生活污水絮凝微生物筛选及其培养条件的优化

Screening of the compound microbial flocculants from the domestic sewage and the culture condition optimization

为获得絮凝微生物和提高其絮凝效率并降低生产成本,以江苏碧程环保工程有限公司生活污水旁50 cm内10 cm深处土壤为絮凝微生物的菌源,采用选择培养基和平板划线方法分离纯化出31株菌株,分离纯化的31株菌株经30℃、160 r/min振荡培养72 h后,用发酵液处理质量分数为0.4%的高岭土悬浊液前后的OD550值的变化来表征絮凝率的大小。筛选出4株具有较高絮凝活性的菌株(T1、T2、T3、T4),将这4株具有较高絮凝活性的菌株自由组合、随机复配,筛选出絮凝率最大的复合菌群为T1+T2+T4。以T1+T2+T4为研究对象,研究其培养条件(温度、接种量、培养时间、p H值等)对絮凝效果的影响,并通过单因素和正交试验,以絮凝率为指标,确定复合微生物絮凝菌群的最佳培养条件。结果表明,培养条件的改变可以影响复合微生物絮凝菌群的絮凝效果,各培养条件对复合微生物絮凝菌群絮凝率的影响程度不同。复合絮凝菌群T1+T2+T4絮凝率最高的培养条件为培养温度30℃、p H=7,培养时间60 h;T1、T2、T4的种子液体积比为0.6∶0.9∶0.3,装液量为90 m L/250 m L,接种量为4.5m L/90 m L。研究表明,在最优条件下复合微生物絮凝剂对高岭土悬浊液的絮凝效率高达81.01%,可以克服单一菌种絮凝效率不稳定的缺点。

The given article intends to introduce the method we have developed in screening of compound microbial flocculants from the domestic sewage and the method for its culture condition optimization. For our research goal,we have cultured highly efficient flocculating microorganism strains which can be widely applied in the sewage treatment. In order to screen the idealistic flocculating microorganisms with highly flocculating efficiency and reduce the production cost,we have collected the original strains from the soil in 10 cm depth and 50 cm close to Jiangsu Bicheng Environmental Protection Engineering Co.,Ltd.. And,then,we have isolated and purified 31 strains with the methods of selective culture medium and streak plates. All the said 31 strains have been cultured for 72 h in the condition of 30 ℃ and 160 r / min,which were intended for treating the 4‰ kaolin soil suspension samples. As a result,we have determined OD550 value variations of the soil suspension in hoping to test the flocculating ability of all the said strains. When we obtained the following 4 strains（ T1,T2,T3,T4） with high flocculation activities through the above mentioned process,we have determined the combination of T1,T2 and T4 strains with the maximum flocculating rate via the random combination test. The best culture conditions（ temperature,inoculation volume,culture time and p H value） we have adopted to test the said strains have been prepared through the single factor and orthogonal experiments with the flocculation rate as the index. The results of our experimental tests indicate that the culture condition can change the flocculating rate of the strain combination whereas different factors prove to have different influential levels on the flocculating rate of the strains. The optimized culture conditions of the strain we have proven can be stated as follows： the best temperature is 30 ℃; p H value should be 7; the culture time is 60 h; the volume ratio of T1,T2 and T4 should be0. 6∶ 0. 9∶ 0. 3; the medium volume is 90 m L /250 m L; and the total inoculation volume is 4. 5 m L /90 m L. Under the optimized conditions the flocculating rate of the strain combination on the kaolin soil suspension can be made as high as up to 81. 01%.Thus,it can be seen that the research results of this paper should enjoy a great prospect in the environment protection if its potential can be fully displayed.