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Matioli Graciette Zanin Gisella M. Gljimarães Manoel F. De moraes Flávio f. 《Applied biochemistry and biotechnology》1998,(1):267-275
Alkalophylic bacilli that produce cyclodextringlycosyltransferase (CGTase) were isolated from Brazilian soil, with a scheme
of two plating steps. In the first step, the bacterial isolate forms a halo in the cultivation medium that contains γ-cyclodextrin
(CD) complexing dyes. The CGTase of an isolate was purified 157-fold by biospecific affinity chromatography, with β-CD showing
a mol wt of 77,580 Daltons. It produces a γ- to β-CD ratio of 0.156 and a small amount of α-CD, using maltodextrin 10% as
substrate, at 50°C, pH 8.0 and 22 h reaction time, reaching 21.4% conversion of the substrate to cyclodextrins. In the second
screening step, the isolates chosen give larger halos with β-CD complexing dyes, and smaller halos with β-CD complexing dyes,
leading to a 30% improvement in γ-CD selectivity, although at lower total yield for cyclodextrins (11.5%). 相似文献
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Matioli Graciette Zanin Gisella M. De Moraes Flávio F. 《Applied biochemistry and biotechnology》2002,98(1-9):947-961
The influence of substrate or product level on the initial velocity of cyclodextrin (CD) production by cyclodextringlycosyltransferase
from a Brazilian isolate of Bacillus firmus was studied. Our results indicate that the product γ-CD is a stronger inhibitor to the reaction than β-CD. Small saccharides
could also inhibit CD production, although to a lesser extent than the products, and maltose was the strongest inhibitor among
small saccharides. Increasing substrate concentration resulted in greater reduction on enzyme activity for the formation of
β-CD than for γ-CD. We modeled the kinetics of CD production with a set of four reversible reactions including the cyclization/coupling
reaction that forms/opens CDs, and three disproportionation reactions. Our model on the initial velocity data explained well
the substrate inhibition phenomenon. Kinetic parameters were determined by fitting the initial velocity data into our model. 相似文献
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Luiz Carlos Matioli Wilfredo Sosa Jinyun Yuan 《Computational Optimization and Applications》2012,52(1):281-292
A family of nonempty closed convex sets is built by using the data of the Generalized Nash equilibrium problem (GNEP). The sets are selected iteratively such that the intersection of the selected sets contains solutions of the GNEP. The algorithm introduced by Iusem-Sosa (Optimization 52:301?C316, 2003) is adapted to obtain solutions of the GNEP. Finally some numerical experiments are given to illustrate the numerical behavior of the algorithm. 相似文献
5.
Matioli Graciette Zanin Gisella M. De Moraes Flávio F. 《Applied biochemistry and biotechnology》2001,91(1-9):643-654
The enzyme cyclod extringly cosyltransferase (CGTase), EC2.4.1.19, which produces cyclodextrins (CDs) from starch, was obtained
from Bacillus firmus strain no. 37 isolated from Brazilian soil and characterized in the soluble form using as substrate 100 g/L of maltodextrin
in 0.05 M Tris-HCl buffer, 5 mM CaCl2, and appropriate buffers. Enzymatic activity and its activation energy were determined as a function of temperature and pH.
The activation energy for the production of β- and γ-CD was 7.5 and 9.9 kcal/mol, respectively. The energy of deactivation
was 39 kcal/mol. The enzyme showed little thermal deactivation in the temperature range of 35–60°C, and Arrhenius-type equations
were obtained for calculating the activity, deactivation, and half-life as a function of temperature. The molecular weight
of the enzyme was determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis, giving 77.6k Da. Results for CGTase
activity as a function of temperature gave maximal activity for the production of β-CD at 65°C, pH 6.0, and 7 1.5 mmol of
β-CD/(min·mg of protein), whereas for γ-CD it was 9.1 m mol of γ-CD/(min·mg of protein) at 70°C and pH 8.0. For long contact
times, the bestuse of the enzymatic activity occurs at 60°C oratalower temperature, and the reaction pH may be selected to
increase the vield of a desired CD. 相似文献
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Miyoshi Juliana H. Castro Juliana C. Fenelon Vanderson C. Garcia Francielle P. Nakamura Celso V. Nogueira Ana C. Ueda-Nakamura Tania de Souza Hâmara M. Mangolim Camila S. Moura-Costa Gislaine F. Matioli Graciette 《Journal of inclusion phenomena and macrocyclic chemistry》2022,102(1-2):117-132
Journal of Inclusion Phenomena and Macrocyclic Chemistry - This research evaluated the chemical composition of Ocimum basilicum and Syzygium aromaticum and to characterize their complex with... 相似文献
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R Pazzetto SB Ferreira EJ Santos C Moriwaki TA Guedes G Matioli 《Molecules (Basel, Switzerland)》2012,17(8):9476-9488
The preservation of Bacillus firmus strain 37 cells by lyophilization was evaluated and response surface methodology (RSM) was used to optimize the β-cyclodextrin (β-CD) production by cells immobilized on loofa sponge. Interactions were studied with the variables temperature, pH and dextrin concentration using a central composite design (CCD). Immobilization time influence on β-CD production was also investigated. B. firmus strain 37 cells remained viable after one year of storage, showing that the lyophilization is a suitable method for preservation of the microorganism. From the three-dimensional diagrams and contour plots, the best conditions for β-CD production were determined: temperature 60 °C, pH 8, and 18% dextrin. Considering that the amount of dextrin was high, a new assay was carried out, in which dextrin concentrations of 10, 15, and 18% were tested and the temperature of 60 °C and pH 8 were maintained. The results achieved showed very small differences and therefore, for economic reasons, the use of 10% dextrin is suggested. Increasing the immobilization time of cells immobilized on synthetic sponge the β-CD production decreased and did not change for cells immobilized on loofa sponge. The results of this research are important for microorganism preservation and essential in the optimization of the biosynthesis of CD. 相似文献
8.
Portilho M Matioli G Zanin GM de Moraes FF Scamparini AR 《Applied biochemistry and biotechnology》2006,131(1-3):864-869
Agrobacterium isolated from soil samples produced two extracellular polysaccharides: succinoglycan, an acidic soluble polymer, and curdlan gum, a neutral, insoluble polymer. Maize glucose, cassava glucose, and maize maltose were used in fermentation medium to produce insoluble polysaccharide. Two Agrobacterium sp. strains which were used (ATCC 31749 and IFO 13140) in the production of insoluble exopolysaccharide presented equal or superior yields compared to the literature. The strain ATCC 31749 yielded better production when using maize maltose, whose yield was 85%, whereas strain IFO 13140 produced more when fed maize glucose, producing a yield of 50% (on reducing sugars). 相似文献
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Matioli Graciette Zanin Gisella M. de Moraes Flávio F. 《Applied biochemistry and biotechnology》2000,84(1-9):955-962
The production of cyclodextrins (CDs) by cyclodextrin-glycosyl-transferase (CGTase) from Bacillus firmus was studied, with respect to the effect of the source of starch upon CD yield and on the selectivity for producing γ-CD.
Cyclodextrin production tests were run for 24 h at 50°C, pH 8.0, and 1 mg/L of CGTase, and substrates were maltodextrin or
the starches of rice, potato, cassava, and corn hydrolyzed up to D. E. 10. Cornstarch was the best substrate for producing
γ-CD. Later, glycyrrhizin (2.5% [w/v]), which forms a stable complex with γ-CD, was added to the cornstarch reaction medium
and increased the yield of γ-CD to about four times that produced with only maltodextrin, but the total yield of CDs remained
practically unchanged. Therefore, the results showed that the studied CGTase is capable of giving relatively high yield of
γ-CD in the presence of glycyrrhizin as complexant and cornstarch as substrate. 相似文献
10.
Luciano Belato Alves Graciette Matioli Flávio Faria De Moraes Gisella Maria Zanin José Eduardo Olivo 《Journal of inclusion phenomena and macrocyclic chemistry》2002,44(1-4):399-402
Different culture media have been testedfor the production of the enzyme CGTase (cyclodextringlycosyltransferase) from Bacillus firmus (strain #37). The concentration of different carbon and nitrogen sources have been varied and the enzyme activity, cell concentration, reducing sugars, total reducing sugars, soluble protein and pH have been followed during cultivation. Results indicate that higher concentrations of yeast extract and polypeptone lead to increased synthesis of CGTase, whereas when starch is substituted by glucose there is a drastic inhibition of CGTase production. 相似文献
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