固定化氧化亚铁硫杆菌培养条件对黄铁矾沉淀的影响

以聚乙烯醇-海藻酸钠复合材料为载体，Ca(NO3)2为交联剂对氧化亚铁硫杆菌进行包埋固定化。该固定化细胞的连续培养技术可以用于处理H2S、SO2，为了减少减少固定化细胞培养过程中带来许多不利效应的黄铁矾沉淀 (NH4Fe3(SO4)2(OH)6），采取了改变初始pH值和目前普遍采用的9K培养基中的(NH4)2SO4浓度，K2HPO4浓度三种方法。结果显示：在三种方法中，降低(NH4)2SO4浓度是比较可行的一种方法，当(NH4)2SO4从3.0 g/L降低到0.5g/L,Fe2+氧化速率几乎没有受到影响，沉淀形成速率却减少了45%。在固定化细胞连续运行时，降低9K培养基中(NH4)2SO4的含量，当稀释率为0.4 h-1，运行时间为96 h，Fe2+氧化速率高达3.75 g/L.H,结果显示反应柱内沉淀明显减少，同时Fe2+氧化速率并没有明显变化。

Effect of culture conditons on Jarosite for immobilized Acidothiobacillus ferrooxidans

With Ca(NO3)2 (1%~5%) solution as crosslinking agent, Acidithiobacillus ferrooxidans was immobilized by the complex of PVA solution and sodium alginate solution. Continuous culture of immobilized Acidithiobacillus ferrooxidans can be used to remove H2S and SO2. In order to reduce the negative effect of jarosite which formed during the oxidation of Fe2+ by immobilized cells, the changing of initial pH and the ingredient in 9K medium were tried. The results showed: among the three methods, decreasing the concentration (NH4)2SO4 was more feasible than two others. By decreasing the concentration of (NH4)2SO4 from 3 g/L to 0.5 g/L in batch culture, the forming rate of jarosite was decreased by 50%, while Fe2+ oxidation rate was hardly affected. Based on the results from batch culture, a modified 9K medium containing less ammonium sulfate was used to develope an immobilized bioreactor system in which long-term continuous ferrous iron oxidation for about 96h of operation at dilution rates of 0.4 h-1, were successfully achieved with a small amount of jarosite which has many negative effects and a high Fe2+ oxidation rate of 3.75 g/L.h .