三种高盐苯胺废水对细菌群落结构的影响

采用PCR-DGGE技术分析了含有不同CODCr、盐、总磷、氨态氮、氯离子、苯胺浓度的3种高盐苯胺废水(1#、2#、3#)驯化的细菌群落结构变化,从分子水平阐明高盐苯胺废水对细菌群落结构的影响.结果表明,不同浓度高盐苯胺废水驯化过程中,2#废水随着浓度的升高,细菌群落多样性逐渐下降;1#废水驯化的细菌群落多样性指数以5%的废水最高,20%与40%的废水最低;3#废水驯化的细菌群落多样性指数以0%和5%的废水最高,20%的废水最低.不同废水对细菌群落多样性有不同的影响,表明适应和突变是驯化过程中细菌适应环境的一个重要作用力.3种不同高盐苯胺废水驯化的细菌群落多样性指数与CODCr、盐含量之间均存在显著负相关,但与氯离子和苯胺含量之间相关不显著.3种废水驯化的细菌的遗传多样性有较大差异,多态位点百分率、Shannon's信息指数和Nei's指数均以3#废水最高,1#废水次之,2#废水最低.但遗传多样性指标与CODCr、盐含量、氯离子和苯胺含量之间均相关不显著.可知细菌群落多样性的变化是由于废水中所含的污染物质的综合作用结果,而非单一的因素.3种废水的5种不同浓度驯化细菌之间的平均遗传距离分别为0.4724、0.4350和0.4902,其中3#废水驯化的细菌遗传变异最大.聚类分析表明,5种不同浓度高盐苯胺废水驯化细菌均可明显地分为两组.1#和2#废水均为0%、5%和10%废水驯化细菌聚成一组,而20%和40%废水驯化细菌聚成另一组; 3#废水为0%与5%废水驯化细菌聚成一组,而10%、20%和40%废水驯化细菌聚成另一组.不同的废水由于水质背景值不同,选择压力不同,导致细菌突变的阈值不同,使得诱导细菌变异程度不同,从而最终引起细菌群落结构的不同.驯化过程中微生物种群的变化使得整个微生物群落能够快速适应外部环境变化.

Impacts of three different hypersaline aniline\|containing waste water compositions on the bacterial community structure

In order to reveal the molecular mechanism of how high-salinity aniline-containing waste water affects the bacterial community structure, the PCR-DGGE technique was used to analyse the change of the bacterial community structure acclimated to three different hypersaline aniline-containing waste waters, with different content of chemical oxygen demand (COD), salts, phosphorus, nitrogen, chloride and aniline. The results were as follows. During acclimation to No. 2 waste water, the bacterial community diversity indices decreased when the concentration of waste water increased. During acclimation to No. 1 waste water, bacterial diversity was the highest in 5% waste water, while those in 20% and 40% were the lowest. During acclimation to No. 3 waste water, diversities in 0% and 5% of waste water were the highest, while those in 20% were the lowest. The different waste water compositions had different effects on the bacterial community diversity, indicating that adaptation and mutation might play important roles in the relationship between bacteria and their environment. The bacterial community diversity indices correlated negatively with the concentration of COD and salinity, but not with the concentration of chloride and aniline. The genetic variation of bacteria acclimated to three different high-salinity aniline-containing waste waters was very high: the percentage of polymorphic bands, Shannon′s informative index and Nei′s gene diversity index of bacteria acclimated to No. 3 waste water was the highest, while those of bacteria acclimated to No. 1 waste water took second place and those of bacteria acclimated to No. 2 waste water was the lowest. The genetic diversity indices were not significantly correlated with the concentration of COD, salinity, chloride or aniline. This suggested that the change of the bacterial community diversity might not due to a single factor rather to the integrated effects of all the contaminants in the waste water. The pairwise genetic distance between bacteria acclimated to five different concentrations of three different waste waters averaged 0.4724、0.4350 and 0.4902, indicating that the genetic variation induced to No. 3 waste water was the highest. Bacteria acclimated to five different concentrations of waste water could be clustered into two groups. During the acclimation to No. 1 and No. 2 waste water, bacteria acclimated to 0%, 5% and 10% waste water were clustered into one group while those acclimated by 20% and 40% wastewater were clustered into another group. Bacteria acclimated to 0% and 5% of No. 3 waste water were clustered into one group and those acclimated to 10%, 20% and 40% wastewater were clustered into another group. The change of the microbial communities could indicate a rapid adaptation of microorganisms to the change of the external environment.