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1.
There are many changes, both qualitative and quantitative, in eucalypt waste during growth and fructification of Lentinula edodes. Wet chemical analysis and near-infrared (NIR) spectroscopy were used in conjunction with multivariate regression and principal
components analysis to monitor biodegradation of eucalyptus waste during growth of several L. edodes strains. Weight and component losses of eucalypt residue after biodegradation by L. edodes strains were compared for periods of 1 to 5 mo. Decrease in cellulose, hemicellulose, and lignin contents occurred, however
it was not concomitant. Measurement of lignin degradation by NIR and wet chemical analysis indicated its attack in the early
stages of biodegradation. Selective lignin degradation by L. edodes was observed up to 2 mo of biodegradation for strains DEBIQ and FEB-14. One group of degraded substrate was identified based
on the principal component analysis (PCA) of the data on their biodegradation time. Samples treated for 5 months by L. edodes strains (DEBIQ, UFV or FEB-14) differed from other, but no discrimination was observed among them. By the end of 5 mo, NIR
analyses showed decrease of about 18–47% cellulose, 35–47% polyose and 39–60% lignin. These data were used for comparison
with those obtained by wet chemical method for the degradation of the substrate by other five L. edodes strains cultivated at the same conditons. NIR calibration developed in this study was proven to be perfectly suitable as
an analytical method to predict the changes in lignocellulose composition during biodegradation. 相似文献
2.
Effects of pH and Temperature on Recombinant Manganese Peroxidase Production and Stability 总被引:1,自引:0,他引:1
Jiang F Kongsaeree P Schilke K Lajoie C Kelly C 《Applied biochemistry and biotechnology》2008,146(1-3):15-27
The enzyme manganese peroxidase (MnP) is produced by numerous white-rot fungi to overcome biomass recalcitrance caused by
lignin. MnP acts directly on lignin and increases access of the woody structure to synergistic wood-degrading enzymes such
as cellulases and xylanases. Recombinant MnP (rMnP) can be produced in the yeast Pichia pastoris αMnP1-1 in fed-batch fermentations. The effects of pH and temperature on recombinant manganese peroxidase (rMnP) production
by P. pastoris αMnP1-1 were investigated in shake flask and fed-batch fermentations. The optimum pH and temperature for a standardized fed-batch
fermentation process for rMnP production in P. pastoris αMnP1-1 were determined to be pH 6 and 30 °C, respectively. P. pastoris αMnP1-1 constitutively expresses the manganese peroxidase (mnp1) complementary DNA from Phanerochaete chrysosporium, and the rMnP has similar kinetic characteristics and pH activity and stability ranges as the wild-type MnP (wtMnP). Cultivation
of P. chrysosporium mycelia in stationary flasks for production of heme peroxidases is commonly conducted at low pH (pH 4.2). However, shake
flask and fed-batch fermentation experiments with P. pastoris αMnP1-1 demonstrated that rMnP production is highest at pH 6, with rMnP concentrations in the medium declining rapidly at
pH less than 5.5, although cell growth rates were similar from pH 4–7. Investigations of the cause of low rMnP production
at low pH were consistent with the hypothesis that intracellular proteases are released from dead and lysed yeast cells during
the fermentation that are active against rMnP at pH less than 5.5. 相似文献
3.
Oil pumpkin (Cucurbita pepo L. var. Styriaca) is an economically important horticultural plant cultivated for oil production. After harvesting seeds, the residual biomass
has a limited application and is usually left in the field. An experimental study was performed to evaluate the chemical composition
of the seeded fruit oil pumpkin biomass (OP) dried by solvent-exchange using ethanol. The sugar composition of polysaccharides
obtained by sequential extraction with water and dilute alkali indicated the prevalence of pectic polysaccharides. Hemicelulloses
were released in higher amounts in the alkaline step. The chemical composition of OP and its individual tissues (peel, flesh
and hairy flesh) was investigated and compared to the corresponding preparations of standard pumpkin (SP, Cucurbita pepo L.). The content of components (on oven-dry basis), calculated from the analysis data of the individual tissues, was estimated
for OP: 7.9 % ash, 7.6 % Klason lignin, 19.3 % pectin (as uronic acids), 34.1 % neutral carbohydrates, and 27.4 % α-cellulose
and for SP: 6.4 % ash, 4.0 % Klason lignin, 20.9% pectin (as uronic acids), 38.1% neutral carbohydrates, and 29.2 % α-cellulose,
respectively. The OP biomass showed a higher proportion of hemicelluloses. 相似文献
4.
Phytofiltration involves the use of plants to remove toxic compounds from water. Arsenic is an element of considerable environmental and toxicological interest because of its potential deleterious effects upon human health. In this research, a laboratory-constructed hydroponic system was employed to characterize phytofiltration for the uptake of arsenic and macronutrients by two arsenic hyperaccumulators, Pteris cretica cv Mayii (Moonlight fern) and Pteris vittata (Chinese brake fern). Arsenic was shown to preferentially accumulate in the leaves and stems of P. cretica cv Mayii compared to roots. The amounts of the macronutrients calcium and phosphorous absorbed were compared for control plants (growth solution) and plants exposed to arsenic(III) (growth solution and arsenic(III)). Significant differences in the concentration levels of the macronutrients were observed in roots, stems, and leaves between the control and arsenic-exposed plants. The arsenic contents of entire P. vittata plants exposed to hydroponic solutions containing arsenic(III) and arsenic(V) were compared, and no significant difference was observed. 相似文献
5.
Lignin peroxidase was purified (72-fold) from Acinetobacter calcoaceticus NCIM 2890. The purified lignin peroxidase (55–65 kDa) showed dimeric nature. The maximum enzyme activity was observed at
pH 1.0, between a broad temperature range of 50 and 70°C, at H2O2 concentration (40 mM) and the substrate concentration (n-propanol, 100 mM). Purified lignin peroxidase was able to oxidize a variety of substrates including Mn2+, tryptophan, mimosine, l-Dopa, hydroquinone, xylidine, n-propanol, veratryl alcohol, and ten textile dyes of various groups indicating as a versatile peroxidase. Most of the dyes
decolorized up to 90%. Tryptophan stabilizes the lignin peroxidase activity during decolorization of dyes. 相似文献
6.
Data are presented on the composition of anthocyans of the fruits and pulp of the food plants bilberry (Vaccinium myrtillis L), high-bush cranberry (Viburnum opulus L.), elderberry (Sambucus nigra L.), cherry (Cerasus vulgaris Mill.), crowberry (Empetrum nigrum L.), cranberry (Oxycoccus palustris Pers.), currant (Ribes nigrum L.), and mulberry (Morus nigra L.) growing in the Ukraine. The anthocyan pigments differ qualitatively and quantitatively owing to genetic peculiarities in the different species of fruits and the localization of the pigments in them.Odessa State Academy of Food Technology, fax (0482) 25 32 84. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 118–120, March–April, 2000. 相似文献
7.
Treatment with lignin residue 总被引:1,自引:0,他引:1
Björklund Linda Larsson Simona Jönsson Leif J. Reimann Anders Nivebrant Nils-Olof 《Applied biochemistry and biotechnology》2002,98(1-9):563-575
Acid hydrolysis of lignocellulose to hydrolysates intended for production of fuel ethanol results in the formation of byproducts
in addition to fermentable sugars. Some of the byproducts, such as phenolic compounds and furan aldehydes, are inhibitory
to the fermenting microorganism. Detoxification of the hydrolysates may be necessary for production of ethanol at a satisfactory
rate and yield. The lignin residue obtained after hydrolysis is a material with hydrophobic properties that is produced in
large amounts as a byproduct within an ethanol production process based on lignocellulosic raw materials. We have explored
the possibility of using this lignin residue for detoxification of spruce dilute-acid hydrolysates prior to fermentation with
Saccharomyces cerevisiae. Three dilute-acid hydrolysates of spruce were treated with lignin residue, which in all cases resulted in improved fermentability
in terms of productivity and yield of ethanol. The effect was improved by washing the lignin before treatment, by using larger
amounts of lignin in the treatment, and by performing the treatment at low temperature. Treatment with the lignin residue
removed up to 53% of the phenolic compounds and up to 68% of the furan aldehydes in a spruce dilute-acid hydrolysate. A larger
fraction of furfural was removed compared to the less hydrophobic 5-hydroxymethylfurfural. 相似文献
8.
Claudia I. Ishizawa Tina Jeoh William S. Adney Michael E. Himmel David K. Johnson Mark F. Davis 《Cellulose (London, England)》2009,16(4):677-686
It has previously been shown that the improved digestibility of dilute acid pretreated corn stover is at least partially due
to the removal of xylan and the consequent increase in accessibility of the cellulose to cellobiohydrolase enzymes. We now
report on the impact that lignin removal has on the accessibility and digestibility of dilute acid pretreated corn stover.
Samples of corn stover were subjected to dilute sulfuric acid pretreatment with and without simultaneous (partial) lignin
removal. In addition, some samples were completely delignified after the pretreatment step using acidified sodium chlorite.
The accessibility and digestibility of the samples were tested using a fluorescence-labeled cellobiohydrolase (Trichoderma reesei Cel7A) purified from a commercial cellulase preparation. Partial delignification of corn stover during dilute acid pretreatment
was shown to improve cellulose digestibility by T. reesei Cel7A; however, decreasing the lignin content below 5% (g g−1) by treatment with acidified sodium chlorite resulted in a dramatic reduction in cellulose digestibility. Importantly, this
effect was found to be enhanced in samples with lower xylan contents suggesting that the near complete removal of xylan and
lignin may cause aggregation of the cellulose microfibrils resulting in decreased cellulase accessibility. 相似文献
9.
Valdecoxib is a new anti-inflammatory drug that is highly selective for inhibition of the inducible form of cyclooxygenase
(COX-2). In the present study, biotransformation of valdecoxib was investigated in cell cultures of five medicinal plants,
viz., Catharanthus roseus, Azadirachta indica, Capsicum annuum, Ervatamia heyneana, and Nicotiana tabacum. Identification of the biotransformed products was carried out by using high-performance liquid chromatography coupled with
diode array detection and liquid chromatography–tandem mass spectrometry analysis. All the cultures transformed valdecoxib
into more polar compounds, and C. roseus also produced one unknown compound that is less polar than the substrate. The reactions performed by these plant cell cultures
include hydroxylation, methylation, and demethylation. Optimization studies were performed to investigate the effect of the
day of extraction and substrate concentration on biotransformation. 相似文献
10.
Different extraction methods for the subsequent gas chromatographic determination of the composition of essential oils and
related compounds from marjoram (Origanum majorana L.), caraway (Carum carvi L.), sage (Salvia officinalis L.), and thyme (Thymus vulgaris L.) have been compared. The comparison was also discussed with regard to transformation processes of genuine compounds, particularly
in terms of expenditure of time. Hydrodistillation is the method of choice for the determination of the essential oil content
of plants. For investigating the composition of genuine essential oils and related, aroma-active compounds, hydrodistillation
is not very useful, because of discrimination and transformation processes due to high temperatures and acidic conditions.
With cold solvent extraction, accelerated solvent extraction, and supercritical fluid extraction, discrimination of high and
non-volatile aroma-active components as well as transformation processes can be diminished, but non-aroma-active fats, waxes,
or pigments are often extracted, too. As solid-phase microextraction is a solvent-free fully automizable sample preparation
technique, this was the most sparing to sensitive components and the most time-saving method for the rapid determination of
the aroma compounds composition in marjoram, caraway, sage, and thyme. Finally, solid-phase microextraction could be successfully
optimized for the extraction of the aroma components from the plants for their subsequent gas chromatographic determination. 相似文献
11.
Jacqueline Heard Bruce B. Johnson John D. Wells Michael J. Angove 《Colloids and surfaces. B, Biointerfaces》2009,72(2):289-294
Attempts to measure the hydrophobicity of the cell surfaces of Gordonia amarae and Rhodococcus erythropolis, filamentous bacteria found in wastewater treatment plants, by several methods—microbial adhesion to hydrocarbons (MATH) or bacterial adhesion to hydrocarbons (BATH), contact angle, and micro-sphere adhesion to cells (MAC)—were unsuccessful. The results were erratic and inconsistent. This was in part because of the filamentous growth habit of G. amarae, but it was also a consequence of the fact that the ‘hydrophobicity’ of bacterial cells is not a clearly defined quantity. A technique is introduced in which bacteria are suspended in solutions of synthetic surfactants (non-ionic, cationic and anionic), and the suspensions aerated under defined conditions. The partitioning of bacterial cells between the foam and liquid phases was reproducible. The method was tested in model systems in which the bacteria were replaced by silica particles with defined surface modifications. Although this technique is not a direct measure of ‘hydrophobicity’, the partitioning of cells depends in part upon their surface hydrophobicity. In addition, qualitative information is gained about ionic interactions between the bacteria and the bubble surface. The results are pertinent to the problem of foaming in wastewater treatment plants. 相似文献
12.
Enhanced expression of B-subunit of Escherichia coli heat-labile enterotoxin in tobacco by optimization of coding sequence 总被引:2,自引:0,他引:2
Kang TJ Han SC Jang MO Kang KH Jang YS Yang MS 《Applied biochemistry and biotechnology》2004,117(3):175-187
Escherichia coli heat-labile toxin (LT) is a potent mucosal immunogen and immunoadjuvant for coadministered antigens. We synthesized a gene
encoding the B-subunit of LT(LTB) adapted to the coding sequence of tobacco plants and fused to the endoplasmic reticulum
retention signal SEKDEL to enhance its level of expression in plants. The synthetic LTB gene was cloned into a plant expression
vector adjacent to the CaMV 35S promoter and was introduced into tobacco by Agrobacterium-mediated transformation. The amount of LTB protein detected in transgenic tobacco leaves was 2.2% of the total soluble plant
protein, which is approx 200-fold higher than in previous reports of native LTB gene expression in transgenic plants. Enzyme-linked
immunosorbent assay indicated that plant-synthesized LTB protein bound specifically to GM1-ganglioside, suggesting that the LTB subunits formed active pentamers. 相似文献
13.
Alfred Vendl 《Monatshefte für Chemie / Chemical Monthly》1979,110(1):103-108
The crystal structure of NbMoN1–x
has been determined from X-ray powder patterns. It is isotypic with the formerly described1,2 complex nitrides NbCrN and Ta1–x
Cr1+x
N. The tetragonal unit cell contains 6 atoms and belongs to the space groupP4/nmm-D
4h
7. The lattice parameters are:a=3,095 Å,c=7,799 Å. The structure is characterized by relatively close packed double layers of Nb-atoms and Mo-atoms parallel to the base plane. The nitrogen atoms are within the octahedral interstitial sites. 相似文献
14.
The formation of SiSi-bonds by a photochemical reaction of silylmercury compounds is described. The silylmercury compounds [(X
3Si)3Si]2Hg (X=Cl, OCH3) were synthesized via theVyazankin Hydrid method with (X
3Si)3SiH and Bis(t-butyl)mercury. By UV-irradiation of these products in hexane as a solvent, the oligosilanes [(X
3Si)3Si]2 are formed in good yields. All these compounds are charactericed by spectroscopical methods. 相似文献
15.
I. Capek 《Central European Journal of Chemistry》2003,1(3):291-304
The kinetics of free-radical copolymerization and terpolymerization of acrylamide (AAm), N, N′-methylenebis(acrylamide) (MBA) and methacrylic acid (MA) in the inverse water/monomer/cyclohexane/Tween 85 miniemulsion was
investigated. Polymerizable sterically-stable miniemulsions were formulated in cyclohexane as a continuous medium. Polymerizations
are very fast and reach the final conversion within several minutes. The dependence of the polymerization rate vs. conversion
is described by a curve with two nonstationary rate intervals. The maximum rate of polymerization slightly increases with
increasing concentration of crosslinking monomer (MBA) and strongly decreases by the addition of MA. The rate of polymerization
is inversely proportional to the 0.9
th
and 1.8
th
power of the particle concentration without and with MA, respectively. The number of polymer particles is inversely proportional
to the 0.18
th
and 0.13
th
power of MBA concentration. The kinetic and colloidal parameters of the miniemulsion polymerization are discussed in terms
of microemulsion polymerization model. 相似文献
16.
In the theoretical model it is assumed that a graphite disk electrode is covered by a thin film of solution of decamethylferrocene
(dmfc) and some electrolyte CX in nitrobenzene and immersed in an aqueous solution of the electrolyte MX. Oxidation of dmfc is accompanied by the transfer of anion X
− from water into nitrobenzene since it is also assumed that cations dmfc
+ and C
+ are insoluble in water and cation M
+ is insoluble in nitrobenzene. Kinetic parameters of the electrode reaction can be determined if the total potential difference
across the nitrobenzene/water interface is maintained constant by adding the electrolytes CX and MX in concentrations which are much higher than the initial concentration of dmfc in nitrobenzene. 相似文献
17.
Phenylpropanoids from Medicinal Plants: Distribution, Classification, Structural Analysis, and Biological Activity 总被引:3,自引:0,他引:3
V. A. Kurkin 《Chemistry of Natural Compounds》2003,39(2):123-153
The literature and our own research results on phenylpropanoids from medicinal plants were reviewed and systematized. Data were presented for the distribution of phenylpropanoids. Their classification was proposed. The biological structure-activity relationships for compounds found in roseroot (Rhodiola rosea), thorny eleutherococcus (Eleutherococus senticosus), common lilac (Syringa vulgaris), purple echinacea (Echinacea purpurea), medicinal melissa (Melissa officinalis), variegated milk-thistle (Silybum marianum), and others were discussed. 相似文献
18.
麝香草的新单萜配糖物的分离与合成 总被引:1,自引:0,他引:1
从麝香草(Thymus vulgaris L)的甲醇萃取物中分离出三个单萜配糖物. 用核磁共振光谱确定了它们的结构为对伞花-9-基-β-D-葡糖苷(1), 5-β-D-葡糖苷百里氢醌(2)和2-β-D-葡糖苷百里氢醌(3). 其中1是新化合物, 用以对伞花-9-醇为原料的对映体选择性合成方法确定了化合物1的8位的立体化学为R型. 相似文献
19.
Raja L. M. V. Elamvaluthy G. Palaniappan R. Krishnan R. M. 《Applied biochemistry and biotechnology》1991,(1):827-841
Propylene oxide (PO), propylene glycol (PG), and polyols are produced from propylene via propylene chlorohydrin. Effluents
from these plants contain biological oxygen demand/chemical oxygen demand (BOD/COD) loads besides high chloride concentrations.
The high salinity poses severe problem to adopt conventional methods like activated sludge processes. Presently, a simple,
economically viable and versatile microbiological process has been developed to get more than 90% biodegradation in terms
of BOD/COD, utilizing specially developedPseudomonas andAerobacter. The process can tolerate high salinity up to 10 wt% NaCl or 5 wt% CaCl2 and can withstand wide variations inpH (5.5–11.0) and temperature (15–45°C). The biodegradation of glycols involves two steps. The enzymatic conversion of glycols
to carboxylic and hydroxycarboxylic acids is aided byPseudo- omonas. Further degradation to CO2 and H2O by carboxylic acid utilizingAerobacter, and possible metabolic degradative pathway of glycols are discussed. Various process parameters obtained in the lab scale
(50 L bioreactor) and pilot scale (20 m3 bioreactor), and unique features of our process are also discussed. 相似文献
20.
Streptomyces viridosporus produces an intracellular aromatic aldehyde oxidase that oxidizes aromatic and α, β-unsaturated aromatic aldehydes to their
corresponding acids. It also produces extracellular oxidase as shown by zones of clearing when grown on agar containing insoluble
dehydrodivanillin (DHDV). This extracellular form may be responsible for oxidizing aldehyde groups in lignin. The extracellular
oxidase was expressed maximally after 3 d growth in medium containing only yeast extract. However, higher levels were produced
when lignocellulose was in the medium. The enzyme was partially purified and its molecular weight was approximated to be about
80,000 daltons. Mutant cultures that had lost the ability to produce zones of clearing on DHDV-containing agar solubilized
smaller quantities of lignin as compared to the wild type, except for one strain. A partially purified oxidase preparation
was shown to oxidize a natural lignocellulose substrate. 相似文献