【摘要】 目的:从土壤中筛选具有良好絮凝活性的菌株进行优化培养并研究其絮凝特性。方法:采用平板划线法分离纯化获得目的菌株,通过单因素和正交实验确定最适培养、絮凝条件,考察该菌的生长及产絮凝剂的周期和絮凝活性分布等特征,及其对次甲基兰的脱色能力。结果:得到絮凝活性较高的菌株C5,其最适产絮条件为:初始pH值7.5,温度36℃,培养时间48h;最适培养基为:葡萄糖10g,KH2PO42g,K2HPO45g,(NH4)2SO40.2g,尿素0.5g,酵母膏0.5g,NaCl0.1g,MgSO4.7H2O0.2g,絮凝率可达92.0%;最适絮凝条件为:2.5mL发酵液,pH6.0,5mL CaCl2溶液;絮凝活性成分主要为多糖和蛋白质,多分布于胞外上清液中;发酵液的絮凝活性与细胞生长量均在培养48h时达最大;对次甲基兰的脱色能力优于硫酸铝和聚丙烯酰胺,2min内脱色率可达97%。结论:菌株C5可产高絮凝活性的絮凝剂,具有良好的应用前景。更多还原

【Abstract】 Objectives: A bioflocculant-producing strain with high flocculating activity was isolated from soil, and its flocculating characteristics were investigated. Methods: The target strain was obtained by plate thread separate method, purify and screen paths. Optimal culture-flocculating conditions were found by single fact and multi factors orthogonal experiments. The growth period, flocculant-producing period and activity distribution were investigated. The decolorization experiments of methylene blue by bioflocculant, Al2(SO4)3 and polyacrylamide were carried out, respectively. Results: A bioflocculant-producing strain named C5 with high flocculating activity was obtained. The optimum culture conditions were: pH7.5 of initial pH, 36℃ of culture temperature, and 48h of culture period, and the optimum culture medium were glucose 10g,KH2PO4 2g,K2HPO4 5g,(NH4)2SO4 0.2g,urea 0.5g,yeast 0.5g,NaCl 0.1g,MgSO4·7H2O 0.2g, and 92.0% of flocculating rate was reached. Through orthogonal test, the optimal flocculating conditions were found to be: 2.5mL of microbial flocculant dosage, pH 6.0 and 5mL of 1% CaCl2. Most of the bioflocculants were concentrated in the supernatant, and were mainly composed of polysaccharide and protein. Both the highest growth of cells and the highest flocculating activity were obtained at 48h of culture. The decolorizing rate of methylene blue by bioflocculant was better than that of Al2(SO4)3 and polyacrylamide, and 97% of decolorizing rate was reached in 2 minutes. Conclusion: High flocculating activity was found in bioflocculant-producing strain C5 which had a good potential in application.更多还原