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-For immobilization of puerarin glycosidase from Microbacterium oxydans CGMCC 1788 on DEAE-52 cellulose, the optimal amount of enzyme protein was 12 mg protein: 1 g DEAE-52 cellulose; the optimal pH was 6.5; and the optimal immobilization time was 6 hr. The specific activity of immobilized enzyme was 36.67 mU.g -1 carrier with an immobilization yield of 98.87% and an enzyme recovery yield of 92.43%. The molar transformation rates of puerarin by immobilized enzyme and by the relative bacterial cell amount equal to the same amount of enzyme were 53.3% and 2.2%, respectively, after 1 hr of transformation. The former molar transformation rate, which was similar to that for free enzyme, was more than 24-fold greater than the latter. The immobilized puerarin glycosidase showed improved enzymatic properties and stability. The immobilized puerarin glycosidase retained 88% of its initial activity after being reused 10 times.

We propose a high-power, noise-like pulse (NLP), Tm-doped fiber oscillator applying the nonlinear polarization rotation method. The repetition rate is 12.94 MHz resulting in a pulse energy of 75.7 nJ. The emitted mode-locking spectrum can be tuned from 1885 nm to 1949 nm in a 64 nm spectral range. A theoretical model is built to illustrate the NLP dynamics and its boundary conditions with a soliton pulse inside the 2 μm fiber ring cavity. The corresponding simulation results match well with our experimental results.