【作者】 赵芯；

【导师】 陈强；

【作者基本信息】 四川农业大学 ， 环境工程， 2007， 硕士

【摘要】 在水的一级处理中，常用到各类絮凝剂，而微生物絮凝剂因其絮凝效果好且无毒、无害、易生物降解、不产生二次污染而成为水处理领域的研究热点。从四川不同地方采集的30份土壤和四川农业大学污水处理站活性污泥为材料，采用稀释平板法分离，划线法纯化，结合镜检获得纯菌株。本论文筛选出高效絮凝剂产生菌并对其进行生长条件和性能的研究，研究结果如下：（1）分离纯化出141株细菌，初筛获得絮凝活性较高的菌株进行复筛，最后得到絮凝活性稳定且最高的菌株Ⅰ-3，经鉴定该菌株为肠杆菌。该菌株是未见报道的絮凝剂产生菌。（2）对Ⅰ-3的絮凝剂产物分布情况和生长曲线的研究结果表明，絮凝剂是在菌体的生长过程中分泌的，是菌体胞外产物；随着菌株培养时间的增加，絮凝剂絮凝率逐渐增大，在对数生长期达到最大，为99.0％。（3）对培养基条件和絮凝条件的研究：选取方便、易得、价廉的培养基，通过正交实验确定了菌株产生絮凝剂的最佳条件。筛选得出最适宜该菌株的培养基：红薯150g／L、尿素1.5g／L，絮凝率为91％左右；在最佳培养基中对菌株进行了培养条件和絮凝条件的研究，最佳培养条件为：初始pH=9，装液量30ml，转速180r／min时，絮凝率为95.5％；最佳絮凝条件：絮凝剂用量为10ml／L，高岭土悬液的pH=8时，絮凝率为98.1％。Na⁺、Ca²⁺、Fe³⁺溶液对絮凝剂均不起助凝作用。继而，本研究探讨了利用畜禽废水作为培养基发酵，结果表明，Ⅰ-3菌株也可产生一定量的絮凝剂，其絮凝率达71.5％，培养基中加入0.5g的蔗糖后絮凝率上升到87.5％。（4）对微生物絮凝剂的化学组成进行了分析，结果表明：絮凝剂的成分含量64．9％是多糖，9.1％是蛋白质；还原糖未检测出，其余26％的成分未确定其组成。（5）将Ⅰ-3所产絮凝剂的实际应用于实践，分别处理石材厂废水、江水洪水期的水和畜禽废水，其絮凝效果分别为98.4％、99％和39％，对畜禽废水COD有一定的去除效果，去除率达15％。该微生物絮凝剂的絮凝效果好、沉降速度快，显示了微生物絮凝剂广阔的生产应用前景。更多还原

【Abstract】 In the field of water preliminary treatment system, interests are focused on bioflocculant, since it is non-poisonous, non-harmful, and bio-degradeable easily, and there is no secondary pollution produced. Bioflocculant has been used widely in the world and its good flocculating effect has been proved. The bioflocculant producing bacterial strains have been isolated and studied in this thesis.（1） 141 strains from 30 soil samples and active sludge were isolated and purified, and one high effective bioflocculant-producing strain, namedⅠ-3, was screened.Ⅰ-3 was identified as Enterobacter sp., and has never been reported before.（2） Bioflocculant produced byⅠ-3 was determined; the results showed that the bioflocculant was secreted out of the bacteria. The growth curve ofⅠ-3 and the bioflocculant producing dynamics indicated that the activity of flocculating increased withⅠ-3 growing. When cultivated 24-30 hours, the flocculating rate of bioflocculant got to the highest, and the flocculating rate was 99%.（3） Cheap, convenience culture materia used to ferment strainⅠ-3 has been studied. The optimum conditions of flocculant production of strainⅠ-3 was determined through orthogonal experiment. The results suggested that the optimum conditions were: 150g/L sweet potato as carbon source, 1.5g/L urea as nitrogen source, the flocculating rate was about 91%; meanwhile, the optimum cultivating conditions was: original culture pH was 9, the culture capacity was 30ml, and rotate speed was 180r/min, and the flocculating rate was 95.5%.The optimum flocculating conditions was: adding 10 ml/L of flocculant ferment liquid, keeping kaolin solution pH 8, then the flocculating rate reached to 98.1%. metal ions such as Na⁺、Ca²⁺、Fe³⁺ solution didn’t have any effect on flocculating. Furthermore,Ⅰ-3 strain could use domestic animal wastewater to produce bioflocculant, and the rate of flocculating rate was 71.5%; when adding 0.5g sugar into the domestic animal wastewater, the flocculating rate was 87.5%.（4） The chemical composition of bioflocculant was analyzed preliminarily; the results showed that the bioflocculant was consisted of polysaccharides（64.9%）, a little amount of proteins（9.1%）; and the other components（26%） was not clear.（5） The bioflocculant used to treat rock material wastewater, domestic animal wastewater and the floodwater to remove the suspended substances was studied. The results showed that flocculanting rate was 98.4%, 39% and 99%, repectively; which suggested that bioflocculant have good flocculating effect, and the flocculanting course was fast; hence, the bioflocculant will have broad application prospects in practice.更多还原