Optimization on Fermentation and Purification of the Fibrinolytic Enzyme from Stenotrophomonas maltophilia / 中国生物工程杂志

The optimization on liquid fermentation and purification of the fibrinolytic enzyme from Stenotrophomonas maltophilia(DR-929) was investigated.The results showed the best fermentation are amidulin 2.0%,soya flour 1.0%,yeast extract 0.5%,NaCl 1.0%,CaCl2 0.02%,MgSO4 0.05%,inoculum of 36 hours,fermental time 4d,initial pH 8.0 or 9.0,temperature 25℃,volume of media 30ml,volume of inoculum 5% or 6%.The purification process includes the following steps: removing cells by the centrifugation,25%~70% saturation ammonium sulfate precipitation,HIC with Phenyl FF(high sub),IEC with Q-Sepharose FF,gel filtration chromatography with Superdex 75.SDS-PAGE electrophoresis was used to examine the purification effect,and the results indicated that homogeneous strap in SDS-PAGE and has a molecular weight around 28.3kDa.The purification factor and activity recovery of the fibrinolytic enzyme are 271.5 and 24.5%,respectively.

Isolation and Identification of the Immunopotentiating Compound Prepared from the Metabolites of Bacillus Mycoides / 微生物学通报

An immunopotentiating compound has been isolated from the metabolites of Bacillus mycoides under the bioassay-guided isolation and identification for its immunopotentiating effect and chemical structure. The isolation and purification of the compound were consisted of macroporous adsorptive resins, silicagel chromatographic column and Sephadex G-200 chromatographic column. The immunopotentiating effect was assayed in every step isolation. At last, the only substance having the strongest immunopotentiating effect had been isolated and purified. Through the procedure consisiting of Ultra-Violet spectroscopy (UV), IR (Infrared Radiation), Time of Flight Mass Spectrum (TOF-MS), Nuclear Magnetic Resonance (NMR) and Element analysis, the possible structure of compound M had been identified as cyclic (Pro-Gly) dipeptide (C7H10O2N2) (Diketopiperazine). To be determined the immunopotentiating effect, the mice were treated by intraperitoneal injection of cyclic (Pro-Gly) dipeptide in the treatment group and physiologic saline in the control group. At the 14th day after the injection, the SOD activity and the phagocytosis activities reached the peak value and were significantly higher than those in control group. At the 21st day, the bactericidal activity reached peak value and was significantly higher than that in the control group. From the above results, we concluded that the main active component enhancing the immunity of mice was cyclic (Pro-Gly) dipeptide in the metabolism of Bacillus mycoides.