邻氯苯酚抑制光合细菌1D生长的毒性效应

Toxic effect of o-chlorophenol on photosynthetic bacteria growth

以农药厂排污口下游底泥分离筛选得到的红假单胞菌Rhodopseudomonas sp.1D为研究对象,考察了不同质量浓度邻氯苯酚对1D生长和脱氢酶活性的影响。实验结果表明,随着培养液中邻氯苯酚质量浓度的增加,1D的生长明显受到抑制,当培养液中邻氯苯酚质量浓度为800mg·L-1时,1D的生长几乎被完全抑制。菌株1D的脱氢酶活性随着邻氯苯酚质量浓度增加而明显降低,当邻氯苯酚质量浓度为570mg·L-1时,1D的脱氢酶活性下降程度为100%。在此基础上进一步运用化学品对水生生物急性毒性试验的标准方法研究了邻氯苯酚对1D的毒性效应。结果表明,邻氯苯酚对1D生长的安全质量浓度为9.375mg·L-1。通过与湖水中微生物的半致死质量浓度96LC50进行比较可知,1D对毒物邻氯苯酚的耐受性高于自然水体中混合微生物对邻氯苯酚的耐受性。

A strain ofRhodopseudomonas sp. named 1D was isolated and screened from the shallow substrate sludge in downstream side of the sewage outfall of a insecticide factory, and the effect ofo-chlorophenol with different mass concentration on the growth of 1D and dehydrogenase activity of the strain was studied respectively. The growth of 1D was obviously inhibited with the increase of o-chlorophenol mass concentraion in culture medium. In fact, 1D almost all stopped growing when o-chlorophenol mass concentra- tion in culture medium reached 800mg·L-1. The decrease of 1D dehydrogenase activity correlated to the increase of o-chlorophenol mass concentration. Our experiments prove that, dehydrogenase of 1D completely lost activity when the o-chlorophenol mass con- centration was up to 570 mg·L-1. The results gained by using a standard method of aquatic bioassay for evaluating the toxicity of chemicals in our experiments also showed that the safe concentration of o-chlorophenol in culture medium to the strain ID growth was 9.375mg·L-1. Furthermore, the median lethal concentration （LC50） of o-chlorophenol affected to the strain 1D was 265.9 mg·L-1, which was much more high than LC50 to the mixed microorganism in natural waters.