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1.
J Agric Food Chem ; 2024 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-38860833

RESUMEN

Ergothioneine (EGT) is a naturally occurring derivative of histidine with diverse applications in the medicine, cosmetic, and food industries. Nevertheless, its sustainable biosynthesis faces hurdles due to the limited biosynthetic pathways, complex metabolic network of precursors, and high cost associated with fermentation. Herein, efforts were made to address these limitations first by reconstructing a novel EGT biosynthetic pathway from Methylobacterium aquaticum in Escherichia coli and optimizing it through plasmid copy number. Subsequently, the supply of precursor amino acids was promoted by engineering the global regulator, recruiting mutant resistant to feedback inhibition, and blocking competitive pathways. These metabolic modifications resulted in a significant improvement in EGT production, increasing from 35 to 130 mg/L, representing a remarkable increase of 271.4%. Furthermore, an economical medium was developed by replacing yeast extract with corn steep liquor, a byproduct of wet milling of corn. Finally, the production of EGT reached 595 mg/L with a productivity of 8.2 mg/L/h by exploiting fed-batch fermentation in a 10 L bioreactor. This study paves the way for exploring and modulating a de novo biosynthetic pathway for efficient and low-cost fermentative production of EGT.

2.
J Agric Food Chem ; 2024 Jun 12.
Artículo en Inglés | MEDLINE | ID: mdl-38867465

RESUMEN

ß-Alanine, a valuable ß-type amino acid, is experiencing increased demand due to its multifaceted applications in food flavoring, nutritional supplements, pharmaceuticals, and the chemical industry. Nevertheless, the sustainable biosynthesis of ß-alanine currently faces challenges due to the scarcity of robust strains, attributed to the complexities of modulating multiple genes and the inherent physiological constraints. Here, systems metabolic engineering was implemented in Escherichia coli to overcome these limitations. First, an efficient l-aspartate-α-decarboxylase (ADC) was recruited for ß-alanine biosynthesis. To conserve phosphoenolpyruvate flux, we subsequently modified the endogenous glucose assimilation system by inactivating the phosphotransferase system (PTS) and introducing an alternative non-PTS system, which increased ß-alanine production to 1.70 g/L. The supply of key precursors, oxaloacetate and l-aspartate, was synergistically improved through comprehensive modulation, including strengthening main flux and blocking bypass metabolism, which significantly increased the ß-alanine titer to 3.43 g/L. Next, the expression of ADC was optimized by promoter and untranslated region (UTR) engineering. Further transport engineering, which involved disrupting ß-alanine importer CycA and heterologously expressing ß-alanine exporter NCgI0580, improved ß-alanine production to 8.48 g/L. Additionally, corn steep liquor was used to develop a cost-effective medium. The final strain produced 74.03 g/L ß-alanine with a yield of 0.57 mol/mol glucose during fed-batch fermentation.

3.
Food Chem ; 453: 139637, 2024 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-38781897

RESUMEN

Herein, a novel multifunctional enzyme ß-glucosidase/xylanase/feruloyl esterase (GXF) was constructed by fusion of ß-glucosidase and bifunctional xylanase/feruloyl esterase. The activities of ß-glucosidase, xylanase, feruloyl esterase and acetyl xylan esterase displayed by GXF were 67.18 %, 49.54 %, 38.92 % and 23.54 %, respectively, higher than that of the corresponding single functional enzymes. Moreover, the GXF performed better in enhancing aroma and quality of Longjing tea than the single functional enzymes and their mixtures. After treatment with GXF, the grassy and floral odors of tea infusion were significantly improved. Moreover, GXF treatment could improve concentrations of flavonoid aglycones of myricetin, kaempferol and quercetin by 68.1-, 81.42- and 77.39-fold, respectively. In addition, GXF could accelerate the release of reducing sugars, ferulic acid and xylo-oligosaccharides by 9.48-, 8.25- and 4.11-fold, respectively. This multifunctional enzyme may have potential applications in other fields such as food production and biomass degradation.


Asunto(s)
Camellia sinensis , Hidrolasas de Éster Carboxílico , , beta-Glucosidasa , Hidrolasas de Éster Carboxílico/química , Hidrolasas de Éster Carboxílico/metabolismo , beta-Glucosidasa/química , beta-Glucosidasa/metabolismo , Camellia sinensis/química , Camellia sinensis/enzimología , Té/química , Endo-1,4-beta Xilanasas/química , Endo-1,4-beta Xilanasas/metabolismo , Odorantes/análisis
4.
Crit Rev Food Sci Nutr ; : 1-28, 2024 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-38764407

RESUMEN

D-allose, a C-3 epimer of D-glucose and an aldose-ketose isomer of D-allulose, exhibits 80% of sucrose's sweetness while being remarkably low in calories and nontoxic, making it an appealing sucrose substitute. Its diverse physiological functions, particularly potent anticancer and antitumor effects, render it a promising candidate for clinical treatment, garnering sustained attention. However, its limited availability in natural sources and the challenges associated with chemical synthesis necessitate exploring biosynthetic strategies to enhance production. This overview encapsulates recent advancements in D-allose's physicochemical properties, physiological functions, applications, and biosynthesis. It also briefly discusses the crucial role of understanding aldoketose isomerase structure and optimizing its performance in D-allose synthesis. Furthermore, it delves into the challenges and future perspectives in D-allose bioproduction. Early efforts focused on identifying and characterizing enzymes responsible for D-allose production, followed by detailed crystal structure analysis to improve performance through molecular modification. Strategies such as enzyme immobilization and implementing multi-enzyme cascade reactions, utilizing more cost-effective feedstocks, were explored. Despite progress, challenges remain, including the lack of efficient high-throughput screening methods for enzyme modification, the need for food-grade expression systems, the establishment of ordered substrate channels in multi-enzyme cascade reactions, and the development of downstream separation and purification processes.

5.
Bioresour Technol ; 400: 130685, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38599349

RESUMEN

D-arabitol, a versatile compound with applications in food, pharmaceutical, and biochemical industries, faces challenges in biomanufacturing due to poor chassis performance and unclear synthesis mechanisms. This study aimed to enhance the performance of Zygosaccharomyces rouxii to improve D-arabitol production. Firstly, a mutant strain Z. rouxii M075 obtained via atmospheric and room temperature plasma-mediated mutagenesis yielded 42.0 g/L of D-arabitol at 96 h, with about 50 % increase. Transcriptome-guided metabolic engineering of pathway key enzymes co-expression produced strain ZR-M3, reaching 48.9 g/L D-arabitol after 96 h fermentation. Finally, under optimized conditions, fed-batch fermentation of ZR-M3 in a 5 L bioreactor yielded an impressive D-arabitol titer of 152.8 g/L at 192 h, with a productivity of 0.8 g/L/h. This study highlights promising advancements in enhancing D-arabitol production, offering potential for more efficient biomanufacturing processes and wider industrial applications.


Asunto(s)
Fermentación , Ingeniería Metabólica , Mutagénesis , Alcoholes del Azúcar , Transcriptoma , Ingeniería Metabólica/métodos , Alcoholes del Azúcar/metabolismo , Transcriptoma/genética , Reactores Biológicos , Perfilación de la Expresión Génica , Saccharomycetales/genética , Saccharomycetales/metabolismo
6.
ACS Synth Biol ; 13(2): 428-448, 2024 02 16.
Artículo en Inglés | MEDLINE | ID: mdl-38326929

RESUMEN

The CRISPR/Cas9 systems have been developed as tools for genetic engineering and metabolic engineering in various organisms. In this review, various aspects of CRISPR/Cas9 in Saccharomyces cerevisiae, from basic principles to practical applications, have been summarized. First, a comprehensive review has been conducted on the history of CRISPR/Cas9, successful cases of gene disruptions, and efficiencies of multiple DNA fragment insertions. Such advanced systems have accelerated the development of microbial engineering by reducing time and labor, and have enhanced the understanding of molecular genetics. Furthermore, the research progress of the CRISPR/Cas9-based systems in the production of high-value-added chemicals and the improvement of stress tolerance in S. cerevisiae have been summarized, which should have an important reference value for genetic and synthetic biology studies based on S. cerevisiae.


Asunto(s)
Edición Génica , Saccharomyces cerevisiae , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Sistemas CRISPR-Cas/genética , Ingeniería Metabólica , ADN/metabolismo
7.
Bioorg Chem ; 145: 107189, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38350272

RESUMEN

6-Deoxy-l-sorbose (6-DLS) is an imperative rare sugar employed in food, agriculture, pharmaceutical and cosmetic industeries. However, it is a synthetic and very expensive rare sugars, previously synthesized by chemo-enzymatic methods through a long chain of chemical processes. Recently, enzymatic synthesis of rare sugars has attracted a lot of attention due to its advantages over synthetic methods. In this work, a promising approach for the synthesis of 6-DLS from an inexpensive sugar l-fucose was identified. The genes for l-fucose isomerase from Paenibacillus rhizosphaerae (Pr-LFI) and genes for d-tagatose-3-epimerase from Caballeronia fortuita (Cf-DTE) have been used for cloning and co-expression in Escherichia coli, developed a recombinant plasmid harboring pANY1-Pr-LFI/Cf-DTE vector. The recombinant co-expression system exhibited an optimum activity at 50 °C of temperature and pH 6.5 in the presence of Co2+ metal ion which inflated the catalytic activity by 6.8 folds as compared to control group with no metal ions. The recombinant co-expressed system was stable up to more than 50 % relative activity after 12 h and revealed a melting temperature (Tm) of 63.38 °C exhibiting half-life of 13.17 h at 50 °C. The co-expression system exhibited, 4.93, 11.41 and 16.21 g/L of 6-DLS production from initial l-fucose concentration of 30, 70 and 100 g/L, which equates to conversion yield of 16.44 %, 16.30 % and 16.21 % respectively. Generally, this study offers a promising strategy for the biological production of 6-DLS from an inexpensive substrate l-fucose in slightly acidic conditions with the aid of co-expression system harboring Pr-LFI and CF-DTE genes.


Asunto(s)
Isomerasas Aldosa-Cetosa , Hexosas , Sorbosa , Fucosa , Racemasas y Epimerasas/genética , Isomerasas Aldosa-Cetosa/genética , Isomerasas Aldosa-Cetosa/química , Azúcares , Concentración de Iones de Hidrógeno , Proteínas Recombinantes/genética
8.
J Agric Food Chem ; 72(5): 2536-2546, 2024 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-38261597

RESUMEN

Embracing the principles of sustainable development, the valorization of agrowastes into value-added chemicals has nowadays received significant attention worldwide. Herein, Escherichia coli was metabolically rewired to convert cellulosic hydrolysate of corn stover into a key platform chemical, namely, 3-hydroxypropionic acid (3-HP). First, the heterologous pathways were introduced into E. coli by coexpressing glycerol-3-P dehydrogenase and glycerol-3-P phosphatase in both single and fusion (gpdp12) forms, making the strain capable of synthesizing glycerol from glucose. Subsequently, a glycerol dehydratase (DhaB123-gdrAB) and an aldehyde dehydrogenase (GabD4) were overexpressed to convert glycerol into 3-HP. A fine-tuning between glycerol synthesis and its conversion into 3-HP was successfully established by 5'-untranslated region engineering of gpdp12 and dhaB123-gdrAB. The strain was further metabolically modulated to successfully prevent glycerol flux outside the cell and into the central metabolism. The finally remodulated chassis produced 32.91 g/L 3-HP from the cellulosic hydrolysate of stover during fed-batch fermentation.


Asunto(s)
Escherichia coli , Ácido Láctico/análogos & derivados , Zea mays , Escherichia coli/genética , Zea mays/metabolismo , Glicerol/metabolismo , Fermentación , Ingeniería Metabólica
9.
Bioresour Technol ; 393: 130162, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38065516

RESUMEN

Biosynthesis of D-arabitol, a high value-added platform chemical, from renewable carbon sources provides a sustainable and eco-friendly alternative to the chemical industry. Here, a robust brewing yeast, Zygosaccharomyces rouxii, capable of naturally producing D-arabitol was rewired through genome sequencing-based metabolic engineering. The recombinant Z. rouxii obtained by reinforcing the native D-xylulose pathway, improving reductive power of the rate-limiting step, and inhibiting the shunt pathway, produced 73.61% higher D-arabitol than the parent strain. Subsequently, optimization of the fermentation medium composition for the engineered strain provided 137.36 g/L D-arabitol, with a productivity of 0.64 g/L/h in a fed-batch experiment. Finally, the downstream separation of D-arabitol from the complex fermentation broth using an ethanol precipitation method provided a purity of 96.53%. This study highlights the importance of D-xylulose pathway modification in D-arabitol biosynthesis, and pave a complete and efficient way for the sustainable manufacturing of this value-added compound from biosynthesis to preparation.


Asunto(s)
Saccharomycetales , Xilulosa , Zygosaccharomyces , Xilulosa/metabolismo , Glucosa/metabolismo , Alcoholes del Azúcar/metabolismo , Fermentación , Zygosaccharomyces/genética , Zygosaccharomyces/metabolismo
10.
Int J Biol Macromol ; 254(Pt 2): 127859, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37924916

RESUMEN

D-Allose and D-allulose are two important rare natural monosaccharides found in meager amounts. They are considered to be the ideal substitutes for table sugar (sucrose) for, their significantly lower calorie content with around 80 % and 70 % of the sweetness of sucrose, respectively. Additionally, both monosaccharides have gained much attention due to their remarkable physiological properties and excellent health benefits. Nevertheless, D-allose and D-allulose are rare in nature and difficult to produce by chemical methods. Consequently, scientists are exploring bioconversion methods to convert D-allulose into D-allose, with a key enzyme, L-rhamnose isomerase (L-RhIse), playing a remarkable role in this process. This review provides an in-depth analysis of the extractions, physiological functions and applications of D-allose from D-allulose. Specifically, it provides a detailed description of all documented L-RhIse, encompassing their biochemical properties including, pH, temperature, stabilities, half-lives, metal ion dependence, molecular weight, kinetic parameters, specific activities and specificities of the substrates, conversion ratio, crystal structure, catalytic mechanism as well as their wide-ranging applications across diverse fields. So far, L-RhIses have been discovered and characterized experimentally by numerous mesophilic and thermophilic bacteria. Furthermore, the crystal forms of L-RhIses from E. coli and Stutzerimonas/Pseudomonas stutzeri have been previously cracked, together with their catalytic mechanism. However, there is room for further exploration, particularly the molecular modification of L-RhIse for enhancing its catalytic performance and thermostability through the directed evolution or site-directed mutagenesis.


Asunto(s)
Escherichia coli , Fructosa , Escherichia coli/metabolismo , Fructosa/química , Monosacáridos/metabolismo , Sacarosa/metabolismo
11.
Bioresour Technol ; 389: 129843, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37820967

RESUMEN

D-tagatose holds significant importance as a functional monosaccharide with diverse applications in food, medicine, and other fields. This study aimed to explore the oxidoreductive pathway for D-tagatose production, surpassing the contemporary isomerization-mediated biosynthesis approach in order to enhance the thermodynamic equilibrium of the reactions. Initially, a novel galactitol dehydrogenase was discovered through biochemical and bioinformatics analyses. By co-expressing the galactitol dehydrogenase and xylose reductase, the oxidoreductive pathway for D-tagatose synthesis was successfully established in Bacillus subtilis. Subsequently, pathway fine-tuning was achieved via promoter regulation and dehydrogenase-mediated cofactor regeneration, resulting in 6.75-fold higher D-tagatose compared to that produced by the strain containing the unmodified promoter. Finally, optimization of fermentation conditions and medium composition produced 39.57 g/L D-tagatose in a fed-batch experiment, with a productivity of 0.33 g/L/h and a yield of 0.55 mol/mol D-galactose. These findings highlight the potential of the constructed redox pathway as an effective approach for D-tagatose production.


Asunto(s)
Bacillus subtilis , Hexosas , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Galactosa/metabolismo , Oxidación-Reducción
12.
Bioresour Technol ; 389: 129822, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37805087

RESUMEN

3-Hydroxypropionic acid (3-HP) is a top value-added chemical with multifaceted application in chemical, material, and food field. However, limited availability of robust strains and elevated fermentation costs currently impose constraints on sustainable biosynthesis of 3-HP. Herein, transporter engineering, metabolic dynamic modulation, and enzyme engineering were combined to address above limitations. First, a glucose-utilizing 3-HP biosynthetic pathway was constructed in Escherichia coli, followed by recruiting alternative glucose transport system to overcome center metabolism overflow. Next, the Cra (a transcription factor)-dependent switch was applied to autonomously fine-tune carbon flux, which alleviated growth retardation and improved the 3-HP production. Subsequently, inactivation of glycerol facilitator (GlpF) increased intracellular glycerol levels and boosted 3-HP biosynthesis, but caused toxic intermediate 3-hydroxypropionaldehyde (3-HPA) accumulation. Furthermore, semi-rational design of aldehyde dehydrogenase (YdcW) increased its activity and eliminated 3-HPA accumulation. Finally, fed-batch fermentation of the final strain resulted in 52.73 g/L 3-HP, with a yield of 0.59 mol/mol glucose.


Asunto(s)
Acuaporinas , Proteínas de Escherichia coli , Escherichia coli/genética , Escherichia coli/metabolismo , Glicerol/metabolismo , Glucosa/metabolismo , Ingeniería Metabólica/métodos , Acuaporinas/metabolismo
13.
Bioresour Technol ; 386: 129498, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37463614

RESUMEN

This study aimed to produce enhanced fermentable sugars from a novel stover system through the bioprocessing of its soluble sugars and insoluble carbohydrates. The pretreatment conditions were optimized for this high sugar-containing stover (HSS) to control inhibitor formation and obtain enhanced fermentable sugar concentrations. The optimum temperature, acid loading, and reaction time for the pretreatment were 155 °C, 0.5%, and 30 min, respectively, providing up to 97.15% sugar yield and 76.51 g/L total sugars at 10% solid-load. Sugar concentration further increased to 126.9 g/L at 20% solid-load, generating 3.89 g/L acetate, 0.92 g/L 5-hydroxymethyl furfural, 0.82 g/L furfural, and 3.75 g/L total phenolics as inhibitors. To determine the effects of soluble sugars in HSS on fermentable sugar yield and inhibitor formation, sugar-removed HSS was further studied under the optimum conditions. Although prior removal of sugars exhibited a reduction in inhibitor generation, it also decreased total fermentable sugar production to 115.45 g/L.


Asunto(s)
Azúcares , Zea mays , Fermentación , Hidrólisis , Carbohidratos
15.
J Appl Microbiol ; 134(1)2023 Jan 23.
Artículo en Inglés | MEDLINE | ID: mdl-36626732

RESUMEN

AIMS: l-Fuculose is a valuable rare sugar that is used to treat a variety of ailments, including HIV, cancer, Hepatitis B, human lysosomal disease (fucosidosis), and cardio-protective medications. The enzymatic approach for the production of l-fuculose using l-fucose as a substrate would be an advantageous method with a wide range of industrial applications. The objective of this study is the characterization of recombinant l-fucose isomerase from Paenibacillus rhizosphaerae (Pa-LFI) for the production of l-fuculose from an inexpensive and natural source (fucoidan) as well as its comparison with commercial l-fucose (Sigma-Aldrich). METHODS AND RESULTS: Fucoidan, a fucose-containing polysaccharide (FPs), was isolated from Undaria pinnatifida, subsequently hydrolyzed, and characterized before the enzymatic production of l-fuculose. The results elaborate that FPs contain 35.9% of fucose along with other kinds of monosaccharides. The purified Pa-LFI exhibited a single band at 65 kDa and showed it as a hexamer with a native molecular mass of 396 kDa. The highest activity of 104.5 U mg-1 of Pa-LFI was perceived at a temperature of 50°C and pH 6.5 in the presence of 1 mM of Mn2+. The Pa-LFI revealed a melting temperature (Tm) of 75°C and a half-life of 12.6 h at 50°C. It exhibited that Pa-LFI with aldose substrate (l-fucose), has a stronger isomerizing activity, disclosing Km,kcat, and kcat/Km 86.2 mM, 32 831 min-1, and 335 min-1 mM-1, respectively. After reaching equilibrium, Pa-LFI efficiently catalyzed the reaction to convert l-fucose into l-fuculose and the conversion ratios of l-fuculose from 100 g L-1 of FPs and commercial fucose were around 6% (5.6 g L-1) and 30% (30.2 g L-1), respectively. CONCLUSIONS: According to the findings of the current study, the Pa-LFI will be useful in the manufacturing of l-fuculose using an effective and easy approach that produces no by-products.


Asunto(s)
Fucosa , Polisacáridos , Humanos , Fucosa/química , Polisacáridos/química
16.
Biotechnol Adv ; 62: 108075, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36502965

RESUMEN

Microbial conversion of bioenergy-derived waste glycerol into value-added chemicals has emerged as an important bioprocessing technology due to its eco-friendliness, feasible technoeconomics, and potential to provide sustainability in biodiesel and bioethanol production. Glycerol is an abundant liquid waste from bioenergy plants with a projected volume of 6 million tons by 2025, accounting for about 10% of biodiesel and 2.5% of bioethanol yields. 3-Hydroxypropionic acid (3-HP) is a major product of glycerol bioconversion, which is the third largest biobased platform compound with expected market size and value of 3.6 million tons/year and USD 10 billion/year, respectively. Despite these biorefinery values, 3-HP biosynthesis from glycerol is still at an immature stage of commercial exploitation. The main challenges behind this immaturity are the toxic effects of 3-HPA on cells, the distribution of carbon flux to undesirable pathways, low tolerance of cells to glycerol and 3-HP, co-factor dependence of enzymes, low enzyme activity and stability, and the problems of substrate inhibition and specificity of enzymes. To address these challenges, it is necessary to understand the fundamentals of glycerol bioconversion and 3-HP production in terms of metabolic pathways, related enzymes, cell factories, midstream process configurations, and downstream 3-HP recovery, as discussed in this review critically and comprehensively. It is equally important to know the current challenges and limitations in 3-HP production, which are discussed in detail along with recent research efforts and remaining gaps. Finally, possible research strategies are outlined considering the recent technological advances in microbial biosynthesis, aiming to attract further research efforts to achieve a sustainable and industrially exploitable 3-HP production technology. By discussing the use of advanced tools and strategies to overcome the existing challenges in 3-HP biosynthesis, this review will attract researchers from many other similar biosynthesis technologies and provide a common gateway for their further development.


Asunto(s)
Biocombustibles , Glicerol , Glicerol/metabolismo , Proyectos de Investigación , Ingeniería Metabólica
17.
J Agric Food Chem ; 71(1): 522-534, 2023 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-36542783

RESUMEN

d-Arabitol, which is typically found in mushrooms, lichens, and higher fungi, might play an effective role in alleviating visceral fat accumulation and insulin resistance particularly for its low calorie and glycemic index. However, the regulatory mechanisms of d-arabitol for alleviating obesity and associated metabolic disorders remain poorly understood. This study aimed to investigate and analyze the underlying relationship between d-arabitol-mediated gut microbiota and obesity. The results showed that d-arabitol dramatically ameliorated body weight gain, fat accumulation, and insulin resistance in HFD-fed rats. Likewise, d-arabitol remarkably increased the relative abundance of the genera Blautia, Anaerostipes, and Phascolarctobacterium and decreased the genera Romboutsia and Clostridium_sensu_stricto_1. Furthermore, these alterations in gut microflora increased SCFAs, which in turn indirectly promoted AMPK-PGC-1α-related white adipose tissue (WAT) browning. Therefore, d-arabitol would have the potential to alleviate obesity through the gut microbiota-SCFAs-WAT browning axis. It could be considered as a sugar substitute for the obese population and diabetic patients.


Asunto(s)
Microbioma Gastrointestinal , Resistencia a la Insulina , Ratas , Animales , Ratones , Obesidad/metabolismo , Tejido Adiposo Blanco/metabolismo , Dieta Alta en Grasa , Ratones Endogámicos C57BL
18.
Bioresour Technol ; 369: 128438, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36470488

RESUMEN

3-Hydroxypropionic acid (3-HP) and 1,3-propanediol (1,3-PDO) are value-added chemicals with versatile applications in the chemical, pharmaceutical, and food industries. Nevertheless, sustainable production of 3-HP and 1,3-PDO is often limited by the lack of efficient strains and suitable fermentation configurations. Herein, attempts have been made to improve the co-production of both metabolites through metabolic engineering of Escherichia coli and process optimization. First, the 3-HP and 1,3-PDO co-biosynthetic pathways were recruited and optimized in E. coli, followed by coupling the pathways to the transhydrogenase-mediated cofactor regeneration systems that increased cofactor availability and product synthesis. Next, pathway rebalancing and block of by-product formation significantly improved 3-HP and 1,3-PDO net titer. Subsequently, glycerol flux toward 3-HP and 1,3-PDO synthesis was maximized by removing metabolic repression and fine-tuning the glycerol oxidation pathway. Lastly, the combined fermentation process optimization and two-stage pH-controlled fed-batch fermentation co-produced 140.50 g/L 3-HP and 1,3-PDO, with 0.85 mol/mol net yield.


Asunto(s)
Glicerol , Ingeniería Metabólica , Glicerol/metabolismo , Escherichia coli/metabolismo , Glicoles de Propileno/metabolismo , Fermentación , Propilenglicol/metabolismo
19.
Bioresour Technol ; 367: 128251, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36334865

RESUMEN

d-Arabitol is a top value-added compound with wide applications in the food, pharmaceutical and biochemical industries. Nevertheless, sustainable biosynthesis of d-arabitol is limited by lack of efficient strains and suitable fermentation process. Herein, metabolic engineering and process optimization were performed in Zygosaccharomyces rouxii to overcoming these limitations. Adopting systems metabolic engineering include enhancement of innate biosynthetic pathway, supply of precursor substrate d-ribulose-5P and cofactors regeneration, a novel recombinant strain ZR-5A with good performance was obtained, which boosted d-arabitol production up to 29.01 g/L, 59.31 % higher than the parent strain. Further with the optimum medium composition and fed-batch fermentation, the strain ZR-5A finally produced 149.10 g/L d-arabitol with the productivity of 1.04 g/L/h, which was the highest titer ever reported by Z.rouxii system. This is the first report on the use of metabolic engineering to construct Z. rouxii chassis for the sustainable production of d-arabitol.


Asunto(s)
Glucosa , Zygosaccharomyces , Glucosa/metabolismo , Ingeniería Metabólica , Alcoholes del Azúcar/metabolismo , Fermentación , Zygosaccharomyces/genética , Zygosaccharomyces/metabolismo
20.
Enzyme Microb Technol ; 162: 110134, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36166886

RESUMEN

A convenient cell extract based metal organic frameworks (CE-MOF) strategy was used to produce self-assembled hybrid microparticles of enzymes with improved characteristics. It was shown that many metal ions and enzymes could be used to construct catalytically active CE-MOF microparticles. As a proof-of-principle study, the ß-xylosidase BH3683 was used to prepare FeSO4-CE-MOF-BH3683 microparticles to explore the factors influencing preparation of the microparticles. As a result, DNA, RNA, polysaccharides and proteins were found to play important roles in the formation of the microparticles and affected enzyme activities through interaction with enzyme molecules. Compared with the free BH3683, the optimum temperature of FeSO4-CE-MOF-BH3683 increased 5 °C, and the relative activity at 70 °C increased two times. Moreover, FeSO4-CE-MOF-BH3683 have stronger tolerance to different concentrations of various organic solvents and high-concentration xylose than the free BH3683, and the CE-MOF microparticles prepared by BH3683 and xylanase XynII could catalyze high-concentration xylan more efficiently than their free counterparts. In addition, FeSO4-CE-MOF-BH3683 exhibited about 40 % of its initial activity after reused for 10 times, showing satisfactory reusability. To sum up, this strategy might have wide application potential in the fields of biocatalysis, biofuel production, fertilizer industry, etc.


Asunto(s)
Estructuras Metalorgánicas , Extractos Celulares , Catálisis , Proteínas , Metales
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