich hydrolysate. In this study, dilute-acid pretreatment of the combination of wastepaper and OMSW, composite I, as well as garden waste and OMSW, composite II, at severe conditions resulted in "pretreatment hydrolysates" containing 33.7 and 19.4 g/L sugar along with 18.9 and 33.2 g/L soluble starch, respectively. In addition, the hydrolysis of solid remained after the pretreatment of composite I and II resulted in "enzymatic hydrolysates" comprising 19.4 and 33 g/L sugar, respectively. The fermentation of the pretreatment hydrolysates and enzymatic hydrolysates resulted in 3.5 and 6.4 g/L ABE from composite I and 15 and 5.2 g/L ABE from composite II, respectively. In this process, 148 and 173 g ABE (60 and 100 g gasoline equivalent/kg) was obtained from each kg composite I and composite II, respectively, where co-processing of OMSW with lignocellulosic wastes resulted in 10 and 49% higher ABE than that produced from the individual substrates.


Assuntos
Butanóis , Resíduos Sólidos , Fermentação , Hidrólise , Lignina/metabolismo
2.
PLoS One ; 15(9): e0233823, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32941430

RESUMO

Lignin is the second most abundant carbon polymer on earth and despite having more fuel value than cellulose, it currently is considered a waste byproduct in many industrial lignocellulose applications. Valorization of lignin relies on effective and green methods of de-lignification, with a growing interest in the use of microbes. Here we investigate the physiology and molecular response of the novel facultative anaerobic bacterium, Tolumonas lignolytica BRL6-1, to lignin under anoxic conditions. Physiological and biochemical changes were compared between cells grown anaerobically in either lignin-amended or unamended conditions. In the presence of lignin, BRL6-1 accumulates higher biomass and has a shorter lag phase compared to unamended conditions, and 14% of the proteins determined to be significantly higher in abundance by log2 fold-change of 2 or greater were related to Fe(II) transport in late logarithmic phase. Ferrozine assays of the supernatant confirmed that Fe(III) was bound to lignin and reduced to Fe(II) only in the presence of BRL6-1, suggesting redox activity by the cells. LC-MS/MS analysis of the secretome showed an extra band at 20 kDa in lignin-amended conditions. Protein sequencing of this band identified a protein of unknown function with homology to enzymes in the radical SAM superfamily. Expression of this protein in lignin-amended conditions suggests its role in radical formation. From our findings, we suggest that BRL6-1 is using a protein in the radical SAM superfamily to interact with the Fe(III) bound to lignin and reducing it to Fe(II) for cellular use, increasing BRL6-1 yield under lignin-amended conditions. This interaction potentially generates organic free radicals and causes a radical cascade which could modify and depolymerize lignin. Further research should clarify the extent to which this mechanism is similar to previously described aerobic chelator-mediated Fenton chemistry or radical producing lignolytic enzymes, such as lignin peroxidases, but under anoxic conditions.


Assuntos
Aeromonadaceae/metabolismo , Ferro/metabolismo , Lignina/metabolismo , Aeromonadaceae/enzimologia , Aeromonadaceae/crescimento & desenvolvimento , Proteínas de Bactérias/metabolismo , Biomassa , Oxirredução , Sulfatases/metabolismo
3.
Science ; 369(6507)2020 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-32855308

RESUMO

Microbial consortia are a promising alternative to monocultures of genetically modified microorganisms for complex biotransformations. We developed a versatile consortium-based strategy for the direct conversion of lignocellulose to short-chain fatty acids, which included the funneling of the lignocellulosic carbohydrates to lactate as a central intermediate in engineered food chains. A spatial niche enabled in situ cellulolytic enzyme production by an aerobic fungus next to facultative anaerobic lactic acid bacteria and the product-forming anaerobes. Clostridium tyrobutyricum, Veillonella criceti, or Megasphaera elsdenii were integrated into the lactate platform to produce 196 kilograms of butyric acid per metric ton of beechwood. The lactate platform demonstrates the benefits of mixed cultures, such as their modularity and their ability to convert complex substrates into valuable biochemicals.


Assuntos
Clostridium tyrobutyricum/metabolismo , Ácidos Graxos Voláteis/biossíntese , Lignina/metabolismo , Megasphaera elsdenii/metabolismo , Consórcios Microbianos , Veillonella/metabolismo , Biotransformação , Ácido Láctico/metabolismo
4.
Plant Mol Biol ; 104(3): 263-281, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32740898

RESUMO

KEY MESSAGE: Plant-specific Dof transcription factors VDOF1 and VDOF2 are novel regulators of vascular cell differentiation through the course of a lifetime in Arabidopsis, with shifting their transcriptional target genes. Vascular system is one of critical tissues for vascular plants to transport low-molecular compounds, such as water, minerals, and the photosynthetic product, sucrose. Here, we report the involvement of two Dof transcription factors, named VASCULAR-RELATED DOF1 (VDOF1)/VDOF4.6 and VDOF2/VDOF1.8, in vascular cell differentiation and lignin biosynthesis in Arabidopsis. VDOF genes were expressed in vascular tissues, but the detailed expression sites were partly different between VDOF1 and VDOF2. Vein patterning and lignin analysis of VDOF overexpressors and double mutant vdof1 vdof2 suggested that VDOF1 and VDOF2 would function as negative regulators of vein formation in seedlings, and lignin deposition in inflorescence stems. Interestingly, effects of VDOF overexpression in lignin deposition were different by developmental stages of inflorescence stems, and total lignin contents were increased and decreased in VDOF1 and VDOF2 overexpressors, respectively. RNA-seq analysis of inducible VDOF overexpressors demonstrated that the genes for cell wall biosynthesis, including lignin biosynthetic genes, and the transcription factor genes related to stress response and brassinosteroid signaling were commonly affected by VDOF1 and VDOF2 overexpression. Taken together, we concluded that VDOF1 and VDOF2 are novel regulators of vascular cell differentiation through the course of a lifetime, with shifting their transcriptional target genes: in seedlings, the VDOF genes negatively regulate vein formation, while at reproductive stages, the VDOF proteins target lignin biosynthesis.


Assuntos
Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Diferenciação Celular/fisiologia , Lignina/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas de Ligação a DNA , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Ontologia Genética , Inflorescência , Mutação , Caules de Planta/citologia , Caules de Planta/metabolismo , Plantas Geneticamente Modificadas/genética , Sementes , Análise de Sequência
5.
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
6.
Gene ; 758: 144954, 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-32683079

RESUMO

Teosinte branched1/cycloidea/proliferating cell factor1 (TCP) is a plant-specific protein family member involved in plant growth and development. However, the functions of most members of the cotton TCP family are unknown. In this study, the GbTCP5 gene encodes a sea-island cotton class II TCP CIN subclass transcription factor. The GbTCP5 transcription factor is located in the nucleus, has transcriptional activation activity, and can bind to TCP II cis-acting elements. GbTCP5 was widely expressed in tissues with the highest transcript level in the calyx. GbTCP5 is expressed at different developmental stages of the fiber and has significantly high transcriptional level expression in the fibers at 20, 30 and 35 days post anthesis (DPA). Heterologous overexpression of the GbTCP5 gene increased root hair length, root hair and stem trichome density, and stem lignin content in transgenic Arabidopsis compared to the wild type (WT). GbTCP5 binds the promoters of the GL3, EGL3, CPC, MYB46, LBD30, CesA4, VND7, CCOMT1, and CAD5 genes to upregulate their expression. Moreover, the homologous genes of these genes are expressed in the fibers of different developmental stages of the sea-island cotton fiber. These results indicate that GbTCP5 regulates root hair development and secondary wall formation in Arabidopsis and may be a candidate gene for improving cotton fiber quality.


Assuntos
Arabidopsis/genética , Gossypium/genética , Lignina/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Fatores de Transcrição/genética , Tricomas/crescimento & desenvolvimento , Arabidopsis/crescimento & desenvolvimento , Fibra de Algodão/análise , Proteínas de Ligação a DNA/genética , Raízes de Plantas/fisiologia , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/crescimento & desenvolvimento , Regiões Promotoras Genéticas/genética , Ativação Transcricional/genética
7.
Ecotoxicol Environ Saf ; 203: 110997, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32684518

RESUMO

A novel study on biodegradation of 30 mg L-1 of Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) mixture (celecoxib, diclofenac and ibuprofen) by two wood-rot fungi; Ganoderma applanatum (GA) and Laetiporus sulphureus (LS) was investigated for 72 h. The removal efficiency of celecoxib, diclofenac and ibuprofen were 98, 96 and 95% by the fungal consortium (GA + LS). Although, both GA and LS exhibited low removal efficiency (61 and 73% respectively) on NSAIDs. However, 99.5% degradation of the drug mixture (NSAIDs) was achieved on the addition of the fungal consortium (GA + LS) to the experimental set-up. Overall, LS exhibited higher degradation efficiency; 92, 87, 79% on celecoxib, diclofenac and ibuprofen than GA with 89, 80 and 66% respectively. Enzyme analyses revealed significant induction of 201, 180 and 135% in laccase (Lac), lignin peroxidase (LiP) and manganese peroxidase (MnP) by the fungal consortium during degradation of the NSAIDs respectively. The experimental data showed the best goodness of fit when subjected to Langmuir (R2 = 0.980) and Temkin (R2 = 0.979) isotherm models which suggests monolayer and heterogeneous nature exhibited by the mycelia during interactions with NSAIDs. The degradation mechanism followed pseudo-second-order kinetic model (R2 = 0.987) indicating the strong influence of fungal biomass in the degradation of NSAIDs. Furthermore, Gas Chromatography-Mass Spectrometry (GCMS) and High-Performance Liquid Chromatography (HPLC) analyses confirmed the degraded metabolic states of the NSAIDs after treatment with GA, LS and consortium (GA + LS). Hence, the complete removal of NSAIDs is best achieved in an economical and eco-friendly way with the use of fungi consortium.


Assuntos
Anti-Inflamatórios não Esteroides/análise , Poluentes Ambientais/análise , Ganoderma/enzimologia , Ganoderma/crescimento & desenvolvimento , Lignina/metabolismo , Madeira/microbiologia , Anti-Inflamatórios não Esteroides/metabolismo , Biodegradação Ambiental , Biomassa , Poluentes Ambientais/metabolismo , Indução Enzimática/efeitos dos fármacos , Cinética , Lacase/biossíntese , Modelos Biológicos , Peroxidases/biossíntese
8.
Proc Natl Acad Sci U S A ; 117(29): 16776-16781, 2020 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-32636260

RESUMO

A particularly promising approach to deconstructing and fractionating lignocellulosic biomass to produce green renewable fuels and high-value chemicals pretreats the biomass with organic solvents in aqueous solution. Here, neutron scattering and molecular-dynamics simulations reveal the temperature-dependent morphological changes in poplar wood biomass during tetrahydrofuran (THF):water pretreatment and provide a mechanism by which the solvent components drive efficient biomass breakdown. Whereas lignin dissociates over a wide temperature range (>25 °C) cellulose disruption occurs only above 150 °C. Neutron scattering with contrast variation provides direct evidence for the formation of THF-rich nanoclusters (Rg ∼ 0.5 nm) on the nonpolar cellulose surfaces and on hydrophobic lignin, and equivalent water-rich nanoclusters on polar cellulose surfaces. The disassembly of the amphiphilic biomass is thus enabled through the local demixing of highly functional cosolvents, THF and water, which preferentially solvate specific biomass surfaces so as to match the local solute polarity. A multiscale description of the efficiency of THF:water pretreatment is provided: matching polarity at the atomic scale prevents lignin aggregation and disrupts cellulose, leading to improvements in deconstruction at the macroscopic scale.


Assuntos
Biotecnologia/métodos , Lignina/química , Madeira/química , Proteínas de Bactérias/metabolismo , Biomassa , Celulase/metabolismo , Furanos/química , Gluconacetobacter xylinus/enzimologia , Hidrólise , Lignina/metabolismo , Populus/química , Solventes/química , Tensoativos/química
9.
PLoS One ; 15(7): e0227529, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730337

RESUMO

The pretreatment of biomass remains a critical requirement for bio-renewable fuel production from lignocellulose. Although current processes primarily involve chemical and physical approaches, the biological breakdown of lignin using enzymes and microorganisms is quickly becoming an interesting eco-friendly alternative to classical processes. As a result, bioprospection of wild fungi from naturally occurring lignin-rich sources remains a suitable method to uncover and isolate new species exhibiting ligninolytic activity. In this study, wild species of white rot fungi were collected from Colombian forests based on their natural wood decay ability and high capacity to secrete oxidoreductases with high affinity for phenolic polymers such as lignin. Based on high activity obtained from solid-state fermentation using a lignocellulose source from oil palm as matrix, we describe the isolation and whole-genome sequencing of Dictyopanus pusillus, a wild basidiomycete fungus exhibiting ABTS oxidation as an indication of laccase activity. Functional characterization of a crude enzymatic extract identified laccase activity as the main enzymatic contributor to fungal extracts, an observation supported by the identification of 13 putative genes encoding for homologous laccases in the genome. To the best of our knowledge, this represents the first report of an enzymatic extract exhibiting laccase activity in the Dictyopanus genera, offering means to exploit this species and its enzymes for the delignification process of lignocellulosic by-products from oil palm.


Assuntos
Agaricales/genética , Genoma Fúngico , Lignina/metabolismo , Óleo de Palmeira/metabolismo , Agaricales/classificação , Agaricales/enzimologia , Biomassa , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Concentração de Íons de Hidrogênio , Lacase/genética , Lacase/metabolismo , Oxirredução , Filogenia , Temperatura , Sequenciamento Completo do Genoma
10.
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
11.
PLoS One ; 15(7): e0235975, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32649704

RESUMO

Rice cultivar "Weiyou916" (Oryza sativa L. ssp. Indica) were cultured with control (10 mM NO3-) and nitrate deficient solution (0 mM NO3-) for four weeks. Nitrogen (N) deficiency significantly decreased the content of N and P, dry weight (DW) of the shoots and roots, but increased the ratio of root to shoot in O. sativa. N deficiency decreased the photosynthesis rate and the maximum quantum yield of primary photochemistry (Fv/Fm), however, increased the intercellular CO2 concentration and primary fluorescence (Fo). N deficiency significantly increased the production of H2O2 and membrane lipid peroxidation revealed as increased MDA content in O. sativa leaves. N deficiency significantly increased the contents of starch, sucrose, fructose, and malate, but did not change that of glucose and total soluble protein in O. sativa leaves. The accumulated carbohydrates and H2O2 might further accelerate biosynthesis of lignin in O. sativa leaves under N limitation. A total of 1635 genes showed differential expression in response to N deficiency revealed by Illumina sequencing. Gene Ontology (GO) analysis showed that 195 DEGs were found to highly enrich in nine GO terms. Most of DEGs involved in photosynthesis, biosynthesis of ethylene and gibberellins were downregulated, whereas most of DEGs involved in cellular transport, lignin biosynthesis and flavonoid metabolism were upregulated by N deficiency in O. sativa leaves. Results of real-time quantitative PCR (RT-qPCR) further verified the RNA-Seq data. For the first time, DEGs involved oxygen-evolving complex, phosphorus response and lignin biosynthesis were identified in rice leaves. Our RNA-Seq data provided a global view of transcriptomic profile of principal processes implicated in the adaptation of N deficiency in O. sativa and shed light on the candidate direction in rice breeding for green and sustainable agriculture.


Assuntos
Flavonoides/metabolismo , Lignina/metabolismo , Nitratos/metabolismo , Oryza/genética , Fotossíntese , Carboidratos/análise , Clorofila A/química , Regulação da Expressão Gênica de Plantas , Peróxido de Hidrogênio/metabolismo , Malondialdeído/metabolismo , Oryza/metabolismo , Oxirredução , Folhas de Planta/genética , Folhas de Planta/metabolismo , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , RNA de Plantas/química , RNA de Plantas/metabolismo , Análise de Sequência de RNA
12.
Int J Syst Evol Microbiol ; 70(8): 4502-4507, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32598276

RESUMO

An alkali lignin-degrading, Gram-stain-negative, rod-shaped, non-motile and facultatively anaerobic bacterium, designated BM_7T, was isolated from mangrove sediment of the supralittoral zone in the Jiulong river estuary, PR China. The cells of strain BM_7T were 0.4-0.6 µm wide and 1.0-8.5 µm long. Oxidase and catalase activities were positive. Strain BM_7T could grow at 10-37 °C (optimum, 25-28 °C), at pH 6.0-8.0 (optimum, pH 7.0) and in the presence of 0.5-6 % (w/v) NaCl (optimum, 2%). Phylogenetic analysis of 16S rRNA gene sequences indicated that strain BM_7T belonged to the genus Mangrovibacterium of the family Prolixibacteraceae. It showed the highest similarity to Mangrovibacterium diazotrophicum JCM 19152T (96.8 %), followed by Mangrovibacterium marinum KCTC 42253T (96.1%). The values of average nucleotide identity and DNA-DNA hybridization were calculated as 76.9, 24.3 and 76.1, 17.4 % between strain BM_7T with M. diazotrophicum JCM 19152T and M. marinum KCTC 42253T, respectively. The major respiratory quinone of strain BM_7T was MK-7. The polar lipids were detected as phosphatidylethanolamine, three unidentified phospholipids and four unidentified aminolipids. The dominant fatty acids consisted of iso-C15 : 0, anteiso-C15 : 0, C15 : 1 ω6c, iso-C17 : 0 3-OH, C17 : 1 ω6c, C17 : 0 3-OH and C17 : 0. The genome size of strain BM_7T is 5.6 Mb, with G+C content of 43.4 mol%. Based on the phylogenetic and phenotypic characteristics, strain BM_7T was considered to represent a novel species of the genus Mangrovibacterium, and the name Mangrovibacterium lignilyticum sp. nov. is proposed. The type strain is BM_7T (=MCCC 1A15882T=KCTC 72696T).


Assuntos
Bacteroidetes/classificação , Estuários , Sedimentos Geológicos/microbiologia , Lignina/metabolismo , Filogenia , Técnicas de Tipagem Bacteriana , Bacteroidetes/isolamento & purificação , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
13.
Proc Natl Acad Sci U S A ; 117(27): 15400-15402, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32571955

RESUMO

The Casparian strip (CS) is a tight junction-like structure formed by lignin impregnation on the walls of endodermal cells in plant roots. The CS membrane domain (CSDM), demarked by the CASP proteins, is important for orienting lignification enzymes. Here, we report that an endodermis-expressed multicopper oxidase, LACCASE3 (LAC3) in Arabidopsis, locates to the interface between lignin domains and the cell wall during early CS development prior to CASP1 localizing to CSDM and eventually flanks the mature CS. Pharmacological perturbation of LAC3 causes dispersed localization of CASP1 and compensatory ectopic lignification. These results support the existence of a LAC3-based CS wall domain which coordinates with CSDM to provide bidirectional positional information that guides precise CS lignification.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Lacase/metabolismo , Proteínas de Membrana/metabolismo , Raízes de Plantas/metabolismo , Arabidopsis/citologia , Parede Celular/metabolismo , Lacase/genética , Lignina/metabolismo , Proteínas de Membrana/genética , Raízes de Plantas/citologia , Plantas Geneticamente Modificadas , Domínios Proteicos
14.
Sheng Wu Gong Cheng Xue Bao ; 36(5): 861-867, 2020 May 25.
Artigo em Chinês | MEDLINE | ID: mdl-32567269

RESUMO

Lignocellulose is a major biomass resource for the production of biofuel ethanol. Due to its abundance, environmental friendliness and renewability, the utilization of lignocellulose is promising to solve energy shortage. Surfactant can effectively promote the enzymatic hydrolysis of lignocellulose. By discussing the influence and mechanism of different surfactants on the enzymatic hydrolysis, we provide references for finding appropriate surfactants in enzymatic hydrolysis process.


Assuntos
Lignina , Açúcares , Biocombustíveis , Biomassa , Hidrólise/efeitos dos fármacos , Lignina/metabolismo , Açúcares/metabolismo , Tensoativos/farmacologia
15.
Arch Microbiol ; 202(7): 1597-1615, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32451592

RESUMO

Extracellular enzymes produced from Streptomyces have the potential to replace toxic chemicals that are being used in various industries. The endorsement of this replacement has not received a better platform in developing countries. In this review, we have discussed the impact of chemicals and conventional practices on environmental health, and the role of extracellular enzymes to replace these practices. Burning of fossil fuels and agriculture residue is a global issue, but the production of biofuel using extracellular enzymes may be the single key to solve all these issues. We have discussed the replacement of hazardous chemicals with the use of xylanase, cellulase, and pectinase in food industries. In paper industries, delignification was done by the chemical treatment, but xylanase and laccase have the efficient potential to remove the lignin from pulp. In textile industries, the conventional method includes the chemicals which affect the nervous system and other organs. The use of xylanase, cellulase, and pectinase in different processes can give a safe and environment-friendly option to textile industries. Hazardous chemical pesticides can be replaced by the use of chitinase as an insecticide and fungicide in agricultural practices.


Assuntos
Proteínas de Bactérias/metabolismo , Enzimas/metabolismo , Microbiologia Industrial/tendências , Streptomyces/enzimologia , Agricultura , Biocombustíveis , Lignina/metabolismo
16.
Chemosphere ; 256: 127142, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32464362

RESUMO

The development of lignocellulose-based adsorbents for the removal of heavy metals from wastewater has attracted much recent attention. In this work, a high-yield cellulose bacterial strain Comamonas testosteroni FJ17 was evaluated for its capacity to modify rice straw towards increased Cu(II) removal. For optimum modification time (45.5 h), inoculum concentration (1.25%), and rice straw dose (12.6 g L-1) the optimized adsorption capacity was 28.4 mg g-1. After strain FJ17 modification the equilibrium adsorption percentage of rice straw for Cu(II) increased from 6.6 to 27.4% at an initial concentration of 100 mg L-1. This increase was attributed to an increase in rice straw surface modification, leading to improved adsorption ability. SEM-EDS indicated that, following strain FJ17 treatment, the surface of the rice straw became more disintegrated and the specific surface area consequentially increased from 1.9 to 3.7 m2 g-1. FTIR analysis also showed new functional groups (carbonyl) appearing, and CC and CH3CR functionality being enhanced after biomodification. Functional groups associated with the benzene ring, silicified polymer and carbohydrates were all involved in the adsorption process. Adsorption of Cu was well described by the Freundlich isotherm model (R2 > 0.98) where adsorption was endothermic with potential for both chemical and physical interactions to coexist. Reusability experiments showed that the removal efficiency of Cu(II) decreased from 96.9 to 73.2% after five cycles. Overall C.testosteroni-treated rice straw had significant potential as a heavy metal biosorbent.


Assuntos
Comamonas/metabolismo , Cobre/análise , Águas Residuárias/química , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Adsorção , Celulose , Concentração de Íons de Hidrogênio , Cinética , Lignina/metabolismo , Oryza
17.
Plant Mol Biol ; 103(6): 689-704, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32472480

RESUMO

KEY MESSAGE: CmCAD2 and CmCAD3 function more positively than CmCAD1 in oriental melon for lignin synthesis which is important to ensure internal water status and thus for drought tolerance. Well-lignification may be the guarantee of efficient axial water transport and barrier of lateral water flow in oriental melon tolerating drought stress, however remains to be verified. As an important enzyme in monolignol synthesis pathway, five cinnamyl alcohol dehydrogenase (CAD) genes were generally induced in melon seedlings by drought. Here we further revealed the roles of CmCAD1, 2, and 3 in lignin synthesis and for drought tolerance. Results found that overexpressing CmCAD2 or 3 strongly recovered CAD activities, lignin synthesis and composition in Arabidopsis cadc cadd, whose lignin synthesis is disrupted, while CmCAD1 functioned modestly. In melon seedlings, silenced CmCAD2 and 3 individually or collectively decreased CAD activities and lignin depositions drastically, resulting in dwarfed phenotypes. Reduced lignin, mainly composed by guaiacyl units catalyzed by CmCAD3, is mainly due to the limited lignification in tracheary elements and development of Casparion strip. While CmCAD1 and 2 exhibited catalysis to p-coumaraldehyde and sinapaldehyde, respectively. Compared with CmCAD1, drought treatments revealed higher sensitivity of CmCAD2 and/or 3 silenced melon seedlings, accompanying with lower relative water contents, water potentials and relatively higher total soluble sugar contents. Slightly up-regulated expressions of aquaporin genes together with limited lignification might imply higher lateral water loss in stems of silenced lines. In Arabidopsis, CmCAD2 and 3 transgenic lines enhanced cadc cadd drought tolerance through recovering lignin synthesis and root development, accompanying with decreased electrolyte leakage ratios and increased RWCs, thus improved survival rates. Briefly, lignin synthesized by CmCAD2 and 3 functions importantly for drought tolerance in melon.


Assuntos
Plântula/metabolismo , Cucumis melo/metabolismo , Cucumis melo/fisiologia , Secas , Regulação da Expressão Gênica de Plantas/fisiologia , Lignina/metabolismo , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/fisiologia , Plântula/fisiologia
18.
J Vis Exp ; (158)2020 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-32364543

RESUMO

Lignocellulosic materials are plant-derived feedstocks, such as crop residues (e.g., corn stover, rice straw, and sugar cane bagasse) and purpose-grown energy crops (e.g., miscanthus, and switchgrass) that are available in large quantities to produce biofuels, biochemicals, and animal feed. Plant polysaccharides (i.e., cellulose, hemicellulose, and pectin) embedded within cell walls are highly recalcitrant towards conversion into useful products. Ammonia fiber expansion (AFEX) is a thermochemical pretreatment that increases accessibility of polysaccharides to enzymes for hydrolysis into fermentable sugars. These released sugars can be converted into fuels and chemicals in a biorefinery. Here, we describe a laboratory-scale batch AFEX process to produce pretreated biomass on the gram-scale without any ammonia recycling. The laboratory-scale process can be used to identify optimal pretreatment conditions (e.g., ammonia loading, water loading, biomass loading, temperature, pressure, residence time, etc.) and generates sufficient quantities of pretreated samples for detailed physicochemical characterization and enzymatic/microbial analysis. The yield of fermentable sugars from enzymatic hydrolysis of corn stover pretreated using the laboratory-scale AFEX process is comparable to pilot-scale AFEX process under similar pretreatment conditions. This paper is intended to provide a detailed standard operating procedure for the safe and consistent operation of laboratory-scale reactors for performing AFEX pretreatment of lignocellulosic biomass.


Assuntos
Amônia/farmacologia , Biomassa , Lignina/metabolismo , Biocombustíveis , Reatores Biológicos , Glucose/análise , Poaceae , Temperatura , Xilose/análise
19.
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
20.
Nucleic Acids Res ; 48(9): 5169-5182, 2020 05 21.
Artigo em Inglês | MEDLINE | ID: mdl-32246719

RESUMO

One primary objective of synthetic biology is to improve the sustainability of chemical manufacturing. Naturally occurring biological systems can utilize a variety of carbon sources, including waste streams that pose challenges to traditional chemical processing, such as lignin biomass, providing opportunity for remediation and valorization of these materials. Success, however, depends on identifying micro-organisms that are both metabolically versatile and engineerable. Identifying organisms with this combination of traits has been a historic hindrance. Here, we leverage the facile genetics of the metabolically versatile bacterium Acinetobacter baylyi ADP1 to create easy and rapid molecular cloning workflows, including a Cas9-based single-step marker-less and scar-less genomic integration method. In addition, we create a promoter library, ribosomal binding site (RBS) variants and test an unprecedented number of rationally integrated bacterial chromosomal protein expression sites and variants. At last, we demonstrate the utility of these tools by examining ADP1's catabolic repression regulation, creating a strain with improved potential for lignin bioprocessing. Taken together, this work highlights ADP1 as an ideal host for a variety of sustainability and synthetic biology applications.


Assuntos
Acinetobacter/genética , Engenharia Metabólica , Acinetobacter/metabolismo , Clonagem Molecular/métodos , Genoma Bacteriano , Genômica , Lignina/metabolismo , Regiões Promotoras Genéticas , Ribossomos/metabolismo
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