利用固定化XN1菌连续生产微生物絮凝剂的研究

Continuous Production of Bioflocculant Using Immobilized XN1

以多孔聚氨酯泡沫为载体,对固定化絮凝剂产生菌进行摇瓶及发酵罐连续培养试验研究,并通过比较不同初糖浓度、菌龄、转速和发酵周期对固定化XN1菌的生长及其产絮凝剂效能的影响,优化了连续生产絮凝剂的条件。结果表明:在摇瓶中,利用糖浓度为2%的初培养基,在150 r/min、28℃下培养60 h即可获得较高活性的固定化细胞;将固定化细胞接种于1%糖浓度的发酵培养基中,振荡速率调至100 r/min,每8 h更换一次培养基,可连续生产12批次高活性絮凝剂,絮凝活性均在78%以上。采用2 L发酵罐优化工艺,连续生产12批次絮凝剂仅需6.5 d,且所得絮凝剂的絮凝活性均在85%以上,与游离菌生产絮凝剂相比,生产效率提高了453.8%。这说明利用多孔聚酯泡沫颗粒作为固定化载体、分段培养、连续发酵生产絮凝剂的方法是可行的、经济的。

Using porous polyurethane fbam as carrier, continuous cultivation of immobilized XN1 was performed in shake flasks and fermenter. The continuous production conditions were optimized by comparing the impact of initial sugar concentration, cell age, agitation rate and fermentation period on the immobilized XN1 growth and bioflocculant production. The results show that in the shake flask, immobilized cells with high activity can be achieved under the conditions of 2% initial sugar medium, 150 r/min of agitation rate, 28 ℃ and cultivation time of 60 h. 12 batches of bioflocculant with activity of more than 78% can be continuously produced by inoculating the immobilized cells in 1% fermentation medium, regulating the agitation rate at 100 r/min and changing the cultivation medium once per 8 h. In the 2 L fermenter for experimental verification of optimized production process, the continuous production of 12 batches of bioflocculant takes only 6.5 d, and the flocculation activity is more than 85%. As compared with free bacteria, the production efficiency of immobilized XN1 is increased by 453.8%. It is concluded that the production method of bioflocculant by using porous polyurethane foam as carrier, staged cultiva- tion and continuous fermentation is feasible and economic.