Jiang Jiandong, Zhang Ruifu, Li Rong, Gu Ji-Dong, Li Shunpeng
Department of Microbiology, MOA Key Lab of Microbiological Engineering of Agricultural Environment, Nanjing Agricultural University, Nanjing 210095, P.R. China.
Biodegradation. 2007 Aug;18(4):403-12. doi: 10.1007/s10532-006-9075-5. Epub 2006 Nov 8.
A genetically engineered microorganism (GEM) capable of simultaneous degrading methyl parathion (MP) and carbofuran was successfully constructed by random insertion of a methyl parathion hydrolase gene (mpd) into the chromosome of a carbofuran degrading Sphingomonas sp. CDS-1 with the mini-transposon system. The GEM constructed was relatively stable and cell viability and original degrading characteristic was not affected compared with the original recipient CDS-1. The effects of temperature, initial pH value, inoculum size and alternative carbon source on the biodegradation of MP and carbofuran were investigated. GEM cells could degrade MP and carbofuran efficiently in a relatively broad range of temperatures from 20 to 30 degrees C, initial pH values from 6.0 to 9.0, and with all initial inoculation cell densities (10(5)-10(7) CFU ml(-1)), even if alternative glucose existed. The optimal temperature and initial pH value for GEM cells to simultaneously degrade MP and carbofuran was at 30 degrees C and at pH 7.0. The removal of MP and carbofuran by GEM cells in sterile and non-sterile soil were also studied. In both soil samples, 50 mg kg(-1) MP and 25 mg kg(-1) carbofuran could be degraded to an undetectable level within 25 days even if there were indigenous microbial competition and carbon sources effect. In sterile soil, the biodegradation rates of MP and carbofuran were faster, and the decline of the inoculated GEM cells was slower compared with that in non-sterile soil. The GEM constructed in this study was potential useful for pesticides bioremediation in natural environment.
通过利用微型转座子系统将甲基对硫磷水解酶基因（mpd）随机插入到一株能够降解克百威的鞘氨醇单胞菌属菌株CDS - 1的染色体中，成功构建了一种能够同时降解甲基对硫磷（MP）和克百威的基因工程微生物（GEM）。所构建的GEM相对稳定，与原始受体CDS - 1相比，细胞活力和原始降解特性未受影响。研究了温度、初始pH值、接种量和替代碳源对MP和克百威生物降解的影响。GEM细胞能够在20至30摄氏度的较宽温度范围内、6.0至9.0的初始pH值以及所有初始接种细胞密度（10(5)-10(7) CFU ml(-1)）下高效降解MP和克百威，即使存在替代葡萄糖也是如此。GEM细胞同时降解MP和克百威的最佳温度和初始pH值分别为30摄氏度和pH 7.0。还研究了GEM细胞在无菌和非无菌土壤中对MP和克百威的去除情况。在这两种土壤样品中，即使存在本地微生物竞争和碳源影响，50 mg kg(-1)的MP和25 mg kg(-1)的克百威在25天内也可降解至检测不到的水平。在无菌土壤中，MP和克百威的生物降解速率更快，与非无菌土壤相比，接种的GEM细胞数量下降更慢。本研究构建的GEM在自然环境中农药生物修复方面具有潜在应用价值。
