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1.
The snow lotus is an endangered traditional Chinese medicinal herb. Saussurea involucrata, Saussurea laniceps, and Saussurea medusa, the three main snow lotus species (five herbs and two S. involucrata cell cultures), were selected for this study. Snow lotus (XLs) was extracted using 75 % (v/v) ethanol. Two reversed phase-high performance liquid chromatography-diode array detector methods were developed and validated for the determination of 10 representative components in XLs. The antioxidant efficacy of XLs and their components was investigated using DPPH, ABTS free radical scavenging, and ROS inhibition experiments. The results showed that the IC50 for DPPH scavenging ranged from 0.06–0.29 mg/mL for XLs and from 0.13–0.63 mg/mL for ABTS, and could downregulate ROS to varying degrees. The results of the antioxidant activity showed that rutin, quercetin, and isochlorogenic acid A contributed to the antioxidant capacity of XLs. The high content and activity of the cell cultures indicate that they can serve as an effective alternative to snow lotus, thus providing a theoretical basis for the selection of herbs and cell cultures to fulfil various needs.  相似文献   

2.
In this work a new highly fluorescent N,N‐dimethyl benzylamine–palladium(II) yu complex was synthesized by the reaction of [Pd2{(C,N–C6H4CH2N(CH3)2}2(μ‐OAc)]2] with curcumin. The structure of the synthesized complex was characterized using Fourier transform infra‐red (FT‐IR) spectroscopy, 1H nuclear magnetic resonance spectroscopy, and elemental analysis. Fluorescence quantum yield (ΦF) values of the synthesized complex in dimethyl sulfoxide (DMSO), acetonitrile, ethanol, and methanol were 0.160, 0.104, 0.068, and 0.061, respectively. The fluorescence signal of the complex in the organic solvents was very sensitive to the water content of the organic solvent. The quenching effect of water was used to determine trace amounts of water in the heteroatom‐containing organic solvents (ethanol, methanol, acetonitrile) and redox‐active solvents (DMSO). The linear ranges for determination of water (v/v %) in ethanol, DMSO and acetonitrile were found to be 0.03–14.5, 0.08–13.8, and 0.07–18.8, respectively. Two linear ranges were found for determination of water (v/v %) in methanol (0.1–1.2 and 4.7–25.0). Detection limit (DL) values were calculated to be 0.001, 0.05, 0.004, and 0.01 (v/v %) in ethanol, methanol, acetonitrile, and DMSO, respectively. The proposed method overcomes the problems of the standard Karl Fischer method for determination of water in DMSO. In addition, it gave the best DL value for determination of water in ethanol compared with all published papers to date.  相似文献   

3.
Corncob is a potential feedstock in Thailand that can be used for fermentable sugar production through dilute sulfuric acid pretreatment and enzymatic hydrolysis. To recover high amounts of monomeric sugars from corncob, the sulfuric pretreatment conditions were optimized by using response surface methodology with three independent variables: sulfuric acid concentration, temperature, and time. The highest response of total sugars, 48.84 g/L, was found at 122.78°C, 4.65 min, and 2.82% (v/v) H2SO4. With these conditions, total sugars from the confirmation experiment were 46.29 g/L, with 5.51% error from the predicted value. The hydrolysate was used as a substrate for acetone–butanol–ethanol fermentation to evaluate its potential for microbial growth. The simultaneous saccharification and fermentation (SSF) showed that C. beijerinckii TISTR 1461 can generate acetone–butanol–ethanol products at 11.64 g/L (5.29 g/L acetone, 6.26 g/L butanol, and 0.09 g/L ethanol) instantly using sugars from the hydrolysed corncob with Novozymes 50013 cellulase enzyme without an overliming process.  相似文献   

4.
Saccharomyces cerevisiae cells were immobilized in calcium alginate beads for use in the continuous production of ethanol. Yeasts were grown in medium supplemented with ethanol to selectively screen for a culture which showed the greatest tolerance to ethanol inhibition. Yeast beads were produced from a yeast slurry containing 1.5% alginate (w/v) which was added as drops to 0.05M CaCl2 solution. To determine their optimum fermentation parameters, ethanol production using glucose as a substrate was monitored in batch systems at varying physiological conditions (temperature, pH, ethanol concentration), cell densities, and gel concentration. The data obtained were compared to optimum free cell ethanol fermentation parameters. The immobilized yeast cells examined in a packed-bed reactor system operated under optimized parameters derived from batch-immobilized yeast cell experiments. Ethanol production rates, as well as residual sugar concentration were monitored at different feedstock flow rates.  相似文献   

5.
Fructose, glucose, and mannose were treated with subcritical aqueous ethanol for ethanol concentrations ranging from 0 to 80% (v/v) at 180–200 °C. The aldose–ketose isomerization was more favorable than ketose–aldose isomerization and glucose–mannose epimerization. The isomerization of the monosaccharides was promoted by the addition of ethanol. In particular, mannose was isomerized most easily to fructose in subcritical aqueous ethanol. The apparent equilibrium constants for the isomerizations of mannose to fructose, Keq,M→F, and glucose to fructose, Keq,G→F, were independent of ethanol concentration and increased with increasing temperature. Moreover, the Keq,M→F value was much larger than the Keq,G→F value. The enthalpies for the isomerization of mannose to fructose, ΔHM→F, and glucose to fructose, ΔHG→F, were estimated to be 18 and 24 kJ/mol, respectively, according to van’t Hoff equation. Subcritical aqueous ethanol can be used to produce fructose from glucose and mannose efficiently.  相似文献   

6.
Two respiratory-deficient nuclear petites, FY23Δpet191 and FY23Δcox5a, of the yeast Saccharomyces cerevisiae were generated using polymerase-chain-reaction-mediated gene disruption, and their respective ethanol tolerance and productivity assessed and compared to those of the parental grande, FY23WT, and a mitochondrial petite, FY23ρ0. Batch culture studies demonstrated that the parental strain was the most tolerant to exogenously added ethanol with an inhibition constant. K i, of 2.3% (w/v) and a specific rate of ethanol production, q p, of 0.90 g ethanol g dry cells−1 h−1. FY23ρ0 was the most sensitive to ethanol, exhibiting a K i of 1.71% (w/v) and q p of 0.87 g ethanol g dry cells−1 h−1. Analyses of the ethanol tolerance of the nuclear petites demonstrate that functional mitochondria are essential for maintaining tolerance to the toxin with the 100% respiratory-deficient nuclear petite, FY23Δpet191, having a K i of 2.14% (w/v) and the 85% respiratory-deficient FY23Δcox5a, having a K i of 1.94% (w/v). The retention of ethanol tolerance in the nuclear petites as compared to that of FY23ρ0 is mirrored by the ethanol productivities of these nuclear mutants, being respectively 43% and 30% higher than that of the respiratory-sufficient parent strain. This demonstrates that, because of their respiratory deficiency, the nuclear petites are not subject to the Pasteur effect and so exhibit higher rates of fermentation. Received: 22 September 1997 / Accepted: 7 December 1997  相似文献   

7.
The purpose of this study was to evaluate the feasibility of producing bioethanol from palm-oil mill effluent generated by the oil-palm industries through direct bioconversion process. The bioethanol production was carried out through the treatment of compatible mixed cultures such as Thrichoderma harzianum, Phanerochaete chrysosporium, Mucor hiemalis, and yeast, Saccharomyces cerevisiae. Simultaneous inoculation of T. harzianum and S. cerevisiae was found to be the mixed culture that yielded the highest ethanol production (4% v/v or 31.6 g/l). Statistical optimization was carried out to determine the operating conditions of the stirred-tank bioreactor for maximum bioethanol production by a two-level fractional factorial design with a single central point. The factors involved were oxygen saturation level (pO2%), temperature, and pH. A polynomial regression model was developed using the experimental data including the linear, quadratic, and interaction effects. Statistical analysis showed that the maximum ethanol production of 4.6% (v/v) or 36.3 g/l was achieved at a temperature of 32°C, pH of 6, and pO2 of 30%. The results of the model validation test under the developed optimum process conditions indicated that the maximum production was increased from 4.6% (v/v) to 6.5% (v/v) or 51.3 g/l with 89.1% chemical-oxygen-demand removal.  相似文献   

8.
Summary In an effort to establish the reasons for the limitations in the final ethanol concentration of Zymomonas mobilis fermentation, the effects of CO2 and ethanol on the fermentation were investigated using continuous and fed-batch cultivation systems. The nucleation and stripping out of CO2 from the fermenter using diatomaceous earth or nitrogen gas or both exhibited a profound effect on the glucose uptake rate during the early stages of fed-batch fermentation, but did not improve final ethanol yields. The addition of ethanol together with above mentioned experiments confirmed conclusively that ethanol inhibition is responsible for the final ethanol concentration obtainable during Zymomonas mobilis fermentation. The final concentration lies between 90 and 110 gl−1 or approximately 12–15% (v/v) ethanol.  相似文献   

9.
Partially (6-fold) purified plasma membrane ATPase from an ethanol-sensitive yeast, Kloeckera apiculata, had an optimum pH of 6.0, an optimum temperature of 35°C, a K m of 3.6 mm ATP and a V max of 11 mol Pi/min.mg protein. SDS-PAGE of the semi-purified plasma membrane showed a major band of 106 kDa. No in vivo activation of the ATPase by glucose was observed. Although 4% (v/v) ethanol decreased the growth rate by 50% it did not affect the ATPase. Concentrations of ethanol 2% (v/v) did, however, inhibit the enzyme in vitro. The characteristics of the enzyme did not change during growth in the presence of ethanol.  相似文献   

10.
Summary The performance ofZymomonas mobilis strains ATCC 31821 and ATCC 31823 was assessed in batch and continuous culture. In batch culture using a medium containing 250 g/l glucose, identical maximum specific growth rates of 0.16/h were found, though final biomass concentration and growth yield were significantly lower for ATCC 31 823 than for ATCC 31 821. Final ethanol concentrations in this medium were about 110 g/l vor both organisms. In continuous culture at increasing dilution rates using a medium containing 100 g/l glucose, no significant differences were seen between the two strains with respect to the fermentation parameters studied. For ATCC 31 821, maximum rates of glucose uptake (Qs) and ethanol produktion (Qp) of 8.7 g glu/g/h and 4.4 g eth/g/h, respectively, were found. Both strains showed a similar performance at a fixed dilution rate of 0.1/h, where maximum ethanol concentrations of about 68 g/l were reached at a feed glucose concentration of about 139 g/l. At this dilution rate the maximum values of Qs and Qp were about 5.8 g glu/g/h and 2.8 g eth/g/h, respectively. Test tube experiments showed that growth, measured as optical density, decreased with increasing concentrations of exogenous ethanol with complete inhibition of growth at ethanol concentrations >8% (v/v). As evidenced by the results presented here, we have been unable to practice the invention as described in U.S. Patent 4,403,034 (Rogers and Tribe 1983).Nomenclature D Dilution rate, 1/h - max maximum specific growth rate, 1/h - SR Initial substrate concentration, g glucose/1 - S Residual substrate concentration, g glucose/1 - S0 Effluent substrate concentration, g glucose/1 - X Blomass concentration; g cells/l - OD620 Optical density at 620 nm, dimensionless - [P] Product concentration, g ethanol/1 - Yx/s Growth yield, g cells/g glucose used - Yp/s Product yield, g ethanol/g glucose used - %, Yield Percentage yield, Yp/sx100/Y p s/max =Yp/sx100/0.51 - Qs Specific rate of glucose uptake, g glucose/g cells/h - Qp Specific rate of ethanol formation, g ethanol/g cells/h - me Maintenance energy coefficient, g glucose/g cells/h - VP Volumetric productivity, g ethanol/l/h - t Fermentation time, h  相似文献   

11.
Highly oriented fibers of Li-, Na-, K-, and CsDNA were prepared with a previously developed wet spinning method. The procedure gave a large number of equivalent fiber bundle samples (reference length, L0, typically = 12–15 cm) for systematic measurements of the fiber length L in ethanol–water solutions, using a simple mechanochemical set up. The decrease in relative length L/L0 with increasing ethanol concentration at room temperature gave evidence for the B-A transition centered at 76% (v/v) ethanol for NaDNA fibers and at 80 and 84% ethanol for K- and CsDNA fibers. A smaller decrease in L/L0 of LiDNA fibers was attributed to the B-C transition centered at 80% ethanol. In a second type of experiment with DNA fibers in ethanol–water solutions, the heat-induced helix–coil transition, or melting, revealed itself in a marked contraction of the DNA fibers. The melting temperature Tm, decreased linearly with increasing ethanol concentration for fibers in the B-DNA ethanol concentration region. In the B-A transition region, Na- and KDNA fibers showed a local maximum in Tm. On further increase of the ethanol concentration, the A-DXA region followed with an even steeper linear decrease in Tm. The dependence on the identity of the counterion is discussed with reference to the model for groove binding of cations in B-DNA developed by Skuratovskii and co-workers and to the results from Raman studies of the interhelical bonds in A-DNA performed by Lindsay and co-workers. An attempt to apply the theory of Chogovadze and Frank-Kamenetskii on DNA melting in the B-A transition region to the curves failed. However, for Na- and KDNA the Tm dependence in and around the A-B transition region could be expressed as a weighted mean value of Tm of A- and B-DNA. On further increase of the ethanol concentration, above 84% ethanol for LiDNA and above about 90% ethanol for Na-, K-, and CsDNA, a drastic change occurred. Tm increased and a few percentages higher ethanol concentrations were found to stabilize the DNA fibers so that they did not melt at all, not even at the upper temperature limit of the experiments (~ 80°C). This is interpreted as being due to the strong aggregation induced by these high ethanol concentrations and to the formation of P-DNA. Many features of the results are compatible with the counterion–water affinity model. In another series of measurements, Tm of DNA fibers in 75% ethanol was measured at various salt concentrations. No salt effect was observed (with the exception of LiDNA at low salt concentrations). This result is supported by calculations within the Poisson–Boltzmann cylindrical cell model. © 1994 John Wiley & Sons, Inc.  相似文献   

12.
Aims: To find out membrane tolerance strategy to ethanol in Bacillus subtilis that possesses a powerful system of protection against environmental stresses. Methods and Results: Cytoplasmic membranes of B. subtilis were severely affected by even short‐term exposure to 3% (v/v) ethanol: the growth rate and membrane protein synthesis were markedly reduced, and no adaptive alterations in phospholipids were detected. Simultaneously, steady‐state DPH fluorescence anisotropy (rss) showed that the membrane rigidity increased substantially. Analysis of the membrane phosphoproteome using in vitro labelling with [γ‐32P]ATP revealed the association of DnaK and GroEL chaperones with membrane, indicating a stress induction process. Upon a long‐term 3% (v/v) ethanol stress, the cell growth accelerated slightly and the composition of polar head groups and fatty acids of membrane phospholipids underwent an extensive reconstruction. Correspondingly, membrane fluidity turned back to the original rss values of the control cells. Conclusions: In B. subtilis, the adaptive response to short‐term ethanol stress comprises the recruitment of molecular chaperones on the impaired membrane structure; consequently, the phospholipid synthesis is restored and membrane fluidity adapts properly to the continuing ethanol stress. Significance and Impact of the Study: These findings underline the role of membrane lipids in establishing tolerance towards ethanol and also suggest the contribution of molecular chaperones to the membrane and cell recovery.  相似文献   

13.
Extraction of brown seaweed (Undaria pinnatifida) oil was carried out by using supercritical carbon dioxide (SCO2) and ethanol as co-solvent. The flow rate of ethanol was 3.0% (v/v) as compared to that of SCO2. Experiments were performed in a semi-batch flow apparatus on dried samples at temperatures from 303 to 333 K and pressures from 80 to 300 bar. Fucoxanthin and polyphenol were quantitatively analyzed by using HPLC and UV-spectrometer. The highest yields of fucoxanthin and polyphenol were shown at 200 bar, 323 K and 250 bar, 333 K, respectively. The solubility of fucoxanthin in SCO2 agreed well with the Chrastil model.  相似文献   

14.
Jerusalem artichoke (Helianthus tuberosus L.), an important crop, containing over 50% inulin in its tubers on a dry weight basis is an agricultural and industrial crop with a great potential for production of ethanol and industrial products. Inulin is a good substrate for bioethanol production. Saccharomyces cerevisiae 6525 can produce high concentrations of ethanol, but it cannot synthesize inulinase. In this study, a new integration vector carrying inuA1 gene encoding exoinulinase was constructed and transformed into 18SrDNA site of industrial strain S. cerevisiae 6525. The obtained transformant, BR8, produced 1.1 U mL? 1 inulinase activity within 72 h and the dry cell weight reached 12.3 g L? 1 within 48 h. In a small-scale fermentation, BR8 produced 9.5% (v/v) ethanol, with a productivity rate of 0.385 g ethanol per gram inulin, while wild-type S. cerevisiae 6525 produced only 3.3% (v/v) ethanol in the same conditions. In a 5-L fermentation, BR8 produced 14.0% (v/v) ethanol in fermentation medium containing inulin and 1% (w/v) (NH4)2SO4. The engineered S. cerevisiae 6525 carrying inuA1 converted pure nonhydrolyzed inulin directly into high concentrations of ethanol.  相似文献   

15.
The fermentation characteristics of 24 strains of Saccharomyces cerevisiae and one strain of Candida apicola, C. famata, C. guilliermondii, Hanseniospora occidentalis, Pichia subpelicullosa and Schizosaccharomyces pombe were evaluated for the production of cachaça. They were isolated from small cachaça distilleries (27), industrial cachaça distilleries (2) and one sugarcane alcohol distillery. The yeasts showed significant differences in ethanol yield, substrate conversion, efficiency, conversion factors of substrate into ethanol (Y p/s), cells (Y x/s), organic acids (Y ac/s) and glycerol (Y g/s), and maximum specific growth rate ( max). In general the S. cerevisiae strains showed better fermentation potential, with yields between 83 and 91% and max between 0.450 and 0.640 h–1, several of them being comparable with the high performance yeast used in the industrial production of ethanol, which was adopted as a reference. The non-Saccharomyces strains showed high efficiency, very low ethanol yield and very high Y ac/s and Y g/s values, except Pichia subpelliculosa, which behaved very similarly to the S. cerevisiae strains. Hierarchical Cluster Analysis and Principal Component Analysis showed the fermentation yield (or substrate conversion) as being the variable which contributed most to the separation of the strains into different groups.  相似文献   

16.
Cytokinins exhibit great affinity for the polystyrene matrix of Dowex-50 cation exchange resins. Model experiments showed that only c. 20% of the applied 2-methylthio-trans-zeatin and c. 70% of the trans-zeatin are eluted from AG 50W columns with six bed volumes of 1 N NH4 OH. Inclusion of 70% (v/v) ethanol in the eluant increases the recovery to c. 55 and 85% respectively. No additional recovery was obtained upon continued elution to 14 bed volumes. Similar experiments with Duolite CS-101, a weak acid cation exchange resin with acrylic matrix, showed that c. 95% of the applied 2-methylthio derivatives of isopentenyladenine and zeatin are recovered from the resin with six bed volumes of 70% (v/v) ethanol (pH 10) or 1 N NH4OH in 70% (v/v) ethanol. The less modified cytokinins, isopentenyladenosine and ribosylzeatin, are recovered completely under these conditions. Recovery of cytokinins was determined by means of high-pressure liquid chromatography of the column eluates.  相似文献   

17.
The action of ethanol on the activity of membrane-bound and soluble acetylcholinesterase (AChE) in sarcoplasmic reticulum of skeletal muscle has been studied. Treatment of membranes with 2.5–12.5% v/v ethanol produced a slight stimulation of the AChE activity and inhibition at higher concentration. The enzyme remained associated with the membranes after these treatments. The enzyme solubilized with Triton X-100 was inhibited by ethanol in a time-independent manner. Isolated 16 S (A12), 10.5 S (G4) and 4.5 S (G1) forms of AChE were inhibited by ethanol to a similar extent. Samples were reversibly inhibited by ethanol, up to 12.5% v/v, and irreversibly at higher concentrations. Kinetic studies performed with isolated forms in the presence of 5–12.5% v/v ethanol showed that the solvent behaved as a competitive inhibitor of the asymmetric form but as a mixed inhibitor of the tetrameric and monomeric forms. The results show that the solvent interacts with active and/or regulatory sites of AChE from muscle microsomes.  相似文献   

18.
High concentrations of both ethanol and sugar in the fermentation broth inhibit the growth of yeast cells and the rate of product formation. Inhibitory effects of ethanol on the yeast strain Saccharomyces cerevisiae NRRL-Y-132 were studied in batch and continuous chemostat cultures. Growth was limited by either glucose or ethanol. Feed medium was supplemented with different ethanol concentrations. Ethanol was found to inhibit growth and the activity of yeast to produce ethanol in a noncompetitive manner. A linear kinetic pattern for growth and product formation was observed according to μ = μm (1 – P/Pm) and v = vm (1 – P/Pm′), where μm is the maximum specific growth rate at P = 0 (hr?1); Pm is the maximum specific product formation rate at P = 0 (hr?1); Pm is the maximum ethanol concentration above which cells do not grow (g/liter); Pm′ is the maximum ethanol concentration above which cells do not produce ethanol (g/liter). Substrate inhibition studies were carried out using short-time experimental techniques under aerobic and anaerobic condition. The degree of substrate inhibition was found to be higher than that has been reported for ethanol fermentation of pure sugar. The kinetic relationships thus obtained were used to compute growth, substrate utilization, and alcohol production patterns and have been discussed with reference to batch and continuous fermentation of enzymatically produced bagasse hydrolysate.  相似文献   

19.
Song Y  Du B  Zhou T  Han B  Yu F  Yang R  Hu X  Ni Y  Li Q 《Carbohydrate research》2011,(2):958-310
In this work, response surface methodology was used to determine optimum conditions for extraction of polysaccharides from defatted peanut cake. A central composite design including independent variables, such as extraction temperature (x1), extraction time (x2), and ethanol concentration (x3) was used. Selected response which evaluates the extraction process was polysaccharide yield, and the second-order model obtained for polysaccharide yield revealed coefficient of determination of 97.81%. The independent variable with the largest effect on response was ethanol concentration (x3). The optimum extraction conditions were found to be extraction temperature 48.7 °C, extraction time 1.52 h, and ethanol concentration of 61.9% (v/v), respectively. Under these conditions, the extraction efficiency of polysaccharide can increase to 25.89%. The results of structural analysis showed that the main composition of defatted peanut cake polysaccharide was α-galactose.  相似文献   

20.
Abstract

Production of tannase was performed in packed bed reactor filled with an inert support polyurethane foam (PUF) using Bacillus gottheilii M2S2. The influence of process parameters such as fermentation time (24–72?h), tannic acid concentration (0.5–2.5% w/v), inoculum size (7–12% v/v), and aeration rate (0–0.2?L/min) on tannase production with PUF were analyzed using one variable at a time (OVAT) approach. The outcome of OVAT was optimized by central composite design. Based on the statistical investigation, the proposed mathematical model recommends 1% (w/v) of tannic acid, 10% (v/v) of inoculum size and 0.13?L/min of aeration rate for maximum production (76.57?±?1.25?U/L). The crude enzyme was purified using ammonium sulfate salt precipitation method followed by dialysis. The biochemical properties of partially purified tannase were analyzed and found the optimum pH (4.0), temperature (40?°C) for activity, and Km (1.077?mM) and Vmax (1.11?µM/min) with methyl gallate as a substrate. Based on the SDS-PAGE analysis, tannase exhibited two bands with molecular weights of 57.5 and 42.3?kDa. Briefly, the partially purified tannase showed 4.2 fold increase (63?±?1.60?U/L) in comparison to the submerged fermentation and the production of tannase was validated by using NMR spectrometer.  相似文献   

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