Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 6.872
Filtrar
1.
Nat Commun ; 15(1): 8163, 2024 Sep 17.
Artículo en Inglés | MEDLINE | ID: mdl-39289346

RESUMEN

This study introduces a synthetic biology approach that reprograms the yeast mating-type switching mechanism for tunable cell differentiation, facilitating synthetic microbial consortia formation and cooperativity. The underlying mechanism was engineered into a genetic logic gate capable of inducing asymmetric sexual differentiation within a haploid yeast population, resulting in a consortium characterized by mating-type heterogeneity and tunable population composition. The utility of this approach in microbial consortia cooperativity was demonstrated through the sequential conversion of xylan into xylose, employing haploids of opposite mating types each expressing a different enzyme of the xylanolytic pathway. This strategy provides a versatile framework for producing and fine-tuning functionally heterogeneous yet isogenic yeast consortia, furthering the advancement of microbial consortia cooperativity and offering additional avenues for biotechnological applications.


Asunto(s)
Genes del Tipo Sexual de los Hongos , Saccharomyces cerevisiae , Biología Sintética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/citología , Saccharomyces cerevisiae/metabolismo , Genes del Tipo Sexual de los Hongos/genética , Biología Sintética/métodos , Diferenciación Celular , Haploidia , Xilosa/metabolismo , Regulación Fúngica de la Expresión Génica
2.
Biotechnol J ; 19(8): e2400210, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-39167552

RESUMEN

The demand for the essential commodity chemical 1,2-propanediol (1,2-PDO) is on the rise, as its microbial production has emerged as a promising method for a sustainable chemical supply. However, the reliance of 1,2-PDO production in Escherichia coli on anaerobic conditions, as enhancing cell growth to augment precursor availability remains a substantial challenge. This study presents glucose-based aerobic production of 1,2-PDO, with xylose utilization facilitating cell growth. An engineered strain was constructed capable of exclusively producing 1,2-PDO from glucose while utilizing xylose to support cell growth. This was accomplished by deleting the gloA, eno, eda, sdaA, sdaB, and tdcG genes for 1,2-PDO production from glucose and introducing the Weimberg pathway for cell growth using xylose. Enhanced 1,2-PDO production was achieved via yagF overexpression and disruption of the ghrA gene involved in the 1,2-PDO-competing pathway. The resultant strain, PD72, produced 2.48 ± 0.15 g L-1 1,2-PDO with a 0.27 ± 0.02 g g-1-glucose yield after 72 h cultivation. Overall, this study demonstrates aerobic 1,2-PDO synthesis through the isolation of the 1,2-PDO synthetic pathway from the tricarboxylic acid cycle.


Asunto(s)
Escherichia coli , Glucosa , Ingeniería Metabólica , Redes y Vías Metabólicas , Escherichia coli/genética , Escherichia coli/metabolismo , Ingeniería Metabólica/métodos , Glucosa/metabolismo , Redes y Vías Metabólicas/genética , Propilenglicol/metabolismo , Xilosa/metabolismo , Aerobiosis , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Fermentación
3.
Appl Microbiol Biotechnol ; 108(1): 443, 2024 Aug 17.
Artículo en Inglés | MEDLINE | ID: mdl-39153091

RESUMEN

The α-glucosidase from Schwanniomyces occidentalis (GAM1p) was expressed in Komagataella phaffii to about 70 mg/L, and its transferase activity studied in detail. Several isomaltooligosaccharides (IMOS) were formed using 200 g/L maltose. The major production of IMOS (81.3 g/L) was obtained when 98% maltose was hydrolysed, of which 34.8 g/L corresponded to isomaltose, 26.9 g/L to isomaltotriose, and 19.6 g/L to panose. The addition of glucose shifted the IMOS synthesis towards products containing exclusively α(1 → 6)-linkages, increasing the production of isomaltose and isomaltotriose about 2-4 fold, enabling the formation of isomaltotetraose, and inhibiting that of panose to about 12 times. In addition, the potential of this enzyme to glycosylate 12 possible hydroxylated acceptors, including eight sugars and four phenolic compounds, was evaluated. Among them, only sucrose, xylose, and piceid (a monoglucosylated derivative of resveratrol) were glucosylated, and the main synthesised products were purified and characterised by MS and NMR. Theanderose, α(1 → 4)-D-glucosyl-xylose, and a mixture of piceid mono- and diglucoside were obtained with sucrose, xylose, and piceid as acceptors, respectively. Maximum production of theanderose reached 81.7 g/L and that of the glucosyl-xylose 26.5 g/L, whereas 3.4 g/L and only 1 g/L were produced of the piceid mono- and diglucoside respectively. KEY POINTS: • Overexpression of a yeast α-glucosidase producing novel molecules. • Yeast enzyme producing the heterooligosaccharides theanderose and glucosyl-xylose. • Glycosylation of the polyphenol piceid by a yeast α-glucosidase.


Asunto(s)
alfa-Glucosidasas , alfa-Glucosidasas/metabolismo , alfa-Glucosidasas/genética , Glicosilación , Saccharomycetales/enzimología , Saccharomycetales/metabolismo , Saccharomycetales/genética , Glucosa/metabolismo , Oligosacáridos/metabolismo , Maltosa/metabolismo , Isomaltosa/metabolismo , Isomaltosa/análogos & derivados , Xilosa/metabolismo , Glucanos
4.
J Agric Food Chem ; 72(33): 18630-18637, 2024 Aug 21.
Artículo en Inglés | MEDLINE | ID: mdl-39116173

RESUMEN

The formation pathway and mechanism of various pyrazines were investigated during the thermal treatment of the alanine-xylose Amadori compound (Ala-ARP) and exogenous alanine (Ala). 15N-labeled Ala was used to coheated with Ala-ARP to clarify the nitrogen sources and the respective contributions of exogenous Ala and the regenerated Ala released from Ala-ARP to different pyrazine formation. It was found that exogenous Ala exhibited a priority in capturing glyoxal (GO) to form pyrazine during the thermal degradation of ARP. Compared to the Ala-methylglyoxal (MGO) model, a lower activation energy was required for the Ala-GO reaction, where the reaction dynamics of Ala-GO followed a zero-order model. In addition to forming pyrazine, the interaction between existing exogenous Ala and GO would accelerate the thermal degradation of Ala-ARP and retro-aldolization reaction of deoxyxylosones (DXs) to α-dicarbonyls. During this process, the release of regenerated Ala and MGO was promoted. Accordingly, as GO was expended by exogenous Ala during the initial stage of ARP-Ala degradation, the condensation between regenerated Ala and MGO became intensified, leading to the generation of methylpyrazine and 2,5-dimethylpyrazine. As a result, in the thermally treated mixture of Ala-ARP and exogenous Ala, 55% of the formed pyrazine originated from exogenous Ala, while 63% of the formed methylpyrazine and 57% of the formed 2,5-dimethylpyrazine were derived from regenerated Ala (120 °C, 30 min).


Asunto(s)
Alanina , Calor , Pirazinas , Pirazinas/química , Alanina/química , Alanina/análogos & derivados , Marcaje Isotópico , Nitrógeno/química , Xilosa/química , Reacción de Maillard , Cinética
5.
Sheng Wu Gong Cheng Xue Bao ; 40(8): 2695-2709, 2024 Aug 25.
Artículo en Chino | MEDLINE | ID: mdl-39174477

RESUMEN

Lignocellulose is the most abundant renewable resource on earth. Constructing microbial cell factories for synthesizing value-added chemicals with lignocellulose is the key to realize green biomanufacturing. Xylose is the second most fermentable sugar in lignocellulose after glucose. Building microbial cell factories that can efficiently metabolize xylose is of great significance to achieve full utilization of lignocellulose. However, the lower metabolism efficiency of xylose than that of glucose in most microorganisms limits the application of xylose. In recent years, the deepening understanding of microbial metabolic mechanisms and the continuous advancement of synthetic biology have greatly improved the efficiency of microbial metabolism of xylose and expanded the spectrum of xylose-derived products. This article introduces several xylose metabolic pathways that exist in the nature and the derived products, summarizes the strategies for constructing recombinant strains that can co-utilize xylose and glucose, and reviews the research progress in the application of lignocellulose hydrolysates in the synthesis of target products. Finally, this article discusses the current technical bottlenecks and prospects the future development directions in this field.


Asunto(s)
Lignina , Ingeniería Metabólica , Xilosa , Xilosa/metabolismo , Lignina/metabolismo , Glucosa/metabolismo , Microbiología Industrial , Fermentación , Biología Sintética , Bacterias/metabolismo , Bacterias/genética , Redes y Vías Metabólicas
6.
Sheng Wu Gong Cheng Xue Bao ; 40(8): 2710-2730, 2024 Aug 25.
Artículo en Chino | MEDLINE | ID: mdl-39174478

RESUMEN

Microbial production of chemicals from renewable biomass has emerged as a crucial route for sustainable bio-manufacturing. Lignocellulose with a renewable property and wide sources is supposed to be a promising feedstock for the second-generation biorefinery. The efficient co-utilization of mixed sugars from lignocellulosic hydrolysates represents one of the key challenges in reducing the production cost. However, most microorganisms prefer glucose over xylose due to carbon catabolite repression, which constrains the efficiency of lignocellulosic conversion. Therefore, developing the microbial platforms capable of simultaneously utilizing glucose and xylose is paramount for economically viable industrial-scale production. This article reviews the key strategies and studies of metabolic engineering for promoting efficient co-utilization of glucose and xylose by microorganisms. The representative strategies include relieving glucose repression, enhancing xylose transport, constructing xylose metabolic pathways, and directed evolution.


Asunto(s)
Glucosa , Ingeniería Metabólica , Xilosa , Xilosa/metabolismo , Ingeniería Metabólica/métodos , Glucosa/metabolismo , Lignina/metabolismo , Fermentación , Microbiología Industrial/métodos , Represión Catabólica , Bacterias/metabolismo , Bacterias/genética
7.
Microb Cell Fact ; 23(1): 237, 2024 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-39217338

RESUMEN

BACKGROUND: Ectoine as an amino acid derivative is widely applied in many fields, such as the food industry, cosmetic manufacturing, biologics, and therapeutic agent. Large-scale production of ectoine is mainly restricted by the cost of fermentation substrates (e.g., carbon sources) and sterilization. RESULTS: In this study, Halomonas cupida J9 was shown to be capable of synthesizing ectoine using xylose as the sole carbon source. A pathway was proposed in H. cupida J9 that synergistically utilizes both WBG xylose metabolism and EMP glucose metabolism for the synthesis of ectoine. Transcriptome analysis indicated that expression of ectoine biosynthesis module was enhanced under salt stress. Ectoine production by H. cupida J9 was enhanced by improving the expression of ectoine biosynthesis module, increasing the intracellular supply of the precursor oxaloacetate, and utilizing urea as the nitrogen source. The constructed J9U-P8EC achieved a record ectoine production of 4.12 g/L after 60 h of xylose fermentation. Finally, unsterile production of ectoine by J9U-P8EC from either a glucose-xylose mixture or corn straw hydrolysate was demonstrated, with an output of 8.55 g/L and 1.30 g/L of ectoine, respectively. CONCLUSIONS: This study created a promising H. cupida J9-based cell factory for low-cost production of ectoine. Our results highlight the potential of J9U-P8EC to utilize lignocellulose-rich agriculture waste for open production of ectoine.


Asunto(s)
Aminoácidos Diaminos , Biomasa , Fermentación , Halomonas , Lignina , Xilosa , Aminoácidos Diaminos/metabolismo , Aminoácidos Diaminos/biosíntesis , Lignina/metabolismo , Xilosa/metabolismo , Halomonas/metabolismo , Halomonas/genética , Tolerancia a la Sal , Glucosa/metabolismo
8.
Int J Mol Sci ; 25(15)2024 Jul 30.
Artículo en Inglés | MEDLINE | ID: mdl-39125891

RESUMEN

This research cloned and expressed the sugar transporter gene KM_SUT5 from Kluyveromyces marxianus GX-UN120, which displayed remarkable sugar transportation capabilities, including pentose sugars. To investigate the impact of point mutations on xylose transport capacity, we selected four sites, predicted the suitable amino acid sites by molecular docking, and altered their codons to construct the corresponding mutants, Q74D, Y195K, S460H, and Q464F, respectively. Furthermore, we conducted site-directed truncation on six sites of KM_SUT5p. The molecular modification resulted in significant changes in mutant growth and the D-xylose transport rate. Specifically, the S460H mutant exhibited a higher growth rate and demonstrated excellent performance across 20 g L-1 xylose, achieving the highest xylose accumulation under xylose conditions (49.94 µmol h-1 gDCW-1, DCW mean dry cell weight). Notably, mutant delA554-, in which the transporter protein SUT5 is truncated at position delA554-, significantly increased growth rates in both D-xylose and D-glucose substrates. These findings offer valuable insights into potential modifications of other sugar transporters and contribute to a deeper understanding of the C-terminal function of sugar transporters.


Asunto(s)
Proteínas Fúngicas , Kluyveromyces , Xilosa , Xilosa/metabolismo , Kluyveromyces/metabolismo , Kluyveromyces/genética , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/genética , Transporte Biológico , Proteínas de Transporte de Membrana/metabolismo , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/química , Simulación del Acoplamiento Molecular , Mutación , Glucosa/metabolismo
9.
Int J Biol Macromol ; 277(Pt 3): 134176, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39096834

RESUMEN

Exploring efficient and comprehensive utilization of agricultural waste to produce high value-added products has been global research hotspot. In this study, a novel process for integrated production of xylose and docosahexaenoic acid (DHA) from hemicellulose and cellulose in corncob was developed. Corncob was treated with dilute H2SO4 at 121 °C for 1 h and xylose was readily produced with a recovery yield of 79.35 %. The corncob residue was then subject to alkali pretreatment under optimized conditions of 0.1 g NaOH/g dry solid, 60 °C for 2 h, and the contents of cellulose, hemicellulose, and lignin in the resulting residue were 87.49 %, 7.58 % and 2.31 %, respectively. The cellulose in the residue was easily hydrolyzed by cellulase, yielding 74.87 g/L glucose with hydrolysis efficiency of 77.02 %. Remarkably, the corncob residue hydrolysate supported cell growth and DHA production in Schizochytrium sp. ATCC 20888 well, and the maximum biomass of 32.71 g/L and DHA yield of 4.63 g/L were obtained, with DHA percentage in total fatty acids of 36.89 %. This study demonstrates that the corncob residue generated during xylose production, rich in cellulose, can be effectively utilized for DHA production by Schizochytrium sp., offering a cost-effective and sustainable alternative to pure glucose.


Asunto(s)
Celulosa , Ácidos Docosahexaenoicos , Polisacáridos , Xilosa , Zea mays , Xilosa/química , Celulosa/química , Zea mays/química , Ácidos Docosahexaenoicos/química , Polisacáridos/química , Polisacáridos/biosíntesis , Hidrólisis , Biomasa , Fermentación
10.
FEMS Yeast Res ; 242024 Jan 09.
Artículo en Inglés | MEDLINE | ID: mdl-39009031

RESUMEN

Lignocellulose (dry plant biomass) is an abundant cheap inedible residue of agriculture and wood industry with great potential as a feedstock for biotechnological processes. Lignocellulosic substrates can serve as valuable resources in fermentation processes, allowing the production of a wide array of chemicals, fuels, and food additives. The main obstacle for cost-effective conversion of lignocellulosic hydrolysates to target products is poor metabolism of the major pentoses, xylose and L-arabinose, which are the second and third most abundant sugars of lignocellulose after glucose. We study the oversynthesis of riboflavin in the flavinogenic yeast Candida famata and found that all major lignocellulosic sugars, including xylose and L-arabinose, support robust growth and riboflavin synthesis in the available strains of C. famata. To further increase riboflavin production from xylose and lignocellulose hydrolysate, genes XYL1 and XYL2 coding for xylose reductase and xylitol dehydrogenase were overexpressed. The resulting strains exhibited increased riboflavin production in both shake flasks and bioreactors using diluted hydrolysate, reaching 1.5 g L-1.


Asunto(s)
Candida , Lignina , Ingeniería Metabólica , Riboflavina , Xilosa , Lignina/metabolismo , Riboflavina/metabolismo , Riboflavina/biosíntesis , Candida/metabolismo , Candida/genética , Xilosa/metabolismo , Aldehído Reductasa/metabolismo , Aldehído Reductasa/genética , Fermentación , Reactores Biológicos/microbiología , D-Xilulosa Reductasa/metabolismo , D-Xilulosa Reductasa/genética , Arabinosa/metabolismo
11.
Carbohydr Polym ; 342: 122414, 2024 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-39048204

RESUMEN

This study aims to understand the molecular and supramolecular transformations of wheat endosperm biopolymers during bread-making, and their implications to fabricate self-standing films from stale white bread. A reduction in the Mw of amylopectin (51.8 × 106 vs 425.1 × 106 g/mol) and water extractable arabinoxylans WEAX (1.79 × 105 vs 7.63 × 105 g/mol), and a decrease in amylose length (245 vs 748 glucose units) was observed after bread-baking. The chain length distribution of amylopectin and the arabinose-to-xylose (A/X) ratio of WEAX remained unaffected during bread-making, suggesting that heat- or/and shear-induced chain scission is the mechanism responsible for molecular fragmentation. Bread-making also resulted in more insoluble cell wall residue, featured by water unextractable arabinoxylan of lower A/X and Mw, along with the formation of a gluten network. Flexible and transparent films with good light-blocking performance (<30 % transmittance) and DPPH-radical scavenging capacity (~8.5 %) were successfully developed from bread and flour. Bread films exhibited lower hygroscopicity, tensile strength (2.7 vs 8.5 MPa) and elastic modulus (67 vs 501 MPa) than flour films, while having a 6-fold higher elongation at break (10.0 vs 61.2 %). This study provides insights into the changes in wheat biopolymers during bread-making and sets a precedent for using stale bread as composite polymeric materials.


Asunto(s)
Amilopectina , Pan , Harina , Triticum , Xilanos , Triticum/química , Pan/análisis , Harina/análisis , Biopolímeros/química , Xilanos/química , Amilopectina/química , Resistencia a la Tracción , Arabinosa/química , Xilosa/química , Glútenes/química
12.
Carbohydr Polym ; 342: 122399, 2024 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-39048235

RESUMEN

This work demonstrates that sesame (Sesamum indicum L.) hull, an unexploited food industrial waste, can be used as an efficient source for the extraction of hemicellulose and/or pectin polysaccharides to further obtain functional oligosaccharides. Different polysaccharides extraction methods were surveyed including alkaline and several enzymatic treatments. Based on the enzymatic release of xylose, arabinose, glucose, and galacturonic acid from sesame hull by using different enzymes, Celluclast®1.5 L, Pectinex®Ultra SP-L, and a combination of them were selected for the enzymatic extraction of polysaccharides at 50 °C, pH 5 up to 24 h. Once the polysaccharides were extracted, Ultraflo®L was selected to produce arabinoxylo-oligosaccharides (AXOS) at 40 °C up to 24 h. Apart from oligosaccharides production from extracted polysaccharides, alternative approaches for obtaining oligosaccharides were also explored. These were based on the analysis of the supernatants resulting from the polysaccharide extraction, alongside a sequential hydrolysis performed with Celluclast®1.5 L and Ultraflo®L of the starting raw sesame hull. The different fractions obtained were comprehensively characterized by determining low molecular weight carbohydrates and monomeric compositions, average Mw and dispersity, and oligosaccharide structure by MALDI-TOF-MS. The results indicated that sesame hull can be a useful source for polysaccharides extraction (pectin and hemicellulose) and derived oligosaccharides, especially AXOS.


Asunto(s)
Oligosacáridos , Sesamum , Sesamum/química , Oligosacáridos/química , Hidrólisis , Polisacáridos/química , Xilanos/química , Xilanos/aislamiento & purificación , Pectinas/química , Pectinas/aislamiento & purificación , Residuos Industriales , Arabinosa/química , Xilosa/química
13.
J Agric Food Chem ; 72(28): 16010-16017, 2024 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-38965162

RESUMEN

Maillard reaction products (MRPs) of xylose with phenylalanine and xylose with proline exhibit high antibacterial activity. However, the active antibacterial compounds in MRPs have not yet been identified or isolated. This study aimed to isolate the active compounds in the two antibacterial MRPs. The organic layer of the MRP solution was separated and purified using silica gel chromatography and high-performance liquid chromatography. The chemical structures of the isolated compounds were determined by mass spectrometry and nuclear magnetic resonance spectroscopy. The compounds inhibited the growth of Bacillus cereus and Salmonella Typhimurium at 25 °C for 7 days at a concentration of 0.25 mM. Furthermore, the isolated compounds inhibited the growth of naturally occurring microflora of lettuce and chicken thighs at 25 °C for 2 days at a concentration of 0.5-1.0 mM. The antibacterial compounds found in MRPs demonstrated a wide range of effectiveness and indicated their potential as alternative preservatives.


Asunto(s)
Antibacterianos , Pollos , Reacción de Maillard , Fenilalanina , Prolina , Salmonella typhimurium , Xilosa , Antibacterianos/farmacología , Antibacterianos/química , Prolina/química , Fenilalanina/química , Xilosa/química , Salmonella typhimurium/efectos de los fármacos , Animales , Bacillus cereus/efectos de los fármacos , Bacillus cereus/crecimiento & desarrollo , Cromatografía Líquida de Alta Presión
14.
Bioresour Technol ; 407: 131146, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39047799

RESUMEN

The utilization of lignocellulosic substrates for microbial oil production by oleaginous yeasts has been evidenced as an economically viable process for industrial-scale biodiesel preparation. Efficient sugar utilization and tolerance to inhibitors are critical for lipid production from lignocellulosic substrates. This study investigated the lignocellulosic sugar utilization and inhibitor tolerance characteristics of Rhodotorula toruloides C23. The results demonstrated that C23 exhibited robust glucose and xylose assimilation irrespective of their ratios, yielding over 21 g/L of lipids and 11 mg/L of carotenoids. Furthermore, C23 exhibited high resistance and efficiently degradation towards toxic inhibitors commonly found in lignocellulosic hydrolysates. The potential molecular mechanism underlying xylose metabolism in C23 was explored, with several key enzymes and signal regulation pathways identified as potentially contributing to its superior lipid synthesis performance. The study highlights R. toruloides C23 as a promising candidate for robust biofuel and carotenoid production through direct utilization of non-detoxified lignocellulosic hydrolysates.


Asunto(s)
Carotenoides , Lignina , Lípidos , Rhodotorula , Rhodotorula/metabolismo , Rhodotorula/efectos de los fármacos , Lignina/metabolismo , Carotenoides/metabolismo , Glucosa/metabolismo , Xilosa/metabolismo , Biocombustibles
15.
Bioresour Technol ; 407: 131141, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39047800

RESUMEN

Furfural-tolerant and hydrogen-producing microbial consortia were enriched from soil, with hydrogen production of 259.84 mL/g-xylose under 1 g/L furfural stress. The consortia could degrade 2.5 g/L furfural within 24 h in the xylose system, more efficient than in the sugar-free system. Despite degradation of furfural to furfuryl alcohol, the release of reactive oxygen species and lactate dehydrogenase was also detected, suggesting that furfuryl alcohol is also a potential inhibitor of hydrogen production. The butyrate/acetate ratio was observed to decrease with increasing furfural concentration, leading to decreased hydrogen production. Furthermore, microbial community analysis suggested that dominated Clostridium butyricum was responsible for furfural degradation, while Clostridium beijerinckii reduction led to hydrogen production decrease. Overall, the enriched consortia in this study could efficiently degrade furfural and produce hydrogen, providing new insights into hydrogen-producing microbial consortia with furfural tolerance.


Asunto(s)
Furaldehído , Hidrógeno , Consorcios Microbianos , Xilosa , Hidrógeno/metabolismo , Furaldehído/metabolismo , Furaldehído/farmacología , Consorcios Microbianos/fisiología , Xilosa/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Microbiología del Suelo , Clostridium butyricum/metabolismo , Clostridium beijerinckii/metabolismo , L-Lactato Deshidrogenasa/metabolismo , Furanos
16.
Environ Sci Pollut Res Int ; 31(35): 48085-48102, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-39017871

RESUMEN

Biomass pretreatment for the production of second-generation (2G) ethanol and biochemical products is a challenging process. The present study investigated the synergistic efficiency of purified carboxymethyl cellulase (CMCase), ß-glucosidase, and xylanase from Aspergillus fumigatus JCM 10253 in the hydrolysis of alkaline-pretreated sugarcane bagasse (SCB). The saccharification of pretreated SCB was optimised using a combination of CMCase and ß-glucosidase (C + ß; 1:1) and addition of xylanase (C + ß + xyl; 1:1:1). Independent and dependent variables influencing enzymatic hydrolysis were investigated using response surface methodology (RSM). Hydrolysis using purified CMCase and ß-glucosidase achieved yields of 18.72 mg/mL glucose and 6.98 mg/mL xylose. Incorporation of xylanase in saccharification increased the titres of glucose (22.83 mg/mL) and xylose (9.54 mg/mL). Furthermore, characterisation of SCB biomass by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy respectively confirmed efficient structural disintegration and revealed the degree of crystallinity and spectral characteristics. Therefore, depolymerisation of lignin to produce high-value chemicals is essential for sustainable and competitive biorefinery development.


Asunto(s)
Aspergillus fumigatus , Biomasa , Celulosa , Saccharum , Hidrólisis , Aspergillus fumigatus/enzimología , Celulasa/metabolismo , Xilosa/metabolismo , beta-Glucosidasa/metabolismo , Azúcares/metabolismo
17.
J Agric Food Chem ; 72(30): 16930-16940, 2024 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-39038222

RESUMEN

Lysine (Lys) is capable of forming a di-substituted Amadori rearrangement product (ARP) with xylose (Xyl), designated as diXyl-α,ε-Lys-ARP. DiXyl-α,ε-Lys-ARP degradation was characterized by two steps: Initially, Xyl-α- and Xyl-ε-Lys-ARP were formed through elimination or hydrolysis at specific Nα/Nε positions of the corresponding enol and imine intermediates, which were then further degraded to dicarbonyl compounds and regenerated Lys. Xyl-α- or Xyl-ε-Lys-ARP had a reactive free amino group (ε-NH2 or α-NH2), both of which were still highly reactive and able to undergo further reactions with Xyl. Therefore, the diXyl-α,ε-Lys-ARP/Xyl model system was established to explore the impact of extra-added Xyl on diXyl-α,ε-Lys-ARP degradation behavior. Extra-added Xyl remarkably affected the degradation pathway of diXyl-α,ε-Lys-ARP by capturing the Xyl-α- and Xyl-ε-Lys-ARP to regenerate diXyl-α,ε-Lys-ARP. This interaction between Xyl and mono-substituted Lys-ARPs promoted the shift of chemical equilibrium toward the degradation of diXyl-α,ε-Lys-ARP, thereby accelerating its degradation rate. This degradation was markedly facilitated by the elevated temperature and pH values. Interestingly, the yield of Xyl-α- and Xyl-ε-Lys-ARP was particularly dependent on the pH during diXyl-α,ε-Lys-ARP degradation. Xyl-ε-Lys-ARP was the dominant product at pH 5.5-7.5 while Xyl-α-Lys-ARP possessed a relatively higher content under weak alkaline conditions, which was related to the reactivities of the Nα/Nε positions under various reaction conditions.


Asunto(s)
Lisina , Reacción de Maillard , Xilosa , Xilosa/química , Lisina/química , Hidrólisis , Cinética , Calor
18.
Int J Biol Macromol ; 276(Pt 1): 133739, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39002907

RESUMEN

Xylose plants (produce xylose from corncob through dilute acid treatment) generate a large amount of corncob residue (CCR), most of which are burned and lacked of valorization. Herein, to address this issue, CCR was directly used as starting material for high-solid loading enzymatic hydrolysis via a simple strategy by combining PFI homogenization (for sufficient mixing) with batch-feeding. A maximum glucose concentration of 187.1 g/L was achieved after the saccharification with a solid loading of 25 wt% and enzyme dosage of 10 FPU/g-CCR. Furthermore, the residue of enzymatic hydrolysis (REH) was directly used as a bio-adhesive for plywood production with both high dry (1.7 MPa) and wet (1.1 MPa) surface bonding strength (higher than the standard (0.7 MPa)), and the excellent adhesion was due to the interfacial crosslinking between the REH adhesive (containing lignin, free glucose, and nanosized fibers) and cell wall of woods. Compared with traditional reported adhesives, the REH bio-adhesive has advantages of formaldehyde-free, good moisture resistance, green process, relatively low cost and easy realization. This study presents a simple and effective strategy for better utilization of CCR, which also provides beneficial reference for the valorization of other kinds of lignocellulosic biomass.


Asunto(s)
Adhesivos , Fermentación , Lignina , Zea mays , Lignina/química , Hidrólisis , Zea mays/química , Adhesivos/química , Glucosa/metabolismo , Glucosa/química , Xilosa/química , Madera/química , Azúcares/química , Azúcares/metabolismo
19.
World J Microbiol Biotechnol ; 40(9): 266, 2024 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-38997527

RESUMEN

Bacteria within the Paenibacillus genus are known to secrete a diverse array of enzymes capable of breaking down plant cell wall polysaccharides. We studied the extracellular xylanolytic activity of Paenibacillus xylanivorans and examined the complete range of secreted proteins when grown on carbohydrate-based carbon sources of increasing complexity, including wheat bran, sugar cane straw, beechwood xylan and sucrose, as control. Our data showed that the relative abundances of secreted proteins varied depending on the carbon source used. Extracellular enzymatic extracts from wheat bran (WB) or sugar cane straw (SCR) cultures had the highest xylanolytic activity, coincidently with the largest representation of carbohydrate active enzymes (CAZymes). Scaling-up to a benchtop bioreactor using WB resulted in a significant enhancement in productivity and in the overall volumetric extracellular xylanase activity, that was further concentrated by freeze-drying. The enzymatic extract was efficient in the deconstruction of xylans from different sources as well as sugar cane straw pretreated by alkali extrusion (SCRe), resulting in xylobiose and xylose, as primary products. The overall yield of xylose released from SCRe was improved by supplementing the enzymatic extract with a recombinant GH43 ß-xylosidase (EcXyl43) and a GH62 α-L-arabinofuranosidase (CsAbf62A), two activities that were under-represented. Overall, we showed that the extracellular enzymatic extract from P. xylanivorans, supplemented with specific enzymatic activities, is an effective approach for targeting xylan within lignocellulosic biomass.


Asunto(s)
Proteínas Bacterianas , Paenibacillus , Saccharum , Xilanos , Xilosa , Xilosidasas , Xilanos/metabolismo , Paenibacillus/metabolismo , Paenibacillus/enzimología , Proteínas Bacterianas/metabolismo , Saccharum/metabolismo , Saccharum/química , Xilosidasas/metabolismo , Xilosa/metabolismo , Reactores Biológicos/microbiología , Fibras de la Dieta/metabolismo , Endo-1,4-beta Xilanasas/metabolismo , Disacáridos/metabolismo , Glicósido Hidrolasas/metabolismo
20.
Microbiol Res ; 287: 127840, 2024 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-39032267

RESUMEN

Rhodosporidium toruloides has emerged as an excellent option for microbial lipid production due to its ability to accumulate up to 70 % of lipids per cell dry weight, consume multiple substrates such as glucose and xylose, and tolerate toxic compounds. Despite the potential of Rhodosporidium toruloides for high lipid yields, achieving these remains is a significant hurdle. A comprehensive review is essential to thoroughly evaluate the advancements in processes and technologies to enhance lipid production in R. toruloides. The review covers various strategies for enhancing lipid production like co-culture, adaptive evolution, carbon flux analysis, as well as different modes of fermentation. This review will help researchers to better understand the recent developments in technologies for sustainable and scalable lipid production from R. toruloides and simultaneously emphasize the need for developing an efficient and sustainable bioprocess.


Asunto(s)
Fermentación , Metabolismo de los Lípidos , Lípidos , Rhodotorula , Lípidos/biosíntesis , Rhodotorula/metabolismo , Técnicas de Cocultivo , Glucosa/metabolismo , Xilosa/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA