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1.
Theor Appl Genet ; 137(7): 157, 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38861001

RESUMO

KEY MESSAGE: Through the histological, physiological, and transcriptome-level identification of the abscission zone of Pennisetum alopecuroides 'Liqiu', we explored the structure and the genes related to seed shattering, ultimately revealing the regulatory network of seed shattering in P. alopecuroides. Pennisetum alopecuroides is one of the most representative ornamental grass species of Pennisetum genus. It has unique inflorescence, elegant appearance, and strong stress tolerance. However, the shattering of seeds not only reduces the ornamental effect, but also hinders the seed production. In order to understand the potential mechanisms of seed shattering in P. alopecuroides, we conducted morphological, histological, physiological, and transcriptomic analyses on P. alopecuroides cv. 'Liqiu'. According to histological findings, the seed shattering of 'Liqiu' was determined by the abscission zone at the base of the pedicel. Correlation analysis showed that seed shattering was significantly correlated with cellulase, lignin, auxin, gibberellin, cytokinin and jasmonic acid. Through a combination of histological and physiological analyses, we observed the accumulation of cellulase and lignin during 'Liqiu' seed abscission. We used PacBio full-length transcriptome sequencing (SMRT) combined with next-generation sequencing (NGS) transcriptome technology to improve the transcriptome data of 'Liqiu'. Transcriptomics further identified many differential genes involved in cellulase, lignin and plant hormone-related pathways. This study will provide new insights into the research on the shattering mechanism of P. alopecuroides.


Assuntos
Regulação da Expressão Gênica de Plantas , Pennisetum , Reguladores de Crescimento de Plantas , Sementes , Transcriptoma , Pennisetum/genética , Pennisetum/fisiologia , Pennisetum/crescimento & desenvolvimento , Sementes/genética , Sementes/crescimento & desenvolvimento , Reguladores de Crescimento de Plantas/metabolismo , Perfilação da Expressão Gênica , Lignina/metabolismo
2.
World J Microbiol Biotechnol ; 40(8): 239, 2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38862848

RESUMO

Anaerobic digestion (AD) emerges as a pivotal technique in climate change mitigation, transforming organic materials into biogas, a renewable energy form. This process significantly impacts energy production and waste management, influencing greenhouse gas emissions. Traditional research has largely focused on anaerobic bacteria and methanogens for methane production. However, the potential of anaerobic lignocellulolytic fungi for degrading lignocellulosic biomass remains less explored. In this study, buffalo rumen inocula were enriched and acclimatized to improve lignocellulolytic hydrolysis activity. Two consortia were established: the anaerobic fungi consortium (AFC), selectively enriched for fungi, and the anaerobic lignocellulolytic microbial consortium (ALMC). The consortia were utilized to create five distinct microbial cocktails-AF0, AF20, AF50, AF80, and AF100. These cocktails were formulated based on varying of AFC and ALMC by weights (w/w). Methane production from each cocktail of lignocellulosic biomasses (cassava pulp and oil palm residues) was evaluated. The highest methane yields of CP, EFB, and MFB were obtained at 337, 215, and 54 mL/g VS, respectively. Cocktails containing a mix of anaerobic fungi, hydrolytic bacteria (Sphingobacterium sp.), syntrophic bacteria (Sphaerochaeta sp.), and hydrogenotrophic methanogens produced 2.1-2.6 times higher methane in cassava pulp and 1.1-1.2 times in oil palm empty fruit bunch compared to AF0. All cocktails effectively produced methane from oil palm empty fruit bunch due to its lipid content. However, methane production ceased after 3 days when oil palm mesocarp fiber was used, due to long-chain fatty acid accumulation. Anaerobic fungi consortia showed effective lignocellulosic and starchy biomass degradation without inhibition due to organic acid accumulation. These findings underscore the potential of tailored microbial cocktails for enhancing methane production from diverse lignocellulosic substrates.


Assuntos
Biomassa , Fungos , Lignina , Metano , Consórcios Microbianos , Metano/metabolismo , Anaerobiose , Lignina/metabolismo , Fungos/metabolismo , Fungos/classificação , Animais , Rúmen/microbiologia , Biocombustíveis , Hidrólise , Fermentação , Bactérias/metabolismo , Bactérias/classificação , Resíduos Industriais , Agricultura/métodos
3.
Water Sci Technol ; 89(11): 2907-2920, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38877621

RESUMO

In this study, three sequencing batch biofilter granular reactors (SBBGRs) were employed to treat model lignin wastewater containing different lignin models (2,6-dimethoxyphenol, 4-methoxyphenol, and vanillin). After 40 days of cultivation, uniform-shaped aerobic granular sludge (AGS) was successfully developed through nutrient supplementation with synthetic wastewater. During the acclimation stage, the chemical oxygen demand (COD) reduction efficiencies of the three reactors showed a trend of initial decreasing (5-20%) and then recovering to a high reduction efficiency (exceeding 90%) in a short period of time. During the stable operation stage, all three reactors achieved COD reduction efficiencies exceeding 90%. These findings indicated the cultivated AGS's robust resistance to changes in lignin models in water. UV-Vis spectra analysis confirmed the effective degradation of the three lignin models. Microbiological analysis showed that Proteobacteria and Bacteroidetes were always the dominant phyla. At the genus level, while Acinetobacter (15.46%) dominated in the inoculation sludge, Kapabacteriales (7.93%), SBR1031 (11.77%), and Chlorobium (25.37%) were dominant in the three reactors (for 2,6-dimethoxyphenol, 4-methoxyphenol, and vanillin) after degradation, respectively. These findings demonstrate that AGS cultured with SBBGR effectively degrades lignin models, with different dominant strains observed for various lignin models.


Assuntos
Reatores Biológicos , Lignina , Esgotos , Esgotos/microbiologia , Lignina/metabolismo , Lignina/química , Aerobiose , Filtração/métodos , Eliminação de Resíduos Líquidos/métodos , Bactérias/metabolismo
4.
Sci Rep ; 14(1): 13446, 2024 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-38862766

RESUMO

Present study concerns the transformation of the agro-industrial by-products olive mill stone waste (OMSW) and walnut shell (WS) to a protein-enriched animal feedstuff utilizing the solid state fermentation (SSF) technique. For this purpose, various mixtures of these by-products were exploited as substrates of the SSF process which was initiated by the P. ostreatus fungus. The respective results indicated that the substrate consisted of 80% WS and 20% OMSW afforded the product with the highest increase in protein content, which accounted the 7.57% of its mass (69.35% increase). In addition, a 26.13% reduction of lignin content was observed, while the most profound effect was observed for their 1,3-1,6 ß-glucans profile, which was increased by 3-folds reaching the 6.94% of substrate's mass. These results are indicative of the OMSW and WS mixtures potential to act as efficient substrate for the development of novel proteinaceous animal feed supplements using the SSF procedure. Study herein contributes to the reintegration of the agro-industrial by-products aiming to confront the problem of proteinaceous animal feed scarcity and reduce in parallel the environmental footprint of the agro-industrial processes within the context of circular economy.


Assuntos
Ração Animal , Fermentação , Resíduos Industriais , Juglans , Olea , Pleurotus , Pleurotus/metabolismo , Juglans/metabolismo , Juglans/química , Olea/metabolismo , Olea/química , Ração Animal/análise , Resíduos Industriais/análise , Lignina/metabolismo , Animais
5.
World J Microbiol Biotechnol ; 40(8): 242, 2024 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-38869634

RESUMO

Lignocellulosic biomass is a valuable, renewable substrate for the synthesis of polyhydroxybutyrate (PHB), an ecofriendly biopolymer. In this study, bacterial strain E5-3 was isolated from soil in Japan; it was identified as Burkholderia ambifaria strain E5-3 by 16 S rRNA gene sequencing. The strain showed optimal growth at 37 °C with an initial pH of 9. It demonstrated diverse metabolic ability, processing a broad range of carbon substrates, including xylose, glucose, sucrose, glycerol, cellobiose, and, notably, palm oil. Palm oil induced the highest cellular growth, with a PHB content of 65% wt. The strain exhibited inherent tolerance to potential fermentation inhibitors derived from lignocellulosic hydrolysate, withstanding 3 g/L 5-hydroxymethylfurfural and 1.25 g/L acetic acid. Employing a fed-batch fermentation strategy with a combination of glucose, xylose, and cellobiose resulted in PHB production 2.7-times that in traditional batch fermentation. The use of oil palm trunk hydrolysate, without inhibitor pretreatment, in a fed-batch fermentation setup led to significant cell growth with a PHB content of 45% wt, equivalent to 10 g/L. The physicochemical attributes of xylose-derived PHB produced by strain E5-3 included a molecular weight of 722 kDa, a number-average molecular weight of 191 kDa, and a polydispersity index of 3.78. The amorphous structure of this PHB displayed a glass transition temperature of 4.59 °C, while its crystalline counterpart had a melting point of 171.03 °C. This research highlights the potential of lignocellulosic feedstocks, especially oil palm trunk hydrolysate, for PHB production through fed-batch fermentation by B. ambifaria strain E5-3, which has high inhibitor tolerance.


Assuntos
Biomassa , Burkholderia , Fermentação , Hidroxibutiratos , Lignina , Óleo de Palmeira , RNA Ribossômico 16S , Xilose , Lignina/metabolismo , Óleo de Palmeira/metabolismo , Hidroxibutiratos/metabolismo , Burkholderia/metabolismo , Burkholderia/genética , Burkholderia/crescimento & desenvolvimento , Xilose/metabolismo , RNA Ribossômico 16S/genética , Microbiologia do Solo , Glucose/metabolismo , Poliésteres/metabolismo , Concentração de Íons de Hidrogênio , Furaldeído/metabolismo , Furaldeído/análogos & derivados , Celobiose/metabolismo
6.
Plant Physiol Biochem ; 212: 108794, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38850730

RESUMO

With the increasing occurrence of global warming, drought is becoming a major constraint for plant growth and crop yield. Plant cell walls experience continuous changes during the growth, development, and in responding to stressful conditions. The plant WRKYs play pivotal roles in regulating the secondary cell wall (SCW) biosynthesis and helping plant defend against abiotic stresses. qRT-PCR evidence showed that OsWRKY12 was affected by drought and ABA treatments. Over-expression of OsWRKY12 decreased the drought tolerance of the rice transgenics at the germination stage and the seedling stage. The transcription levels of drought-stress-associated genes as well as those genes participating in the ABA biosynthesis and signaling were significantly different compared to the wild type (WT). Our results also showed that less lignin and cellulose were deposited in the OsWRKY12-overexpressors, and heterogenous expression of OsWRKY12 in atwrky12 could lower the increased lignin and cellulose contents, as well as the improved PEG-stress tolerance, to a similar level as the WT. qRT-PCR results indicated that the transcription levels of all the genes related to lignin and cellulose biosynthesis were significantly decreased in the rice transgenics than the WT. Further evidence from yeast one-hybrid assay and the dual-luciferase reporter system suggested that OsWRKY12 could bind to promoters of OsABI5 (the critical component of the ABA signaling pathway) and OsSWN3/OsSWN7 (the key positive regulators in the rice SCW thickening), and hence repressing their expression. In conclusion, OsWRKY12 mediates the crosstalk between SCW biosynthesis and plant stress tolerance by binding to the promoters of different downstream genes.


Assuntos
Parede Celular , Secas , Regulação da Expressão Gênica de Plantas , Oryza , Proteínas de Plantas , Estresse Fisiológico , Fatores de Transcrição , Oryza/genética , Oryza/metabolismo , Parede Celular/metabolismo , Parede Celular/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Estresse Fisiológico/genética , Lignina/biossíntese , Lignina/metabolismo , Plantas Geneticamente Modificadas , Celulose/biossíntese , Celulose/metabolismo , Ácido Abscísico/metabolismo
7.
Sci Rep ; 14(1): 13350, 2024 06 10.
Artigo em Inglês | MEDLINE | ID: mdl-38858437

RESUMO

Lignin, a heterogeneous aromatic polymer present in plant biomass, is intertwined with cellulose and hemicellulose fibrils, posing challenges to its effective utilization due to its phenolic nature and recalcitrance to degradation. In this study, three lignin utilizing bacteria, Klebsiella sp. LEA1, Pseudomonas sp. LEA2, and Burkholderia sp. LEA3, were isolated from deciduous forest soil samples in Nan province, Thailand. These isolates were capable of growing on alkali lignin and various lignin-associated monomers at 40 °C under microaerobic conditions. The presence of Cu2+ significantly enhanced guaiacol oxidation in Klebsiella sp. LEA1 and Pseudomonas sp. LEA2. Lignin-related monomers and intermediates such as 2,6-dimethoxyphenol, 4-vinyl guaiacol, 4-hydroxybenzoic acid, benzoic acid, catechol, and succinic acid were detected mostly during the late stage of incubation of Klebsiella sp. LEA1 and Pseudomonas sp. LEA2 in lignin minimal salt media via GC-MS analysis. The intermediates identified from Klebsiella sp. LEA1 degradation suggested that conversion and utilization occurred through the ß-ketoadipate (ortho-cleavage) pathway under limited oxygen conditions. The ability of these bacteria to thrive on alkaline lignin and produce various lignin-related intermediates under limited oxygen conditions suggests their potential utility in oxygen-limited processes and the production of renewable chemicals from plant biomass.


Assuntos
Florestas , Klebsiella , Lignina , Oxigênio , Pseudomonas , Microbiologia do Solo , Lignina/metabolismo , Pseudomonas/metabolismo , Pseudomonas/isolamento & purificação , Oxigênio/metabolismo , Klebsiella/metabolismo , Klebsiella/isolamento & purificação , Burkholderia/metabolismo , Burkholderia/isolamento & purificação , Biodegradação Ambiental
8.
Appl Microbiol Biotechnol ; 108(1): 321, 2024 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-38709299

RESUMO

Most reduced organic matter entering activated sludge systems is particulate (1-100-µm diameter) or colloidal (0.001-1-µm diameter), yet little is known about colonization of particulate organic matter by activated sludge bacteria. In this study, colonization of biopolymers (chitin, keratin, lignocellulose, lignin, and cellulose) by activated sludge bacteria was compared with colonization of glass beads in the presence and absence of regular nutrient amendment (acetate and ammonia). Scanning electron microscopy and quantitative PCR revealed chitin and cellulose were most readily colonized followed by lignin and lignocellulose, while keratin and glass beads were relatively resistant to colonization. Bacterial community profiles on particles compared to sludge confirmed that specific bacterial phylotypes preferentially colonize different biopolymers. Nitrifying bacteria proved adept at colonizing particles, achieving higher relative abundance on particles compared to bulk sludge. Denitrifying bacteria showed similar or lower relative abundance on particles compared to sludge. KEY POINTS: • Some activated sludge bacteria colonize natural biopolymers more readily than others. • Nitrifying bacteria are overrepresented in natural biopolymer biofilm communities. • Biopolymers in wastewater likely influence activated sludge community composition.


Assuntos
Bactérias , Esgotos , Águas Residuárias , Biopolímeros/metabolismo , Bactérias/metabolismo , Bactérias/genética , Bactérias/classificação , Esgotos/microbiologia , Águas Residuárias/microbiologia , Lignina/metabolismo , Microscopia Eletrônica de Varredura , Celulose/metabolismo , Biofilmes/crescimento & desenvolvimento , Quitina/metabolismo , Nitrificação , Purificação da Água/métodos
9.
Appl Microbiol Biotechnol ; 108(1): 335, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38747981

RESUMO

Glucuronoyl esterases (GEs) are serine-type hydrolase enzymes belonging to carbohydrate esterase family 15 (CE15), and they play a central role in the reduction of recalcitrance in plant cell walls by cleaving ester linkages between glucuronoxylan and lignin in lignocellulose. Recent studies have suggested that bacterial CE15 enzymes are more heterogeneous in terms of sequence, structure, and substrate preferences than their fungal counterparts. However, the sequence space of bacterial GEs has still not been fully explored, and further studies on diverse enzymes could provide novel insights into new catalysts of biotechnological interest. To expand our knowledge on this family of enzymes, we investigated three unique CE15 members encoded by Dyadobacter fermentans NS114T, a Gram-negative bacterium found endophytically in maize/corn (Zea mays). The enzymes are dissimilar, sharing ≤ 39% sequence identity to each other' and were considerably different in their activities towards synthetic substrates. Combined analysis of their primary sequences and structural predictions aided in establishing hypotheses regarding specificity determinants within CE15, and these were tested using enzyme variants attempting to shift the activity profiles. Together, the results expand our existing knowledge of CE15, shed light into the molecular determinants defining specificity, and support the recent thesis that diverse GEs encoded by a single microorganism may have evolved to fulfil different physiological functions. KEY POINTS: • D. fermentans encodes three CE15 enzymes with diverse sequences and specificities • The Region 2 inserts in bacterial GEs may directly influence enzyme activity • Rational amino acid substitutions improved the poor activity of the DfCE15A enzyme.


Assuntos
Zea mays , Especificidade por Substrato , Esterases/genética , Esterases/metabolismo , Esterases/química , Lignina/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/química , Filogenia
10.
Environ Sci Technol ; 58(21): 9446-9455, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38748977

RESUMO

Biological pretreatment is a viable method for enhancing biogas production from straw crops, with the improvement in lignocellulose degradation efficiency being a crucial factor in this process. Herein, a metagenomic approach was used to screen core microorganisms (Bacillus subtilis, Acinetobacter johnsonii, Trichoderma viride, and Aspergillus niger) possessing lignocellulose-degrading abilities among samples from three environments: pile retting wheat straw (WS), WS returned to soil, and forest soil. Subsequently, synthetic microbial communities were constructed for fermentation-enzyme production. The crude enzyme solution obtained was used to pretreat WS and was compared with two commercial enzymes. The synthetic microbial community enzyme-producing pretreatment (SMCEP) yielded the highest enzymatic digestion efficacy for WS, yielding cellulose, hemicellulose, and lignin degradation rates of 39.85, 36.99, and 19.21%, respectively. Furthermore, pretreatment of WS with an enzyme solution, followed by anaerobic digestion achieved satisfactory results. SMCEP displayed the highest cumulative biogas production at 801.16 mL/g TS, which was 38.79% higher than that observed for WS, 22.15% higher than that of solid-state commercial enzyme pretreatment and 25.41% higher than that of liquid commercial enzyme pretreatment. These results indicate that enzyme-pretreated WS can significantly enhance biogas production. This study represents a solution to the environmental burden and energy use of crop residues.


Assuntos
Biocombustíveis , Triticum , Triticum/metabolismo , Anaerobiose , Fermentação , Lignina/metabolismo
11.
Funct Plant Biol ; 512024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38801747

RESUMO

Rapid wound healing is crucial in protecting sweet potatoes (Ipomoea batatas ) against infection, water loss and quality deterioration during storage. The current study investigated how acibenzolar-S-methyl (ASM) treatment influenced wound healing in harvested sweet potatoes by investigating the underlying mechanism. It was found that ASM treatment of wounded sweet potatoes induced a significant accumulation of lignin at the wound sites, which effectively suppressed weight loss. After 4days of healing, the lignin content of ASM-treated sweet potatoes was 41.8% higher than that of untreated ones, and the weight loss rate was 20.4% lower. Moreover, ASM treatment increased the ability of sweet potatoes to defend against wounding stress through enhancing processes such as increased production of reactive oxygen species (ROS), activation of enzymes involved in the ROS metabolism (peroxidase, superoxide dismutase and catalase) and phenylpropanoid pathway (phenylalanine ammonia lyase, cinnamate-4-hydroxylase, 4-coumarate-CoA ligase and cinnamyl alcohol dehydrogenase), and intensive synthesis of phenolics and flavonoids. These results suggest that treating harvested sweet potatoes with ASM promotes wound healing through the activation of the ROS metabolism and phenylpropanoid pathway.


Assuntos
Ipomoea batatas , Lignina , Espécies Reativas de Oxigênio , Ipomoea batatas/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Lignina/metabolismo , Cicatrização/efeitos dos fármacos , Proteínas de Plantas/metabolismo , Fenóis/metabolismo , Fenilalanina Amônia-Liase/metabolismo
12.
J Environ Sci (China) ; 144: 55-66, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-38802238

RESUMO

Composting presents a viable management solution for lignocellulose-rich municipal solid waste. However, our understanding about the microbial metabolic mechanisms involved in the biodegradation of lignocellulose, particularly in industrial-scale composting plants, remains limited. This study employed metaproteomics to compare the impact of upgrading from aerated static pile (ASP) to agitated bed (AB) systems on physicochemical parameters, lignocellulose biodegradation, and microbial metabolic pathways during large-scale biowaste composting process, marking the first investigation of its kind. The degradation rates of lignocellulose including cellulose, hemicellulose, and lignin were significantly higher in AB (8.21%-32.54%, 10.21%-39.41%, and 6.21%-26.78%) than those (5.72%-23.15%, 7.01%-33.26%, and 4.79%-19.76%) in ASP at three thermal stages, respectively. The AB system in comparison to ASP increased the carbohydrate-active enzymes (CAZymes) abundance and production of the three essential enzymes required for lignocellulose decomposition involving a mixture of bacteria and fungi (i.e., Actinobacteria, Bacilli, Sordariomycetes and Eurotiomycetes). Conversely, ASP primarily produced exoglucanase and ß-glucosidase via fungi (i.e., Ascomycota). Moreover, AB effectively mitigated microbial stress caused by acetic acid accumulation by regulating the key enzymes involved in acetate conversion, including acetyl-coenzyme A synthetase and acetate kinase. Overall, the AB upgraded from ASP facilitated the lignocellulose degradation and fostered more diverse functional microbial communities in large-scale composting. Our findings offer a valuable scientific basis to guide the engineering feasibility and environmental sustainability for large-scale industrial composting plants for treating lignocellulose-rich waste. These findings have important implications for establishing green sustainable development models (e.g., a circular economy based on material recovery) and for achieving sustainable development goals.


Assuntos
Biodegradação Ambiental , Compostagem , Lignina , Lignina/metabolismo , Compostagem/métodos , Microbiologia do Solo , Bactérias/metabolismo , Eliminação de Resíduos/métodos
13.
J Microbiol Biotechnol ; 34(5): 1017-1028, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38803105

RESUMO

Lignocellulolytic enzymes play a crucial role in efficiently converting lignocellulose into valuable platform molecules in various industries. However, they are limited by their production yields, costs, and stability. Consequently, their production by producers adapted to local environments and the choice of low-cost raw materials can address these limitations. Due to the large amounts of olive stones (OS) generated in Morocco which are still undervalued, Penicillium crustosum, Fusarium nygamai, Trichoderma capillare, and Aspergillus calidoustus, are cultivated under different fermentation techniques using this by-product as a local lignocellulosic substrate. Based on a multilevel factorial design, their potential to produce lignocellulolytic enzymes during 15 days of dark incubation was evaluated. The results revealed that P. crustosum expressed a maximum total cellulase activity of 10.9 IU/ml under sequential fermentation (SF) and 3.6 IU/ml of ß-glucosidase activity under submerged fermentation (SmF). F. nygamai recorded the best laccase activity of 9 IU/ml under solid-state fermentation (SSF). Unlike T. capillare, SF was the inducive culture for the former activity with 7.6 IU/ml. A. calidoustus produced, respectively, 1,009 µg/ml of proteins and 11.5 IU/ml of endoglucanase activity as the best results achieved. Optimum cellulase production took place after the 5th day under SF, while ligninases occurred between the 9th and the 11th days under SSF. This study reports for the first time the lignocellulolytic activities of F. nygamai and A. calidoustus. Furthermore, it underlines the potential of the four fungi as biomass decomposers for environmentally-friendly applications, emphasizing the efficiency of OS as an inducing substrate for enzyme production.


Assuntos
Fermentação , Lignina , Olea , Lignina/metabolismo , Olea/microbiologia , Aspergillus/enzimologia , Aspergillus/metabolismo , Celulase/metabolismo , Celulase/biossíntese , Lacase/metabolismo , Lacase/biossíntese , Penicillium/enzimologia , Penicillium/metabolismo , beta-Glucosidase/metabolismo , beta-Glucosidase/biossíntese , Fusarium/enzimologia , Fusarium/metabolismo , Trichoderma/enzimologia , Trichoderma/metabolismo , Fungos/enzimologia , Fungos/metabolismo , Marrocos , Proteínas Fúngicas/metabolismo
14.
Bioresour Technol ; 402: 130765, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38692372

RESUMO

Hydrothermal pretreatment has been proposed to enhance straw methane yield during anaerobic digestion recently. However, the combined effect of hydrothermal and organic acid pretreatment (HTOAP) needs further investigation. This study identified optimal pretreatment at 120 °C with 3 % acetic acid for 24 h by orthogonal design method. The HTOAP increased the reducing sugar content by destroying the lignocellulosic structure. A 79 % increment of methane production after HTOAP was observed compared to the untreated group. Microbial analysis showed that HTOAP enriched the relative abundance of lignocellulose-degraders, such as W5053, Thermanaerovibrio, Caldicoprobacter, as well as the syntrophic acetate oxidizing bacteria Syntrophaceticus. Moreover, Methanobacterium conducted hydrogenotrophic methanogenesis dominantly. Furthermore, the potential function analysis showed that HTOAP stimulated the expression of key enzymes in the hydrogenotrophic pathway, including carbon-monoxide dehydrogenase (EC 1.2.7.4) and coenzyme F420 hydrogenase (EC 1.12.98.1). This investigation illustrated the potential of HTOAP of rice straw to facilitate methane production.


Assuntos
Metano , Oryza , Metano/metabolismo , Oryza/metabolismo , Anaerobiose/efeitos dos fármacos , Ácido Acético/farmacologia , Ácido Acético/metabolismo , Bactérias/metabolismo , Bactérias/efeitos dos fármacos , Lignina/metabolismo , Água/química
15.
Bioresour Technol ; 402: 130768, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38697367

RESUMO

The bark represents the outer protective layer of trees. It contains high concentrations of antimicrobial extractives, in addition to regular wood polymers. It represents a huge underutilized side stream in forestry, but biotechnological valorization is hampered by a lack of knowledge on microbial bark degradation. Many fungi are efficient lignocellulose degraders, and here, spruce bark degradation by five species, Dichomitus squalens, Rhodonia placenta, Penicillium crustosum, Trichoderma sp. B1, and Trichoderma reesei, was mapped, by continuously analyzing chemical changes in the bark over six months. The study reveals how fungi from different phyla degrade bark using diverse strategies, regarding both wood polymers and extractives, where toxic resin acids were degraded by Basidiomycetes but unmodified/tolerated by Ascomycetes. Proteome analyses of the white-rot D. squalens revealed several proteins, with both known and unknown functions, that were specifically upregulated during growth on bark. This knowledge can accelerate improved utilization of an abundant renewable resource.


Assuntos
Picea , Casca de Planta , Polissacarídeos , Picea/microbiologia , Casca de Planta/química , Polissacarídeos/metabolismo , Fungos/metabolismo , Lignina/metabolismo , Biodegradação Ambiental , Proteínas Fúngicas/metabolismo
16.
Bioresour Technol ; 402: 130772, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38703959

RESUMO

To explore the enzyme-enhanced strategy of a continuous anaerobic dynamic membrane reactor (AnDMBR), the anaerobic codigestion system of food waste and corn straw was first operated stably, and then the best combination of compound enzymes (laccase, endo-ß-1,4-glucanase, xylanase) was determined via a series of batch trials. The results showed that the methane yield (186.8 ± 19.9 mL/g VS) with enzyme addition was 12.2 % higher than that without enzyme addition. Furthermore, the removal rates of cellulose, hemicellulose and lignin increased by 31 %, 36 % and 78 %, respectively. In addition, dynamic membranes can form faster and more stably with enzyme addition. The addition of enzymes changed the structure of microbial communities while maintaining sufficient hydrolysis bacteria (Bacteroidetes), promoting the proliferation of Proteobacteria as a dominant strain and bringing stronger acetylation ability. In summary, the compound enzyme strengthening strategy successfully improved the methane production, dynamic membrane effect, and degradation rate of lignocellulose in AnDMBR.


Assuntos
Reatores Biológicos , Lignina , Membranas Artificiais , Metano , Lignina/metabolismo , Anaerobiose , Metano/metabolismo , Hidrólise , Zea mays/química , Enzimas/metabolismo , Bactérias/metabolismo
17.
J Biotechnol ; 389: 78-85, 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38718873

RESUMO

In a bid to explore the on-site biorefinery approach for conversion of forestry residues, lignocellulosic biomass into value-added products was studied. The bark white pine wood was subjected to the microwave technique of fast and slow hydrolysis under varying acid and biomass concentrations to produce levulinic acid (LA). The HCl (2% v/v) and plant biomass (1% w/v) were identified as the optimum conditions for fast wood hydrolysis (270 ºC for 12 sec), which led to maximum LA yield of 446.68 g/kgPB. The proposed sustainable approach is mild, quick, and utilized a very low concentration of the HCl for the production of LA. The hydrolysate was used as a medium for Kluyveromyces marxianus growth to produce 2-phenylethanol (2-PE). K. marxianus used 74-95% of furfural from hydrolysate as a co-substrate to grow. The proposed model of the integrated biorefinery is an affordable on-site approach of using forest waste into localized solutions to produce LA and 2-PE.


Assuntos
Biomassa , Ácidos Levulínicos , Álcool Feniletílico , Madeira , Ácidos Levulínicos/metabolismo , Madeira/química , Madeira/metabolismo , Hidrólise , Álcool Feniletílico/metabolismo , Kluyveromyces/metabolismo , Kluyveromyces/crescimento & desenvolvimento , Lignina/metabolismo , Lignina/química , Pinus/metabolismo , Pinus/química
18.
BMC Microbiol ; 24(1): 181, 2024 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-38789935

RESUMO

BACKGROUND: Lignin is an intricate phenolic polymer found in plant cell walls that has tremendous potential for being converted into value-added products with the possibility of significantly increasing the economics of bio-refineries. Although lignin in nature is bio-degradable, its biocatalytic conversion is challenging due to its stable complex structure and recalcitrance. In this context, an understanding of strain's genomics, enzymes, and degradation pathways can provide a solution for breaking down lignin to unlock the full potential of lignin as a dominant valuable bioresource. A gammaproteobacterial strain AORB19 has been isolated previously from decomposed wood based on its high laccase production. This work then focused on the detailed genomic and functional characterization of this strain based on whole genome sequencing, the identification of lignin degradation products, and the strain's laccase production capabilities on various agro-industrial residues. RESULTS: Lignin degrading bacterial strain AORB19 was identified as Serratia quinivorans based on whole genome sequencing and core genome phylogeny. The strain comprised a total of 123 annotated CAZyme genes, including ten cellulases, four hemicellulases, five predicted carbohydrate esterase genes, and eight lignin-degrading enzyme genes. Strain AORB19 was also found to possess genes associated with metabolic pathways such as the ß-ketoadipate, gentisate, anthranilate, homogentisic, and phenylacetate CoA pathways. LC-UV analysis demonstrated the presence of p-hydroxybenzaldehyde and vanillin in the culture media which constitutes potent biosignatures indicating the strain's capability to degrade lignin. Finally, the study evaluated the laccase production of Serratia AORB19 grown with various industrial raw materials, with the highest activity detected on flax seed meal (257.71 U/L), followed by pea hull (230.11 U/L), canola meal (209.56 U/L), okara (187.67 U/L), and barley malt sprouts (169.27 U/L). CONCLUSIONS: The whole genome analysis of Serratia quinivorans AORB19, elucidated a repertoire of genes, pathways and enzymes vital for lignin degradation that widens the understanding of ligninolytic metabolism among bacterial lignin degraders. The LC-UV analysis of the lignin degradation products coupled with the ability of S. quinivorans AORB19 to produce laccase on diverse agro-industrial residues underscores its versatility and its potential to contribute to the economic viability of bio-refineries.


Assuntos
Genoma Bacteriano , Lacase , Lignina , Filogenia , Serratia , Lignina/metabolismo , Serratia/genética , Serratia/metabolismo , Serratia/classificação , Lacase/metabolismo , Lacase/genética , Sequenciamento Completo do Genoma , Genômica , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo
19.
BMC Plant Biol ; 24(1): 453, 2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38789944

RESUMO

BACKGROUND: Impatiens is an important genus with rich species of garden plants, and its distribution is extremely extensive, which is reflected in its diverse ecological environment. However, the specific mechanisms of Impatiens' adaptation to various environments and the mechanism related to lignin remain unclear. RESULTS: Three representative Impatiens species,Impatiens chlorosepala (wet, low degree of lignification), Impatiens uliginosa (aquatic, moderate degree of lignification) and Impatiens rubrostriata (terrestrial, high degree of lignification), were selected and analyzed for their anatomical structures, lignin content and composition, and lignin-related gene expression. There are significant differences in anatomical parameters among the stems of three Impatiens species, and the anatomical structure is consistent with the determination results of lignin content. Furthermore, the thickness of the xylem and cell walls, as well as the ratio of cell wall thickness to stem diameter have a strong correlation with lignin content. The anatomical structure and degree of lignification in Impatiens can be attributed to the plant's growth environment, morphology, and growth rate. Our analysis of lignin-related genes revealed a negative correlation between the MYB4 gene and lignin content. The MYB4 gene may control the lignin synthesis in Impatiens by controlling the structural genes involved in the lignin synthesis pathway, such as HCT, C3H, and COMT. Nonetheless, the regulation pathway differs between species of Impatiens. CONCLUSIONS: This study demonstrated consistency between the stem anatomy of Impatiens and the results obtained from lignin content and composition analyses. It is speculated that MYB4 negatively regulates the lignin synthesis in the stems of three Impatiens species by regulating the expression of structural genes, and its regulation mechanism appears to vary across different Impatiens species. This study analyses the variations among different Impatiens plants in diverse habitats, and can guide further molecular investigations of lignin biosynthesis in Impatiens.


Assuntos
Impatiens , Lignina , Caules de Planta , Lignina/metabolismo , Caules de Planta/genética , Caules de Planta/anatomia & histologia , Caules de Planta/crescimento & desenvolvimento , Caules de Planta/metabolismo , Impatiens/genética , Impatiens/metabolismo , Impatiens/crescimento & desenvolvimento , Ecossistema , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Adaptação Fisiológica/genética , Regulação da Expressão Gênica de Plantas , Especificidade da Espécie , Genes de Plantas , Parede Celular/metabolismo , Parede Celular/genética
20.
Microb Cell Fact ; 23(1): 151, 2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38789996

RESUMO

BACKGROUND: Xylans are polysaccharides that are naturally abundant in agricultural by-products, such as cereal brans and straws. Microbial degradation of arabinoxylan is facilitated by extracellular esterases that remove acetyl, feruloyl, and p-coumaroyl decorations. The bacterium Ruminiclostridium cellulolyticum possesses the Xua (xylan utilization associated) system, which is responsible for importing and intracellularly degrading arabinoxylodextrins. This system includes an arabinoxylodextrins importer, four intracellular glycosyl hydrolases, and two intracellular esterases, XuaH and XuaJ which are encoded at the end of the gene cluster. RESULTS: Genetic studies demonstrate that the genes xuaH and xuaJ are part of the xua operon, which covers xuaABCDD'EFGHIJ. This operon forms a functional unit regulated by the two-component system XuaSR. The esterases encoded at the end of the cluster have been further characterized: XuaJ is an acetyl esterase active on model substrates, while XuaH is a xylan feruloyl- and p-coumaryl-esterase. This latter is active on oligosaccharides derived from wheat bran and wheat straw. Modelling studies indicate that XuaH has the potential to interact with arabinoxylobiose acylated with mono- or diferulate. The intracellular esterases XuaH and XuaJ are believed to allow the cell to fully utilize the complex acylated arabinoxylo-dextrins imported into the cytoplasm during growth on wheat bran or straw. CONCLUSIONS: This study reports for the first time that a cytosolic feruloyl esterase is part of an intracellular arabinoxylo-dextrin import and degradation system, completing its cytosolic enzymatic arsenal. This system represents a new pathway for processing highly-decorated arabinoxylo-dextrins, which could provide a competitive advantage to the cell and may have interesting biotechnological applications.


Assuntos
Lignina , Xilanos , Xilanos/metabolismo , Lignina/metabolismo , Biomassa , Ácidos Cumáricos/metabolismo , Oligossacarídeos/metabolismo , Clostridiales/metabolismo , Óperon , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Família Multigênica , Acetilesterase/metabolismo , Acetilesterase/genética , Hidrolases de Éster Carboxílico
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