摘要本研究通过对土样进行分离筛选，共分离获得11株细菌，通过絮凝活性分析得到一株菌株生物絮凝剂产生菌，将利用细菌的通用引物对该细菌的16S rDNA进行PCR扩增，并将获得的基因序列在NCBI数据库中对细菌的同源性进行比对，结果表明该细菌与Cellulosimicrobium cellulans具有99%的同源性，因此命名该菌株为C. cellulans L804。对L804碳氮源浓度进行优化，最终确定2倍浓度的R2A培养基作为发酵培养基时，菌体生长量最大，生物絮凝剂的产量也随之增加，絮凝活性最高。此外，还发现该菌株不仅可以用于次甲基蓝和甲基橙染料废水脱色，还可以用于处理重金属TE污染的废水，将可溶性的重金属TE还原成不溶性的单质。 

毕业论文关键词：Cellulosimicrobium cellulans L804、微生物絮凝剂、絮凝活性、染料脱色、重金属还原51853

Researches on Characteristics of Strain L804 which can produce bioflocculants

Abstract :In this study, 11 strains were isolated from soil sample among them, one strain showed good flocculating activity. The 16S rRNA of this strain was sequenced after PCR amplification. A total of 1400 bp of 16S rRNA was determined and compared with the sequences of the GenBank from the National Center for Biotechnology Information (NCBI) Database. The highest level of 16S rRNA sequence similarity to Cellulosimicrobium cellulans was 99%. Therefore, the strain was named C. cellulans L804. We did further to find out that the better concentration of medium is 2×R2A medium. The growth curve showed good cell growth and good flocculating activity when 2×R2A medium was used as fermentation medium. Besides, we also find out that L804 can be used to decolorizate methylene blue and methyl orange, and also can convert soluble TE into unsoluble substance, and thus achieve the treatment of TE contaminated wastewater.

Keywords：Cellulosimicrobium cellulans L804; Microbial flocculant; Flocculanting activity; Reduction of heavy metals

目录 1

摘要 2

Abstract 2

前言 3

1材料和方法 5

1.1供试材料 6

1.1.1 试验样品 6

1.1.2 培养基种类 6

1.1.3 仪器 6

1.2 实验方法 7

1.2.1 菌种分离 7

1.2.1.1梯度稀释 7

1.2.1.2 平板涂布 8

1.2.1.3恒温培养 8

1.2.1.4菌种纯化及保存 8

1.2.2 菌种鉴定 9

1.2.2.1 提取16S rDNA 9

1.2.2.2 16S rDNA序列分析 10

1.2.3 絮凝活性测定 10

1.2.4 细菌生长曲线的绘制 10

1.2.5微生物絮凝剂产生菌发酵条件优化 11

1.2.6菌株L804功能探索 11

1.2.6.1染料脱色 11

1.2.6.2重金属还原 11

2 结果与分析 11

2.1 微生物絮凝剂产生菌的筛选 11

2.2 微生物絮凝剂产生菌的鉴定 11

2.2.1 菌株纯化