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1.
Molecules ; 29(11)2024 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-38893337

RESUMO

mRNA vaccines are entering a period of rapid development. However, their synthesis is still plagued by challenges related to mRNA impurities and fragments (incomplete mRNA). Most impurities of mRNA products transcribed in vitro are mRNA fragments. Only full-length mRNA transcripts containing both a 5'-cap and a 3'-poly(A) structure are viable for in vivo expression. Therefore, RNA fragments are the primary product-related impurities that significantly hinder mRNA efficacy and must be effectively controlled; these species are believed to originate from either mRNA hydrolysis or premature transcriptional termination. In the manufacturing of commercial mRNA vaccines, T7 RNA polymerase-catalyzed in vitro transcription (IVT) synthesis is a well-established method for synthesizing long RNA transcripts. This study identified a pivotal domain on the T7 RNA polymerase that is associated with erroneous mRNA release. By leveraging the advantageous properties of a T7 RNA polymerase mutant and precisely optimized IVT process parameters, we successfully achieved an mRNA integrity exceeding 91%, thereby further unlocking the immense potential of mRNA therapeutics.


Assuntos
RNA Polimerases Dirigidas por DNA , RNA Mensageiro , Transcrição Gênica , Proteínas Virais , RNA Mensageiro/genética , RNA Polimerases Dirigidas por DNA/metabolismo , RNA Polimerases Dirigidas por DNA/genética , Proteínas Virais/genética , Proteínas Virais/metabolismo , Vacinas de mRNA
2.
Molecules ; 29(19)2024 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-39407643

RESUMO

The remarkable efficacy of COVID-19 vaccines has established mRNA as a highly promising biomedical technology. However, the adequate application of mRNA therapeutics necessitates additional measures to mitigate the inherent immunogenicity, which is predominantly caused by dsRNA. As a byproduct of the in vitro transcription of mRNA, dsRNA was reported to be originated through several distinct mechanisms, including the extension of 3' loop-back hairpins, the extension of hybridized abortive transcripts, and promoter-independent transcription. The intricate mechanisms involved pose a dilemma as the reduction in dsRNA results in a concomitant decrease in other critical quality attributes of mRNA. Here, we demonstrate that the promoter binding motifs of T7 RNA polymerase directly impact the production of promoter-independent transcription-based dsRNA. Specifically, the G753A mutation significantly reduces the formation of dsRNA byproducts, which can further combine with modified nucleotides to enhance the effectiveness of dsRNA mitigation and with previously reported high-integrity mutation K389A to minimize side effects. Accordingly, the present study reports a cost-effective approach to synthesize high-purity, less immunostimulatory mRNA by using an engineered T7 RNA polymerase mutant.


Assuntos
RNA Polimerases Dirigidas por DNA , RNA Mensageiro , Transcrição Gênica , Proteínas Virais , RNA Mensageiro/genética , RNA Polimerases Dirigidas por DNA/metabolismo , RNA Polimerases Dirigidas por DNA/genética , Proteínas Virais/genética , Proteínas Virais/metabolismo , SARS-CoV-2/genética , Humanos , Vacinas contra COVID-19 , Regiões Promotoras Genéticas , Mutação , RNA de Cadeia Dupla/genética , COVID-19/prevenção & controle , COVID-19/virologia
3.
Molecules ; 27(18)2022 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-36144485

RESUMO

5-Hydroxymethyl-2-furfurylamine (5-HMFA) as an important 5-HMF derivative has been widely utilized in the manufacture of diuretics, antihypertensive drugs, preservatives and curing agents. In this work, an efficient chemoenzymatic route was constructed for producing 5-(hydroxymethyl)furfurylamine (5-HMFA) from biobased D-fructose in deep eutectic solvent Betaine:Glycerol-water. The introduction of Betaine:Glycerol could greatly promote the dehydration of D-fructose to 5-HMF and inhibit the secondary decomposition reactions of 5-HMF, compared with a single aqueous phase. D-Fructose (200 mM) could be catalyzed to 5-HMF (183.4 mM) at 91.7% yield by SG(SiO2) (3 wt%) after 90 min in Betaine:Glycerol (20 wt%), and at 150 °C. E. coli AT exhibited excellent bio-transamination activity to aminate 5-HMF into 5-HMFA at 35 °C and pH 7.5. After 24 h, D-fructose-derived 5-HMF (165.4 mM) was converted to 5-HMFA (155.7 mM) in 94.1% yield with D-Ala (D-Ala-to-5-HMF molar ratio 15:1) in Betaine:Glycerol (20 wt%) without removal of SG(SiO2), achieving a productivity of 0.61 g 5-HMFA/(g substrate D-fructose). Chemoenzymatic valorization of D-fructose with SG(SiO2) and E. coli AT was established for sustainable production of 5-HMFA, which has potential application.


Assuntos
Frutose , Água , Anti-Hipertensivos , Betaína , Solventes Eutéticos Profundos , Diuréticos , Escherichia coli , Frutose/química , Furaldeído/química , Furanos , Glicerol , Dióxido de Silício , Água/química
4.
Bioprocess Biosyst Eng ; 41(4): 501-510, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29279999

RESUMO

Based on the Prussian blue spectrophotometric method, one high-throughput screening strategy for screening lignin-degrading microorganisms was built on 24-well plate at room temperature. One high activity of alkali lignin-degrading strain Rhodococcus pyridinivorans CCZU-B16 was isolated from soil. After the optimization of biodegradation, 30.2% of alkali lignin (4 g/L) was degraded under the nitrogen-limited condition (30/1 of C/N ratio; g/g) at 30 °C for 72 h. It was found that syringyl (S) units and guaiacyl (G) in lignin decreased after biodegradation. Moreover, the accumulated lipid in cells had a fatty acid profile rich in C16 and C18 with four major constituent fatty acids including palmitic acid (C16:0; 22.4%), palmitoleic acid (C16:1; 21.1%), stearic acid (C18:0; 16.2%), and oleic acid (C18:1; 23.1%). In conclusion, Rhodococcus pyridinivorans CCZU-B16 showed high potential application in future.


Assuntos
Lignina/metabolismo , Rhodococcus/metabolismo , Microbiologia do Solo , Rhodococcus/isolamento & purificação
5.
Bioprocess Biosyst Eng ; 40(9): 1427-1436, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28642968

RESUMO

In this study, sequential biological pretreatment (BP) with Galactomyces sp. CCZU11-1 at 30 °C for 3 days and deep eutectic solvent (DES) choline chloride: oxalic acid (ChCl:OA, 1 mol/2 mol) extraction at 120 °C for 1.5 h was used for pretreating BSS. It was found that combination pretreatment could effectively remove xylan and lignin for enhancing enzymatic saccharification. The reducing sugars and glucose from the hydrolysis of 100 g/L pretreated BSS with complexed cellulases of Galactomyces sp. CCZU11-1 were obtained in the yields of 81.0% and 74.1%, respectively. The BSS-hydrolyzates had no inhibitory effects on the lipid-accumulating microorganism Bacillus sp. CCZU11-1, and the cell mass and TAG accumulation were 4.8 g CDW/L and 2.2 g TAG/L, respectively. Fatty acids including palmitic acid (C16:0; 25.3%), palmitoleic acid (C16:1; 24.4%), stearic acid (C18:0; 15.1%), and oleic acid (C18:1; 21.6%) were accumulated in cells. Clearly, this combination pretreatment has high potential application in future.


Assuntos
Celulase/química , Colina/química , Proteínas Fúngicas/química , Ácido Oxálico/química , Brotos de Planta/química , Poaceae/química , Saccharomycetales/enzimologia , Lignina/química , Xilanos/química
6.
Bioprocess Biosyst Eng ; 39(4): 533-43, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26753831

RESUMO

In this study, an effective pretreatment of dilute NaOH-soaked chestnut shell (CNS) with glycerol-HClO4-water (88.8:1.2:10, w/w/w) media at 130 °C for 30 min was successfully demonstrated. Results revealed that the combination pretreatment removed 66.0 % of lignin and 73.7 % of hemicellulose in untreated CNS. The changes in the structural features (crystallinity, morphology, and porosity) of the solid residue of CNS were characterized with Fourier transform infrared spectroscopy, fluorescent microscope, scanning electron microscopy, and X-ray diffraction. Biotransformation of glycerol-HClO4-water pretreated-NaOH-soaked CNS (50 g/L) with a cocktail of enzymes for 72 h, the reducing sugars and glucose were 39.7 and 33.4 g/L, respectively. Moreover, the recovered hydrolyzates containing 20 g/L glucose had no inhibitory effects on the ethanol-fermenting microorganism, and the ethanol production was 0.45 g/g glucose within 48 h. In conclusion, this combination pretreatment shows promise as pretreatment solvent for wheat straw, although the in-depth exploration of this subject is needed.


Assuntos
Etanol/química , Glucose/química , Glicerol/química , Juglans/química , Percloratos/química , Hidróxido de Sódio/química , Lignina/química , Polissacarídeos/química , Água/química
7.
Biotechnol Lett ; 37(1): 183-8, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25214230

RESUMO

Rhodococcus sp. CGMCC 4911 transformed 1,3-propanediol cyclic sulfate (1,3-PDS) and its derivatives into corresponding diols. Ethylene sulfate, glycol sulfide, 1,3-PDS, and 1,2-propanediol cyclic sulfate were effectively hydrolyzed with growing cells. (R)-1,2-Propanediol (>99 % e.e.) was obtained at 44 % yield with growing cells. Glycol sulfide, ethylene sulfate, and 1,3-PDS were converted into the corresponding diols at 94.6, 96.3, and 98.3 %, respectively. Optimal reaction conditions with lyophilized resting cells were 30 °C, pH 7.5, and cell dosage 17.9 mg cell dry wt/ml. 1,3-Propanediol was obtained from 50 mM 1,3-PDS at 97.2 % yield by lyophilized cells after 16 h. Lyophilized cells were entrapped in calcium alginate with a half-life of 263 h at 30 °C, and the total operational time of the immobilized biocatalysts could reach over 192 h with a high conversion rate.


Assuntos
Propilenoglicóis/metabolismo , Rhodococcus/metabolismo , Sulfatos/metabolismo , Proteínas de Bactérias/metabolismo , Biotecnologia , Biotransformação , Células Imobilizadas , Concentração de Íons de Hidrogênio , Propilenoglicóis/análise , Rhodococcus/enzimologia , Sulfatases/metabolismo , Sulfatos/análise
8.
Appl Microbiol Biotechnol ; 98(11): 5275-86, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24691866

RESUMO

Pretreatment of lignocellulosic materials is a prerequisite to facilitate the disruption of the natural recalcitrance of their carbohydrate-lignin shield and to allow enzymes to easily access the crystalline cellulose surfaces. Recently, pretreatment of ionic liquids (ILs) has been widely studied as a promising pretreatment technique; however, it is too expensive to be commercialized. In this study, an efficient acid-catalyzed aqueous IL pretreatment process was developed to optimize the total sugar conversion of pretreated biomass and to reduce IL usage. The experimental results demonstrated that the total sugar conversion was raised to 92.7 % with the synergistic effects of IL (1,3-dimethylimidazolium dimethylphosphate, [MMIM]DMP) and dilute hydrochloric acid (HCl) under pretreatment conditions of 110 °C for 2 h, compared to the conversion of only 27.3 % obtained with untreated corn stover. Moreover, the addition of the inorganic acids, especially HCl, to the IL pretreatment was found to not only significantly destroy the crystalline structure of cellulose in corn stover, promoting the conversion of cellulose and hemicellulose to monomeric sugars, but also provide an opportunity to reduce the usage of expensive IL solvents.


Assuntos
Metabolismo dos Carboidratos , Hidrolases/metabolismo , Lignina/metabolismo , Ácidos , Temperatura Alta , Hidrólise , Líquidos Iônicos , Zea mays/efeitos dos fármacos
9.
Biotechnol Lett ; 36(2): 341-7, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24101250

RESUMO

The nitrilase from Rhodococcus sp. CCZU10-1 catalyses the hydrolysis of dinitriles to acids without the formation of amides and cyanocarboxylic acids. It was induced by benzonitrile and its analogues (tetrachloroterephthalonitrile > Îµ-caprolactam > benzonitrile > phenylacetonitrile), and had activity towards aromatic nitriles (terephthalonitrile > tetrachloroterephthalonitrile > isophthalonitrile > tetrachloroisophthalonitrile > tetrafluoroterephthalonitrile > benzonitrile). After the optimization, the highest nitrilase induction [311 U/(g DCW)] was achieved with tetrachloroterephthalonitrile (1 mM) in the medium after 24 h at 30 °C after optimum enzyme activity was at pH 6.8 and at 30 °C. Efficient biocatalyst recycling was achieved by cell immobilization in calcium alginate, with a product-to-biocatalyst ratios of 776 g terephthalic acid/g DCW and 630 g isophthalic acid/g DCW.


Assuntos
Aminoidrolases/metabolismo , Clorobenzenos/metabolismo , Nitrilas/metabolismo , Ácidos Ftálicos/metabolismo , Rhodococcus/enzimologia , Rhodococcus/metabolismo , Meios de Cultura/química , Concentração de Íons de Hidrogênio , Rhodococcus/efeitos dos fármacos , Temperatura , Fatores de Tempo , Ativação Transcricional
10.
Int J Biol Macromol ; 256(Pt 2): 128297, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38007019

RESUMO

Silver nanoparticles were prepared by loading Ag+ into biochar of waste barley distillers' grains shell by reduction with trisodium citrate, and this silver-loaded biochar was introduced into polyvinyl alcohol-chitosan. Various analysis with Fourier Transform Infrared spectroscopy, X-ray diffraction, Thermogravimetric analysis, and water contact angle revealed that biochar-based silver nanoparticle was incorporated into the polyvinyl alcohol-chitosan film, the biochar-based silver nanoparticles-polyvinyl alcohol-chitosan (C-Ag-loaded PVA/CS) composite film had good thermostability and hydrophobicity. Through the analysis via disk diffusion method, the composite containing 3 % of biochar-based silver nanoparticles-polyvinyl alcohol-chitosan had high antibacterial activity (inhibition zone: 18 mm against E. coli and 15 mm against S. aureus), and the bacterial membrane permeability was measured, indicating that C-Ag-loaded PVA/CS composite film could destroy the cell membrane, release intracellular substances, and have high antioxidant activity. During the storage, the weight loss rate of the biochar-based silver nanoparticles-polyvinyl alcohol-chitosan plastic wrap group was 0.14 %, and the titratable acid content only decreased by 0.061 %, which had a good effect on extending the shelf life of blueberries. The C-Ag-loaded PVA/CS composite film could also delay deterioration of blueberries and prolong storage time. Overall, this composite film had potential in food packaging and extending food shelf-life aspects.


Assuntos
Carvão Vegetal , Quitosana , Nanopartículas Metálicas , Álcool de Polivinil/química , Prata/química , Antioxidantes/farmacologia , Nanopartículas Metálicas/química , Quitosana/química , Escherichia coli , Frutas , Staphylococcus aureus , Antibacterianos/farmacologia , Antibacterianos/química , Embalagem de Alimentos
11.
Int J Biol Macromol ; 271(Pt 2): 132453, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38772472

RESUMO

Ultrasonic extraction of Osmanthus fragrans was used for reducing Ag+ to prepare AgNPs, which were further loaded on barley distiller's grains shell biochar. By supplementary of sodium alginate and tannic acid, composite gel beads were prepared. The physical properties of biochar-based AgNPs­sodium alginate-tannic acid composite gel beads (C-Ag/SA/TA) were characterized. SEM, FTIR, and XRD showed that biochar-based AgNPs were compatible with sodium alginate-tannic acid. CAg greatly improved the dissolution, swelling, and expansion of gel beads. Through the analysis by the agar diffusion method, C-Ag/SA/TA gel beads had high antibacterial activity (inhibition zone: 22 mm against Escherichia coli and 20 mm against Staphylococcus aureus). It was observed that C-Ag/SA/TA composite gel beads had high antioxidant capacity and the free radical scavenging rate reached 89.0 %. The dye adsorption performance of gel beads was studied by establishing a kinetic model. The maximum adsorption capacities of C-Ag/SA/TA gel beads for methylene blue and Congo red were 166.57 and 318.06 mg/g, respectively. The removal rate of Cr(VI) reached 96.4 %. These results indicated that the prepared composite gel beads had a high adsorption capacity for dyes and metal ions. Overall, C-Ag/SA/TA composite gel beads were biocompatible and had potential applications in environmental pollution treatment.


Assuntos
Alginatos , Antibacterianos , Antioxidantes , Carvão Vegetal , Cromo , Nanopartículas Metálicas , Prata , Taninos , Prata/química , Carvão Vegetal/química , Alginatos/química , Taninos/química , Nanopartículas Metálicas/química , Antibacterianos/farmacologia , Antibacterianos/química , Antioxidantes/química , Antioxidantes/farmacologia , Adsorção , Cromo/química , Géis/química , Corantes/química , Cinética , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Poluentes Químicos da Água/química , Polifenóis
12.
Int J Biol Macromol ; 275(Pt 1): 133344, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38914391

RESUMO

The novel multifunctional active packaging composite film with antimicrobial, antioxidant, water-vapor and UV-barrier, and corrosion resistance properties was successfully prepared from waste biomass. In this study, waste poplar sawdust was pretreated using green liquor to extract black liquor (BL). BL was then mixed with polyvinyl alcohol (PVA) solution for synthesizing silver nanoparticles (AgNPs). PVA-BL-AgNPs film was fabricated by solution casting method, and the microstructure characterization and macroscopic performance testing of the composite film were conducted. The results revealed that PVA-BL-AgNPs film exhibited inhibitory effects against Staphylococcus aureus (inhibition zone: 33.6 mm), Pseudomonas aeruginosa (inhibition zone: 31.6 mm), and Escherichia coli (inhibition zone: 32.0 mm). It could eliminate over 99 % of 2,2-diazodi (3-ethyl-benzothiazol-6-sulfonic acid) (ABTS) free radicals and provided 100 % UV-blocking, reducing light-induced food damage. It exhibited the improvement of water-vapor barrier properties and corrosion resistance. In vitro cytotoxicity assays demonstrated that no significant impact occurred on cell proliferation, confirming the safety of the film. Packaging experiments showed that PVA-BL-AgNPs film effectively inhibited milk spoilage and prolonged the shelf-life of bread and bananas. Therefore, PVA-BL-AgNPs film might extend the shelf-life of food and offer significant opportunities in addressing the issues of low safety and environmental pollution associated with traditional packaging films.


Assuntos
Antibacterianos , Antioxidantes , Embalagem de Alimentos , Lignina , Nanopartículas Metálicas , Prata , Raios Ultravioleta , Antibacterianos/farmacologia , Antibacterianos/química , Antioxidantes/química , Antioxidantes/farmacologia , Lignina/química , Corrosão , Embalagem de Alimentos/métodos , Prata/química , Prata/farmacologia , Nanopartículas Metálicas/química , Frutas/química , Álcool de Polivinil/química , Staphylococcus aureus/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Testes de Sensibilidade Microbiana
13.
Bioresour Technol ; 413: 131526, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-39321936

RESUMO

Lignin is a plentiful and readily accessible renewable resource. Vanillylamine is a crucial raw material used to synthesize pharmaceuticals and high-value furan compounds that can be acquired by aminating lignin-derived vanillin (Van). However, effectually achieving the biocatalytic synthesis of vanillylamine has remained challenging. In this study, a dimethyl sulfoxide (DMSO)-H2O (1:9, vol/vol) bioreaction medium was constructed, and a recombinant E. coli ATA1012 carrying ω-transaminase from Caulobacter sp. D5 was used as the ω-transaminase biocatalyst to acquire the effectual biocatalytic synthesis of vanillylamine. Under optimized bioreaction conditions (37 ℃ and pH 7.5) by supplementary of isopropylamine (IPA) (Van/IPA = 1:5, mol/mol), 80-100 mM Van could be effectually converted by ATA1012 whole cells in DMSO-H2O (1:9, vol/vol) within 12 h, yielding 91.2 %-95.4 % vanillylamine, with >99 % selectivity. An efficient amination process was developed using ATA1012 with superior transaminase catalytic activity and substrate tolerance to effectively convert Van to vanillylamine in a DMSO-H2O medium.


Assuntos
Benzaldeídos , Caulobacter , Dimetil Sulfóxido , Escherichia coli , Lignina , Transaminases , Benzaldeídos/metabolismo , Transaminases/metabolismo , Caulobacter/enzimologia , Lignina/metabolismo , Água/química , Biocatálise , Aminação
14.
Bioresour Technol ; 395: 130398, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38286168

RESUMO

The efficient utilization of biomass resources has gained widespread attention in current research. This study focused on the conversion of hemicellulose into xylo-oligosaccharides and furfural, as well as enhanced cellulose saccharification and lignin removal from residual biomass. The solid acid catalyst AT-Sn-MMT was prepared by sulfonation and tin ion loading of montmorillonite K-10. In a mixture of deep eutectic solvent and γ-valerolactone (3:7, v/v), AT-Sn-MMT was used to catalyze Phyllostachys edulis (PE) at 160 °C for 20 min, obtaining a furfural yield of 85.7 % and 1.5 g/L xylo-oligosaccharides. The delignification of pretreated PE was 59.5 %, reaching an accessibility of 221.3 g dye/g material. While the enzymatic saccharification efficiency was increased to 73.1 %. This work drew on the merits of solid acid catalysts and mixed solvent systems, and this constructed pretreatment method could be efficiently applied for co-production of reducing sugars, xylooligosaccharide and furfural, realizing the efficient valorization of PE.


Assuntos
Furaldeído , Glucuronatos , Açúcares , Solventes , Oligossacarídeos , Lignina , Poaceae , Biomassa , Hidrólise
15.
Bioresour Technol ; 398: 130531, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38447620

RESUMO

Glycolic acid is widely employed in chemical cleaning, the production of polyglycolic acid-lactic acid, and polyglycolic acid. Currently, the bottleneck of glycolate biosynthesis lies on the imbalance of metabolic flux and the deficiency of NADPH. In this study, a dynamic regulation system was developed and optimized to enhance the metabolic flux from glucose to glycolate. Additionally, the knockout of transhydrogenase (sthA), along with the overexpression of pyridine nucleotide transhydrogenase (pntAB) and the implementation of the Entner-Doudoroff pathway, were performed to further increase the production of the NADPH, thereby increasing the titer of glycolate to 5.6 g/L. To produce glycolate from corn stover hydrolysate, carbon catabolite repression was alleviated and glucose utilization was accelerated. The final strain, E. coli Mgly10-245, is inducer-free, achieving a glycolate titer of 46.1 g/L using corn stover hydrolysate (77.1 % of theoretical yield). These findings will contribute to the advancement of industrial glycolate production.


Assuntos
Escherichia coli , NADP Trans-Hidrogenases , Escherichia coli/genética , Escherichia coli/metabolismo , Zea mays/metabolismo , NADP/metabolismo , Glicolatos/metabolismo , NADP Trans-Hidrogenases/metabolismo , Ácido Poliglicólico/metabolismo , Glucose/metabolismo , Engenharia Metabólica
16.
Int J Biol Macromol ; 281(Pt 4): 136512, 2024 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-39406320

RESUMO

A multifunctional composite gel with efficient bacteriostatic and dye adsorption properties was prepared using polyvinyl alcohol, chitosan, and soybean isolate protein as carriers, CuNPs prepared by green reduction of dandelion extract as bacteriostatic agent, and glutaraldehyde as cross-linking agent. The composite gel showed good inhibition capacity of Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa with the diameter of inhibition zone of 27.0-28.3 mm by agar diffusion method. The composite gel antibacterial rate remained above 90 % after 14 days of preparation. After 6 times reuse of composite gel in water, the antibacterial rate remained above 90 %, proving its good stability and reusability. Adding dandelion extract and CuNPs greatly improved the gel antioxidant property, acquiring free radical scavenging rate at 95.6 %. This composite gel had good biocompatibility and adsorption performance, and the maximum adsorption amount of methylene blue and methyl orange was 40.36 mg/g and 41.81 mg/g, respectively. To sum up, the green composition of composite gel has good antimicrobial performance and high dye adsorption, which holds significant promising for treating the water body pollution and protecting the environment. To build cost-effective antibacterial and dye adsorption process on a large-scale, in-depth exploration about this topic is still needed to develop.

17.
Bioresour Technol ; 399: 130579, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38479628

RESUMO

An effective deep eutectic solvent (DES) and Iron(III) chloride (FeCl3) combination pretreatment system was developed to improve the removal efficiency of lignin and hemicellulose from corn stover (CS) and enhance its saccharification. N-(2-hydroxyethyl)ethylenediamine (NE) was selected as the hydrogen-bond-donor for preparing ChCl-based DES (ChCl:NE), and a mixture of ChCl:NE (60 wt%) and FeCl3 (0.5 wt%) was utilized for combination pretreatment of CS at 110 ℃ for 50 min. FeCl3/ChCl:NE effectively removed lignin (87.0 %) and xylan (55.9 %) and the enzymatic hydrolysis activity of FeCl3/ChCl:NE-treated CS was 5.5 times that of CS. The reducing sugar yield of pretreated CS was 98.6 %. FeCl3/ChCl:NE significantly disrupted the crystal structure of cellulose in CS and improved the removal of lignin and hemicellulose, enhancing the conversion of cellulose and hemicellulose into monomeric sugars. Overall, this combination of FeCl3 and DES pretreatment methods has high application potential for the biological refining of lignocellulose.


Assuntos
Compostos Férricos , Lignina , Lignina/química , Cloretos , Zea mays/química , Solventes Eutéticos Profundos , Solventes/química , Biomassa , Celulose/química , Xilanos , Hidrólise
18.
Biotechnol Biofuels Bioprod ; 17(1): 59, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38702823

RESUMO

BACKGROUND: Taurine, a semi-essential micronutrient, could be utilized as a sulfur source for some bacteria; however, little is known about its effect on the accumulation of fermentation products. Here, it investigated the effect of taurine on co-production of bioethanol and Monascus azaphilone pigments (MonAzPs) for a fungus. RESULTS: A newly isolated fungus of 98.92% identity with Monascus purpureus co-produced 23.43 g/L bioethanol and 66.12, 78.01 and 62.37 U/mL red, yellow and orange MonAzPs for 3 d in synthetic medium (SM). Taurine enhanced bioethanol titer, ethanol productivity and ethanol yield at the maximum by 1.56, 1.58 and 1.60 times than those of the control in corn stover hydrolysates (CSH), and red, yellow and orange MonAzPs were raised by 1.24, 1.26 and 1.29 times, respectively. Taurine was consumed extremely small quantities for M. purpureus and its promotional effect was not universal for the other two biorefinery fermenting strains. Taurine intensified the gene transcription of glycolysis (glucokinase, phosphoglycerate mutase, enolase and alcohol dehydrogenase) and MonAzPs biosynthesis (serine hydrolases, C-11-ketoreductase, FAD-dependent monooxygenase, 4-O-acyltransferase, deacetylase, NAD(P)H-dependent oxidoredutase, FAD-dependent oxidoredutase, enoyl reductase and fatty acid synthase) through de novo RNA-Seq assays. Furthermore, taurine improved cell membrane permeability through changing cell membrane structure by microscopic imaging assays. CONCLUSIONS: Taurine reinforced co-production of bioethanol and MonAzPs by increasing gene transcription level and cell membrane permeability for M. purpureus. This work would offer an innovative, efficient and taurine-based co-production system for mass accumulation of the value-added biofuels and biochemicals from lignocellulosic biomass.

19.
Front Bioeng Biotechnol ; 12: 1356354, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38655387

RESUMO

Introduction: Circular RNAs (circRNAs) are endogenous noncoding RNAs (ncRNAs) with transcriptional lengths ranging from hundreds to thousands. circRNAs have attracted attention owing to their stable structure and ability to treat complicated diseases. Our objective was to create a one-step reaction for circRNA synthesis using wild-type T7 RNA polymerase as the catalyst. However, T7 RNA polymerase is thermally unstable, and we streamlined circRNA synthesis via consensus and folding free energy calculations for hotspot selection. Because of the thermal instability, the permuted intron and exon (PIE) method for circRNA synthesis is conducted via tandem catalysis with a transcription reaction at a low temperature and linear RNA precursor cyclization at a high temperature. Methods: To streamline the process, a multisite mutant T7 RNA polymerase (S430P, N433T, S633P, F849I, F880Y, and G788A) with significantly improved thermostability was constructed, and G788A was used. Results: The resulting mutant exhibited stable activity at 45°C for over an hour, enabling the implementation of a one-pot transcription and cyclization reaction. The simplified circRNA production process demonstrated an efficiency comparable to that of the conventional two-step reaction, with a cyclization rate exceeding 95% and reduced production of immunostimulatory dsRNA byproducts.

20.
J Agric Food Chem ; 72(39): 21741-21751, 2024 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-39297229

RESUMO

Flutriafol, a globally utilized triazole fungicide in agriculture, is typically applied as a racemic mixture, but its enantiomers differ in bioactivity and environmental impact. The synthesis of flutriafol enantiomers is critically dependent on chiral precursors: 2,2-bisaryl-substituted oxirane [(2-fluorophenyl)-2-(4-fluorophenyl)oxirane, 1a] and 1,2-diol [1-(2-fluorophenyl)-1-(4-fluorophenyl)ethane-1,2-diol, 1b]. Here, we engineered a Rhodotorula paludigensis epoxide hydrolase (RpEH), obtaining mutant Escherichia coli/RpehH336W/L360F with a 6.4-fold enhanced enantiomeric ratio (E) from 5.5 to 35.4. This enabled a gram-scale resolution of rac-1a by E. coli/RpehH336W/L360F, producing (S)-1a (98.2% ees) and (R)-1b (75.0% eep) with 44.3 and 55.7% analytical yields, respectively. As follows, chiral (S)-flutriafol (98.2% ee) and (R)-flutriafol (75.0% ee) were easily synthesized by a one-step chemocatalytic process from (S)-1a and a two-step chemocatalytic process from (R)-1b, respectively. This chemoenzymatic approach offers a superior alternative for the asymmetric synthesis of flutriafol enantiomers. Furthermore, molecular dynamics simulations revealed insight into the enantioselectivity improvement of RpEH toward bulky 2,2-bisaryl-substituted oxirane 1a.


Assuntos
Epóxido Hidrolases , Proteínas Fúngicas , Fungicidas Industriais , Rhodotorula , Triazóis , Fungicidas Industriais/química , Fungicidas Industriais/síntese química , Fungicidas Industriais/metabolismo , Triazóis/química , Triazóis/metabolismo , Triazóis/síntese química , Epóxido Hidrolases/metabolismo , Epóxido Hidrolases/genética , Epóxido Hidrolases/química , Estereoisomerismo , Rhodotorula/enzimologia , Rhodotorula/genética , Rhodotorula/química , Rhodotorula/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Biocatálise , Escherichia coli/genética , Escherichia coli/enzimologia , Escherichia coli/metabolismo , Engenharia de Proteínas
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