絮凝剂产生菌克雷伯氏杆菌的筛选、鉴定及培养条件优化

Screening and Identification of Bioflocculant-producing Klebsiella M2 and Optimal Study on Culture Conditions

采用常规细菌分离方法从木薯淀粉黄浆废水中筛选得到一株微生物絮凝剂产生菌,编号为M2。经过形态学特征、生理生化反应试验和16S rDNA基因序列分析鉴定该菌株为克雷伯氏杆菌,命名为Klebsiella sp.M2。通过单因素实验对菌株M2培养条件进行优化,结果表明最佳培养基种类、培养基初始pH值、培养温度及摇床转速分别为查氏培养基、5、30℃及150r/min。与大部分微生物絮凝剂产生菌上清液表现出絮凝性不同,菌株M2的菌体本身表现出絮凝活性;经过使用超声波破碎仪证明菌体本身具有絮凝活性,最佳絮凝率达到93.20%,具有易于运输、便于使用的优点。菌株M2在以蔗糖作为碳源、KNO3作为氮源的情况下絮凝活性最好。

A bacterial strain named M2 which can produce bioflocculant with high flocculating activity was screened from Cassava starch yellow pulp wastewater by means of the common bacteria screening and purification method. The strain was identified as Klebsiella sp. M2 according to its morphological, physiological and biochemical reaction, as well as 16S rDNA sequence analysis. The optimum culture conditions were obtained according to the single factor test. The optimum medium, initial culture pH, culture temperature and agitation rate are Czapek, 5 ℃, 30 ℃ and 150 r/min, respectively. Using the ultrasoni processor further proved Strain M2 shows the floccula-bility of bacteria itself different of most bioflocculant-producing supernatant fluid show the flocculability. With the advantages of easy to transport and use, the best flocculating rate of strain M2 is 93.20%. Strain M2 had good flocculating rate in sucrose as carbon source KNO3 as nitrogen source.