本文選題：微生物絮凝劑 + 分離鑒定�。� 參考：《長安大學》2015年碩士論文

【摘要】：微生物絮凝劑(MBF)是一類由微生物產(chǎn)生的具有絮凝活性的物質(zhì),主要化學成分是糖蛋白、多糖、蛋白質(zhì)、纖維素、核酸等大分子物質(zhì),因其特定的結(jié)構(gòu)和組成而形成了良好的絮凝沉淀性能。與傳統(tǒng)絮凝劑相比,微生物絮凝劑具有安全、無毒、可生物降解、無二次污染的優(yōu)點,是具有生物分解性和安全性的水處理劑,在給水處理、城市生活污水處理、食品加工、發(fā)酵、化工、畜牧、建材等行業(yè)廢水處理等方面的具有廣泛的應用前景。膠質(zhì)芽胞桿菌與其他微生物絮凝劑產(chǎn)生菌株相比,發(fā)酵培養(yǎng)不需要氮源,對營養(yǎng)條件要求低、容易培養(yǎng)和鑒別,在很大程度上降低了其生產(chǎn)成本,因而具有較高的實際應用價值。本文采用選擇性無氮培養(yǎng)基從土樣及造紙廠活性污泥樣品中篩選分離得到90株菌株,采用高嶺土懸浮液測定絮凝活性的方法進行復篩,得到一株菌落邊緣整齊、粘稠、挑起時有拉絲、彈性大且效絮凝活性大于90%的絮凝劑產(chǎn)生菌MY6-2。結(jié)合形態(tài)學、生理生化分析及16SrDNA分析,鑒定該菌株為膠質(zhì)芽孢桿菌(Baccillus mucilaginous)。采用單因素及響應面等方法優(yōu)化菌株MY6-2發(fā)酵培養(yǎng)基及培養(yǎng)條件,以提高其絮凝劑產(chǎn)量及絮凝活性。通過對二次多項線性回歸方程及響應面圖分析可知,該菌最佳發(fā)酵培養(yǎng)基配方為:0.5%蔗糖,不需要氮源;最佳培養(yǎng)條件:裝液量約100mL/250mL三角瓶、初始pH 8、接種量為10%。在此條件下,膠質(zhì)芽孢桿菌MY6-2絮凝活性為:絮凝劑用量為0.5mL發(fā)酵液/100mL高嶺土時,絮凝率約為90%。通過對其絮凝物質(zhì)進行提取并且對其成分進行分析,結(jié)果發(fā)現(xiàn):該絮凝物質(zhì)主要分布在發(fā)酵液中。利用醇沉法提取絮凝物質(zhì),凍干后得到白色粉狀固體。通過物理、化學等方法分析知該物質(zhì)主要為多糖類物質(zhì),具有良好的熱穩(wěn)定性。絮凝特性研究結(jié)果表明,絮凝劑使用條件為:pH7,助凝離子為3mL Ca2+/100 mL高嶺土,絮凝劑用量為0.1mg/100mL高嶺土,其絮凝活性90%;初步的應用實驗結(jié)果表明該絮凝劑對黃土、活性炭、膨潤土、硅藻土等幾種常見懸浮體系均具有良好的絮凝效果。采用單因素試驗對膠質(zhì)芽孢桿菌MY6-2絮凝劑吸附鐵離子的特性進行了研究。結(jié)果表明:絮凝體系pH為5,絮凝劑用量為6 mL,溫度為30℃,鐵離子濃度為60 mg/L至800 mg/L時,MY6-2絮凝劑鐵離子的吸附絮凝率均大于90%以上。
[Abstract]:Microbial flocculant (MBF) is a class of flocculating substances produced by microbes. The main chemical components are glycoprotein, polysaccharide, protein, cellulose, nucleic acid and other macromolecular substances. Because of its specific structure and composition, good flocculation and precipitation performance has been formed. Compared with traditional flocculants, microbial flocculants have the advantages of safety, non-toxicity, biodegradability and no secondary pollution. They are biodegradable and safe water treatment agents, such as water treatment, municipal sewage treatment, food processing, etc. Fermentation, chemical, animal husbandry, building materials and other industries wastewater treatment has a wide range of applications. Compared with other microbial flocculant producing strains, the fermentation culture of Bacillus glia does not require nitrogen source, and requires less nutrition conditions, so it is easy to be cultured and identified, which greatly reduces the production cost. Therefore, it has high practical application value. In this paper, 90 strains were isolated from soil samples and activated sludge samples of paper mill by selective nitrogen-free medium. The flocculation activity was determined by kaolin suspension. The flocculant producing strain MY6-2 with high elasticity and more than 90% flocculant activity. Combined with morphological, physiological and biochemical analysis and 16SrDNA analysis, the strain was identified as Baccillus mucilaginousus. Single factor and response surface were used to optimize the fermentation medium and culture conditions of the strain MY6-2 in order to improve its flocculant yield and flocculation activity. By analyzing the quadratic linear regression equation and response surface diagram, we can know that the optimum fermentation medium of the strain is: 0.5% sucrose without nitrogen source, and the optimum culture conditions are: the volume of liquid is about 100mL/250mL triangle bottle, the initial pH is 8, and the inoculation amount is 10. Under these conditions, the flocculation activity of Bacillus glia MY6-2 is as follows: when the dosage of flocculant is 0.5mL fermentation broth / 100ml kaolin, the flocculation rate is about 90%. The results showed that the flocculant was mainly distributed in fermentation broth. The flocculant was extracted by alcohol precipitation, and the white powder solid was obtained after freeze-drying. Through physical and chemical analysis, it was found that the substance was mainly polysaccharide and had good thermal stability. The results showed that the flocculant was used under the conditions of: pH7, 3mL Ca2 / 100ml kaolinite and 0.1mg/100mL kaolin. The preliminary application results showed that the flocculant was applied to loess, activated carbon and bentonite. Several common suspensions such as diatomite have good flocculation effect. The adsorption of iron ions by MY6-2 flocculants of Bacillus glia was studied by single factor test. The results showed that the adsorption flocculation rate of the flocculant was more than 90% when pH was 5, the dosage of flocculant was 6 mL, the temperature was 30 鈩，

本文編號：1991099