絮凝菌JMH 48的鉴定及其产絮凝剂条件的优化研究

Identification of Flocculant-Producing Microbial JMH 48 and Optimization of Its Flocculant Producing Conditions

从活性污泥中分离筛选得到具有高絮凝活性的微生物絮凝菌JMH 48。采用分子生物学结合经典的生理生化对JMH 48絮凝菌进行鉴定及絮凝体系研究,16S r DNA序列分析、生物化学、生理学特性确定JMH48絮凝菌为一种蜡状芽孢杆菌(Bacillus cereus),使其具有高聚凝活性的最佳碳氮比是葡萄糖与蛋白胨(43:1);最佳培养条件为接种量4%,初始p H 7.0,培养时间3 d,温度20℃;最佳培养基(g/L)为:葡萄糖20 g、K_H_2PO_42 g、K_2HPO_45 g、(NH_4)_2SO_40.2 g、Na Cl 0.1 g、蛋白胨0.5 g、Mg SO_4·7H_2O 0.2 g。最优培养条件下,JMH48的絮凝率可高达98.26%。处理时间为20 min,加入絮凝剂的量为0.6 m L,Ca Cl_2的加入量为1.25 m L,p H值为7时絮凝效果最好。絮凝体系中絮凝率达到96.54%。

In this experiment, we isolated and screened a high flocculating activity microbial bioflocculant JMH 48 from the activated sludge. We identified JMH 48 through the combination of molecular biology and classical physiology and studied the flocculation system to found that JMH48 focculating bacteria was a Bacillus cere us based on sequence analysis, biochemistry and physiological characteristics of 16S rDNA. By optimizing its culture conditions, the results showed that the best ratio of carbon and nitrogen sources was 43：1 （glucose and peptone）, which made JMH48 create a high polymer coagulant activity; the optimal culture conditions was 4% inoculum, initial pH 7.0, incubation time of 3 d, and temperature of 20℃; the optimal culture medium （g/L） was： glucose 20 g, KH2PO4 2 g, K2HPO4 5 g, （NH4）2SO4 0.2 g, NaCl 0.1 g, peptone 0.5 g, MgSO4·7H2O 0.2 g. Under the optimal culture condition, the flocculation rate of JMH48 could reach as high as 98.26%. By researching the flocculation conditions of flocculant, we found that the best effect occurred when the processing time was 20 min, the amount of flocculant added was 0.6 mL, the addition amount of CaCl2 was 1.25 mL, and pH value was 4： 0, under which condition the flocculation rate was up to 96.54%.