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Isolation and characterization of a phytase with improved properties from Citrobacter braakii
Han-Woo Kim1, Young-Ok Kim, Jeong-Ho Lee
1Biotechnology Research Center, National Fisheries Research and Development Institute, 408-1 Sirangri, Gigang-eup, Gigang-gun, Busan 619-902, Korea.
Biotechnology Letters
|September 30, 2003
Abstract:
Citrobacter braakii YH-15 produced an intracellular phytase which was purified 12800 fold to homogeneity with the specific activity of 3457 units mg(-1), which is 1.9 times higher than E. coli phytase previously recorded as having the highest specific activity. Its molecular weight was 47 kDa by SDS-PAGE gel. Enzyme activity was optimal at pH 4 and at 50 degrees C. The Km value for sodium phytate was 0.46 mM with a Vmax 6027 U mg(-1). The phytase was resistant to proteases such as trypsin, pepsin, papain, pancreatin, and elastase.