RESUMO
OBJECTIVES: This study aimed to investigate the effect of the n-butanol fraction of the methanol leaf extract of Artemisia campestris (BFAC), growing wild in the arid zone of Tunisia, on induced obesity in male Wistar rats. METHODS: The total phenolic content and antioxidant capacity of the BFAC were estimated. The main phenolic composition of the BFAC was determined using the high-performance chromatography system coupled with a diode array detector technics. Five groups of rats received either a standard diet (SD group), a high-fat diet (HFD group), or an HFD supplemented with oral administration of BFAC for eight weeks. RESULTS: The BFAC showed higher phenolic content and antioxidant potential than the total leaf methanol extract. Chlorogenic acid, rutin, and dicaffeoylquinic acids were identified in the BFAC. HFD increased body and relative liver weights, as well as serum and hepatic levels of triglycerides and total cholesterol, compared to SD. HFD generated significant oxidative stress in the liver by increasing lipid peroxidation and reducing glutathione-S-transferase, catalase, and glutathione peroxidase activities, compared to SD. These HFD-altered parameters were restored to normal values by oral treatment with the BFAC. CONCLUSIONS: These findings give first evidence about the antiobesity efficacy of A. campestris. Such a study would enhance existing information and promote the use of this species.
Assuntos
Artemisia , 1-Butanol/metabolismo , 1-Butanol/farmacologia , Animais , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Artemisia/química , Artemisia/metabolismo , Dieta Hiperlipídica , Fígado , Masculino , Metanol/farmacologia , Obesidade/tratamento farmacológico , Obesidade/metabolismo , Estresse Oxidativo , Fenóis/farmacologia , Extratos Vegetais/química , Ratos , Ratos WistarRESUMO
Butyrate is produced by chemical synthesis based on crude oil, produced by microbial fermentation, or extracted from animal fats (M. Dwidar, J.-Y. Park, R. J. Mitchell, and B.-I. Sang, The Scientific World Journal, 2012:471417, 2012, https://doi.org/10.1100/2012/471417). Butyrate production by anaerobic bacteria is highly favorable since waste or sustainable resources can be used as the substrates. For this purpose, the native hyper-butanol producer Clostridium saccharoperbutylacetonicum N1-4(HMT) was used as a chassis strain due to its broad substrate spectrum. BLASTp analysis of the predicted proteome of C. saccharoperbutylacetonicum N1-4(HMT) resulted in the identification of gene products potentially involved in acetone-butanol-ethanol (ABE) fermentation. Their participation in ABE fermentation was either confirmed or disproven by the parallel production of acids or solvents and the respective transcript levels obtained by transcriptome analysis of this strain. The genes encoding phosphotransacetylase (pta) and butyraldehyde dehydrogenase (bld) were deleted to reduce acetate and alcohol formation. The genes located in the butyryl-CoA synthesis (bcs) operon encoding crotonase, butyryl-CoA dehydrogenase with electron-transferring protein subunits α and ß, and 3-hydroxybutyryl-CoA dehydrogenase were overexpressed to channel the flux further towards butyrate formation. Thereby, the native hyper-butanol producer C. saccharoperbutylacetonicum N1-4(HMT) was converted into the hyper-butyrate producer C. saccharoperbutylacetonicum ΔbldΔpta [pMTL83151_BCS_PbgaL]. The transcription pattern following deletion and overexpression was characterized by a second transcriptomic study, revealing partial compensation for the deletion. Furthermore, this strain was characterized in pH-controlled fermentations with either glucose or Excello, a substrate yielded from spruce biomass. Butyrate was the main product, with maximum butyrate concentrations of 11.7 g·L-1 and 14.3 g·L-1, respectively. Minimal amounts of by-products were detected. IMPORTANCE Platform chemicals such as butyrate are usually produced chemically from crude oil, resulting in the carry-over of harmful compounds. The selective production of butyrate using sustainable resources or waste without harmful by-products can be achieved by bacteria such as clostridia. The hyper-butanol producer Clostridium saccharoperbutylacetonicum N1-4(HMT) was converted into a hyper-butyrate producer. Butyrate production with very small amounts of by-products was established with glucose and the sustainable lignocellulosic sugar substrate Excello extracted from spruce biomass by the biorefinery Borregaard (Sarpsborg, Norway).
Assuntos
Butiratos , Petróleo , 1-Butanol/metabolismo , Acetona/metabolismo , Butanóis/metabolismo , Butiratos/metabolismo , Clostridium/genética , Clostridium/metabolismo , Etanol/metabolismo , Fermentação , Glucose/metabolismo , Lignina , Petróleo/metabolismo , Açúcares/metabolismoRESUMO
To reveal the mechanism of anti-renal fibrosis effects of an n-butanol extract from Amygdalus mongolica, renal fibrosis was induced with unilateral ureteral obstruction (UUO) and then treated with an n-butanol extract (BUT) from Amygdalus mongolica (Rosaceae). Sixty male Sprague-Dawley rats were randomly divided into the sham-operated, renal fibrosis (RF) model, benazepril hydrochloride-treated model (1.5 mg kg-1) and BUT-treated (1.75, 1.5 and 1.25 g kg-1) groups and the respective drugs were administered intragastrically for 21 days. Related biochemical indices in rat serum were determined and histopathological morphology observed. Serum metabolomics was assessed with HPLC-Q-TOF-MS. The BUT reduced levels of blood urea nitrogen, serum creatinine and albumin and lowered the content of malondialdehyde and hydroxyproline in tissues. The activity of superoxide dismutase in tissues was increased and an improvement in the severity of RF was observed. Sixteen possible biomarkers were identified by metabolomic analysis and six key metabolic pathways, including the TCA cycle and tyrosine metabolism, were analyzed. After treatment with the extract, 8, 12 and 9 possible biomarkers could be detected in the high-, medium- and low-dose groups, respectively. Key biomarkers of RF, identified using metabolomics, were most affected by the medium dose. A. mongolica BUT extract displays a protective effect on RF in rats and should be investigated as a candidate drug for the treatment of the disease.
Assuntos
Nefropatias , Rim , Ratos , Masculino , Animais , Rim/metabolismo , Rim/patologia , 1-Butanol/metabolismo , 1-Butanol/farmacologia , 1-Butanol/uso terapêutico , Ratos Sprague-Dawley , Biomarcadores/metabolismo , Extratos Vegetais/farmacologia , FibroseRESUMO
n-Butanol is often considered a potential substitute for gasoline due to its physicochemical properties being closely related to those of gasoline. In this study, we extend our earlier work to convert endogenously producing butyrate via the FASII pathway using thioesterase TesBT to its corresponding alcohol, i.e., butanol. We first assembled pathway genes, i.e., car encoding carboxylic acid reductase from Mycobacterium marinum, sfp encoding phosphopantetheinyl transferase from Bacillus subtilis, and adh2 encoding alcohol dehydrogenase from S. cerevisiae, responsible for bioconversion of butyrate to butanol in three different configurations (Operon, Pseudo-Operon, and Monocistronic) to achieve optimum expression of each gene and compared with the clostridial solventogenic pathway for in vivo conversion of butyrate to butanol under aerobic conditions. An E. coli strain harboring car, sfp, and adh2 in pseudo-operon configuration was able to convert butyrate to butanol with 100% bioconversion efficiency when supplemented with 1 g/L of butyrate. Further, co-cultivation of an upstream strain (butyrate-producing) with a downstream strain (butyrate to butanol converting) at different inoculation ratios was investigated, and an optimized ratio of 1:4 (upstream strain: downstream strain) was found to produce â¼2 g/L butanol under fed-batch fermentation. Further, a mono-cultivation approach was applied by transforming a plasmid harboring tesBT gene into the downstream strain. This approach produced 0.42 g/L in a test tube and â¼2.9 g/L butanol under fed-batch fermentation. This is the first report where both mono- and co-cultivation approaches were tested and compared for butanol production, and butanol titers achieved using both strategies are the highest reported values in recombinant E. coli utilizing FASII pathway.
Assuntos
1-Butanol/metabolismo , Vias Biossintéticas/genética , Escherichia coli/química , Engenharia Metabólica/métodos , 1-Butanol/química , Álcool Desidrogenase/genética , Proteínas de Bactérias/genética , Técnicas de Cultura Celular por Lotes , Ácido Butírico/química , Ácido Butírico/metabolismo , Escherichia coli/metabolismo , Ácidos Graxos/biossíntese , Proteínas Fúngicas/genética , Oxirredutases/genética , Plasmídeos/genética , Plasmídeos/metabolismo , Transferases (Outros Grupos de Fosfato Substituídos)/genéticaRESUMO
High titer 1-butanol production in Escherichia coli has previously been achieved by overexpression of a modified clostridial 1-butanol production pathway and subsequent deletion of native fermentation pathways. This strategy couples growth with production as 1-butanol pathway offers the only available terminal electron acceptors required for growth in anaerobic conditions. With further inclusion of other well-established metabolic engineering principles, a titer of 15g/L has been obtained. In achieving this titer, many currently existing strategies have been exhausted, and 1-butanol toxicity level has been surpassed. Therefore, continued engineering of the host strain for increased production requires implementation of alternative strategies that seek to identify non-obvious targets for improvement. In this study, a metabolomics-driven approach was used to reveal a CoA imbalance resulting from a pta deletion that caused undesirable accumulation of pyruvate, butanoate, and other CoA-derived compounds. Using metabolomics, the reduction of butanoyl-CoA to butanal catalyzed by alcohol dehydrogenase AdhE2 was determined as a rate-limiting step. Fine-tuning of this activity and subsequent release of free CoA restored the CoA balance that resulted in a titer of 18.3g/L upon improvement of total free CoA levels using cysteine supplementation. By enhancing AdhE2 activity, carbon flux was directed towards 1-butanol production and undesirable accumulation of pyruvate and butanoate was diminished. This study represents the initial report describing the improvement of 1-butanol production in E. coli by resolving CoA imbalance, which was based on metabolome analysis and rational metabolic engineering strategies.
Assuntos
1-Butanol/metabolismo , Álcool Desidrogenase , Aldeído Oxirredutases , Coenzima A , Proteínas de Escherichia coli , Escherichia coli , Metaboloma , Metabolômica , Álcool Desidrogenase/genética , Álcool Desidrogenase/metabolismo , Aldeído Oxirredutases/genética , Aldeído Oxirredutases/metabolismo , Coenzima A/genética , Coenzima A/metabolismo , Cisteína/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismoRESUMO
We have developed butanol-producing consolidated bioprocessing from cellulosic substrates through coculture of cellulolytic clostridia and butanol-producing Clostridium saccharoperbutylacetonicum strain N1-4. However, the butanol fermentation by strain N1-4 (which has an optimal growth temperature of 30°C) is sensitive to the higher cultivation temperature of 37°C; the nature of this deleterious effect remains unclear. Comparison of the intracellular metabolites of strain N1-4 cultivated at 30°C and 37°C revealed decreased levels of multiple primary metabolites (notably including nucleic acids and cofactors) during growth at the higher temperature. Supplementation of the culture medium with 250 mg/liter adenine enhanced both cell growth (with the optical density at 600 nm increasing from 4.3 to 10.2) and butanol production (increasing from 3.9 g/liter to 9.6 g/liter) at 37°C, compared to those obtained without adenine supplementation, such that the supplemented 37°C culture exhibited growth and butanol production approaching those observed at 30°C in the absence of adenine supplementation. These improved properties were based on the maintenance of cell viability. We further showed that adenine supplementation enhanced cell viability during growth at 37°C by maintaining ATP levels and inhibiting spore formation. This work represents the first demonstration (to our knowledge) of the importance of adenine-related metabolism for clostridial butanol production, suggesting a new means of enhancing target pathways based on metabolite levels.IMPORTANCE Metabolomic analysis revealed decreased levels of multiple primary metabolites during growth at 37°C, compared to 30°C, in C. saccharoperbutylacetonicum strain N1-4. We found that adenine supplementation restored the cell growth and butanol production of strain N1-4 at 37°C. The effects of adenine supplementation reflected the maintenance of cell viability originating from the maintenance of ATP levels and the inhibition of spore formation. Thus, our metabolomic analysis identified the depleted metabolites that were required to maintain cell viability. Our strategy, which is expected to be applicable to a wide range of organisms, permits the identification of the limiting metabolic pathway, which can serve as a new target for molecular breeding. The other novel finding of this work is that adenine supplementation inhibits clostridial spore formation. The mechanism linking spore formation and metabolomic status in butanol-producing clostridia is expected to be the focus of further research.
Assuntos
Adenina/farmacologia , Butanóis/metabolismo , Clostridium/efeitos dos fármacos , Clostridium/metabolismo , Viabilidade Microbiana/efeitos dos fármacos , 1-Butanol/metabolismo , Acetona/metabolismo , Trifosfato de Adenosina , Clostridium/crescimento & desenvolvimento , Meios de Cultura/química , Etanol/metabolismo , Fermentação , Glucose/metabolismo , Redes e Vias Metabólicas/efeitos dos fármacos , Metabolômica , Esporos Bacterianos/efeitos dos fármacos , TemperaturaRESUMO
BACKGROUND: Clostridium pasteurianum is becoming increasingly attractive for the production of chemicals and fuels such as n-butanol and 1,3-propanediol. Previously we have shown that dual substrate fermentation using glucose and glycerol enhanced the cell growth and butanol production significantly. Although C. pasteurianum can grow efficiently with either glucose or glycerol alone, under certain conditions, glucose limitation in the mixed substrate fermentation leads to growth cessation. To understand this phenomenon and for process optimization, fermentation experiments were performed in the presence of excess glycerol but with varied initial concentrations of glucose which were followed by physiological, metabolic and proteomic analyses. RESULTS: Physiological characterization showed that the observed cease of growth is not due to the toxicity of n-butanol. Furthermore, the growth can be resumed by addition of glucose or the intermediate oxaloacetate. Proteomic analysis shed more light on the system-level regulation of many proteins directly or indirectly associated with this phenomenon. Surprisingly, it is found that the specific growth rate of C. pasteurianum in the different growth phases (e.g. before and after glucose limitation) correlated well with the expression level of the ATP dependent pyruvate carboxylase and with the expression level of biotin synthase which provides the cofactor biotin for the formation of oxaloacetate from pyruvate. Bioenergetic analysis based on the formation rates of metabolites further show that ATP supply is not a limiting factor for the pyruvate carboxylation to oxaloacetate. CONCLUSIONS: The results of physiological and proteomic analyses clearly show that the anaplerotic synthesis of oxaloacetate plays a key role in determining the growth behaviour of C. pasteurianum in fermentations with mixed substrates of glucose and glycerol. This study provides interesting targets for metabolic engineering of this emerging industrial microorganism.
Assuntos
1-Butanol/metabolismo , Proteínas de Bactérias/química , Clostridium/metabolismo , Propilenoglicóis/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Clostridium/química , Clostridium/genética , Clostridium/crescimento & desenvolvimento , Fermentação , Glucose/metabolismo , ProteômicaRESUMO
Lignocellulosic biomass and dedicated energy crops such as Jerusalem artichoke are promising alternatives for biobutanol production by solventogenic clostridia. However, fermentable sugars such as fructose or xylose released from the hydrolysis of these feedstocks were subjected to the incomplete utilization by the strains, leading to relatively low butanol production and productivity. When 0.001 g/L ZnSO4·7H2O was supplemented into the medium containing fructose as sole carbon source, 12.8 g/L of butanol was achieved with butanol productivity of 0.089 g/L/h compared to only 4.5 g/L of butanol produced with butanol productivity of 0.028 g/L/h in the control without zinc supplementation. Micronutrient zinc also led to the improved butanol production up to 8.3 g/L derived from 45.2 g/L xylose as sole carbon source with increasing butanol productivity by 31.7%. Moreover, the decreased acids production was observed under the zinc supplementation condition, resulting in the increased butanol yields of 0.202 g/g-fructose and 0.184 g/g-xylose, respectively. Similar improvements were also observed with increasing butanol production by 130.2 % and 8.5 %, butanol productivity by 203.4% and 18.4%, respectively, in acetone-butanol-ethanol fermentations from sugar mixtures of fructose/glucose (4:1) and xylose/glucose (1:2) simulating the hydrolysates of Jerusalem artichoke tubers and corn stover. The results obtained from transcriptional analysis revealed that zinc may have regulatory mechanisms for the sugar transport and metabolism of Clostridium acetobutylicum L7. Therefore, micronutrient zinc supplementation could be an effective way for economic development of butanol production derived from these low-cost agricultural feedstocks.
Assuntos
1-Butanol/metabolismo , Acetona/metabolismo , Etanol/metabolismo , Fermentação , Frutose/metabolismo , Xilose/metabolismo , Zinco/metabolismo , Biomassa , Metabolismo dos Carboidratos/efeitos dos fármacos , Clostridium acetobutylicum/efeitos dos fármacos , Clostridium acetobutylicum/metabolismo , Fermentação/efeitos dos fármacos , Glucose/metabolismo , Helianthus/química , Helianthus/metabolismo , Zea mays/química , Zea mays/metabolismo , Zinco/farmacologiaRESUMO
BACKGROUND: There is a strong interest in using photosynthetic cyanobacteria as production hosts for biofuels and chemicals. Recent work has shown the benefit of pathway engineering, enzyme tolerance, and co-factor usage for improving yields of fermentation products. RESULTS: An n-butanol pathway was inserted into a Synechocystis mutant deficient in polyhydroxybutyrate synthesis. We found that nitrogen starvation increased specific butanol productivity up to threefold, but cessation of cell growth limited total n-butanol titers. Metabolite profiling showed that acetyl-CoA increased twofold during nitrogen starvation. Introduction of a phosphoketolase increased acetyl-CoA levels sixfold at nitrogen replete conditions and increased butanol titers from 22 to 37 mg/L at day 8. Flux balance analysis of photoautotrophic metabolism showed that a Calvin-Benson-Bassham-Phosphoketolase pathway had higher theoretical butanol productivity than CBB-Embden-Meyerhof-Parnas and a reduced butanol ATP demand. CONCLUSION: These results demonstrate that phosphoketolase overexpression and modulation of nitrogen levels are two attractive routes toward increased production of acetyl-CoA derived products in cyanobacteria and could be implemented with complementary metabolic engineering strategies.
Assuntos
1-Butanol/metabolismo , Acetilcoenzima A/metabolismo , Synechocystis/metabolismo , 1-Butanol/química , Trifosfato de Adenosina/metabolismo , Aldeído Liases/genética , Aldeído Liases/metabolismo , Biomassa , Engenharia Metabólica , Metaboloma , NAD/química , NAD/metabolismo , Nitrogênio/metabolismoRESUMO
We proposed a potential production platform of n-butanol in Escherichia coli. First, a butyrate-conversion strain was developed by removal of undesired genes and recruiting endogenous atoDA and Clostridium adhE2. Consequently, this E. coli strain grown on the M9 mineral salt with yeast extract (M9Y) was shown to produce 6.2g/L n-butanol from supplemented butyrate at 36h. The molar conversion yield of n-butanol on butyrate reaches 92%. Moreover, the production platform was advanced by additional inclusion of a butyrate-producing strain. This strain was equipped with a pathway comprising atoDA and heterologous genes for the synthesis of butyrate. Without butyrate, the butyrate-conversion and the butyrate-producing strains were co-cultured in M9Y medium and produced 5.5g/L n-butanol from glucose at 24h. The production yield on glucose accounts for 69% of the theoretical yield. Overall, it indicates a promise of the developed platform for n-butanol production in E. coli.
Assuntos
1-Butanol/metabolismo , Escherichia coli , Proteínas de Bactérias/biossíntese , Proteínas de Bactérias/genética , Butiratos/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Engenharia Metabólica/métodos , Oxirredutases/biossíntese , Oxirredutases/genéticaRESUMO
In Traditional Chinese Medicine, liver targeting is usually achieved by coadministration with Vinegar-baked Radix Bupleuri (VBRB), but the mechanism is unclear. In this paper, the influence of VBRB on the activity of ß-glucuronidase was investigated and compared with that of saikosaponins. The activity of ß-glucuronidase was measured by microplate reader using a 4-nitrophenyl-ß-d-glucuronide substrate. The change of 4-nitrophenol content was used to characterize the activity of ß-glucuronidase. Bupleurum chinenes were found to be the inhibitor of ß-glucuronidase. The inhibition rate of Bupleurum chinenes extracts BC1 (high molecular weight polysaccharides), BC2 (ethanol soluble/water insoluble component), BC3 (extracted by n-butanol, soluble in water), and BC4 (low molecular weight water soluble parts) on the activity of ß-glucuronidase was found to be 45.15%, 33.94%, 24.94%, and 34.54%, respectively, after 1 h incubation, with BC1 showing the highest inhibition rate. In contrast, the saikosaponins were demonstrated to be the promoter of ß-glucuronidase, with promotion rates of 333.56%, 217.04%, 247.87%, 149.75%, and 92.50% for saikosaponin standard samples A, B, B2, C, and D, respectively, (p<0.05). In conclusion, inhibiting the activity of ß-glucuronidase might be one of the reasons why VBRB could influence drug distribution upon its coadministration with other drugs. Since saikosaponins and VBRB extracts have opposite effect, more attention should be paid to the content of saikosaponins in the extracts upon its application.
Assuntos
Ácido Acético/química , Bupleurum/química , Medicamentos de Ervas Chinesas/farmacologia , Glucuronidase/metabolismo , Ácido Oleanólico/análogos & derivados , Saponinas/farmacologia , 1-Butanol/metabolismo , Glucuronatos/metabolismo , Glucuronidase/antagonistas & inibidores , Fígado/efeitos dos fármacos , Fígado/metabolismo , Nitrofenóis/metabolismo , Ácido Oleanólico/farmacologiaRESUMO
This study describes cleaning of a waste gas stream using bench scale biofilters (BFs) or biotrickling filters (BTFs). The gas stream contained a mixture of acetone, n-butanol, methane, ethylene, and ammonia, and was diverted uniformly to six biofilters and four biotrickling filters. The biofilters were packed with either perlite (BF-P), polyurethane foam (BF-F), or a mixture of compost, wood chips, and straw (BF-C), whereas the biotrickling filters contained either perlite (BTF-P) or polyurethane foam (BTF-F). Experimental results showed that both BFs and BTFs packed with various media were able to achieve complete removal of highly soluble compounds such as acetone, n-butanol, and ammonia of which the dimensionless Henry's constants (H) are less than 0.01. Methane was not removed due to its extreme insolubility (H>30). However, the ethylene (H ≈ 9) removal efficiencies depended on trickle water flow rates, media surface areas, and ammonia gas levels.
Assuntos
Poluentes Atmosféricos/metabolismo , Poluição do Ar/prevenção & controle , Reatores Biológicos , Filtração/métodos , 1-Butanol/metabolismo , Acetona/metabolismo , Óxido de Alumínio , Amônia/metabolismo , Etilenos/metabolismo , Metano/metabolismo , Poliuretanos , Esgotos/microbiologia , Dióxido de Silício , Espectroscopia de Infravermelho com Transformada de Fourier , MadeiraRESUMO
A gene encoding a synthetic truncated Candida antarctica lipase B (CALB) was generated via automated PCR and expressed in Saccharomyces cerevisiae. Western blot analysis detected five truncated CALB variants, suggesting multiple translation starts from the six in-frame ATG codons. The longest open reading frame, which corresponds to amino acids 35-317 of the mature lipase, appeared to be expressed in the greatest amount. The truncated CALB was immobilized on Sepabeads® EC-EP resin and used to produce ethyl and butyl esters from crude corn oil and refined soybean oil. The yield of ethyl esters was 4-fold greater from corn oil than from soybean oil and was 36% and 50% higher, respectively, when compared to a commercially available lipase resin (Novozym 435) using the same substrates. A 5:1 (v/v) ratio of ethanol to corn oil produced 3.7-fold and 8.4-fold greater yields than ratios of 15:1 and 30:1, respectively. With corn oil, butyl ester production was 56% higher than ethyl ester production. Addition of an ionic catalytic resin step prior to the CALB resin increased yields of ethyl esters from corn oil by 53% compared to CALB resin followed by ionic resin. The results suggest resin-bound truncated CALB has potential application in biodiesel production using biocatalysts.
Assuntos
1-Butanol/metabolismo , Enzimas Imobilizadas/metabolismo , Etanol/metabolismo , Ácidos Graxos/metabolismo , Proteínas Fúngicas/metabolismo , Lipase/metabolismo , Proteínas Recombinantes/metabolismo , 1-Butanol/química , Sequência de Aminoácidos , Sequência de Bases , Reatores Biológicos , Óleo de Milho/química , Óleo de Milho/metabolismo , Enzimas Imobilizadas/química , Enzimas Imobilizadas/genética , Esterificação , Etanol/química , Ácidos Graxos/química , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Lipase/química , Lipase/genética , Dados de Sequência Molecular , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Resinas Sintéticas , Saccharomyces cerevisiae/genética , Óleo de Soja/química , Óleo de Soja/metabolismoRESUMO
Concentrated cassava bagasse hydrolysate (CBH) containing 584.4 g/L glucose was studied for acetone-butanol-ethanol (ABE) fermentation with a hyper-butanol-producing Clostridium acetobutylicum strain in a fibrous bed bioreactor with gas stripping for continuous butanol recovery. With periodical nutrient supplementation, stable production of n-butanol from glucose in the CBH was maintained in the fed-batch fermentation over 263 h with an average sugar consumption rate of 1.28 g/L h and butanol productivity of 0.32±0.03 g/L h. A total of 108.5 g/L ABE (butanol: 76.4 g/L, acetone: 27.0 g/L, ethanol: 5.1 g/L) was produced, with an overall yield of 0.32±0.03 g/g glucose for ABE and 0.23±0.01 g/g glucose for butanol. The gas stripping process generated a product containing 10-16% (w/v) of butanol, ~4% (w/v) of acetone, a small amount of ethanol (<0.8%) and almost no acids, resulting in a highly concentrated butanol solution of ~64% (w/v) after phase separation.
Assuntos
1-Butanol/isolamento & purificação , 1-Butanol/metabolismo , Técnicas de Cultura Celular por Lotes/métodos , Reatores Biológicos/microbiologia , Celulose/metabolismo , Clostridium acetobutylicum/metabolismo , Manihot/microbiologia , Extratos Vegetais/metabolismo , Fermentação , HidróliseRESUMO
Phenolics in dry Artemisia princeps Pampanini, an herbal plant traditionally consumed as food ingredients in Korea was extracted, fractionated, and quantified as well as evaluated for its neuroprotection for PC-12 cells. Whole extract had 5,852 mg gallic acid equivalents/100 g of total phenolics and 6,274 mg and 9,698 mg vitamin C equivalents/100 g of antioxidant capacities assayed by DPPH and ABTS radicals, respectively. The fraction extracted with n-butanol had the highest levels of total phenolics and antioxidant capacity than the other fractions (n-hexane, chloroform, ethyl acetate, and water). Using a reversed-phase HPLC system, caffeoylquinic acid (CQA) and its derivatives such as 3-CQA, 4-CQA, 5-CQA, 1,5-diCQA, 3,4-diCQA, 3,5-diCQA, and 4,5-diCQA were isolated and quantified. The whole extract and its n-butanol fraction yielded 3,5-diCQA with the highest amount, which consisted of approximately 36.8% and 33.5%, respectively. The whole extract, the n-butanol fraction, and 3,5-diCQA showed neuroprotective effect on PC-12 cells under the insult of amyloid ß peptide in a dose-dependent manner. Treatments of the whole extract and the n-butanol fraction for PC-12 cells under oxidative stress increased approximately 1.6 and 2.4 times higher cell viability, compared with the control without treatments. For PC-12 cells treated with 3,5-diCQA, intracellular oxidative stress decreased by 51.3% and cell viability increased up to 2.8 times compared to the control with oxidative insult of amyloid ß peptide only. These results indicate that phenolics from A. princeps Pampanini alleviated the oxidative stress and enhanced the viability of PC-12 cells, suggesting that it may be applied as a dietary antineurodegenerative agent in functional foods.
Assuntos
Artemisia/química , Fármacos Neuroprotetores/farmacologia , Estresse Oxidativo , Extratos Vegetais/farmacologia , Ácido Quínico/análogos & derivados , 1-Butanol/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Antioxidantes/farmacologia , Sobrevivência Celular , Ácido Gálico/farmacologia , Células PC12 , Ácido Quínico/farmacologia , Ratos , República da CoreiaRESUMO
Alcohols and inhaled anesthetics enhance the function of GABA(A) receptors containing α, ß, and γ subunits. Molecular analysis has focused on the role of the α subunits; however, there is evidence that the ß subunits may also be important. The goal of our study was to determine whether Asn265, which is homologous to the site implicated in the α subunit (Ser270), contributes to an alcohol and volatile anesthetic binding site in the GABA(A) receptor ß(2) subunit. We substituted cysteine for Asn265 and exposed the mutant to the sulfhydryl-specific reagent octyl methanethiosulfonate (OMTS). We used two-electrode voltage-clamp electrophysiology in Xenopus laevis oocytes and found that, after OMTS application, GABA-induced currents were irreversibly potentiated in mutant α(1)ß(2)(N265C)γ(2S) receptors [but not α(1)ß(2)(I264C)γ(2S)], presumably because of the covalent linking of octanethiol to the thiol group in the substituted cysteine. It is noteworthy that this effect was blocked when OMTS was applied in the presence of octanol. We found that potentiation by butanol, octanol, or isoflurane in the N265C mutant was nearly abolished after the application of OMTS, suggesting that an alcohol and volatile anesthetic binding site at position 265 of the ß(2) subunit was irreversibly occupied by octanethiol and consequently prevented butanol or isoflurane from binding and producing their effects. OMTS did not affect modulation or direct activation by pentobarbital, but there was a partial reduction of allosteric modulation by flunitrazepam and alphaxalone in mutant α(1)ß(2)(N265C)γ(2S) receptors after OMTS was applied. Our findings provide evidence that Asn265 may contribute to an alcohol and anesthetic binding site.
Assuntos
Álcoois/farmacologia , Anestésicos/farmacologia , Asparagina/fisiologia , Receptores de GABA-A/química , Receptores de GABA-A/metabolismo , 1-Butanol/metabolismo , 1-Butanol/farmacologia , 1-Octanol/metabolismo , 1-Octanol/farmacologia , Álcoois/metabolismo , Substituição de Aminoácidos/fisiologia , Anestésicos/metabolismo , Animais , Sítios de Ligação/efeitos dos fármacos , Sítios de Ligação/fisiologia , Cisteína/genética , Cisteína/metabolismo , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Etanol/metabolismo , Etanol/farmacologia , Feminino , Humanos , Ativação do Canal Iônico/efeitos dos fármacos , Ativação do Canal Iônico/fisiologia , Isoflurano/metabolismo , Isoflurano/farmacologia , Oócitos/efeitos dos fármacos , Oócitos/fisiologia , Técnicas de Patch-Clamp , RNA Complementar/genética , Ratos , Receptores de GABA-A/genética , Ácidos Tiossulfônicos/metabolismo , Ácidos Tiossulfônicos/farmacologia , Xenopus laevis , Ácido gama-Aminobutírico/farmacologiaRESUMO
Whereas microbial fermentation processes for producing ethanol and related alcohol biofuels are well established, biodiesel (methyl esters of fatty acids) is exclusively derived from plant oils. Slow cycle times for engineering oilseed metabolism and the excessive accumulation of glycerol as a byproduct are two major drawbacks of deriving biodiesel from plants. Although most bacteria produce fatty acids as cell envelope precursors, the biosynthesis of fatty acids is tightly regulated at multiple levels. By introducing four distinct genetic changes into the E. coli genome, we have engineered an efficient producer of fatty acids. Under fed-batch, defined media fermentation conditions, 2.5 g/L fatty acids were produced by this metabolically engineered E. coli strain, with a specific productivity of 0.024 g/h/g dry cell mass and a peak conversion efficiency of 4.8% of the carbon source into fatty acid products. At least 50% of the fatty acids produced were present in the free acid form.