Krishna K Rama, Philip Ligy
Department of Civil Engineering, Indian Institute of Technology Madras, Chennai, India.
J Environ Sci Health B. 2009 Jan;44(1):18-30. doi: 10.1080/03601230802519520.
This paper discusses the degradation kinetics of mixed (lindane, methyl parathion and carbofuran) pesticides by mixed pesticide enriched cultures (MEC) under various environmental conditions. The bacterial strains isolated from the mixed microbial consortium were identified as Pseudomonas aeruginosa (MTCC 9236), Bacillus sp. (MTCC 9235) and Chryseobacterium joostei (MTCC 9237). Batch studies were conducted to estimate the biokinetic parameters like the maximum specific growth rate (mu(max)), Yield Coefficient (Y(T)), half saturation concentration (K(s)) and inhibition concentration (Ki) for individual and mixed pesticide enriched cultures. The cultures enriched in a particular pollutant always showed high growth rate and low inhibition in that particular pollutant compared to MEC. After seven weeks of incubation, mixed pesticide enriched cultures were able to degrade 72% lindane, 95% carbofuran and 100% of methyl parathion in facultative co-metabolic conditions. In aerobic systems, degradation efficiencies of lindane methyl parathion and carbofuran were increased by the addition of 2g L(- 1) of dextrose. Though many metabolic compounds of mixed pesticides were observed at different time intervals, none of the metabolites were persistent. Based on the observed metabolites, a degradation pathway was postulated for different pesticides under various environmental conditions.
本文探讨了混合农药富集培养物（MEC）在不同环境条件下对混合（林丹、甲基对硫磷和呋喃丹）农药的降解动力学。从混合微生物群落中分离出的细菌菌株被鉴定为铜绿假单胞菌（MTCC 9236）、芽孢杆菌属（MTCC 9235）和乔氏金黄杆菌（MTCC 9237）。进行了批次研究，以估计单个和混合农药富集培养物的生物动力学参数，如最大比生长速率（μ(max)）、产率系数（Y(T)）、半饱和浓度（K(s)）和抑制浓度（Ki）。与MEC相比，富集特定污染物的培养物在该特定污染物中总是表现出高生长速率和低抑制作用。经过七周的培养，混合农药富集培养物在兼性共代谢条件下能够降解72%的林丹、95%的呋喃丹和100%的甲基对硫磷。在好氧系统中，添加2g L(-1)的葡萄糖可提高林丹、甲基对硫磷和呋喃丹的降解效率。尽管在不同时间间隔观察到了混合农药的许多代谢化合物，但没有一种代谢物是持久的。基于观察到的代谢物，推测了不同农药在不同环境条件下的降解途径。
