一株高效重金属吸附工程菌的廉价培养研究

Cost-effective Cultivation of an Effective Engineering Strain for Biosorption of Heavy Metals

为了使生物吸附剂能更好地在实际中得到应用，研究了1株对中低浓度含Cr废水具有高效吸附能力的工程菌的廉价培养方法。研究表明，利用3％的制糖厂废弃糖蜜结合20g/L的城市污水厂回流污泥作为工程菌的廉价发酵底物能很好地生产生物吸附剂。工程茵对碳源的需求量大，能在较宽的偏酸性环境下生长，在pH值为3．0～7．0时生物吸附剂的产量为43．3～38．7g／L。发酵效果基本不受接种液种龄的限制，发酵启动稳定。底物初始pH值对生物吸附剂吸附能力的影响较大，最优pH值为3．0，此时对总Cr的去除率为99．9％；当pH值增加到5．0后，对总Cr的去除率仅为pH值为3．0时的一半。发酵时间在一定程度上影响生物吸附剂的产量，但其吸附性能在整个发酵过程中均能保持较高水平（去除率〉80％），具有良好的稳定性。

To promote the wide application of biosorbents in environmental pollution control, a cost-effective cultivation method of an engineering strain for effective biosorption of middle and low con- centration chromium was investigated. An effective biosorbent for heavy metal can be produced by using 3% abandoned molasses and 20 g/L municipal sludge as the fermentation substrate of engineering strain. A large amount of carbon source is needed by the engineered strain, and a slightly acidic environment is favorable for its growth. When the pH is 3.0 to 7.0, the biosorbent productivity is 43.3 g/L to 38.7 g/L. The age of inoculum has little effect on fermentation, implicating that the start-up of fermentation is stable. The adsorptive capacity of the biosorbent is significantly affected by initial pH of the culture. The optimal pH is 3.0, and the corresponding removal rate of total chromium is 99.9%. When the initial pH of the culture is increased to 5.0, the corresponding removal rate of total chromium is decreased by half. The fermentation time affects the biosorbent production to some extent. However, the removal rates of heavy metals by the biosorbent remain above 80% throughout the fermentation process.