共查询到20条相似文献,搜索用时 15 毫秒
1.
Hill D. L. Phelps T. J. Palumbo A. V. White D. C. Strandberg G. W. Donaldson T. L. 《Applied biochemistry and biotechnology》1989,(1):233-243
The degradation of 4-chlorobiphenyl (4CB) was compared in field lysimeters containing 60 Kg of soil contaminated with 5–10
mg/Kg of polychlorinated biphenyls.Alcaligenes A5, a bacterium carrying a plasmid for 4CB degradation, was inoculated into three lysimeters. When compared to an untreated
control, soil samples from water, mineral, and yeast extract treated lysimeters with and without a bacterial inoculum exhibited
greater than 10-fold increases in the rate of [1-14 C-acetate incorporation into lipids and14CO2 production from [U-14C-4-chlorobiphenyl. Gene probe analyses for the 4CB plasmid and most-probable-number enumerations demonstrated the presence
of biodegradative populations in lysimeters and the probable survival of the addedAlcaligenes A5. 相似文献
2.
Owen S. Jeong B. C. Poole P. S. Macaskie L. E. 《Applied biochemistry and biotechnology》1992,(1):693-707
Tributyl phosphate (TBP), a plasticizer and solvent, is used in nuclear fuel reprocessing, generating TBP wastes laden with
residual uranium. ACitrobacter sp. accumulated heavy metals via a phosphohydrolase(s) that precipitated metals with inorganic phosphate liberated from an
organic phosphate “donor” molecule (TBP). Mutant analysis suggested that TBP hydrolysis was not attributable to a previously
documented acid phosphatase (monoesterase). Purified monoesterase had little activity against phospho di- and triesters, had
no requirement for Mg2+ or Mn2+, and was EDTA-resistant. Conversely, TBP cleavage by immobilized cells was enhanced by Mg2+, and ininhibited by Mn2+ and EDTA. A separate phosphotri/diesterase was implicated. 相似文献
3.
A new type of reactor, the attrition bioreactor, has been developed to increase the rate of the enzymatic hydrolysis of cellulose
and also to cut pretreatment costs. It was found that the attrition bioreactor could be operated continuously or semicontinuously
in conjunction with a membrane filter to produce a high cellulose conversion rate and low enzyme consumption. The membrane
filter served to contain the enzyme and cellulose within the reactor while allowing sugar to permeate as a product. 相似文献
4.
5.
Urease has been purified from the seeds of Cajanus Cajan. The purification process involves three solvent extraction steps followed by DEAE-cellulose column chromatography. The specific activity of the purified enzyme is found to be 1920 U/mg with the recovery of 8%. The application of the purified enzyme in a biosensor construction is discussed. 相似文献
6.
Kawakami Mitsuyasu Koya Hidekazu Gondo Shinichiro 《Applied biochemistry and biotechnology》1991,(1):211-219
A glucose electrode was fabricated by immobilizing glucose oxidase covalently onto a platinized platinum electrode. The sensor
showed rapid response with response time of 2—4 s, and also the linear response to the glucose concentration, ranging from
2 x 10-3 to 5 mM. The sensitivity was found to be correlated with the surface area of a base electrode used. 相似文献
7.
Amperometric enzyme electrode for glucose is described based on the incorporation of glucose oxidase (GOD) into graphite paste modified with tetracyanoquinodimethane (TCNQ). The incorporated enzyme exhibits high activity and long-term stability over the earlier TCNQ-based glucose sensor (1). The sensor provides a linear response to glucose over a wide concentration range. The response time of the sensor is 15-50 sec, and the detection limit is 0.5 mM. Stable response to the substrate was obtained during a period of 35 d. Application of the sensor in the plasma analysis is reported. 相似文献
8.
Comparison of the model with experimental data is currently in progress. It appears that more detailed studies of the adsorption
dynamics, not just adsorption equilibrium, are needed. 相似文献
9.
Nawaz Mohamed S. Davis John W. Wolfram James H. Chapatwala Kirit D. 《Applied biochemistry and biotechnology》1991,(1):865-875
A bacterium capable of utilizing acetonitrile (methyl cyanide) as the sole source of carbon and nitrogen was isolated from
soil and identified asPseudomonas aeruginosa. This bacterium could also utilize and oxidize numerous lower-mol-wt nitrile compounds and their corresponding amides as growth
substrates. A metabolite of acetonitrile in the culture medium was determined to be ammonia. The accumulation of ammonia in
the culture medium was proportional to the concentration of the substrate and the inoculum. Cell extracts of the bacterium
contained activities corresponding to nitrile aminohydrolase (E C 3.5.5.1) and amidase (E C 3.5.1.4), which regulate the degradation
of acetonitrile. Both enzymes were inducible and hydrolyzed a wide range of substrates, and it was determined that the specific
activity of amidase was far greater than the activity of nitrile aminohydrolase. 相似文献
10.
John D. Wright Charles E. Wyman Karel Grohmann 《Applied biochemistry and biotechnology》1988,18(1):75-90
Simultaneous saccharification and fermentation (SSF) processes for producing ethanol from lignocellulose are capable of improved
hydrolysis rates, yields, and product concentrations compared to separate hydrolysis and fermentation (SHF) systems, because
the continuous removal of the sugars by the yeasts reduces the end-product inhibition of the enzyme complex. Recent experiments
using Genencor 150L cellulase and mixed yeast cultures have produced yields and concentrations of ethanol from cellulose of
80% and 4.5%, respectively. The mixed culture was employed because B.clausenii has the ability to ferment cellobiose (further reducing end-product inhibition), while the brewing yeastS. cerevisiae provides a robust ability to ferment the monomeric sugars. These experimental results are combined with a process model to
evaluate the economics of the process and to investigate the effect of alternative processes, conditions, and organisms. 相似文献
11.
Hiroshi Ooshima Masahiro Kurakake Jyoji Kato Yoshio Harano 《Applied biochemistry and biotechnology》1991,31(3):253-266
Hydrolysis of pure cellulose Avicel has been carried out, using Meicelase from Trichoderma viride, where the enzymatic activity of cellulase adsorbed on cellulose and its changes during the hydrolysis were investigated. A rapid drop of the hydrolysis rate during the reaction, that is always observed in enzymatic hydrolysis of cellulose, could be explained by a decline of specific activity of adsorbed enzyme, and it was implied that the decline results from a loss of synergistic action between endoglucanase and exoglucanase. An empirical equation expresses the change of hydrolysis rate during the reaction and also shows that the change of the hydrolysis rate is caused by the decline of the specific enzymatic activity of adsorbed enzyme. 相似文献
12.
Thompson David N. Hames Bonnie R. Reddy C. A. Grethlein Hans E. 《Applied biochemistry and biotechnology》1998,(1):967-982
The abilities of lignin peroxidase (LIP) and manganese peroxidase (MNP) fromPhanerochaete chrysosporium to degrade an insoluble hardwood lignin in vitro in aqueous media were tested. Neither LIP nor MNP appreciably changed the
mass or lignin content, although both produced small amounts of unique solubilized lignin fragments. Treatment with both LIP
and MNP, however, decreased the mass by 11%, decreased the lignin content by 5.1% (4.2% as total weight), and solubilized
unique lignin-derived molecules. These results suggest that LIP and MNP synergistically degrade high molecular weight insoluble
lignin, but singly, neither enzyme is sufficient to effect lignin degradation. 相似文献
13.
Patricia M. G. Paiva Luana C. B. B. Coelho 《Applied biochemistry and biotechnology》1992,36(2):113-118
Two additional electrophoretically distinct molecular forms, isoforms (iso) 2 and 3, with lectin properties were isolated
fromCratylia mollis Mart, seeds (FABACEAE), by extraction with 0.15M NaCl and ammonium sulfate fractionation, followed by chromatography on Sephadex
G-75 and Bio-Gel P-200 (iso 2), as well as CM-Cellulose and Sephadex G-75 (iso 3). Both isoforms were human group nonspecific
and showed distinct specificity. Polyacrylamide gel electrophoresis resolved iso 2 and 3 in polypeptides of apparent mol wts
60 and 31 kDa, respectively; a distinct isoelectric focusing pattern was obtained for iso 2 and 3, under denaturing and reducing
conditions. 相似文献
14.
A method for the convenient and reliable preparation of magnetizable agarose beads containing iron particles is described. The beads were treated with the triazine dye, Reactive Red 120, and the matrix was examined for the ability to extract proteins from crude preparations using lactate dehydrogenase from porcine muscle as a model. The recovery and specific activity values of enzyme obtained using this matrix and magnetic field separation were significantly greater than those for enzyme purified by centrifugation and conventional dye ligand chromatography. 相似文献
15.
16.
Effectiveness of cross-linked phyllosilicates for intercalative immobilization of soybean lipoxygenase 总被引:1,自引:0,他引:1
A novel procedure was developed to intercalate enzymes into dispersed phyllosilicates that were cross-linked with silicate polymers formed by the hydrolysis of tetramethyl orthosilicate (TMOS). Lipoxygenase (LOX) intercalated into cross-linked phyllosilicates exhibited high enzymatic activity. The enzyme-phyllosilicate composite prepared by this procedure had an improved pore network. Alkylamines were used to occupy the charge sites of the phyllosilicate, which increased the hydrophobicity of the phyllosilicate and reduced charge-charge interaction between LOX and the phyllosilicate. The amount of macropores and the enzymatic activity of the lipoxygenase-phyllosilicate composites increased with an increase in the ratio of trimethylammonium (TMA)-phyllosilicate to cross-linking reagent TMOS. LOX intercalatively immobilized into phyllosilicates displayed good storage stability and reusability at ambient temperature. 相似文献
17.
Cortez Ely V. Pessoa Adalberto Assis Adilson N. 《Applied biochemistry and biotechnology》1998,(1):661-666
Xylans are the major components of the hemicellulosic fraction of lignocellulosic biomass and their hydrolysis can be obtained
using xylanases fromPenicillium janthinellum. In this work, sugarcane bagasse hemicellulosic hydrolysate was used as the substrate for producing xylanase. The precipitation
of these enzymes was studied using ethanol and Na2SO4 as precipitating agents. Ethanol precipitation experiments were performed batchwise in concentrations ranging from 10 to
80%, pH 4.0 to 7.0, at 4áC. The concentrations used in the precipitations with Na2SO4 were from 5 to 60% at pH 5.5 and 25áC. Solubility curves as a function of xylanase activity and total protein for both precipitating
agents were made. According to the results, Na2SO4 is not appropriate for precipitating xylanases in this medium since at salt concentrations higher than 25%, the enzyme was
denaturated and at this concentration less than 80% of the enzyme and total protein were precipitated. Because of differences
in xylanase and total protein solubility, a fractionated precipitation using ethanol can be performed, since with 40% ethanol,
49% of the total protein was precipitated and more than 95% of the enzyme was kept in solution. On the other hand approx 100%
of the xylanases were recovered by precipitation after adding 80% ethanol. 相似文献
18.
Streptomyces setonii 75Vi2 produces an extracellular coal-solubilizing component(s) in the absence of coal. The heat stability, relatively low
molecular weight, and insensitivity to proteases of the substance(s) responsible for coal solubilization indicate that the
process is nonenzymatic. This report describes factors affecting the production and activity of this substance(s) and the
similarity in its action to alkaline buffer solutions in solubilizing coal. 相似文献
19.
Isolation,identification, and keratinolytic activity of several feather-degrading bacterial isolates
Several feather-degrading bacterial isolates were isolated from Egyptian soil. These isolates were able to degrade chicken
feather, when grown on basal medium containing 1% native feather as a source of energy, carbon, and nitrogen. Feather waste,
generated in large quantities as a byproduct of commercial poultry processing, is nearly pure keratin, which is not easily
degradable by common proteolytic enzymes. The isolates were identified according to the morphological characteristics, biochemical
tests, and API 50 CHBBacillus system. Proteolytic and keratinolytic activities of these isolates were monitored throughout the cultivation of the bacterial
isolates on feather. Resulting soluble proteins, which were released as a result of the biodegradation of feather, were demonstrated
by SDS-PAGE. 相似文献
20.
A 1,4-β-d-glucan cellobiohydrolase (EC 3.2.1.91) and l,4-β-d-glucan glucanohydrolase (EC 3.2.1.4) were purified from the culture filtrates ofPenicillium funiculosum by using preparative isoelectric focusing. Both the enzymes were homogeneous on polyacrylamide gel with and without sodium
dodecyl sulphate. The mol wt of the cellobiohydrolase and endoglucanase were 14,400 and 25,000 respectively. The purified
enzymes were free of β-glucosidase activity. Acting in isolation, the cellobiohydrolase had little capacity for solubilizing
Avicel or Walseth cellulose, but showed increased rates of hydrolysis when combined with endoglucanase. Cellobiose inhibition
(50%) was observed in the initial rate of the hydrolysis of Walseth cellulose. It was also observed that cellobiohydrolase
initiates the attack on crystalline cellulose.
† NCL communication no. 3898. 相似文献