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1.
Molecules ; 27(20)2022 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-36296474

RESUMO

Although the fruit of Ficus tikoua Bur. has been consumed by montanic people in China for centuries, its chemical and biological composition was still unclear. A series of comprehensive investigations on its chemical constituents and bioactivities were carried out for the first time. As a result, six compounds were isolated and identified as the main components in this fruit. GC-MS analysis of the lipid components demonstrated that Ficus tikoua Bur. fruit contains some wholesome constituents such as fatty acids, vitamins, triterpenoids, and phytosterols. The fatty acids are mainly composed of linolenic acid (61.27%) and linoleic acid (22.79%). Furthermore, this fruit contains a relative high content of crude protein (9.41 ± 0.03%), total amino acids (9.28%), and total polyphenols (0.86 ± 0.01 g/100 g). The analysis of monosaccharide composition showed that the total polysaccharide mainly consists of glucose, glucuronic acid, xylose, arabinose, mannose, galactose, galacturonic acid, and rhamnose. The polysaccharide, polyphenol, water, ethanol, and flavonoid extracts exhibited prominent antioxidant activity determined by ABTS, DPPH, and FRAPS methods. Meanwhile, the total polysaccharide exhibited significant immunomodulatory effect by enhancing the release of cytokines and expression of iNOS and COX-2 in RAW264.7 cells, significantly decreasing the expression of c-Jun and p65 proteins in the cytoplasm; increasing the translocation of c-Jun and p65 to the nucleus; and regulating the phosphorylation level of Akt, PI3K, and PDK1 in the PI3K/AKT signaling pathway. This study proved that the fruit of F. tikoua is a reliable source of functional food.


Assuntos
Ficus , Fitosteróis , Triterpenos , Humanos , Ficus/química , Antioxidantes/química , Frutas/química , Polifenóis/farmacologia , Polifenóis/análise , Ciclo-Oxigenase 2 , Galactose/análise , Manose/análise , Arabinose/análise , Ramnose/análise , Xilose/análise , Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt , Polissacarídeos/química , Flavonoides/análise , Monossacarídeos/análise , Citocinas/análise , Água/análise , Lipídeos/análise , Vitaminas/análise , Triterpenos/análise , Fitosteróis/análise , Glucose/análise , Etanol/análise , Aminoácidos/análise , Glucuronatos , Ácidos Linolênicos , Ácidos Linoleicos/análise
2.
Food Chem ; 386: 132797, 2022 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-35344725

RESUMO

The objective of this study was to investigate the effect of oximation reagents in simultaneous analysis of mono and di-saccharides using gas chromatography. Sugar oximation with O-ethylhydroxylamine separated all the mono- and di-saccharides while hydroxylamine and O-benzylhydroxylamine could make most of the saccharides separable except for xylose and arabinose. Resolution of xylose: arabinose, galactose: glucose, and fructose: galactose oximated by O-ethylhydroxylamine in DB-1ms column were 1.66, 2.15, and 6.19, respectively, which were above 1.5 and were officially acceptable for quantitative analysis according to the AOAC guideline. The applied method was then verified by the method validation parameters; LOD (0.011-0.02 mg/100 g), LOQ (0.032-0.061 mg/100 g), linearity (R2 = 0.9991-1.0000) and precision (repeatability RSD: 1.4-3.3%, reproducibility RSD: 1.7-7.6%). The greatest amounts of xylose (19.03 ± 0.38 mg/100 g), maltose (6,274.48 ± 173.59 mg/100 g) were found in the oyster sauce, and the contents of glucose (10,565.00 ± 125.31 mg/100 g), galactose (170.40 ± 4.62 mg/100 g) were greatest in soybean paste.


Assuntos
Arabinose , Xilose , Arabinose/análise , Carboidratos , Cromatografia Gasosa , Dissacarídeos/análise , Galactose/análise , Glucose/análise , Indicadores e Reagentes/análise , Reprodutibilidade dos Testes , Xilose/análise
3.
Carbohydr Polym ; 281: 119086, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35074113

RESUMO

During processing of plant-based foods, cell wall polysaccharides and polyphenols, such as procyanidins, interact extensively, thereby affecting their physicochemical properties along with their potential health effects. Although hemicelluloses are second only to pectins in affinity for procyanidins in cell walls, a detailed study of their interactions lacks. We investigated the interactions between representative xylose-containing water-soluble hemicelluloses and procyanidins. Turbidity, ITC and DLS were used to determine the relative affinities, and theoretical calculations further ascertained the interactions mechanisms. Xyloglucan and xylan exhibited respectively the strongest and weakest interactions with procyanidins. The different arabinoxylans interacted with procyanidins in a similar strength, intermediate between xyloglucans and xylans. Therefore, the strength of the interaction depended on the structure itself rather than on some incidental properties, e.g., viscosity and molar mass. The arabinose side-chain of arabinoxylan did not inhibit interactions. The computational investigation corroborated the experimental results in that the region of interaction between xyloglucan and procyanidins was significantly wider than that of other hemicelluloses.


Assuntos
Proantocianidinas , Parede Celular/química , Pectinas/química , Polissacarídeos/química , Proantocianidinas/química , Xilanos/química , Xilose/análise
4.
ACS Synth Biol ; 10(9): 2266-2275, 2021 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-34412469

RESUMO

Xylose is the raw material for the synthesis of many important platform compounds. At present, xylose is commercially produced by chemical extraction. However, there are still some bottlenecks in the extraction of xylose, including complicated operation processes and the chemical substances introduced, leading to the high cost of xylose and of synthesizing the downstream compounds of xylose. The current market price of xylose is 8× that of glucose, so using low-cost glucose as the substrate to produce the downstream compounds of xylose can theoretically reduce the cost by 70%. Here, we designed a pathway for the biosynthesis of xylose from glucose in Escherichia coli. This biosynthetic pathway was achieved by overexpressing five genes, namely, zwf, pgl, gnd, rpe, and xylA, while replacing the native xylulose kinase gene xylB with araL from B. subtilis, which displays phosphatase activity toward d-xylulose 5-phosphate. The yield of xylose was increased to 3.3 g/L by optimizing the metabolic pathway. Furthermore, xylitol was successfully synthesized by introducing the xyl1 gene, which suggested that the biosynthetic pathway of xylose from glucose is universally applicable for the synthesis of xylose downstream compounds. This is the first study to synthesize xylose and its downstream compounds by using glucose as a substrate, which not only reduces the cost of raw materials, but also alleviates carbon catabolite repression (CCR), providing a new idea for the synthesis of downstream compounds of xylose.


Assuntos
Escherichia coli/metabolismo , Glucose/metabolismo , Engenharia Metabólica/métodos , Xilose/biossíntese , Bacillus subtilis/enzimologia , Carbono/química , Carbono/metabolismo , Cromatografia Líquida de Alta Pressão , Escherichia coli/genética , Redes e Vias Metabólicas/genética , Fosfotransferases (Aceptor do Grupo Álcool)/genética , Xilose/análise
5.
Carbohydr Polym ; 263: 117932, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33858566

RESUMO

According to the high interest in agro-industrial waste reutilisation, underutilised lignocellulosic materials, such as walnut shell (WS) and pea pod (PP), come in focus. The aim of this paper was to evaluate WS and PP as sources for the production of xylooligosaccharides (XOS). Hemicelluloses from WS and PP were recovered by combining varying parameters of delignification and alkaline extraction. At optimal recovery conditions, the fractions were further hydrolysed to XOS using GH11 endo-xylanase, by varying time and enzyme concentration. Xylose was predominant in the monomeric composition of the obtained hemicelluloses, building low-branched (arabino)glucuronoxylan, in WS exclusively, while in PP some xyloglucan as well. Delignification was essential for high recovery of total xylose from the materials, up to at least 70 %. High xylan conversions were obtained for 24 h hydrolysis, resulting in xylobiose and xylotriose when using low enzyme concentration, while in xylose and xylobiose with high enzyme concentration.


Assuntos
Fracionamento Químico/métodos , Glucuronatos/química , Juglans/química , Juglans/metabolismo , Oligossacarídeos/química , Pisum sativum/química , Pisum sativum/metabolismo , Glucuronatos/isolamento & purificação , Hidrólise , Juglans/anatomia & histologia , Oligossacarídeos/isolamento & purificação , Pisum sativum/anatomia & histologia , Extratos Vegetais/química , Polissacarídeos/química , Polissacarídeos/metabolismo , Açúcares/análise , Xilanos/química , Xilanos/isolamento & purificação , Xilose/análise , Xilose/isolamento & purificação , Xilose/metabolismo
6.
Anal Chem ; 93(2): 1179-1184, 2021 01 19.
Artigo em Inglês | MEDLINE | ID: mdl-33320543

RESUMO

Simple, rapid, and accurate detection methods for saccharides are potentially applicable to various fields such as clinical and food chemistry. However, the practical applications of on-site analytical methods are still limited. To this end, herein, we propose a 96-well microtiter plate made of paper as a paper-based chemosensor array device (PCSAD) for the simultaneous classification of 12 saccharides and the quantification of fructose and glucose among 12 saccharides. The mechanism of the saccharide detection relied on an indicator displacement assay (IDA) on the PCSAD using four types of catechol dyes, 3-nitrophenylboronic acid, and the saccharides. The design of the PCSAD and the experimental conditions for the IDA were optimized using a central composite design. The chemosensors exhibited clear color changes upon the addition of saccharides on the paper because of the competitive boronate esterification. The color changes were employed for the subsequent qualitative, semiquantitative, and quantitative analyses using an automated algorithm combined with pattern recognition for digital images. A qualitative linear discrimination analysis offered discrimination of 12 saccharides with a 100% classification rate. The semiquantitative analysis of fructose in the presence of glucose was carried out from the viewpoint of food analysis utilizing a support vector machine, resulting in clear discrimination of the various concentrations of fructose. Most importantly, the quantitative detection of fructose in two types of commercial soft drinks was also successfully carried out without sample pretreatments. Thus, the proposed PCSAD can be a powerful method for on-site food analyses that can meet the increasing demand from consumers for sensors of saccharides.


Assuntos
Ácidos Borônicos/química , Catecóis/química , Colorimetria , Corantes Fluorescentes/química , Papel , Acetilglucosamina/análise , Arabinose/análise , Frutose/análise , Fucose/análise , Galactose/análise , Glucose/análise , Ramnose/análise , Ribose/análise , Espectrometria de Fluorescência , Xilose/análise
7.
ACS Synth Biol ; 9(10): 2714-2722, 2020 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-32886884

RESUMO

Genetically encoded biosensors are extensively utilized in synthetic biology and metabolic engineering. However, reported xylose biosensors are far too sensitive with a limited operating range to be useful for most sensing applications. In this study, we describe directed evolution of Escherichia coli XylR, and construction of biosensors based on XylR and the corresponding operator xylO. The operating range of biosensors containing the mutant XylR was increased by nearly 10-fold comparing with the control. Two individual amino acid mutations (either L73P or N220T) in XylR were sufficient to extend the linear response range to upward of 10 g/L xylose. The evolved biosensors described here are well suited for developing whole-cell biosensors for detecting varying xylose concentrations across an expanded range. As an alternative use of this system, we also demonstrate the utility of XylR and xylO as a xylose inducible system to enable graded gene expression through testing with ß-galactosidase gene and the lycopene synthetic pathway. This evolution strategy identified a less-sensitive biosensor for real applications, thus providing new insights into strategies for expanding operating ranges of other biosensors for synthetic biology applications.


Assuntos
Técnicas Biossensoriais , Proteínas de Escherichia coli/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Engenharia Metabólica/métodos , Fatores de Transcrição/metabolismo , Xilose/análise , Aminoácidos/genética , DNA Bacteriano/genética , Proteínas de Escherichia coli/genética , Expressão Gênica , Regulação Bacteriana da Expressão Gênica , Licopeno/metabolismo , Proteínas Mutantes , Mutação , Regiões Promotoras Genéticas , Biologia Sintética/métodos , Fatores de Transcrição/genética , Xilose/metabolismo , beta-Galactosidase/genética
8.
J Biotechnol ; 321: 35-47, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32622841

RESUMO

This work investigated the integration of a two-stage hydrothermal treatment for production of xylooligosaccharides (XOS), a high-value product, into the isolation process of cellulose nanofibrils (CNF) from sugarcane bagasse. Under optimized conditions, the first stage yielded a XOS-rich, high purity hydrolysate and in the second stage only a xylose-rich hydrolysate could be obtained at high purity. The resulting solid cellulosic fraction was delignified and bleached to obtain a cellulose-rich pulp, which was mechanically defibrillated by disc ultra-refining to CNF. Except for the viscosity, the sugarcane CNF showed properties (i.e., thermal stability, crystallinity and diameter size) comparable or superior to the CNF prepared from commercial bleached eucalyptus Kraft pulp. In conclusion, the integration of the two-stage hydrothermal treatment is an efficient and promising strategy to obtain hemicellulose-derived high-value co-products in the process of isolating CNF. In addition, lignin was also recovered as a co-product with yield comparable to other biomass fractionation approaches.


Assuntos
Celulose/química , Glucuronatos , Nanofibras , Oligossacarídeos , Xilose , Biomassa , Celulose/análise , Glucuronatos/análise , Glucuronatos/química , Temperatura Alta , Hidrólise , Nanofibras/análise , Nanofibras/química , Oligossacarídeos/análise , Oligossacarídeos/química , Saccharum/química , Xilose/análise , Xilose/química
9.
Int J Biol Macromol ; 162: 116-126, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32565299

RESUMO

In this study, a novel water-soluble polysaccharide (PVLP-1) was extracted and purified from Sacha inchi (Plukenetia volubilis L.) seeds and the structure, antioxidant and immunomodulatory activity of PVLP-1 were investigated. PVLP-1 (144 kDa) consisted of glucose (69.76%), mannose (14.86%), arabinose (10.53%), galactose (2.42%), ribose (1.23%), rhamnose (0.27%) and xylose (0.93%). PVLP-1 displayed characteristic polysaccharide bands in Fourier transform NMR spectra and infrared. The primary structure of PVLP-1 was a heteropolysaccharide with a backbone of (1 â†’ 6)-linked glucose, sidechains of (1 â†’ 4)-linked mannose, (1 â†’ 4)-linked glucose and (1 â†’ 3, 6)-linked mannose and a residue unit of →1)-linked arabinose as revealed the methylation analysis. PVLP-1 possessed good water-holding capacity (WHC), oil-holding capacity (OHC) and antioxidant capacities. Besides, PVLP-1 induced the proliferation of RAW264.7 cell and enhanced the expression of inflammatory cytokines IL-6, TNF-alpha(TNF-α) and IL-1 beta (IL-1ß). The present study indicated that PVLP-1 possessed immune-enhancing bioactivities and could be functional food or adjuvant drug to improve biological immunity of immunodeficiency diseases and hypoimmunity.


Assuntos
Adjuvantes Imunológicos/farmacologia , Antioxidantes/farmacologia , Proliferação de Células/efeitos dos fármacos , Euphorbiaceae/química , Polissacarídeos/análise , Polissacarídeos/farmacologia , Sementes/química , Animais , Arabinose/análise , Sobrevivência Celular/efeitos dos fármacos , Carboidratos da Dieta/metabolismo , Carboidratos da Dieta/farmacologia , Galactose/análise , Glucose/análise , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Manose/análise , Camundongos , Fagocitose/efeitos dos fármacos , Óleos de Plantas/química , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Células RAW 264.7 , Ramnose/análise , Ribose/análise , Espectroscopia de Infravermelho com Transformada de Fourier , Fator de Necrose Tumoral alfa/metabolismo , Água/química , Xilose/análise
10.
Int J Biol Macromol ; 162: 31-42, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32553956

RESUMO

A polysaccharide (ESPS) purified from Eupolyphaga sinensis Walker by ion exchange chromatography and gel chromatography was investigated, including its structure characterization and antitumor activity. The results showed that ESPS was composed of rhamnose, fucose, arabinose, xylose, glucose, and galactose in a molar ratio of 7.4: 3.1: 13.9: 9.3: 39.7: 26.5, with the mean weight (Mw) of 2.14 × 104Da; the main chain of ESPS was mainly composed of → 4) - α - D - Glcp - (1 â†’ and → 3) - ß - D - Galp - (1 →, and the side chains were connected to the main chain through the O-6 atom of glucose and O-4 and O-6 atom of galactose. In addition, ESPS promoted the lymphocyte proliferation and inhibited liver cancer cells growth through enhancing lymphocyte activity in vitro, mainly NK cells. Moreover, ESPS markedly stimulated immunity in H22-bearing mice by increasing the spleen and thymus indices and effectively inhibited H22 cell growth in vivo. These data indicated that ESPS was a polysaccharide component possessing high anti-hepatocellular carcinoma activity, representing a potential immunotherapy candidate for the treatment of liver cancer.


Assuntos
Antineoplásicos/administração & dosagem , Carcinoma Hepatocelular/imunologia , Baratas/química , Células Matadoras Naturais/efeitos dos fármacos , Neoplasias Hepáticas/imunologia , Ativação Linfocitária/efeitos dos fármacos , Polissacarídeos/administração & dosagem , Animais , Arabinose/análise , Carcinoma Hepatocelular/tratamento farmacológico , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cromatografia em Gel , Cromatografia por Troca Iônica , Feminino , Fucose/análise , Galactose/análise , Glucose/análise , Células Matadoras Naturais/imunologia , Neoplasias Hepáticas/tratamento farmacológico , Ativação Linfocitária/imunologia , Espectroscopia de Ressonância Magnética , Camundongos , Camundongos Endogâmicos BALB C , Polissacarídeos/análise , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Ramnose/análise , Xilose/análise
11.
Int J Biol Macromol ; 162: 127-135, 2020 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-32553965

RESUMO

An efficient enzymatic hydrolysis method was developed and optimized for the degradation of auricularia auricula polysaccharide (AAP) and the degradation product of AAP was characterized. Cellulase was used for the degradation of AAP. The yield of reducing sugar and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging rate were used as indices to optimize the enzymatic hydrolysis of AAP, based on response surface methodology (RSM). The resulting optimal enzymolysis conditions were as follows: enzyme dosage, 13,500 U/g; enzymolysis temperature, 50 °C; and pH, 4.2. Under these conditions, the actual yield of reducing sugar was 16.50 mg/mL and the DPPH radical scavenging rate was 87.97%. The degradation product of AAP (C-EAAP) was homogeneous and contained alpha and beta glycoside bonds, but did not contain protein or nucleic acid. The molecular weight of the degradation product was 5.94 × 105 Da. Monosaccharide composition analysis revealed that C-EAAP was composed of mannose (57.1%), glucuronic acid (10.0%), rhamnose (0.4%), glucose (22.5%), galactose (2.9%), xylose (6.0%), and fucose (1.1%). The antioxidant activity of the polysaccharide indicated that C-EAAP had better antioxidant activity than AAP. The scavenging rates of C-EAAP for hydroxyl radicals (·OH) and superoxide anion radicals (O2-·) were 1.65 and 1.90 times those of AAP.


Assuntos
Antioxidantes/química , Auricularia/química , Polissacarídeos Fúngicos/análise , Hidrólise/efeitos dos fármacos , Compostos de Bifenilo/química , Celulase/química , Cromatografia Líquida de Alta Pressão , Fucose/análise , Polissacarídeos Fúngicos/química , Galactose/análise , Glucose/análise , Ácido Glucurônico/análise , Radical Hidroxila/química , Lactonas , Espectroscopia de Ressonância Magnética , Manose/análise , Peso Molecular , Monossacarídeos/análise , Ramnose/análise , Superóxidos/química , Xilose/análise
12.
Food Microbiol ; 91: 103454, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32539957

RESUMO

This research determined the concentration of trehalose, xylose and l-citrulline in fresh and fermented cucumbers and their utilization by Lactobacillus pentosus, Lactobacillus plantarum, Lactobacillus brevis and Lactobacillus buchneri. Targeted compounds were measured by HPLC and the ability of the lactobacilli to utilize them was scrutinized in fermented cucumber juice. Fresh cucumber juice was supplemented with trehalose, xylose and l-citrulline to observed mixed culture fermentations. Changes in the biochemistry, pH and colony counts during fermentations were monitored. Trehalose, xylose and l-citrulline were detected in fermentations to15.51 ± 1.68 mM, a fresh cucumber sample at 36.05 mM and in fresh and fermented cucumber samples at 1.05 ± 0.63 mM, respectively. Most of the LAB tested utilized trehalose and xylose in FCJM at pH 4.7. l-citrulline was utilized by L. buchneri and produced by other LAB. l-citrulline (12.43 ± 2.3 mM) was converted to ammonia (14.54 ± 3.60 mM) and the biogenic amine ornithine (14.19 ± 1.07 mM) by L. buchneri at pH 4.7 in the presence of 0.5 ± 0.2 mM glucose enhancing growth by 0.5 log CFU/mL. The use of a mixed starter culture containing L. buchneri aided in the removal of l-citrulline and enhanced the fermentation stability. The utilization of l-citrulline by L. buchneri may be a cause of concern for the stability of cucumber fermentations at pH 3.7 or above. This study identifies the use of a tripartite starter culture as an enhancer of microbial stability for fermented cucumbers.


Assuntos
Citrulina/metabolismo , Cucumis sativus , Alimentos Fermentados/microbiologia , Lactobacillus/metabolismo , Trealose/metabolismo , Xilose/metabolismo , Reatores Biológicos/microbiologia , Citrulina/análise , Contagem de Colônia Microbiana , Cucumis sativus/química , Cucumis sativus/microbiologia , Fermentação , Microbiologia de Alimentos , Glucose/metabolismo , Concentração de Íons de Hidrogênio , Lactobacillus/classificação , Lactobacillus/crescimento & desenvolvimento , Trealose/análise , Xilose/análise
13.
Molecules ; 25(9)2020 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-32384787

RESUMO

The Opuntia ficus indica (L.) (OFI) is used as a nutritional and pharmaceutical agent in various dietary and value added products. This study underlines the possible use of native prickly pear cladode powder as a functional ingredient for health-promoting food production. To summarise, chemical characterization of polyphenols, minerals and soluble dietary fibre was performed; furthermore, the antioxidant activity and bioaccessibility of polyphenols and minerals were assessed. Eleven compounds between phenolic acids and flavonoids were identified, with piscidic acid and isorhamnetin derivatives being the most abundant. Opuntia's dietary fibre was mainly constituted of mucilage and pectin, and was composed of arabinose, galactose, glucose, mannose, rhamnose, and xylose sugars. The polyphenols' bioaccessibility was very high: piscidic acid at 200%, eucomic and ferulic acids >110% and flavonoids from 89% to 100%. The prickly pear cladode powder is also a source of minerals, as cations (calcium, sodium, potassium and magnesium) and anions (sulphate and chloride), with high magnesium bioaccessibilty (93%). OFI powder showed good capacity of radical scavenging measured by DPPH and ABTS methods, with 740 and 775 µmol Trolox/100 g OFI, respectively. Finally, the presented results allow the consideration of this natural product as a source of several essential nutrients, with a possible use in the food industry as a functional ingredient.


Assuntos
Antioxidantes/análise , Fibras na Dieta/análise , Frutas/química , Micronutrientes/análise , Opuntia/química , Polifenóis/análise , Polissacarídeos/análise , Ânions/análise , Arabinose/análise , Benzotiazóis/química , Disponibilidade Biológica , Compostos de Bifenilo/química , Cátions/análise , Ácidos Cumáricos/análise , Flavonoides/análise , Galactose/análise , Glucose/análise , Hidroxibenzoatos/análise , Manose/análise , Minerais/análise , Pectinas/análise , Pectinas/isolamento & purificação , Picratos/química , Mucilagem Vegetal/análise , Mucilagem Vegetal/isolamento & purificação , Ramnose/análise , Ácidos Sulfônicos/química , Xilose/análise
14.
J Vis Exp ; (158)2020 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-32364543

RESUMO

Lignocellulosic materials are plant-derived feedstocks, such as crop residues (e.g., corn stover, rice straw, and sugar cane bagasse) and purpose-grown energy crops (e.g., miscanthus, and switchgrass) that are available in large quantities to produce biofuels, biochemicals, and animal feed. Plant polysaccharides (i.e., cellulose, hemicellulose, and pectin) embedded within cell walls are highly recalcitrant towards conversion into useful products. Ammonia fiber expansion (AFEX) is a thermochemical pretreatment that increases accessibility of polysaccharides to enzymes for hydrolysis into fermentable sugars. These released sugars can be converted into fuels and chemicals in a biorefinery. Here, we describe a laboratory-scale batch AFEX process to produce pretreated biomass on the gram-scale without any ammonia recycling. The laboratory-scale process can be used to identify optimal pretreatment conditions (e.g., ammonia loading, water loading, biomass loading, temperature, pressure, residence time, etc.) and generates sufficient quantities of pretreated samples for detailed physicochemical characterization and enzymatic/microbial analysis. The yield of fermentable sugars from enzymatic hydrolysis of corn stover pretreated using the laboratory-scale AFEX process is comparable to pilot-scale AFEX process under similar pretreatment conditions. This paper is intended to provide a detailed standard operating procedure for the safe and consistent operation of laboratory-scale reactors for performing AFEX pretreatment of lignocellulosic biomass.


Assuntos
Amônia/farmacologia , Biomassa , Lignina/metabolismo , Biocombustíveis , Reatores Biológicos , Glucose/análise , Poaceae , Temperatura , Xilose/análise
15.
Appl Microbiol Biotechnol ; 104(7): 3133-3144, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-32076780

RESUMO

Six local isolates of yeasts were screened for cell mass and lipid production in mixed glucose and xylose medium. Candida tropicalis SY005 and Trichosporon (Apiotrichum) loubieri SY006 showed significant lipid accumulation of 24.6% and 32% (dry cell weight), respectively when grown in medium containing equal mass of both the sugars. SY005 produced relatively higher cell mass of 9.66 gL-1 due to higher rate of sugar consumption, which raised the lipid productivity of the organism to 0.792 gL-1day-1 as compared to 0.446 gL-1day-1 in SY006. When grown with each sugar separately, the xylose consumption rate of SY005 was found to be 0.55 gL-1 h-1 after 4 days as compared to 0.52 gL-1 h-1 for SY006. Transcript expression of the high affinity xylose transporter (Cthaxt), xylose reductase (Ctxyl1), and xylitol dehydrogenase (Ctxyl2) of SY005 was monitored to unravel such high rate of sugar consumption. Expression of all the three genes was observed to vary in mixed sugars with Cthaxt exhibiting the highest expression in presence of only xylose. Expression levels of both Ctxyl1 and Ctxyl2, involved in xylose catabolism, were maximum during 24-48 h of growth, indicating that xylose utilization started in the presence of glucose, which was depleted in the medium after 96 h. Together, the present study documents that C. tropicalis SY005 consumes xylose concomitant to glucose during early period of growth, and it is a promising yeast strain for viable production of storage lipid or other high-value oleochemicals utilizing lignocellulose hydrolysate.


Assuntos
Candida tropicalis/metabolismo , Lipídeos/biossíntese , Xilose/metabolismo , Candida tropicalis/genética , Candida tropicalis/crescimento & desenvolvimento , Meios de Cultura/química , Fermentação , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Regulação Fúngica da Expressão Gênica , Glucose/análise , Glucose/metabolismo , Especificidade da Espécie , Trichosporon/genética , Trichosporon/crescimento & desenvolvimento , Trichosporon/metabolismo , Xilose/análise , Leveduras/classificação , Leveduras/genética , Leveduras/crescimento & desenvolvimento , Leveduras/metabolismo
16.
Food Chem ; 315: 126221, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32000077

RESUMO

Xylo- and arabinoxylo-oligosaccharides (XOS and AXOS) are of interest for their prebiotic activity. The production of these oligomers might be accompanied with monosaccharides. The measurement of both oligosaccharides and monosaccharides usually requires two methods. The current work presents an HPAEC-PAD method based on gradient elution of aqueous solvents sodium hydroxide and sodium acetate, in contrast to conventional isocratic elution, for the simultaneous separation of 16 standards of monosaccharides, xylo-oligosaccharides, arabinoxylo-oligosaccharides and uronic acids using CarboPac PA 200 column. The presented method showed a stable baseline and high-resolution separation of the standards. The method showed acceptable accuracy and precision. Limits of Detection and Quantitation (LOD and LOQ) were estimated for all the standards. The method was applied to measure the activity of a commercial endoxylanase on wheat bran; a steady release of xylose monosaccharide was observed. Enzyme action on oligosaccharide standards showed a preference for the larger oligosaccharides.


Assuntos
Monossacarídeos/análise , Oligossacarídeos/análise , Prebióticos/análise , Triticum/química , Arabinose/análise , Arabinose/metabolismo , Cromatografia por Troca Iônica , Fibras na Dieta , Grão Comestível/química , Endo-1,4-beta-Xilanases/metabolismo , Limite de Detecção , Monossacarídeos/metabolismo , Oligossacarídeos/metabolismo , Reprodutibilidade dos Testes , Ácidos Urônicos/química , Xilose/análise , Xilose/metabolismo
17.
Food Funct ; 10(8): 4497-4504, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31237268

RESUMO

Insoluble fermentable cell wall matrix fibers have been shown to support beneficial butyrogenic gut Clostridia, but have restricted use in food products. Here, a soluble fiber matrix was developed that exhibited a similar effect. A low arabinose/xylose ratio corn bran arabinoxylan (CAX) was extracted with two concentrations of sodium hydroxide, 0.25 M and 1.5 M, to give soluble polymers with relatively low (L) and high (H) residual levels of bound ferulic acid (FA) (CAX-LFA and CAX-HFA). After laccase treatment to make diferulate crosslinks, soluble matrices were formed with average 3.5 to 4.5 mer. In vitro human fecal fermentation of CAX-LFA, CAX-HFA, soluble crosslinked ∼3.5 mer CAX-LFA (SCCAX-LFA), and ∼4.5 mer SCCAX-HFA revealed that the SCCAX matrices had somewhat slower fermentation properties by measuring the gas production, total short chain fatty acids, and carbohydrate disappearance, with a higher butyrate proportion in SCCAX-HFA. 16S rRNA gene sequencing showed that SCCAX-HFA promoted OTUs associated with butyrate production including unassigned Ruminococcaceae, unassigned Blautia, Fecalibacterium prausnitzii, and unassigned Clostridium. Thus, when the physical form of an individual soluble polysaccharide was changed to a soluble crosslinked matrix, in vitro fermentation was shifted to Clostridial butyrate producers. This study shows that the physical form of the fiber influences the competition for substrate among the gut bacteria. Crosslinking of soluble fibers may be a strategy for developing soluble matrices with good physical functionalities for beverages and other foods to improve gut health.


Assuntos
Bactérias/metabolismo , Butiratos/metabolismo , Microbioma Gastrointestinal , Extratos Vegetais/metabolismo , Xilanos/metabolismo , Zea mays/química , Arabinose/análise , Arabinose/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Ácidos Graxos Voláteis/metabolismo , Trato Gastrointestinal/metabolismo , Trato Gastrointestinal/microbiologia , Humanos , Extratos Vegetais/química , Xilanos/química , Xilose/análise , Xilose/metabolismo
18.
Plant Foods Hum Nutr ; 74(3): 376-382, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31222476

RESUMO

Water-extracted arabinoxylans (WEAXs) of different varieties and structures have important effects on wheat end products. However, the functional performances of WEAXs, particularly relating to prebiotic potential, are not yet clear. The present study compared the structural features, physicochemical properties, and prebiotic potential of WEAXs from three wheat varieties, which were used as special wheat varieties to make steamed buns, bread flour, and noodles. The results showed that WEAX-1, WEAX-2, and WEAX-3, derived from Jinqiang wheat, American red hard spring wheat, and Australian white wheat, respectively, had different structural properties, gelation properties, and prebiotic potential. WEAX-3 had a low arabinose to xylose (A/X) ratio (0.49), high ferulic acid content (2300 µg/g), and excellent gelation capacity. WEAX-2 had a high A/X ratio (0.62), low ferulic acid content (1300 µg/g), and poor gelation capacity. When fermented with human feces, WEAX-3 significantly increased the numbers of bifidobacteria and lactobacilli and increased the production of short-chain fatty acids (SCFAs), while WEAX-2 had weaker effects on the number of beneficial bacteria and SCFAs production (P < 0.05). The physicochemical properties and prebiotic potential of WEAXs depended strongly on their structural properties. WEAX with a low A/X ratio and a high ferulic acid content showed excellent gelation property and a strong prebiotic potential.


Assuntos
Ácidos Cumáricos/análise , Prebióticos , Triticum/química , Xilanos/química , Arabinose/análise , Pão , Fenômenos Químicos , Farinha , Água/química , Xilose/análise
19.
Molecules ; 23(12)2018 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-30469531

RESUMO

Brewers' spent grain (BSG) accounts for 85% of the total amount of by-products generated by the brewing industries. BSG is a lignocellulosic biomass that is rich in proteins, lipids, minerals, and vitamins. In the present study, BSG was subjected to pretreatment by two different methods (microwave assisted alkaline pretreatment and organosolv) and was evaluated for the liberation of glucose and xylose during enzymatic saccharification trials. The highest amount of glucose (46.45 ± 1.43 g/L) and xylose (25.15 ± 1.36 g/L) were observed after enzymatic saccharification of the organosolv pretreated BSG. The glucose and xylose yield for the microwave assisted alkaline pretreated BSG were 34.86 ± 1.27 g/L and 16.54 ± 2.1 g/L, respectively. The hydrolysates from the organosolv pretreated BSG were used as substrate for the cultivation of the oleaginous yeast Rhodosporidium toruloides, aiming to produce microbial lipids. The yeast synthesized as high as 18.44 ± 0.96 g/L of cell dry weight and 10.41 ± 0.34 g/L lipids (lipid content of 56.45 ± 0.76%) when cultivated on BSG hydrolysate with a C/N ratio of 500. The cell dry weight, total lipid concentration and lipid content were higher compared to the results obtained when grown on synthetic media containing glucose, xylose or mixture of glucose and xylose. To the best of our knowledge, this is the first report using hydrolysates of organosolv pretreated BSG for the growth and lipid production of oleaginous yeast in literature. The lipid profile of this oleaginous yeast showed similar fatty acid contents to vegetable oils, which can result in good biodiesel properties of the produced biodiesel.


Assuntos
Grão Comestível/química , Metabolismo dos Lipídeos , Rhodotorula/crescimento & desenvolvimento , Biocombustíveis , Biomassa , Fermentação , Glucose/análise , Glucose/metabolismo , Hidrólise , Lipídeos/análise , Rhodotorula/metabolismo , Xilose/análise , Xilose/metabolismo
20.
Molecules ; 23(9)2018 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-30142972

RESUMO

This study presents the effect of two new products based on atomized extracts from edible wild mushrooms (RoBioMush1, RoBioMush2) on the microbiota of three target groups: clinically healthy (NG) individuals, individuals with nutritional disorders (ND), and individuals with cardiovascular diseases (CVD). The microbiota fingerprints were determined by quantitative polymerase chain reaction (qPCR). Modulations in the simulated microbiome were established and correlated with the presence of phenolic compounds released in the in vitro environment (a three-stage culture system GIS2 simulator, www.gissystems.ro). The high metabolizing capacity of NG and CVD correlated positively with the rest of the biological activities expressed in vitro. ND microbiota consumed a wide spectrum of monosaccharides from the products. Xylose was present in large quantities in the descending segment (minimum: 175 µg/mL for ND). The primary conclusion was that the microbiological ecosystem was modulated, as proven by the presence of specific biomarkers (e.g., ammonium levels and fingerprints of short-chain fatty acids⁻SCFAs), which stimulate the organism's health status and were correlated with the restoration of a normal microbiota fingerprint.


Assuntos
Microbioma Gastrointestinal/fisiologia , Agaricales/química , Ácido Gálico/análise , Humanos , Microbiota/fisiologia , Reação em Cadeia da Polimerase , Xilose/análise
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