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1.
Chemistry ; 30(21): e202400269, 2024 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-38329391

RESUMO

Recently, catalytic valorization of biomass-derived furans has received growing interest. 5-Aminomethyl-2-furancarboxylic acid (AMFC), a furan amino acid, holds great promise in the aeras of polymer and pharmaceutical, but its synthesis remains limited. In this work, we report a chemobiocatalytic route toward AMFC by combining laccase-TEMPO system and recombinant Escherichia coli (named E. coli_TAF) harboring ω-transaminase (TA), L-alanine dehydrogenase (L-AlaDH) and formate dehydrogenase (FDH), starting from 5-hydroxymethylfurfural (HMF). In the cascade, HMF is oxidized into 5-formyl-2-furancarboxylic acid (FFCA) by laccase-TEMPO system, and then the resulting intermediate is converted into AMFC by E. coli_TAF via transamination with cheap ammonium formate instead of costly organic amine donors, theoretically generating H2O and CO2 as by-products. The tandem process was run in a one-pot twostep manner, affording AMFC with approximately 81 % yield, together with 10 % 2,5-furandicarboxylic acid (FDCA) as by-product. In addition, the scale-up production of AMFC was demonstrated, with 0.41 g/L h productivity and 8.6 g/L titer. This work may pave the way for green manufacturing of the furan-containing amino acid.


Assuntos
Escherichia coli , Furaldeído/análogos & derivados , Lacase , Escherichia coli/metabolismo , Lacase/química , Aminoácidos , Furanos/química , Furaldeído/química , Furaldeído/metabolismo , Ácidos Dicarboxílicos/química
2.
Crit Rev Food Sci Nutr ; 63(26): 8048-8065, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35319324

RESUMO

Members of Bifidobacterium are among the first microbes to colonize the human intestine naturally, their abundance and diversity in the colon are closely related to host health. Recently, the gut microbiota has been gradually proven to be crucial mediators of various metabolic processes between the external environment and the host. Therefore, the health-promoting benefits of Bifidobacterium spp. and their applications in food have gradually been widely concerned. The main purpose of this review is to comprehensively introduce general features, colonization methods, and safety of Bifidobacterium spp. in the human gut, highlighting its health benefits and industrial applications. On this basis, the existing limitations and scope for future research are also discussed. Bifidobacteria have beneficial effects on the host's digestive system, immune system, and nervous system. However, the first prerequisite for functioning is to have enough live bacteria before consumption and successfully colonize the colon after ingestion. At present, strain breeding, optimization (e.g., selecting acid and bile resistant strains, adaptive evolution, high cell density culture), and external protection technology (e.g., microencapsulation and protectants) are the main strategies to address these challenges in food application.


Assuntos
Microbioma Gastrointestinal , Probióticos , Humanos , Bifidobacterium/metabolismo , Alimento Funcional
3.
Int J Mol Sci ; 24(6)2023 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-36982937

RESUMO

In the study, monodispersed silver nanoparticles (AgNPs) with an average diameter of 9.57 nm were efficiently and controllably biosynthesized by a reductase from Fusarium solani DO7 only in the presence of ß-NADPH and polyvinyl pyrrolidone (PVP). The reductase responsible for AgNP formation in F. solani DO7 was further confirmed as 1,4-α-glucosidase. Meanwhile, based on the debate on the antibacterial mechanism of AgNPs, this study elucidated in further depth that antibacterial action of AgNPs was achieved by absorbing to the cell membrane and destabilizing the membrane, leading to cell death. Moreover, AgNPs could accelerate the catalytic reaction of 4-nitroaniline, and 86.9% of 4-nitroaniline was converted to p-phenylene diamine in only 20 min by AgNPs of controllable size and morphology. Our study highlights a simple, green, and cost-effective process for biosynthesizing AgNPs with uniform sizes and excellent antibacterial activity and catalytic reduction of 4-nitroaniline.


Assuntos
Fusarium , Nanopartículas Metálicas , Prata/metabolismo , alfa-Glucosidases , Testes de Sensibilidade Microbiana , Antibacterianos/farmacologia , Fusarium/metabolismo
4.
J Sci Food Agric ; 103(6): 2762-2772, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36220972

RESUMO

BACKGROUND: Great efforts have been made to improve the oral bioaccessibility of lipophilic ingredients with multi-functionalities. Achieving intestinal delivery of lipophilic ingredients and their encapsulation in micelles composed of bile salts and lipid hydrolysates (i.e. fatty acids) is critical for improving oral bioaccessibility. Therefore, oil-core microcapsules are considered ideal carriers of lipophilic ingredients. Previous studies have reported oil-core/zein-shell microcapsules constructed by a one-step anti-solvent process. Still, its efficacy as an intestinal delivery system was limited because if the porous shell structure. RESULTS: Zein solution was pretreated with ultrasound and tannic acid (TA) cross-linking. Composite oil-core microcapsule (COM) with a compact shell structure was successfully prepared by using modified zein solution in the anti-solvent process. Fourier-transform infrared spectroscopy and circular dichroism analyses indicated that ultrasound and TA synergistically promote the conformational transition of zein from α-helix to ß-sheet and enhance the hydrophobic interactions among protein chains. The above changes contribute to the strengthen of shell zein network. Correspondingly, COM presents superior encapsulation efficiency and environmental stability over the simple oil-core microcapsule (SOM) prepared without the use of ultrasound and TA. Furthermore, antioxidant activity of ß-carotene was well retained during the encapsulation process. In vitro studies indicated that COM was more resistant to digestibility and acid-induced swelling. More than 87% of ß-carotene could be released in the intestine in a sustainable way. The controllable release behavior thus promoted a significant increase in bioaccessibility of ß-carotene encapsulated in COM compared to SOM (85.9% versus 48.5%). CONCLUSION: The COM generated here shows potential for bioaccessibility improvement of lipophilic ingredients. © 2022 Society of Chemical Industry.


Assuntos
Zeína , Cápsulas , Zeína/química , beta Caroteno/química , Micelas , Intestinos , Solventes
5.
Crit Rev Food Sci Nutr ; 62(23): 6341-6358, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-33749401

RESUMO

Lactoferrin (Lf), a bioactive protein initially found in many biological secretions including milk, is regarded as the nutritional supplement or therapeutic ligand due to its multiple functions. Research on its mode of action reveals that intact Lf or its active peptide (i.e., lactoferricin) shows an important multifunctional performance. Oral delivery is considered as the most convenient administration route for this bioactive protein. Unfortunately, Lf is sensitive to the gastrointestinal (GI) physicochemical stresses and lactoferricin is undetectable in GI digesta. This review introduces the functionality of Lf at the molecular level and its degradation behavior in GI tract is discussed in detail. Subsequently, the absorption and transport of Lf from intestine into the blood circulation, which is pivotal to its health promoting effects in various tissues, and some assisting labeling methods are discussed. Stabilization technologies aiming at preserving the structural integrity and functional properties of orally administrated Lf are summarized and compared. Altogether, this work comprehensively reviews the structure-function relationship of Lf, its oral fate and the development of stabilization technologies for the enhancement of the oral bioavailability of Lf. The existing limitations and scope for future research are also discussed.


Assuntos
Lactoferrina , Leite , Animais , Fenômenos Químicos , Trato Gastrointestinal/metabolismo , Leite/química
6.
Small ; 17(20): e2007586, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33825336

RESUMO

Zeolitic imidazolate frameworks (ZIFs) serving as platforms for bioactive guest encapsulation have attracted growing attention, yet the tailoring of its architectures and bioactivity remains a major challenge. Herein, a versatile competitive coordination strategy is proposed by using amorphous zinc nucleotide gel as template for step-by-step growth of ZIFs, which enables the tailoring of bioactive ZIF composites under facile conditions. Mechanism investigation reveals that introduced nucleotide determines the hierarchical pore structure and hydrophilicity, leading to customized activity retention and stability of the resultant bioactive ZIF composites. Furthermore, nucleoside monophosphate enhances the acidic tolerance of ZIFs. To the authors' knowledge, this is the first example showing the dynamic evolution of amorphous gels to crystalline ZIFs for in situ encapsulation of enzymes with tailored catalytic performance. This study provides insights for rational design of ZIF-based biocomposites and broadens the application of bioactive metal-organic frameworks.


Assuntos
Estruturas Metalorgânicas , Zeolitas , Catálise , Zinco
7.
Nanotechnology ; 32(24)2021 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-33690179

RESUMO

An oral multi-unit delivery system was developed by incorporating the nanoparticle (NP) into the nanofiber mat and its efficiency for intestinal-specific delivery and controlled release of a peptide (insulin) was investigated. Initially, the influence of deacetylation degree (DD) of chitosan and ionic gelation methods on the properties of NPs was studied. High DD (95%) chitosan was attributed to higher encapsulation efficiency and stability when crosslinked with polyanion tripolyphosphate. Subsequently, the multi-unit system was fabricated using a pH-sensitive polymer (sodium alginate) as the coating layer to further encapsulate the NP. Fiber mat with an average diameter of 481 ± 47 nm could significantly decrease the burst release of insulin in acidic condition and release most amount of insulin (>60%) in the simulated intestinal medium. Furthermore, the encapsulated peptide remained in good integrity. This multi-unit carrier provides the better-designed vehicle for intestinal-specific delivery and controlled release of the peptide.


Assuntos
Quitosana/química , Insulina/administração & dosagem , Administração Oral , Células CACO-2 , Preparações de Ação Retardada , Composição de Medicamentos , Sistemas de Liberação de Medicamentos , Humanos , Concentração de Íons de Hidrogênio , Insulina/química , Nanopartículas , Polifosfatos/química
8.
World J Microbiol Biotechnol ; 37(3): 43, 2021 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-33547538

RESUMO

Pullulanase (EC 3.2.1.41) is a starch-debranching enzyme in the α-amylase family and specifically cleaves α-1,6-glycosidic linkages in starch-type polysaccharides, such as pullulan, ß-limited dextrin, glycogen, and amylopectin. It plays a key role in debranching and hydrolyzing starch completely, thus bring improved product quality, increased productivity, and reduced production cost in producing resistant starch, sugar syrup, and beer. Plenty of researches have been made with respects to the discovery of either thermophilic or mesophilic pullulanases, however, few examples meet the demand of industrial application. This review presents the progress made in the recent years from the first aspect of characteristics of pullulanases. The heterologous expression of pullulanases in different microbial hosts and the methods used to improve the expression effectiveness and the regulation of enzyme production are also described. Then, the function evolution of pullulanases from a protein engineering view is discussed. In addition, the immobilization strategy using novel materials is introduced to improve the recyclability of pullulanases. At the same time, we indicate the trends in the future research to facilitate the industrial application of pullulanases.


Assuntos
Bactérias/crescimento & desenvolvimento , Glicosídeo Hidrolases/genética , Engenharia de Proteínas/métodos , Bactérias/genética , Bactérias/metabolismo , Enzimas Imobilizadas/metabolismo , Evolução Molecular , Glicosídeo Hidrolases/metabolismo , Hidrólise , Proteínas Recombinantes/metabolismo , Especificidade por Substrato
9.
J Sci Food Agric ; 100(12): 4400-4408, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32388876

RESUMO

BACKGROUND: Increasing food safety awareness of consumers promotes the development of rapid and sensitive detection techniques for pesticide residues. In this study, a new type of rapid detection card for organophosphorus and carbamate pesticide residues was developed by electrospinning. The card involved enzyme fiber mat (EFM) and substrate fiber mat (SFM) which were prepared by mixing poly(vinyl alcohol) with acetylcholinesterase (AChE) and indolyl acetate (IA), respectively. RESULTS: The mean diameter of fibers was 240 ± 53 nm for EFM and 387 ± 84 nm for SFM. Results of Fourier transform infrared and X-ray photoelectron spectroscopies confirmed that AChE and IA were successfully encapsulated into the fibers. The minimum concentrations of AChE and IA for effective detection were 1 and 3 mg mL-1 , respectively, and the optimal detection time was 15 min. The limits of detection for this card were 0.5 mg L-1 for omethoate, 1.5 mg L-1 for malathion, 0.1 mg L-1 for carbaryl and 0.02 mg L-1 for carbofuran. The detection card exhibited good storage stability and its activity could be maintained when stored at room temperature for at least 4 months. Additionally, the EFM can be reused three times. CONCLUSIONS: The detection card obtained here was superior to a commercial card in detecting pesticide residues in real food samples. Hence, this electrospun detection card has potential for simple, rapid and sensitive analysis of pesticide residues. © 2020 Society of Chemical Industry.


Assuntos
Técnicas Biossensoriais/métodos , Inseticidas/análise , Resíduos de Praguicidas/análise , Acetilcolinesterase/química , Técnicas Biossensoriais/instrumentação , Carbamatos/análise , Contaminação de Alimentos/análise , Compostos Organofosforados/análise
10.
World J Microbiol Biotechnol ; 36(3): 35, 2020 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-32088779

RESUMO

Odd-chain fatty acids (OCFAs) naturally occur in bacteria, higher animals, and in plants. During recent years, they have received increasing attention due to their unique pharmacological properties and usefulness for agricultural and industrial applications. Recently, OCFAs have been identified and quantified in a few organisms, and new pharmacological functions of OCFAs have been reported. Some of the publications are related to the optimization of OCFA production through fermentation and genetic engineering. The present review aims to provide a summary on the recent progress in the field of microbial-derived OCFAs. More specifically, we outline the publications of OCFAs related to (i) different sources of OCFAs; (ii) endogenous synthesis of OCFAs; (iii) production of OCFAs through fermentation; (iv) genetic engineering related to OCFA; and (v) role of OCFAs in human health and disease. Finally, some areas that require further research are discussed.


Assuntos
Bactérias/metabolismo , Ácidos Graxos/biossíntese , Fermentação , Engenharia Genética
11.
Biotechnol Bioeng ; 116(12): 3333-3348, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31502661

RESUMO

Considerable attention has been given to the development of robust fermentation processes, but microbial contamination and phage infection remain deadly threats that need to be addressed. In this study, a robust Escherichia coli BL21(DE3) strain was successfully constructed by simultaneously introducing a nitrogen and phosphorus (N&P) system in combination with a CRISPR/Cas9 system. The N&P metabolic pathways were able to express formamidase and phosphite dehydrogenase in the host cell, thus enabled cell growth in auxotrophic 3-(N-morpholino)propanesulfonic acid medium with formamide and phosphite as nitrogen and phosphorus sources, respectively. N&P metabolic pathways also allowed efficient expression of heterologous proteins, such as green fluorescent protein (GFP) and chitinase, while contaminating bacteria or yeast species could hardly survive in this medium. The host strain was further engineered by exploiting the CRISPR/Cas9 system to enhance the resistance against phage attack. The resultant strain was able to grow in the presence of T7 phage at a concentration of up to 2 × 107 plaque-forming units/ml and produce GFP with a yield of up to 30 µg/109 colony-forming units, exhibiting significant advantages over conventional engineered E. coli. This newly engineered, robust E. coli BL21(DE3) strain therefore shows great potential for future applications in industrial fermentation.


Assuntos
Bacteriófago T7 , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/genética , Engenharia Metabólica , Microrganismos Geneticamente Modificados/crescimento & desenvolvimento , Microrganismos Geneticamente Modificados/genética , Sistemas CRISPR-Cas , Escherichia coli/virologia , Redes e Vias Metabólicas
12.
J Sci Food Agric ; 99(14): 6219-6226, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31250449

RESUMO

BACKGROUND: Temperatures that special fat faces in a real environment fluctuate, thus, understanding the property changes of special fats under fluctuating temperatures will be helpful in guiding how to keep its high quality in the production and application process. Therefore, a comparative study was carried out on the storage stability of physical blend-based and interesterified blend-based special fats (PBSFs and IBSFs) and their oxidative stability, crystallization and physical properties were studied under fluctuating temperatures. RESULTS: The peroxide values of IBSFs and PBSFs were less than 10.0 mmol kg-1 after 4 weeks of storage, and IBSFs had better oxidative stability. There was little change in the solid fat content, and the hardness decreased when IBSFs and PBSFs were stored for 4 weeks. X-ray diffraction results indicated that PBSFs had only ß-crystal, but IBSFs had ß- and ß'-crystal after storage. Moreover, in IBSFs, the transformation from ß'- to ß-form in PS:RO-IBSF was more obvious than that in PS:SO-IBSF (PS, palm stearin; SO, soybean oil; RO, rapeseed oil) after 4 weeks of storage, and the good integrity of crystalline network in fast-frozen special fats during fluctuating temperature storage followed the order: IBSF > PBSF, PS:RO-PBSF > PS:SO-PBSF. CONCLUSION: The results suggest IBSF can better maintain its quality during fluctuating temperature storage than PBSF. © 2019 Society of Chemical Industry.


Assuntos
Gorduras/química , Óleo de Brassica napus/química , Óleo de Soja/química , Triglicerídeos/química , Cristalização , Esterificação , Armazenamento de Alimentos , Oxirredução , Óleo de Palmeira/química , Temperatura , Difração de Raios X
13.
World J Microbiol Biotechnol ; 35(11): 164, 2019 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-31637528

RESUMO

Odd-chain fatty acids (OCFAs) have been reported to possess pharmacological activity and have been used in the manufacture of agricultural and industrial chemicals. We here provided a new method to increase the OCFAs content in oil produced by Rhodococcus opacus PD630 through addition of 1-propanol to the fermentation media. The OCFAs in oil of R. opacus PD630 are primarily pentadecanoic acid (C15:0), heptadecanoic acid (C17:0) and heptadecenoic acid (C17:1). After adding 0.5-1.5% (v/v) 1-propanol, the production of oil increased from 1.27 g/L to 1.31-1.61 g/L, and the OCFAs content in oil increased by 46.7-55.1%. Metabolic intermediates determination and transcriptome analysis revealed that R. opacus assimilated 1-propanol through methylmalonyl-CoA pathway. When the nitrogen source was limited, propionyl-CoA was converted to propionyl-acyl carrier protein (ACP) which could be used as primer during the elongation of fatty acid synthesis. Then OCFAs were produced when odd number of propionyl-ACP was incorporated in the cycles of fatty acid synthesis.


Assuntos
1-Propanol/farmacologia , Ácidos Graxos/biossíntese , Rhodococcus/efeitos dos fármacos , Rhodococcus/metabolismo , 1-Propanol/metabolismo , Acil Coenzima A , Álcoois/farmacologia , Biomassa , Ácidos Graxos/metabolismo , Ácidos Graxos Monoinsaturados/metabolismo , Fermentação , Redes e Vias Metabólicas , Rhodococcus/crescimento & desenvolvimento , Transcriptoma
14.
J Food Sci Technol ; 55(6): 2326-2333, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29892133

RESUMO

The extraction conditions and antioxidant activities of rutin from Sophora japonica bud by deep eutectic solvents were investigated. Box-Behnken design was used to optimize the extraction conditions and the scavenging activities of DPPH, O2- and ·OH of purified rutin were evaluated. The highest yield of 279.8 mg/g was achieved in the extraction medium of choline chloride/triethlene glycol (1/4) under the optimum conditions: water content of the DES 18.1%, extraction time 28.3 min, extraction temperature 70 °C and liquid-solid ratio 10 mg/1 g. The highest extraction amount was slightly different from the predicted value of the established second-order polynomial equation. In addition, The EC50 of DPPH scavenging, O2- scavenging and ·OH scavenging of rutin were 5.68 µg/mL, 0.19 and 0.28 mg/mL, respectively. The above results indicate rutin extracted by the choline chloride/triethylene glycol has excellent antioxidant activity and was an admirable free radical scavenger.

15.
Microb Cell Fact ; 15: 5, 2016 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-26758368

RESUMO

BACKGROUND: Enantiopure (S)-1-(4-methoxyphenyl) ethanol {(S)-MOPE} can be employed as an important synthon for the synthesis of cycloalkyl [b] indoles with the treatment function for general allergic response. To date, the biocatalytic resolution of racemic MOPE through asymmetric oxidation in the biphasic system has remained largely unexplored. Additionally, deep eutectic solvents (DESs), as a new class of promising green solvents, have recently gained increasing attention in biocatalysis for their excellent properties and many successful examples in biocatalytic processes. In this study, the biocatalytic asymmetric oxidation of MOPE to get (S)-MOPE using Acetobacter sp. CCTCC M209061 cells was investigated in different two-phase systems, and adding DES in a biphasic system was also explored to further improve the reaction efficiency of the biocatalytic oxidation. RESULTS: Of all the examined water-immiscible organic solvents and ionic liquids (ILs), 1-butyl-3-methylimidazolium hexafluorophoshpate ([C4MIM][PF6]) afforded the best results, and consequently was selected as the second phase of a two-phase system for the asymmetric oxidation of MOPE with immobilized Acetobacter sp. CCTCC M209061 cells. For the reaction performed in the [C4MIM][PF6]/buffer biphasic system, under the optimized conditions, the initial reaction rate, the maximum conversion and the residual substrate e.e. recorded 97.8 µmol/min, 50.5 and >99.9 % after 10 h reaction. Furthermore, adding the DES [ChCl][Gly] (10 %, v/v) to the aqueous phase, the efficiency of the biocatalytic oxidation was rose markedly. The optimal substrate concentration and the initial reaction rate were significantly increased to 80 mmol/L and 124.0 µmol/min, respectively, and the reaction time was shortened to 7 h with 51.3 % conversion. The immobilized cell still retained over 72 % of its initial activity after 9 batches of successive reuse in the [C4MIM][PF6]/[ChCl][Gly]-containing buffer system. Additionally, the efficient biocatalytic process was feasible up to a 500-mL preparative scale. CONCLUSION: The biocatalytic asymmetric oxidation of MOPE with Acetobacter sp. CCTCC M209061 cells was successfully conducted in the [C4MIM][PF6]-containing biphasic system with high conversion and enantioselectivity, and the reaction efficiency was further enhanced by adding [ChCl][Gly] to the reaction system. The efficient biocatalytic process was promising for the preparation of enantiopure (S)-MOPE.


Assuntos
Acetobacter/metabolismo , Etanol/química , Etanol/metabolismo , Solventes/farmacologia , Acetobacter/efeitos dos fármacos , Oxirredução/efeitos dos fármacos , Estereoisomerismo
16.
Biotechnol Bioeng ; 112(1): 65-73, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25067792

RESUMO

In this work, 28 cholinium ionic liquids (ILs), most of which are good solvents for dissolving lignin, were used for rice straw pretreatment to improve subsequent enzymatic hydrolysis. The anion exerted a significant effect on the pretreatment effectiveness of the IL as well as the subsequent enzymatic hydrolysis efficiency of rice straw residues. The presence of the basic group(s) in the anion significantly enhanced the IL pretreatment effectiveness, while the carboxyl, hydroxyl and aromatic groups had a negative impact on IL delignification. Except for amino acid-based ILs, the delignification abilities of the ILs are linearly and positively correlated with the pKa values of the conjugate acids of the anions. Of the ILs tested, amino acid-based ILs, especially basic amino acid-based ILs, are the most effective pretreatment solvents. Satisfactory reducing sugar yields (81% for glucose and 26% for xylose) were obtained in the enzymatic hydrolysis of rice straw pretreated by cholinium argininate ([Ch][Arg]) under a pretty mild pretreatment severity (60°C, 6 h). The results presented in this work may be useful for rational design of novel and green ILs for delignification of lignocellulose.


Assuntos
Ânions/química , Biomassa , Líquidos Iônicos/química , Lignina/química , Oryza/química , Aminoácidos , Biotecnologia , Celulase , Hidrólise , Solubilidade , Xilanos
17.
Microb Cell Fact ; 13: 84, 2014 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-24916156

RESUMO

BACKGROUND: Enantiomerically pure alcohols are important building blocks for production of chiral pharmaceuticals, flavors, agrochemicals and functional materials and appropriate whole-cell biocatalysts offer a highly enantioselective, minimally polluting route to these valuable compounds. At present, most of these biocatalysts follow Prelog's rule, and thus the (S)-alcohols are usually obtained when the smaller substituent of the ketone has the lower CIP priority. Only a few anti-Prelog (R)-specific whole cell biocatalysts have been reported. In this paper, the biocatalytic anti-Prelog reduction of 2-octanone to (R)-2-octanol was successfully conducted with high enantioselectivity using whole cells of Acetobacter pasteurianus GIM1.158. RESULTS: Compared with other microorganisms investigated, Acetobacter pasteurianus GIM1.158 was shown to be more effective for the reduction reaction, affording much higher yield, product enantiomeric excess (e.e.) and initial reaction rate. The optimal temperature, buffer pH, co-substrate and its concentration, substrate concentration, cell concentration and shaking rate were 35°C, 5.0, 500 mmol/L isopropanol, 40 mmol/L, 25 mg/mL and 120 r/min, respectively. Under the optimized conditions, the maximum yield and the product e.e. were 89.5% and >99.9%, respectively, in 70 minutes. Compared with the best available data in aqueous system (yield of 55%), the yield of (R)-2-octanol was greatly increased. Additionally, the efficient whole-cell biocatalytic process was feasible on a 200-mL preparative scale and the chemical yield increased to 95.0% with the product e.e. being >99.9%. Moreover, Acetobacter pasteurianus GIM1.158 cells were proved to be capable of catalyzing the anti-Prelog bioreduction of other prochiral carbonyl compounds with high efficiency. CONCLUSIONS: Via an effective increase in the maximum yield and the product e.e. with Acetobacter pasteurianus GIM1.158 cells, these results open the way to use of whole cells of this microorganism for challenging enantioselective reduction reactions on laboratory and commercial scales.


Assuntos
Acetobacter/metabolismo , Cetonas/metabolismo , Técnicas de Cultura Celular por Lotes , Biocatálise , Concentração de Íons de Hidrogênio , Cetonas/química , Octanóis/química , Octanóis/metabolismo , Oxirredução , Estereoisomerismo , Especificidade por Substrato , Temperatura
18.
Int J Biol Macromol ; 265(Pt 1): 130813, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38479667

RESUMO

In this study, an active and intelligent nanofilm for monitoring and maintaining the freshness of pork was developed using ethyl cellulose/gelatin matrix through electrospinning, with the addition of natural purple sweet potato anthocyanin. The nanofilm exhibited discernible color variations in response to pH changes, and it demonstrated a higher sensitivity towards volatile ammonia compared with casting film. Notably, the experimental findings regarding the wettability and pH response performance indicated that the water contact angle between 70° and 85° was more favorable for the smart response of pH sensitivity. Furthermore, the film exhibited desirable antioxidant activities, water vapor barrier properties and also good antimicrobial activities with the incorporation of ε-polylysine, suggesting the potential as a food packaging film. Furthermore, the application preservation outcomes revealed that the pork packed with the nanofilm can prolong shelf life to 6 days, more importantly, a distinct color change aligned closely with the points indicating the deterioration of the pork was observed, changing from light pink (indicating freshness) to light brown (indicating secondary freshness) and then to brownish green (indicating spoilage). Hence, the application of this multifunctional film in intelligent packaging holds great potential for both real-time indication and efficient preservation of the freshness of animal-derived food items.


Assuntos
Celulose/análogos & derivados , Carne de Porco , Carne Vermelha , Suínos , Animais , Gelatina , Ração Animal , Antocianinas , Embalagem de Alimentos , Concentração de Íons de Hidrogênio
19.
Int J Biol Macromol ; 264(Pt 1): 130556, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38431014

RESUMO

The aim of this study was to investigate the effects of acetylation modification on the structural, interfacial and emulsifying properties of Millettia speciosa Champ polysaccharide (MSCP). Besides, the influence of acetylation modification on the encapsulation properties of polysaccharide-based emulsion was also explored. Results indicated that modification resulted in a prominent reduction in molecular weight of MSCP and the interfacial layer thickness formed by acetylated MSCP (AC-MSCP) was also decreased, but the adsorption rate and ability of AC-MSCP to reduce interfacial tension were improved. AC-MSCP formulated emulsion possessed smaller droplet size (6.8 µm) and exhibited better physical stability under stressful conditions. The chemical stability of ß-carotene was also profoundly enhanced by AC-MSCP fabricated emulsion. Moreover, AC-MSCP improved lipids digestion extent, thus facilitating the formation of micelle and increasing bioaccessibility of ß-carotene. This study provided insights for rational modification of polysaccharide-based emulsifier and designing delivery system for chemically labile hydrophobic bioactive components.


Assuntos
Millettia , beta Caroteno , Emulsões/química , beta Caroteno/química , Polissacarídeos/química , Emulsificantes/química
20.
J Agric Food Chem ; 72(8): 4155-4169, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38366990

RESUMO

In this study, we used traditional laboratory methods, bioinformatics, and cellular models to screen novel ACE inhibitory (ACEI) peptides with strong ACEI activity, moderate absorption rates, and multiple targets from bovine colostrum immunoglobulin G (IgG). The purified fraction of the compound proteinase hydrolysate of IgG showed good ACEI activity. After nano-UPLC-MS/MS identification and in silico analysis, eight peptides were synthesized and verified. Among them, SFYPDY, TSFYPDY, FSWF, WYQQVPGSGL, and GVHTFP were identified as ACEI peptides, as they exhibited strong ACEI activity (with IC50 values of 104.7, 80.0, 121.2, 39.8, and 86.3 µM, respectively). They displayed good stability in an in vitro simulated gastrointestinal digestion assay. In a Caco-2 monolayer model, SFYPDY, FSWF, and WYQQVPGSGL exhibited better absorption rates and lower IC50 values than the other peptides and were thereby identified as novel ACEI peptides. Subsequently, in a H2O2-induced endothelial dysfunction (ED) model based on HUVECs, SFYPDY, FSWF, and WYQQVPGSGL regulated ED by reducing apoptosis and ROS accumulation while upregulating NOS3 mRNA expression. Network pharmacology analysis and RT-qPCR confirmed that they regulated multiple targets. Overall, our results suggest that SFYPDY, FSWF, and WYQQVPGSGL can serve as novel multitarget ACEI peptides.


Assuntos
Imunoglobulina G , Doenças Vasculares , Humanos , Feminino , Gravidez , Animais , Bovinos , Farmacologia em Rede , Espectrometria de Massas em Tandem , Células CACO-2 , Colostro/metabolismo , Peróxido de Hidrogênio , Peptídeos/química , Peptidil Dipeptidase A/química , Hidrolisados de Proteína/química , Simulação de Acoplamento Molecular
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