【作者】 范瑞梅；

【导师】 范家恒； 张洪勋；

【作者基本信息】 昆明理工大学 ， 生物化工， 2007， 硕士

【摘要】 由于铅锌矿的泛滥开采，造成含有铅、锌等重金属工业废水治理形式的严峻，同时也严重影响到人类的健康状况。从世界能源危机和我国废水处理的经济承受能力等角度考虑，寻找廉价、高效、无毒的生物吸附剂是当前环境生物学家面临的首要的问题。目前，此种生物吸附剂的主要来源于酿酒发酵工业生产中产生的废酵母，其吸附效果不甚理想。但利用酶发酵工业中废菌体作为生物吸附剂研究的较少，由于碱性果胶酶在医药、食品、纺织业中的特殊用途，本文作者首次以发酵生产碱性果胶酶为出发点，从碱性富矿土样中筛选到两株高产果胶酶的菌株S-2和S-4，其固态发酵酶活为1560u／g和1150u／g，而且对自身环境中的铅、锌等重金属产生一定的抗性。并通过经典传统微生物学鉴定手段和现代分子生物学鉴定手段得知菌株S-2和S-4分别属芽胞杆菌属，分别命名为B．gibsonii和B．clausii，中文名称为吉氏芽孢杆菌和克劳氏芽孢杆菌，并对发酵过程中产生的废菌体能否作为铅、锌生物吸附剂作出了判断。进而，对此吸附剂吸附铅、锌的吸附性能作了详细的研究。研究结果发现两株嗜碱性B．gibsonii和B．clausii对铅、锌两种重金属具有很好的吸附作用，由于生物吸附材料对不同重金属的选择性，其中，B．gibsonii吸附铅的性能好，最大的吸附量为333.3mg/g，而且clausii吸附锌的性能好，最大吸附容量为57.5mg/g。同时，对影响吸附性能的因素比如最优pH值、温度、吸附平衡时间等进行了研究，研究结果其最优pH值为4.5左右，温度为20℃、30℃、40℃时，其吸附容量依次升高。吸附平衡时间为20～30min，分别用拟一级速度方程和拟二级速度方程对其吸附动力学进行分析，其吸附数据与拟二级速度方程拟合的较好。用朗缪尔方程和费兰德利希方程对其吸附等温线进行了拟合，其吸附等温线与朗缪尔方程拟合的较好。目前，科学工作者对于生物吸附剂比较系统的吸附剂机制还处于争论状态，还没有得到共识。本文作者利用红外光谱和扫描电镜能谱以及单晶X-衍射能谱等现代化较先进手段首次对其吸附机理做了深入的研究。研究结果表明，在B．gibsonii和B．clausii吸附铅、锌的过程中，主要参与吸附作用的化学物质与基团是-OH、-NH₄⁺、-COOH、（-CO-NH-）、-C₆H₅、Mg²⁺、Na⁺、Ca²⁺等，主要作用的部位为细胞壁，而且B．gibsonii和B．clausii吸附铅、锌两种金属的过程是多种物理和化学作用相结合的多元化过程，其主要发生的化学反应有络合反应、离子交换反应。其次，作者首次从应用的角度出发对S-2和S-4吸附铅、锌的工业应用前景作出了初步的判断。从吸附剂的解吸效果和固定化效果来看，在酸性条件下，其解吸率（％）分别为95.7和83.2。作为细胞固定化载体而言，选用明胶-海藻酸钠和聚乙烯醇-海藻酸钠等两种载体对B．gibsonii和B．clausii废菌体进行包埋吸附铅、锌的效果很好。由此可知：B．gibsonii和B．clausii两种铅、锌吸附剂具有循环使用的工业应用价值。总之，B．gibsonii和B．clausii除具有固态发酵产生碱性果胶酶功能外，更重要的是还可以利用其发酵后的废菌体作为铅、锌的生物吸附剂的优质材料，实现了发酵废弃物的资源化再利用。更多还原

【Abstract】 With Lead-zinc mining spreadly, It is grim to control metal wastewater and threatens human health. The main problem faced by environmental biologists is to search cheap, efficient, and non-toxic biosorbents, based on world crisis and economical endurance in wastewater drainage industries. Currently, the kind of biosorbents is mainly waste yeasts from wine fermentation industry but absorption results are not ideal. However, as a biosorbent, the waste microbial biomass from enzyme ferment is rarely studied. Compared alkaline pectic enzyme with acid pectic enzyme, the former is more attracting in many fields such as medicine, foods, weaving and so on. We isolated two producing pectic enzyme strains of S-2 and S-4 with appearing certain resistant for heavy metal of Lead and Zinc from rich alkaline mine soil, which pectinase activity is 1560u/g and 1150u/g. The two strains were identified Bacillus through traditional and modern-molecule genetic method, which is named B. gibsonii and B. clausii respectively.We investigated absorption performance of B. gibsonii and B. clausii in order to make biomass applied fully. The result has shown that lead and zinc can be removed by B. gibsonii and B. clausii in ferment efficiently. We found that it is suitable to choose Lead absorbed by B. gibsonii and Zinc by B. clausii according to the electivity. The adsorption capacity of Lead is 333.3mg/g, and that of Zinc is 57.5 mg/g. Also, we studied the influential factor such as absorption optimal pH, absorption temperature, absorption balance time. The results are listed as following as below: The optimal pH is at 4.5 or so; The absorption capacity is ascended with different temperatures 20, 30 and 40 °C; The absorption balance time is 20 30 min; The absorption data is fit well with Pseudo-second-order equation in kinetics analysis; The absorption isotherms is fit well with Langmiur equation.Today, scientists still agree with on the systemic absorption mechanism. In order to further study the absorption mechanism of Lead by B. gibsonii and Zinc by B. clausii, we made many efforts through FTIR （Fourier transform infrared ray）, EDX（Energy Dispersive X-ray analysis） and XRD（X-ray powder diffraction）.Some changes the adsorption of bond groups and metal ions can be observed on the cell wall surface of B. gibsonii and Bacillusclausii ,such as -OH, -NH₄⁺> -COOH、 （-CO-NH-）、 -C₆H₅、 Mg²⁺、 Na⁺、 Ca²⁺and so on. The cell wall is main absorption site. The research shows that the process of absorption is very complex process including all kinds of physical and chemic reaction such as integrate, ions exchange and so on.Finally, we make a judgment of application prospects that S-2 and S-4 absorb Lead and Zinc. From experiments results of desorption and immobilition, the desorption efficiency of Lead and Zinc is 95.7、 83.2 percent under acidic conditions. Moreover, lead and zinc can be removed well by immobilized vector B. gibsonii and B. clausii with PVA-sodium-alginate and gelatin-sodium-alginate. The data tell us that biosorbents can be cycled in industries with very promising wastewater treatment application technology.In summary, Bacillus gibsonii and Bacillus clausii are excelent Lead-Zinc biosorbent materials, including producing pectic enzyme. All that have shown biomass can be reused.更多还原