高效微生物絮凝剂产生菌BJ-Ⅰ的筛选鉴定及絮凝特性研究

从活性污泥中筛选出1株高效微生物絮凝剂产生菌BJ-Ⅰ，其絮凝率达87．6％．通过生理生化分析及16S rDNA序列鉴定该菌株为短芽孢杆菌（Bacillus brevis）．该菌产絮凝剂的最适碳源和氮源分别为20g/L的葡萄糖和2．0g／L的蛋白胨；适宜的初始pH和培养温度分别为7．0和30℃；在培养基中添加0．5g／L的Mg^2＋有利于菌体生长，但对絮凝剂合成无影响．对该絮凝剂的特性研究结果表明：菌液投放量3％、pH值在5．9、温度为60℃条件下絮凝效果最好，加入浓度为8％的Ca^2＋可显著提高其絮凝活性．实验证明，该菌起絮凝作用的物质存在于发酵液中，主要成分为杂多糖．

The Screening of a Bio- flocculant- producing Bacterium,Optimizing of Its Culture Conditions and Characteristics of the Bio - flocculant

A strain BJ- Ⅰ with a high capabihty of producing bio- flocculant was isolated from activated sludge of Sequencing Batch Reactor. Its flocculating efficiency could achieve 87.6%. The strain was identified as Bacillus brevis based on its morphological, physio logical properties and 16S rDNA sequence analysis. This study showed that the optimum pH and temper ature for producing bio - flocculant were 7.0 and 30℃, respectively. The best single carbon source is 20 g/L glucose, the best nitrogen source is 2.0 g/L peptone, and Mg^2＋ was able to facilitate the growth of the strain at 0.5 g/L. Results show that a good flocculation effect was found at the condition of 60 ℃ and pH 5 - 9. Adding a small amount of Ca^2＋ to wastewater could also increase the flocculation ability. Most of the bio- flocculants were concentrated in the supernatant, and were mainly composed of polysaccharide.