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1.
Food Chem ; 315: 126287, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32007809

RESUMO

ß-Glucosidase and ß-xylosidase were investigated for their ability to improve the aroma of instant green tea. The aroma and corresponding contributors were analyzed by sensory evaluation, gas chromatography-mass spectrometry, and odor activity value. Their specific contributions to aroma attributes were further examined by aroma reconstruction and omission experiments. The ß-glucosidase treatment significantly enhanced floral and grassy notes, on account of the increases of geraniol, nonanal, and cis-3-hexen-1-ol, and weakened the caramel note, attributable to the increases of nonanal, cis-3-hexen-1-ol, geraniol, methyl salicylate, and decanal. The co-treatment with ß-glucosidase and ß-xylosidase further enhanced the grassy note, with further increase in nonanal and cis-3-hexen-1-ol, and further weakened the caramel note, with additional increase in nonanal, cis-3-hexen-1-ol, methyl salicylate, and decanal. The synergistic action of ß-glucosidase and ß-xylosidase provides new clues to the production of instant green tea infusions with high aroma quality.


Assuntos
Odorantes/análise , Chá/química , Xilosidases/metabolismo , beta-Glucosidase/metabolismo , Cromatografia Gasosa-Espectrometria de Massas/métodos , Chá/metabolismo
2.
PLoS One ; 15(2): e0224776, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32078630

RESUMO

The Target Of Rapamycin (TOR) signaling pathway is known to regulate growth in response to nutrient availability and stress in eukaryotic cells. In the present study, we have investigated the TOR pathway in the white-rot fungus Phanerochaete chrysosporium. Inhibition of TOR activity by rapamycin affects conidia germination and hyphal growth highlighting the conserved mechanism of susceptibility to rapamycin. Interestingly, the secreted protein content is also affected by the rapamycin treatment. Finally, homologs of the components of TOR pathway can be identified in P. chrysosporium. Altogether, those results indicate that the TOR pathway of P. chrysosporium plays a central role in this fungus.


Assuntos
Proteínas Fúngicas/metabolismo , Phanerochaete/crescimento & desenvolvimento , Phanerochaete/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Sítios de Ligação , Proteínas Fúngicas/antagonistas & inibidores , Humanos , Ligação de Hidrogênio , Reação em Cadeia da Polimerase , Estrutura Secundária de Proteína , Proteoma , Transdução de Sinais/efeitos dos fármacos , Sirolimo/farmacologia , Esporos Fúngicos/metabolismo , Serina-Treonina Quinases TOR/antagonistas & inibidores , beta-Glucosidase/metabolismo
3.
Environ Pollut ; 256: 113265, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31733968

RESUMO

Recent studies have demonstrated the ability of mealworm (Tenebrio molitor) for plastic degradation. This study is focused on changes in microbiome structure depending on diets. Microbial community obtained from oat and cellulose diet formed similar group, two kinds of polyethylene formed another group, while polystyrene diet showed the highest dissimilarity. The highest relative abundance of bacteria colonizing gut was in PE-oxodegradable feeding, nevertheless all applied diets were higher in comparison to oat. Dominant phyla consisted of Proteobacteria, Bacteroides, Firmicutes and Actinobacteria, however after PS feeding frequency in Planctomycetes and Nitrospirae increased. The unique bacteria characteristic for cellulose diet belonged to Selenomonas, while Pantoea were characteristic for both polyethylene diets, Lactococcus and Elizabethkingia were unique for each plastic diet, and potential diazotropic bacteria were characteristic for polystyrene diet (Agrobacterium, Nitrosomonas, Nitrospira). Enzymatic similarity between oatmeal and cellulose diets, was shown. All three plastics diet resulted in different activity in both, digestive tract and bacteria. The enzymes with the highest activity were included phosphatases, esterases, leucine arylamidase, ß-galactosidase, ß-glucuronidase, α-glucosidase, ß-glucosidase, chitinase, α-mannosidase and α-fucosidase. The activity of digestive tract was stronger than cultured gut bacteria. In addition to known polyethylene degradation methods, larvae may degrade polyethylene with esterase, cellulose and oatmeal waste activity is related with the activity of sugar-degrading enzymes, degradation of polystyrene with anaerobic processes and diazotrophs.


Assuntos
Celulose/metabolismo , Microbioma Gastrointestinal/efeitos dos fármacos , Polietileno/metabolismo , Poliestirenos/metabolismo , Tenebrio/enzimologia , Ração Animal , Animais , Biodegradação Ambiental , Trato Gastrointestinal/metabolismo , Trato Gastrointestinal/microbiologia , Larva/metabolismo , Microbiota/efeitos dos fármacos , Tenebrio/efeitos dos fármacos , Tenebrio/microbiologia , beta-Glucosidase/metabolismo
4.
Enzyme Microb Technol ; 133: 109465, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31874695

RESUMO

Beta-glucosidase (BGL1) is widely used in animal feed industries. However, degradation caused by digestive enzymes in the intestine hampers its application. Improving the resistance of feed enzymes against proteases is crucial in livestock farming. To improve the resistance of beta-glucosidase against pepsin and trypsin, a rational molecular design based on the inhibition of bound-state formation and secondary design was developed. The strategy includes: (1) prediction of the interaction surface of the pepsin-BGL1 complex structure, (2) prediction of key amino acids affecting the formation of the complex, (3) optimization of pepsin-resistant mutants by structural evaluation, (4) secondary molecular design based on pepsin-resistant mutants, and optimization of pepsin and trypsin-resistant mutants. Two BGL1 protein mutants (BGL1Q627C and BGL1Q627C/R543H/R646W) were constructed, and then mutated and wild-type BGL1s were expressed in Pichia pastoris. The half-life of BGL1Q627C and BGL1Q627C/R543H/R646W were 1.36 and 1.51 times that of the wild type upon pepsin exposure, respectively. For trypsin resistance, the half-life were 0.93 and 1.53 times that of the wild type, respectively. Compare to those of the wild type, most of the basic enzymatic properties of both mutants were not significantly changed except for increased Michaelis constants. The rational design method can be used as a guide for modifying other feed enzymes.


Assuntos
Pepsina A/metabolismo , Trichoderma/enzimologia , Tripsina/metabolismo , beta-Glucosidase/genética , Hidrólise , Trichoderma/genética , beta-Glucosidase/metabolismo
5.
Biosci Biotechnol Biochem ; 84(1): 198-207, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31566090

RESUMO

High glycosidase-producing strains of Aspergillus luchuensis were isolated from 2-deoxyglucose (2-DG) resistant mutants. α-Amylase, exo-α-1,4-glucosidase, ß-glucosidase and ß-xylosidase activity in the mutants was ~3, ~2, ~4 and ~2.5 times higher than the parental strain RIB2604 on koji-making conditions, respectively. Citric acid production and mycelia growth of the mutants, however, approximately halved to that of the parent. Compared to the parent, the alcohol yield from rice and sweet potato shochu mash of the mutant increased ~5.7% and 3.0%, respectively. The mutant strains showed significantly low glucose assimilability despite the fructose one was almost normal, and they had a single missense or nonsense mutation in the glucokinase gene glkA. The recombinant strain that was introduced at one of the mutations, glkA Q300K, demonstrated similar but not identical phenotypes to the mutant strain. This result indicates that glkA Q300K is one of the major mutations in 2-DG resistant strains.


Assuntos
Aspergillus/genética , Aspergillus/isolamento & purificação , Separação Celular/métodos , Códon sem Sentido/genética , Genes Fúngicos/genética , alfa-Glucosidases/metabolismo , Aspergillus/classificação , Aspergillus/metabolismo , Catepsina A/metabolismo , Ácido Cítrico/metabolismo , Desoxiglucose/farmacologia , Farmacorresistência Fúngica , Etanol/metabolismo , Fermentação , Alimentos e Bebidas Fermentados/microbiologia , Frutose/metabolismo , Glucoquinase/genética , Glucose/metabolismo , Ipomoea batatas/química , Oryza/química , Fenótipo , Saccharomyces cerevisiae/classificação , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/isolamento & purificação , Saccharomyces cerevisiae/metabolismo , Xilosidases/metabolismo , alfa-Amilases/metabolismo , beta-Glucosidase/metabolismo
6.
Food Chem ; 309: 125790, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31784075

RESUMO

A higher fermentation efficiency was achieved, using multistarter fermentation of glutinous rice supplemented with Fu brick tea (FGR-FBT), than when using traditional fermentation. The effects of multistarter fermentation on the microbial, chemical, and volatile compositions were determined. When FBT was incorporated during glutinous rice fermentation, increased population of yeasts and fungi, as well as enhanced α-amylase, proteinase and ß-glucosidase activities, were observed. Specific fungi were isolated and identified as Aspergillus spp., which are known to secrete extracellular enzymes that modify the chemical properties, including ethanol levels, pH, total acids, and total soluble solids. The aroma profile of fermented glutinous rice was studied in the absence and presence of FBT, using HS-SPME-GC-MS and the electronic-nose. This analysis indicated that 35 characteristic volatile compounds were only found in FGR-FBT. The results show that FBT can be added during the fermentation of food products to enhance microbial biotransformation and modify flavour metabolism.


Assuntos
Aspergillus/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas/métodos , Oryza/química , Chá/química , Compostos Orgânicos Voláteis/análise , Aspergillus/classificação , Técnicas de Cultura Celular por Lotes , Análise Discriminante , Nariz Eletrônico , Oryza/metabolismo , Análise de Componente Principal , Extração em Fase Sólida , Compostos Orgânicos Voláteis/isolamento & purificação , alfa-Amilases/metabolismo , beta-Glucosidase/metabolismo
7.
Enzyme Microb Technol ; 132: 109444, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31731952

RESUMO

The microbial production of industrial enzymes requires a large number of complex biochemical steps for purification which increases their production cost. Additionally, poor thermo-stability of the purified enzymes under the operational conditions along with the challenges in their recovery and subsequent reuse, limit their usage in an industrial bioprocess. Surface display of heterologous enzymes on bacterial cells appear to be a suitable alternative. Bacillus subtilis, the most well characterized Gram-positive bacterium, is being increasingly studied as a host for surface display. We displayed a glucose-tolerant ß-glucosidase (UnBgl1A) on the surface of B. subtilis cells using CWBb as the anchor protein. These cells displaying UnBgl1A (SD-01) were directly employed for biocatalysis without cell lysis and enzyme purification. The SD-01 cells elicited ∼2 times more catalytic activity compared to the cells expressing the enzyme intracellularly (IN-01). The displayed enzyme and the purified enzyme elucidated similar glucose tolerance (IC50 ∼0.9 M glucose), temperature optima (∼50 °C), and pH optima (∼6.0). The surface displayed UnBgl1A retained ∼50% activity after 4 h when stored at 50 °C whereas the purified UnBgl1A lost all its activity by the 4th hour. Additionally, the SD-01 cells could be efficiently reused for 3 sets of reactions. Further, supplementation of a cellulase cocktail with the cells of the SD-01 strain resulted in ∼2 times more glucose release from sugarcane bagasse compared to supplementation with the purified UnBgl1A. Therefore, displaying enzymes on the B. subtilis cell surface could be an attractive platform for the commercial production of industrial enzymes.


Assuntos
Bacillus subtilis/enzimologia , Glucose/metabolismo , beta-Glucosidase/metabolismo , Bacillus subtilis/genética , Proteínas de Bactérias/metabolismo , Biocatálise , Celulose , Clonagem Molecular , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Temperatura
8.
Enzyme Microb Technol ; 132: 109414, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31731961

RESUMO

ß-glucosidase (BG) plays a key role in determining the efficiency of the enzymatic complex cellulase for the degradation of cellulose into sugars. It hydrolyses the cellobiose, an inhibitor of the enzymatic complex. Therefore, the immobilization of BG is a great challenge for the industrial application of cellulases. Cellulases usually contains a BG amount insufficient to avoid inhibition by cellobiose. Here the BG was immobilized by matrix assisted pulsed laser evaporation (MAPLE) technique. The frozen matrix was composed of water, water/m-DOPA and water/m-DOPA/quinone. The effect of the excipients on the final conformation of the enzyme after the MAPLE processing was determined. The enzyme secondary structure was studied by FTIR analysis. The catalytic performances of the deposited films were tested in the cellobiose hydrolysis reaction. The results demonstrate that the presence of the oxidized form of m-DOPA, the O-quinone form, can protect the protein native structure, with the laser inducing little or no damage. In fact, only the samples deposited from this target preserved the secondary structure of the polypeptide chain and allowed a complete hydrolysis of cellobiose for four consecutive runs, showing a high operational stability of the biocatalyst.


Assuntos
Benzoquinonas/metabolismo , Di-Hidroxifenilalanina/análogos & derivados , Di-Hidroxifenilalanina/metabolismo , beta-Glucosidase/metabolismo , Catálise , Celobiose/metabolismo , Celulase/metabolismo , Enzimas Imobilizadas/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Complexos Multienzimáticos , Quinonas/metabolismo , Temperatura
9.
World J Microbiol Biotechnol ; 35(12): 194, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31776792

RESUMO

Lignocellulosic plant biomass is the world's most abundant carbon source and has consequently attracted attention as a renewable resource for production of biofuels and commodity chemicals that could replace fossil resources. Due to its recalcitrant nature, it must be pretreated by chemical, physical or biological means prior to hydrolysis, introducing additional costs. In this paper, we tested the hypothesis that fungi which thrive on lignocellulosic material (straw, bark or soil) would be efficient in degrading untreated lignocellulose. Wheat straw was used as a model. We developed a fast and simple screening method for cellulase producers and tested one hundred Trichoderma strains isolated from wheat straw. The most potent strain-UB483FTG2/ TUCIM 4455, was isolated from substrate used for mushroom cultivation and was identified as T. guizhouense. After optimization of growth medium, high cellulase activity was already achieved after 72 h of fermentation on raw wheat straw, while the model cellulase overproducing strain T. reesei QM 9414 took 170 h and reached only 45% of the cellulase activity secreted by T. guizhouense. Maximum production levels were 1.1 U/mL (measured with CMC as cellulase substrate) and 0.7 U/mL (ß-glucosidase assay). The T. guizhouense cellulase cocktail hydrolyzed raw wheat straw within 35 h. Our study shows that screening for fungi that successfully compete for special substrates in nature will lead to the isolation of strains with qualitatively and quantitatively superior enzymes needed for their digestion which could be used for industrial purposes.


Assuntos
Celulase/metabolismo , Trichoderma/enzimologia , Trichoderma/metabolismo , Triticum/microbiologia , Biocombustíveis , Carboximetilcelulose Sódica/metabolismo , DNA Fúngico , Fermentação , Hidrólise , Cinética , Filogenia , Trichoderma/genética , Trichoderma/isolamento & purificação , beta-Glucosidase/metabolismo
10.
Environ Monit Assess ; 191(11): 662, 2019 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-31650269

RESUMO

The episodic monsoon condition in a tropical estuarine environment inputs high allochthonous materials that are rich in carbohydrates and are mainly broken down by enzymatic hydrolysis thus alter both organic matter and microbial community composition of an estuary. ß-Glucosidases are one of the enzymes mediating the degradation of carbohydrates and are majorly produced by heterotrophic bacteria. The present study elucidated ß-glucosidase-producing culturable bacterial diversity and measured their activity during non-monsoon and monsoon seasons in Zuari estuary. The results revealed that both bacterial abundance and ß-glucosidase activity decreased significantly from non-monsoon to monsoon, whereas phylogenetic diversity increased. Majority of ß-glucosidase producers during non-monsoon belonged to the members of Bacillales (53%), Pseudomonadales (26%), and Vibrionales (11%) which shifted to the members of Enterobacteriales (51%), Bacillales (14%), Alteromonadales (12%), Aeromonadales (9%), Xanthomonadales (7%), Pseudomonadales (5%), and Flavobacteriales (2%) during the monsoon. The shift in bacterial community structure points out the occurrence of different allochthonous forms with carbohydrate-metabolizing ability during the monsoon, and their relevance in ecology and health of this estuary can be elucidated by studying their functional diversity and is a step ahead.


Assuntos
Bactérias/enzimologia , Bactérias/isolamento & purificação , Monitoramento Ambiental/métodos , Estuários , beta-Glucosidase/metabolismo , Bactérias/metabolismo , Tempestades Ciclônicas , Filogenia , Estações do Ano
11.
Biotechnol Lett ; 41(10): 1201-1211, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31489522

RESUMO

OBJECTIVES: Characterization of glucose tolerant beta glucosidase (GT-BGL) secreted by Aspergillus unguis NII 08123, determination of the gene and protein sequences of the enzyme and establishing its performance in blends for lignocellulose hydrolysis. RESULTS: Supplementation of A. unguis beta glucosidase (BGL) to cellulase released 1.6 times more sugar within 12 h during the hydrolysis of lignocellulosic biomass. The enzyme was determined to be similar to BGL-F from Emericella nidulans by MALDI-TOF analysis, and was found to be a GH3 family protein. Molecular Docking simulation studies showed that the enzyme has lesser affinity for glucose (- 5.7 kcal/mol) compared to its substrate cellobiose (- 7.5 kcal/mol). The residues present in the N-terminal domain are mostly involved in bond formation with both the substrate and the product, while the C-terminal domain contains the catalytic region. In-silico studies showed that its predicted structure is unlike that of previously reported BGLs, which might provide a clue to its exceptional catalytic activity. CONCLUSION: The GT-BGL from A. unguis NII 08123 was proven effective as a blend in for biomass hydrolyzing enzyme cocktails and the possible reasons for its glucose tolerance was determined through studies on its modeled structure.


Assuntos
Aspergillus/enzimologia , Inibidores Enzimáticos/metabolismo , Glucose/metabolismo , Lignina/metabolismo , Plantas/química , beta-Glucosidase/isolamento & purificação , beta-Glucosidase/metabolismo , Biomassa , Domínio Catalítico , Celobiose/metabolismo , Hidrólise , Conformação Proteica , Domínios Proteicos , Análise de Sequência de DNA , Especificidade por Substrato , beta-Glucosidase/química , beta-Glucosidase/genética
12.
Molecules ; 24(18)2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31487855

RESUMO

ß-Glucosidases are enzymes with high importance for many industrial processes, catalyzing the last and limiting step of the conversion of lignocellulosic material into fermentable sugars for biofuel production. However, ß-glucosidases are inhibited by high concentrations of the product (glucose), which limits the biofuel production on an industrial scale. For this reason, the structural mechanisms of tolerance to product inhibition have been the target of several studies. In this study, we performed in silico experiments, such as molecular dynamics (MD) simulations, free energy landscape (FEL) estimate, Poisson-Boltzmann surface area (PBSA), and grid inhomogeneous solvation theory (GIST) seeking a better understanding of the glucose tolerance and inhibition mechanisms of a representative GH1 ß-glucosidase and a GH3 one. Our results suggest that the hydrophobic residues Y180, W350, and F349, as well the polar one D238 act in a mechanism for glucose releasing, herein called "slingshot mechanism", dependent also on an allosteric channel (AC). In addition, water activity modulation and the protein loop motions suggest that GH1 ß-Glucosidases present an active site more adapted to glucose withdrawal than GH3, in consonance with the GH1s lower product inhibition. The results presented here provide directions on the understanding of the molecular mechanisms governing inhibition and tolerance to the product in ß-glucosidases and can be useful for the rational design of optimized enzymes for industrial interests.


Assuntos
Glucose/química , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , beta-Glucosidase/química , Aminoácidos , Domínio Catalítico , Glucose/metabolismo , Cinética , Ligantes , Conformação Molecular , Ligação Proteica , Relação Estrutura-Atividade , Especificidade por Substrato , beta-Glucosidase/metabolismo
13.
J Agric Food Chem ; 67(38): 10744-10755, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31525900

RESUMO

We previously reported that ß-glucosidase BGL1 at low concentration (15 µg mL-1) from Coprinopsis cinerea exhibited hydrolytic activity only toward laminarioligosaccharides but not toward cellooligosaccharides and gentiobiose. This study shows that BGL1 at high concentration (200 µg mL-1) also hydrolyzed cellobiose and gentiobiose, which accounted for only 0.83 and 2.05% of its activity toward laminaribiose, respectively. Interestingly, BGL1 at low concentration (1.5 µg mL-1) showed transglycosylation but BGL1 at high concentration (200 µg mL-1) did not. BGL1 utilizes only laminarioligosaccharides but not glucose, gentiobiose, and cellobiose to synthesize the higher oligosaccharides. BGL1 transferred one glucosyl residue from substrate laminarioligosaccharide to another laminarioligosaccharide as an acceptor in a ß(1 → 3) or ß(1 → 6) fashion to produce higher laminarioligosaccharides or 3-O-ß-d-gentiobiosyl-d-laminarioligosaccharides. The BGL1-digested laminaritriose exhibited approximately 90% enhancement in the anti-oxidant activity compared to that of untreated laminaritriose, implying a potential application of BGL1-based transglycosylation for the production of high value-added rare oligosaccharides.


Assuntos
Agaricales/enzimologia , Dissacarídeos/metabolismo , Proteínas Fúngicas/química , Oligossacarídeos/metabolismo , beta-Glucosidase/química , Agaricales/química , Agaricales/genética , Sequência de Aminoácidos , Dissacarídeos/química , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Glicosilação , Hidrólise , Cinética , Estrutura Molecular , Oligossacarídeos/química , Especificidade por Substrato , beta-Glucosidase/genética , beta-Glucosidase/metabolismo
14.
Int J Mol Sci ; 20(16)2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31394870

RESUMO

Platycodin D (PD), a major saponin (platycoside) in Platycodi radix (balloon flower root), has higher pharmacological activity than the other major platycosides; however, its content in the plant root is only approximately 10% (w/w) and the productivities of PD by several enzymes are still too low for industrial applications. To rapidly increase the total PD content, the ß-glucosidase from Caldicellulosiruptor bescii was used for the deglucosylation of the PD precursors platycoside E (PE) and platycodin D3 (PD3) in the root extract into PD. Under the optimized reaction conditions, the enzyme completely converted the PD precursors into PD with the highest productivity reported so far, increasing the total PD content to 48% (w/w). In the biotransformation process, the platycosides in Platycodi radix were hydrolyzed by four pathways: deapiosylated (deapi)-PE → deapi-PD3 → deapi-PD, PE → PD3 → PD, polygalacin D3 → polygalacin D, and 3″-O-acetyl polygalacin D3 → 3″-O-acetyl polygalacin D.


Assuntos
Biotransformação , Firmicutes/metabolismo , Raízes de Plantas/metabolismo , Platycodon/metabolismo , Saponinas/metabolismo , Triterpenos/metabolismo , beta-Glucosidase/metabolismo , Hidrólise , Redes e Vias Metabólicas , Estrutura Molecular , Saponinas/química , Especificidade por Substrato , Triterpenos/química , beta-Glucosidase/química
15.
Appl Microbiol Biotechnol ; 103(18): 7795-7804, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31388733

RESUMO

The effects of sodium sulfite pretreatment on the delignification rate, cellulose content, enzymatic hydrolysis efficiency, and glucose yield of corncob residues (CCR) were investigated. The optimum pretreatment conditions were as follows: 12% sodium sulfite, with a pH value of 7, a temperature of 160 °C, and a holding time of 20 min. Under the optimal conditions, the cellulose content in the pretreated residue was 85.17%, and sodium lignosulfonate with a sulfonation degree of 0.677 mmol/g was obtained in the waste liquids. A delignification rate of 77.45% was also achieved after the pretreatment. Enzymatic hydrolysis of pretreated CCR was carried out with cellulase (5 FPU/g substrate) and ß-glucosidase (10 IU/g substrate) for 48 h. The untreated CCR were hydrolyzed using cellulase (20 FPU/g substrate) and ß-glucosidase (10 IU/g substrate) for 48 h. The comparison results showed that sodium sulfite pretreatment improved the enzymatic hydrolysis efficiency and glucose yield, which increased by 28.80% and 20.10%, respectively. These results indicated that despite the application of low cellulase dosage, high enzymatic hydrolysis efficiency substrate could be produced, and the sodium lignosulfonate which can be used for oilfields and concrete additives was obtained from the sodium sulfite-pretreated CCR.


Assuntos
Celulase/metabolismo , Lignina/metabolismo , Sulfitos/química , Zea mays/metabolismo , beta-Glucosidase/metabolismo , Biotecnologia , Glucose/metabolismo , Hidrólise , Temperatura
16.
Ultrason Sonochem ; 58: 104614, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31450302

RESUMO

Ultrasound has been regarded as an efficient novel technique for debitterizing of the apricot kernels, but its influence is severely concerned on the possible epimerization of d-amygdalin to the l-amygdalin, a more potentially toxigenic compound. Considering this, the experiments were conducted to investigate the epimerization of d-amygdalin and the volatile components in the debitterizing water, which were separated and identified by the high performance liquid chromatography (HPLC) and gas chromatography with a mass spectrometer (GC-MS), respectively. The results indicate that the ultrasonically-debitterizing did not cause the epimerization of d-amygdalin to the l-amygdalin, while the procedure can be greatly accelerated due to the rapid mass transfer and degradation of d-amygdalin induced by ultrasound irradiation. In addition, the water from the ultrasonically-debitterizing of apricot kernels exerted more aromas compared with that of the conventional debitterizing, which might have more applications about this kind of water. In a word, ultrasound can be safely applied in the debitterizing industry of apricot kernels.


Assuntos
Amigdalina/análise , Manipulação de Alimentos , Prunus armeniaca/química , Paladar , Ondas Ultrassônicas , Compostos Orgânicos Voláteis/análise , Amigdalina/química , Amigdalina/metabolismo , Indústria Alimentícia , Estereoisomerismo , Água/química , beta-Glucosidase/metabolismo
17.
Org Biomol Chem ; 17(30): 7204-7214, 2019 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-31317164

RESUMO

A series of analogs of the iminosugars 1-deoxynojirimycin (DNJ) and 1-deoxymannojirimycin (DMJ), in which an extra five or six-membered ring has been fused to the C1-C2 bond have been prepared. The synthetic strategy exploits a key 2-keto-C-allyl iminosugar, easily accessible from gluconolactam, which upon Grignard addition and RCM furnishes a bicyclic scaffold that can be further hydroxylated at the C[double bond, length as m-dash]C bond. This strategy furnished DNJ mimics with the piperidine ring locked in a 1C4 conformation with all substituents in axial orientation when fused to a six-membered ring. Addition of an extra ring to DNJ and DMJ motif proved to strongly modify the glycosidase inhibition profile of the parent iminosugars leading to modest inhibitors. The 2-keto-C-allyl iminosugar scaffold was further used to access N-acetylglycosamine analogs via oxime formation.


Assuntos
1-Desoxinojirimicina/farmacologia , Inibidores de Glicosídeo Hidrolases/farmacologia , alfa-Glucosidases/metabolismo , beta-Glucosidase/antagonistas & inibidores , 1-Desoxinojirimicina/síntese química , 1-Desoxinojirimicina/química , Animais , Bovinos , Café/enzimologia , Relação Dose-Resposta a Droga , Inibidores de Glicosídeo Hidrolases/síntese química , Inibidores de Glicosídeo Hidrolases/química , Fígado/enzimologia , Conformação Molecular , Oryza/enzimologia , Relação Estrutura-Atividade , beta-Glucosidase/metabolismo
18.
Biotechnol J ; 14(9): e1800704, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31283105

RESUMO

Xylitol is a highly valuable commodity chemical used extensively in the food and pharmaceutical industries. The production of xylitol from d-xylose involves a costly and polluting catalytic hydrogenation process. Biotechnological production from lignocellulosic biomass by micro-organisms like yeasts is a promising option. In this study, xylitol is produced from lignocellulosic biomass by a recombinant strain of Saccharomyces cerevisiae (S. cerevisiae) (YPH499-SsXR-AaBGL) expressing cytosolic xylose reductase (Scheffersomyces stipitis xylose reductase [SsXR]), along with a ß-d-glucosidase (Aspergillus aculeatus ß-glucosidase 1 [AaBGL]) displayed on the cell surface. The simultaneous cofermentation of cellobiose/xylose by this strain leads to an ≈2.5-fold increase in Yxylitol/xylose (=0.54) compared to the use of a glucose/xylose mixture as a substrate. Further improvement in the xylose uptake by the cell is achieved by a broad evaluation of several homologous and heterologous transporters. Homologous maltose transporter (ScMAL11) shows the best performance in xylose transport and is used to generate the strain YPH499-XR-ScMAL11-BGL with a significantly improved xylitol production capacity from cellobiose/xylose coutilization. This report constitutes a promising proof of concept to further scale up the biorefinery industrial production of xylitol from lignocellulose by combining cell surface and metabolic engineering in S. cerevisiae.


Assuntos
Celobiose/metabolismo , Saccharomyces cerevisiae/metabolismo , Xilose/metabolismo , beta-Glucosidase/metabolismo , Biomassa , Lignina/metabolismo
19.
Appl Microbiol Biotechnol ; 103(17): 7003-7015, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31289903

RESUMO

Use of recombinant glycosidases is a promising approach for the production of minor ginsenosides, e.g., Compound K (CK) and F1, which have potential applications in the food industry. However, application of these recombinant enzymes for food-grade preparation of minor ginsenosides are limited by the lack of suitable expression hosts and low productivity. In this study, Corynebacterium glutamicum ATCC13032, a GRAS strain that has been used extensively for the industrial-grade production of additives for foodstuffs, was employed to express a novel ß-glucosidase (MT619) from Microbacterium testaceum ATCC 15829 with high ginsenoside-transforming activity. A cellulose-binding module was additionally fused to the N-terminus of MT619 for immobilization on cellulose, which is an abundant and safe material. Via one-step immobilization, the fusion protein in cell lysates was efficiently immobilized on regenerated amorphous cellulose at a high density (maximum 984 mg/g cellulose), increasing the enzyme concentration by 286-fold. The concentrated and immobilized enzyme showed strong conversion activities against protopanaxadiol- and protopanaxatriol-type ginsenosides for the production of CK and F1. Using gram-scale ginseng extracts as substrates, the immobilized enzyme produced 7.59 g/L CK and 9.42 g/L F1 in 24 h. To the best of our knowledge, these are the highest reported product concentrations of CK and F1, and this is the first time that a recombinant enzyme has been immobilized on cellulose for the preparation of minor ginsenosides. This safe, convenient, and efficient production method could also be effectively exploited in the preparation of food-processing recombinant enzymes in the pharmaceutical, functional food, and cosmetics industries.


Assuntos
Enzimas Imobilizadas/metabolismo , Ginsenosídeos/metabolismo , beta-Glucosidase/metabolismo , Actinomycetales/enzimologia , Actinomycetales/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biotransformação , Celulose/química , Clonagem Molecular , Corynebacterium glutamicum/enzimologia , Corynebacterium glutamicum/genética , Corynebacterium glutamicum/metabolismo , Enzimas Imobilizadas/química , Enzimas Imobilizadas/genética , Expressão Gênica , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Sapogeninas/metabolismo , beta-Glucosidase/química , beta-Glucosidase/genética
20.
J Agric Food Chem ; 67(30): 8393-8401, 2019 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-31291721

RESUMO

The ginsenoside 20-O-ß-glucopyranosyl-20(S)-protopanaxadiol or compound K is an essential ingredient in functional food, cosmetics, and traditional medicines. However, no study has reported the complete conversion of all protopanaxadiol (PPD)-type ginsenosides from ginseng extract into compound K using whole-cell conversion. To increase the production of compound K from ginseng extract using whole recombinant cells, the ß-glucosidase enzyme from Caldicellulosiruptor bescii was coexpressed with a chaperone expression system (pGro7), and the cells expressing the coexpression system were permeabilized with ethylenediaminetetraacetic acid. The permeabilized cells carrying the chaperone coexpression system showed a 2.6-fold increase in productivity and yield as compared with nontreated cells, and completely converted all PPD-type ginsenosides from ginseng root extract into compound K with the highest productivity among the results reported so far. Our results will contribute to the industrial biological production of compound K.


Assuntos
Proteínas de Bactérias/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Firmicutes/enzimologia , Ginsenosídeos/metabolismo , Chaperonas Moleculares/genética , Sapogeninas/metabolismo , beta-Glucosidase/genética , Proteínas de Bactérias/metabolismo , Biotransformação , Escherichia coli/química , Firmicutes/genética , Engenharia Genética , Ginsenosídeos/química , Chaperonas Moleculares/metabolismo , Panax/química , Sapogeninas/química , beta-Glucosidase/metabolismo
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