Cycoń Mariusz, Wójcik Marcin, Piotrowska-Seget Zofia
Department of Microbiology, Faculty of Pharmacy, Medical University of Silesia, Jagiellońska 4, 41-200 Sosnowiec, Poland.
Chemosphere. 2009 Jul;76(4):494-501. doi: 10.1016/j.chemosphere.2009.03.023. Epub 2009 Apr 7.
An enrichment culture technique was used for the isolation of bacteria responsible for biodegradation of diazinon in soil. Three bacterial strains were screened and identified by MIDI-FAME profiling as Serratia liquefaciens, Serratia marcescens and Pseudomonas sp. All isolates were able to grow in mineral salt medium (MSM) supplemented with diazinon (50 mgL(-1)) as a sole carbon source, and within 14d 80-92% of the initial dose of insecticide was degraded by the isolates and their consortium. Degradation of diazinon was accelerated when MSM was supplemented with glucose. However, this process was linked with the decrease of pH values, after glucose utilization. Studies on biodegradation in sterilized soil showed that isolates and their consortium exhibited efficient degradation of insecticide (100mg kg(-1) soil) with a rate constant of 0.032-0.085d(-1), and DT(50) for diazinon was ranged from 11.5d to 24.5d. In contrast, degradation of insecticide in non-sterilized soil, non-supplemented earlier with diazinon, was characterized by a rate constant of 0.014d(-1) and the 7-d lag phase, during which only 2% of applied dose was degraded. The results suggested a strong correlation between microbial activity and chemical processes during diazinon degradation. Moreover, isolated bacterial strains may have potential for use in bioremediation of diazinon-contaminated soils.
采用富集培养技术从土壤中分离出负责降解二嗪农的细菌。通过MIDI-FAME分析筛选并鉴定出三株细菌,分别为液化沙雷氏菌、粘质沙雷氏菌和假单胞菌属。所有分离菌株都能够在添加二嗪农(50 mgL(-1))作为唯一碳源的矿物盐培养基(MSM)中生长,在14天内,分离菌株及其混合菌群降解了80%-92%的初始剂量杀虫剂。当MSM中添加葡萄糖时,二嗪农的降解加速。然而,在葡萄糖被利用后,这个过程与pH值的降低有关。在灭菌土壤中的生物降解研究表明,分离菌株及其混合菌群对杀虫剂(100mg kg(-1)土壤)表现出高效降解,降解速率常数为0.032-0.085d(-1),二嗪农的DT(50)范围为11.5d至24.5d。相比之下,在未预先添加二嗪农的未灭菌土壤中,杀虫剂的降解速率常数为0.014d(-1),有7天的滞后期,在此期间仅降解了2%的施用量。结果表明,二嗪农降解过程中微生物活性与化学过程之间存在很强的相关性。此外,分离出的细菌菌株可能具有用于二嗪农污染土壤生物修复的潜力。