利用基因工程菌BL21处理有机磷混合农药废水的研究

研究了悬浮状态和固定化状态的基因工程菌BL21对有机磷混合农药废水的降解特性.工程菌能快速、高效地降解有机磷混合农药,其最适底物是对硫磷,而马拉硫磷不能被工程菌降解.不同农药降解速率的差别造成了不同有机磷农药的降解过程需要用不同的动力学模型来描述.比较固定化状态和悬浮状态的工程菌的降解效果可知,固定化工程菌的降解活性较后者明显降低,其比降解速率大约仅为后者的20%.考察固定化工程菌长期运行的效果,发现其降解活性保存良好,工程菌稳定性大大提高,未出现固定化细胞溶涨、破碎现象.固定化后,工程菌的比降解速率虽然比悬浮工程菌降低了,但固定化工程菌更适用于长期运行的废水处理系统.

Degradation of organophosphorus pesticides mixtures using genetically engineered Escherichia coli BL21

The suspended genetically engineered Escherichia coli BL21 and the PVA-immobilized cell were used in degrading of organophosphorus pesticides (OPs) mixtures. The strain rapidly degraded 1 000 mg/L of OPs mixtures, and parathion was the most favorite substrate of the five OPs investigated in this study. Malathion could not be degraded by the strain. The specific biodegradation rate was quite dissimilar for different kinds of OPs, which made the degradation process of different OPs to be described with different sorts of degradation kinetics. After immobilization, the degradation capacity were decreased dramatically, and the specific degradation rate of immobilized cell was only about 20% of that of suspended culture. The immobilized cells was also investigated with the long-term operation, and it retained 85% of degradation capability over 50-days of usage and storage. No undesirable softening of the gel or its dissolution were happened. Immobilized cells were more suitable for the wastewater treatment system than the suspended cells, although the specific degradation rates of suspended cultures were much higher.