【摘要】 从受DDT污染的土壤中采取土样,经驯化富集后分离得到一株能够降解DDT的革兰氏阳性细菌W-1,通过生理生化鉴定,结合16SrDNA聚类分析,将W-1鉴定为短波单胞菌属(Brevunmdimonas sp.)。采用室内培养方法,研究了该菌株的降解特性。结果表明,W-1能在含10mg·L-1DDT的基础盐液体培养基中降解DDT,10d后降解率达到67.4%。添加葡萄糖可以促进W-1菌体生长及对DDT的降解;结构类似物联苯和4-氯苯甲酸能抑制W-1对DDT的降解,而添加表面活性剂Triton100和Tween20均可以提高W-1对DDT的降解。该菌株在250mL摇瓶中降解DDT的最适温度为30℃,最适pH值为8.0。更多还原

【Abstract】 DDT [1,1,1-trichloro-2,2-bis-(p-chlorophenyl) ethane] resides in soil, bioaccumulate and biomagnify along the food chain and pose risks to ecological components including human beings. Bioremediation is a potential option for the degradation of DDT in soils and slurries. There are very few studies addressing the degradation of DDT by pure cultures. A Gram-negative bacterial strain W-1 was isolated after domestication from DDT contaminated soil, which could utilize DDT as the sole carbon source for growth. This strain was identified as Brevunmdimonas sp. based on morphology, physiological tests, a partial analysis of the 16S rRNA gene and phylogenetic characteristics. The optimal conditions (temperature, pH value, inoculating dose, cultural time and added nutrition) for W-1 to degrade DDT were studied. In a shaky flask containing 10 mg·L-1 DDT, the degrading rate of W-1 on DDT was recorded highest at temperature 30 ℃, pH 8.0. The addition of 10 mg·L-1 glucose or surfactant, i.e., Triton100 or Tween20, to the culture medium increased the bacterial mass and the degradation of DDT. The structural homolog biphenyl and 4-chlorobenzoate (4-CBA) were found to inhibit the growth of bacterial cells and the degradation of DDT. This microbial culture has great potential utility for the bioremediation of waste waster or soil contaminated with DDT and its analogues.更多还原