水体中的微生物对壬基酚聚氧乙烯醚的生物降解

BIODEGRADATION OF NONYLPHENOL ETHOXYLATES BY MICROORGANISMS IN SEWAGE

为有效控制水体中壬基酚聚氧乙烯醚的污染 ,以芽孢杆菌、假单胞菌、诺卡氏菌和假丝酵母为试验菌株 ,研究了其对壬基酚聚氧乙烯醚的生物降解特性。试验结果表明 ,4菌株在一定的条件下对水体中的壬基酚聚氧乙烯醚均有一定的降解率。若按体积比 1∶ 2∶ 1∶ 1的比例将四菌株组合成复合菌群 ,可大幅度提高处理效率 ,降解率可达 61 %。应用该复合菌对影响壬基酚聚氧乙烯醚降解的各种主要因素进行了研究 ,发现降解菌在θ为 2 5～ 30℃ ,p H值为 5.5～ 8.5及壬基酚聚氧乙烯醚初始质量浓度ρ(NP1 0 EO)为 0～ 1 0 0 mg/ L范围内保持高活性 ;当底物质量浓度大于 1 0 0 mg/ L 时 ,平均降解速率线性下降 ;当接种量标准为 1× 1 0 8CFU/ m L (即菌悬液 /反应液为1 0 % )

The present article aims to study how to degrade the nonylphenol ethoxylates so as to improve the treatment of sewage in the sewage purifying plants. As is known, Nenol ethoxylates is a kind of non ion surface active agent. Once entering into the water, it has acute toxicity and therefore brings detrimental estrogenic effect on the aquatic creatures. In addition, when it is accumulated in human bodies or aquatic creatures, it may cause threat to human health and the death of the aquatic creatures. The statistics shows that the treatment efficiency of sewage in the sewage treatment plants can be decreased to about sixty percent. In order to reduce the harmful influence mentioned above, four strains have been used in our experiments, including Bacillus sp.,Pseudomonas sp., Norcardia sp. and Candida sp. in hoping to reduce the pollution caused by the nonylphenol ethoxylates in the sewage. The experimental results of ours indicate that under the optimum conditions nonylphenol ethoxylates could be degraded by the four strains. The ratio of the compound strains of Bacillus sp. to Pseudomonas sp. to Norcardia sp. to Candida sp. being 1∶2∶1∶1. Actually, it is still possible to increase the treatment efficiency much greater. The actual degradation rate of nonylphenol ethoxylates proves to be able to reach 61%. At the same time, the main factors affecting the biodegradation has also been studied. The biodegradation rate has also been was proved to the maximum when the initial concentration of nonylphenol ethoxylates rangs over 0 and 100 mg/L at pH 5.5~8.5 and 25~30 ℃.The average degradation rate proves to be decreasing in a linear form when the concentration is beyond 100 mg/L. It can be considered to be highly efficient if the amount of the microorganism in the solution with nonylphenol ethoxylates can reach 1×10 8 CFU/mL (10 mL bacteria degraded 100 mL solution containing nonylphenol ethoxylates). It remains to be studied further as to the biodegradation mechanism and the relationship between the different microorganisms during the treatment system though the biodegradation features of nonylphenol ethoxylates with Bacillus sp., Pseudomonas sp., Norcardia sp. and Candida sp. has also been discussed.