沸石固定化细胞降解氰化物的实验研究

Biodegradation of Cyanide by Immobilized Cells on the Zeolite

利用本实验室保藏的一株产碱杆菌DN25作为降氰菌株,以沸石为载体进行固定化,研究了固定化细胞的降解特性。实验表明采用吸附生长法能有效实现菌株DN25在沸石上固定化,生物固定量可达到0.228g干细胞·(gzeolite)?1。固定化细胞的最适降解温度为30℃,最适pH为8.0,与游离细胞基本一致。将固定化细胞分别用于50mgCN?·L?1和500mgCN?·L?1的含氰液的降解,发现对于低浓度含氰废水固定化细胞的初始降解率仅为游离细胞的一半,而对于高浓度氰废水,固定化细胞的降解速率与游离细胞基本相同。固定化细胞可重复使用10天,降解率仍能达到90%。

The cyanide-biodegradation characteristics of the immobilized Alcaligenes sp DN25, isolated from contaminated soil and immobilized on the zeolite as carrier was investigated. The results show that the immobilization could be realized through the growth of the cell on the zeolite during the culture process and the biomass immobilized can reach 0.228 g dry weight &middot (g zeolite)-1. For the immobilized cell, the optimum biodegradation temperature and pH are 30°C and 8.0 respectively, which are almost similar to that of the free cell. The biodegradation curves of the simulated wastewater containing 50 mg CN- &middot L-1 and 500 mg CN- &middot L-1 respectively were measured and it is found that the initial degradation rate of the immobilized cell is only 50% of that of the free cell for wastewater containing 50 mg CN- &middot L-1 and becomes the same for the wastewater containing 500 mg CN- &middot L-1. The immobilized cell can be used repeatedly for 10 days and the degradation rate still maintains above 90%.