利用沼液制备微生物絮凝剂及产絮条件优化

Production of Bioflocculants from Biogas Slurry and Optimization of Fermentation Conditions

为降低微生物絮凝剂发酵成本,采用以牛粪和秸秆为底物的大型沼气发酵工程厌氧消化的沼液作为制取微生物絮凝剂的替代培养基,并优化了产絮菌F2-F6的发酵条件。结果表明,经预处理并添加5 g/L的K2HPO4、2 g/L的KH2PO4和2 g/L葡萄糖且灭菌后,絮凝菌可以利用其进行正常产絮。利用响应曲面法对发酵条件进行优化,得到絮凝菌利用沼液作为替代培养基进行发酵的最佳条件是:发酵温度为29.5℃、培养基初始pH值为7.5、接种量为8.5%、发酵时间为23 h,在最优发酵条件下絮凝率为87.13%。

In order to reduce the cost of bioflocculant fermentation, the biogas slurry from the bio- gas digester using cow dung and straw as substrates acted as a substitute for culture medium of biofloecu- lant-producing bacteria, and the fermentation conditions of flocculant-producing bacteria named F2-F6 were optimized. The results showed that after pretreatment, addition of 5 g/L K2HPQ, 2 g/L KH2PQ and 2 g/L glucose and sterilization, bioflocculant-producing bacteria could produce flocculant normally. The fermentation conditions were optimized by response surface method. The optimal fermentation condi- tions were as follows ： fermentation temperature of 29.5 ℃, the initial pH of 7.5, inoculation rate of 8.5% and fermentation time of 23 h. Under these conditions, the focculating rate was 87.13%.