Abstract: A bioflocculant MBF-18 with high flocculating activity was produced by Pseudomonas fluorescens strain JX18. Measurements of chemical analysis，UV and IR spectroscopies revealed that the bioflocculant MBF-18 is mainly composed of polysaccharides and distributed in the fermentation broth. Flocculation property study showed that MBF-18 has a high thermal stability and a wide pH serviceable range. The flocculating activity showed no decrease even at 100℃and kept stable with higher than 85% at pH 3.0—10.0. Further investigation revealed that the optimum concentration of this bioflocculant for flocculation was 2.5 mg/L，and CaCl2 was proved to be the best coagulant aid with an optimum concentration of 0.5 g/L. Scanning electron microscopy image of the solid-state MBF-18 showed that the bioflocculant has a linear morphology，and connected with Kaolin clay molecules upon flocculation.

摘要： 分析了荧光假单胞菌JX18所产絮凝活性物质MBF-18，絮凝物质主要分布在发酵液中；通过化学检测和紫外、红外光谱分析，初步表明絮凝物质含有大量多糖。对絮凝物质絮凝特性研究表明，该物质有很好的热稳定性和较广的pH值适用范围，在100 ℃絮凝活性基本无损失，pH值在3～10范围内絮凝率稳定在85%以上，表现出良好的应用前景。进一步研究表明，絮凝物质的最适用量为2.5 mg/L，CaCl2作为最适助凝剂，用量为0.5 g/L。扫描电子显微镜观察发现，MBF-18微观形态为线状；絮凝后，高岭土小颗粒通过絮凝物质结合，聚集成团。