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Properties and applications of β‐glycosidase from Bacteroides thetaiotaomicron that specifically hydrolyses isoflavone glycosides
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Da‐Hye Byun Hye‐Jeong Choi Hye‐Won Lee Hye‐Yeon Jeon Woo‐Jae Choung Jae‐Hoon Shim 《International Journal of Food Science & Technology》2015,50(6):1405-1412
To modify the glycan part of glycosides, the gene encoding β‐glycosidase was cloned from Bacteroides thetaiotaomicron VPI‐5482. The cloned gene, bt_1780, was expressed in Escherichia coli MC1061 and the expressed enzyme was purified using Ni‐NTA affinity chromatography. The purified enzyme, BTBG, showed optimal activity at 50 °C and pH 5.5. Interestingly, this enzyme did not have any hydrolysing activity on ordinary β‐linkage–containing substrates such as xylobiose, lactose and cello‐oligosaccharide, but specifically hydrolysed isoflavone glycosides such as daidzin, genistin and glycitin. Compared to a commercial beta glucosidase, BTBG selectively hydrolysed isoflavone glycosides in soybean extract mixture solution. These results suggest that BTBG may be a specialized enzyme for the hydrolysis of glycosides and that the substrate specificity of BTBG is applicable for the bioconversion of isoflavone glycosides in the food industry. 相似文献
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H.W. Choi C.W. Jeon M.D. Dawson 《Photonics Technology Letters, IEEE》2004,16(1):33-35
The fabrication and performance of an InGaN light-emitting diode (LED) array based on a microring device geometry is reported. This design has been adopted in order to increase the surface area for light extraction and to minimize losses due to internal reflections and reabsorption. Electrical characteristics of these devices are similar to those of a conventional large-area LED, while the directed light extraction proves to be superior. In fact, these devices are found to be more efficient when operated at higher currents. This may be attributed to improved heat sinking due to the large surface area to volume ratio. The potential applications of these devices are also discussed. 相似文献
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Seong-Ku Kim Joon Kyu Lee Yong-Mo Kim Jae-Hyun Ahn 《Journal of Mechanical Science and Technology》2002,16(7):1009-1018
The Representative Interactive Flamelet (RIF) concept has been applied to numerically simulate the combustion processes and
pollutant formation in the direct injection diesel engine. Due to the ability for interactively describing the transient behaviors
of local flame structures with CFD solver, the RIF concept has the capabilities to predict the auto-ignition and subsequent
flame propagation in the diesel engine combustion chamber as well as to effectively account for the detailed mechanisms of
soot formation, NOX formation including thermal NO path, prompt and nitrous NOX formation, and reburning process. Special emphasis is given to the turbulent combustion model which properly accounts for
vaporization effects on the mixture fraction fluctuations and the pdf model. The results of numerical modeling using the RIF
concept are compared with experimental data and with numerical results of the commonly applied procedure which the low-temperature
and high-temperature oxidation processes are represented by the Shell ignition model and the eddy dissipation model, respectively.
Numerical results indicate that the RIF approach including the vaporization effect on turbulent spray combustion process successfully
predicts the ignition delay time and location as well as the pollutant formation. 相似文献