大同盆地高砷地下水中可培养耐砷微生物的群落结构

大同盆地是典型的高砷地下水分布区。利用从地方性砷中毒严重病区山阴县采集的高砷地下水样品,用稀释培养法实验研究了外加砷源对地下水中微生物数量的影响;同时基于生物学可培养法和16SrDNA序列比对法,选取代表性高砷水样,研究了耐砷菌的种群特征。结果表明,外加砷源对地下水中微生物数量影响显著,高浓度砷会抑制大部分微生物生长,使微生物数量减少;低浓度砷对微生物生长具有一定促进作用。通过多次分离、纯化从3个不同砷含量地下水样中分离到多株砷抗性菌,经鉴定属于主要为Bacillus、Pseudomonas、Paenibacillus、Aeromonas、Enterobacter5个属。从RDP(RibosomalDatabaseProject)分析显示3个水样可培养微生物组成不同,都有生存能力强能够耐低浓度NaAsO2的Bacillales,优势耐砷菌是γ-proteobacteria,其中Enterbacter具有耐高浓度NaAsO2的能力。

Community Structure of Culturable Arsenic-Resistant Microorganisms in High Arsenic Groundwater of Datong Basin

Datong Basin is a typical area with high-arsenic groundwater. High As groundwater was sampled from Shanyin County which is one of the areas of most serious arsenicosis. The effect of arsenic with various concentrations on the microorganisms quantity was investigated by dilution culture method. Also, the characteristics of arsenic-resistant bacteria populations were studied by water samples selected from some representative high-arsenic areas using 16S rDNA sequence comparison method and biology culture method. Results indicated that applied arsenic obviously affected the quantity of microorganisms in groundwater. High-concentration As could inhibit the growth of most microbes so that the quantity of microorganisms decreased, while low-concentration arsenic promoted the growth of the microorganism. Arsenic-resistant bacteria were isolated from three groundwater samples with different arsenic contents through multiply separation and purification. The phylogenetic analysis indicated that the cultural strains belonged to the genus Bacillus, Pseudomonas, Paenibacillus, Aeromonas, Enterobacter. RDP analysis showed that three groundwater samples have different cultured microbial components. Bacillales exist in all of groundwater samples, which have strong tolerance to low concentration NaAsO2. Dominated arsenic-resistant bacteria is γ-proteobacteria. Enterbacter has the ability to resist high concentration NaAsO2.