红平红球菌产微生物絮凝剂的发酵条件及分离纯化

Fermenting Condition of Producing Microbial Flocculant(MBF) by Rhodococcus erythropolis and Separation and Purification

优化了红平红球菌(Rhodococcus erythropolis)产微生物絮凝剂(MBF)的发酵条件,并对该微生物絮凝剂(MBF)进行了分离纯化。结果表明:以红平红球菌为出发菌株,以廉价的蔗糖和尿素作为碳源和氮源,发酵培养液的配方为蔗糖30.0 g/L,尿素7.5 g/L,CaCl20.5 g/L,MgSO41.0 g/L,NaCl 0.2 g/L,pH 9,在30.0 L发酵罐中,以发酵温度35℃,搅拌转速350 r/min,发酵时间96 h的条件下发酵,其发酵液中絮凝率为89.31%;发酵液经离心后,用0.5%三氯甲烷∶正丁醇(4∶1)处理,利用不同浓度乙醇分级沉淀,初步分离得到粗制MBF,再通过DEAE-纤维素层析柱交换层析,最终可获得纯度高的MBF。

The paper discussed the optimized fermenting condition of producing microbial flocculant （MBF） by Rhodococcus erythropolis. In this research, a kind of high purity of MBF was separated and purified by ethanol classification precipitation and DEAE-cellulose exchange layer column. The result showed that MBF of R. erythropolis could be produced wich of sucrose,urea and some inexpensive substance to instead of the standard culture medium. This new culture medium was made of sucrose 30. 0 g/L,urea 7.5 g/L, CaCI2 0. 5 g/L, MgSO4 1.0 g/L, NaC1 0. 2 g/L, pH 9. In the 30.0 L fermentor, with culture mediums at 35 ℃ ,whisk rotate speed at 350 r/min, ferment time 96 h, flocculation rate at 89.31% on average. After the ferment liquid was centrifuged, 0. 5%chloroform and n-butyl alcohol （4 ： 1）were used to deal with kinds of impurities. Ethanol with different concentrations deposited impurities of different molecular weight in the crude MBF and then the crude MEF was separated and purified by DEAE-cellulose exchange layer column, which was validated by ultraviolet scanning and SDS-PAGE electrophoretogram.