The purpose of this investigation was to study the effect of Streptomyces erumpens cells immobilized in various matrices, i.e., agar–agar, polyacrylamide, and luffa (Luffa cylindrica L.) sponge for production of α-amylase. Luffa sponge was found to be 21% and 51% more effective in enzyme yield than agar–agar
and polyacrylamide, respectively. Response surface methodology was used to evaluate the effect of three main variables, i.e.,
incubation period, pH, and temperature on enzyme production with immobilized luffa cells. The experimental results showed
that the optimum incubation period, pH, and temperature were 36h, 6.0, and 50 °C, respectively. The repeated batch fermentation
of immobilized cells in shake flasks showed that S. erumpens cells were more or less equally physiologically active on the support even after three cycles of fermentation (3,830–3,575
units). The application of S. erumpens crude enzyme in liquefying cassava starch was studied. The maximum hydrolysis of cassava starch (85%) was obtained with the
application of 4ml (15,200 units) of crude enzyme after 5 h of incubation. 相似文献
We used response surface methodology to optimize microcapsule preparation conditions, including the ratio of pectin:α-tocopherol (TP) (X1), emulsifier concentration (X2), and CaCl2 concentration (X3) for maximal entrapment efficiency (EE) of TP-loaded Ca-pectinate microcapsules. The values of X1, X2, and X3, optimized for maximal EE were a ratio of 9.7:6.3, and 1.33% and 5.09%, respectively. The experimental results obtained from the optimum formulation agreed with the predicted results, indicating the usefulness of models for EE. TP release from the Ca-pectinate microcapsules prepared according to the optimized conditions was slow and incomplete in simulated gastric fluid, whereas it was relatively rapid and considerably sustained in simulated intestinal fluid. An in vivo release study revealed that physical entrapment of TP within Ca-pectinate microcapsules can be a good technique to demonstrate the sustained release pattern of TP and to improve the bioavailability for TP following oral administration. 相似文献
Finding a clear route to new structures : The design of an adaptable time warping (ATW) methodology (see figure) for automatically, quickly, and reliably deciphering X‐ray diffraction patterns is described.
Optimization of photo-Fenton degradation of copper phthalocyanine blue was achieved by response surface methodology (RSM) constructed with the aid of a sequential injection analysis (SIA) system coupled to a homemade photo-reactor. Highest degradation percentage was obtained at the following conditions [H2O2]/[phthalocyanine] = 7, [H2O2]/[FeSO4] = 10, pH = 2.5, and stopped flow time in the photo reactor = 30 s. The SIA system was designed to prepare a monosegment containing the reagents and sample, to pump it toward the photo-reactor for the specified time and send the products to a flow-through spectrophotometer for monitoring the color reduction of the dye. Changes in parameters such as reagent molar ratios, residence time and pH were made by modifications in the software commanding the SI system, without the need for physical reconfiguration of reagents around the selection valve. The proposed procedure and system fed the statistical program with degradation data for fast construction of response surface plots. After optimization, 97% of the dye was degraded. 相似文献
In this paper multivariate response surface methodology (RSM) has been used for the optimization of hydrodistillation-headspace solvent microextraction (HD-HSME) of thymol and carvacrol in Thymus transcaspicus. Quantitative determination of compounds of interest was performed simultaneously using gas chromatography coupled with flame ionization detector (GC-FID). Parameters affecting the extraction efficiency were assessed and the optimized values were 5 min, 2 μL and 3 min for the extraction time, micro-drop volume and cooling time after extraction, respectively. The amounts of analyte extracted increased with plant weight. The calibration curves were linear in the ranges of 6.25-81.25 and 1.25-87.50 mg L−1 for thymol and carvacrol, respectively. Limit of detection (LOD) for thymol and carvacrol was 1.87 and 0.23 mg L−1, respectively. Within-day and between-day precisions for both analytes were calculated in three different concentrations and recoveries obtained were in the range of 89-101% and 95-116% for thymol and carvacrol, respectively. 相似文献
An asymmetric synthesis of (S)- and (R)-3-amino-4,4,4-trifluorobutanoic acid via DBU-catalyzed asymmetric 1,3-proton shift transfer reaction of (Z)-3-[(R)-1-phenylethylamino]-4,4,4-trifluoro-N-[(R)-1-phenylethyl]but-2-enamide has been developed. The intermediate Schiff base (S,R′)-9 was found to be relatively configurationally stable under the highly basic reaction conditions allowing preparation of the target amino acid in high chemical yield and enantioselectivity. This method was demonstrated to be practical for large (>25 g) scale synthesis of the target β-amino acid. 相似文献
Optimization of the fermentation medium components for maximum gentamicin production by Micromonospora echinospora ATCC 15838 was carried out. Response surface methodology was applied to optimize the medium constituents. A 24full-factorial central composite design was chosen to explain the combined effects of the four medium constituents, viz. starch,
soyabean meal, K2HPO4, and CoCl2 and to design a minimum number of experiments. A second order model was developed and fitted using least square method. The
R2 value of the model was 0.9723, which shows that model is best fit for the present studies. The results of analysis of variance
and regression of a second order model showed that the linear effects of starch (p<0.001697) and CoCl2(p<7.99E-13), and cross product effects of starch and soyabean meal (p<0.029876) and soyabean meal and CoCl2 (p<0.008909) were more significant, suggesting that these were critical variables having the greatest effect on the production
of gentamicin in the production medium. The optimized medium consisting of 9 g/L starch, 3 g/L soyabean meal, 0.9 g/L K2HPO4, and 0.01 g/L CoCL2 predicted 850 mg/L of gentamicin which was almost 110% higher than that of the unoptimized medium. The amounts of starch,
soyabean meal, and K2HPO4 required were also reduced with RSM. 相似文献
Ultrasound-assisted extraction was evaluated as a simpler and more effective alternative to conventional extraction method for the isolation of xyloglucan from apple pomace. The apple pomace samples were extracted under indirect sonication in an ultrasound cleaning bath. The ultrasound extraction was compared with the conventional method, on the productions of xyloglucan. It was found that the ultrasound-assisted extraction of xyloglucan was about three times faster than the traditional extraction method. Response surface methodology was employed to study the effect of liquid:solid ratio, KOH concentration and ultrasound-assisted extraction time on the yield of xyloglucan from apple pomace. Regression analysis was performed on the data obtained. The most relevant variable was the quadratic of liquid:solid ratio. The coefficient determination (R2) was good for the second-order model. The optimum combination was determined as a liquid:solid ratio of 34.4:1 (v/w), a KOH concentration of 3.3 M and an ultrasound-assisted extraction time of 2.5 h. 相似文献