Isolation and characterization of facultative mixotrophic ammonia-oxidizing bacteria from constructed wetlands  

作　　者：Soulwène Kouki Neila Saidi Fadhel M'hiri Houda Nasr Hanène Cherif Hadda Ouzari Abdennaceur Hassen 

机构地区：[1]Laboratory of Treatment and Water Recycling,Centre of Research and Water Technologies,Technopark of Borj-Cedria,BP 273,8020,Soliman,Tunisia [2]Unit of Transfer and Innovation Technologies,Tunis International Centre for Environmental Technologies,Boulevard of the Leader Yasser Arafat,La Charguia,1080,Tunis,Tunisia [3]Laboratory of Microbiology and Active Biomolecules,Department of Biology,Faculty of Sciences of Tunis,2092,Tunis,Tunisia

出　　处：《Journal of Environmental Sciences》2011年第10期1699-1708,共10页环境科学学报（英文版）

基　　金：supported by a grant from the Tunisian Higher Education and Scientific Research Ministry

摘　　要：Autotrophic ammonia-oxidizing bacteria （AOB） have been widely studied in constructed wetlands systems, while mixotrophic AOB have been less thoroughly examined. Heterotrophic bacteria were isolated from wastewater and rhizospheres of macrophytes of constructed wetlands, and then cultivated in a mixotrophic medium containing ammonium and acetic acid. A molecular characterization was accomplished using ITS-PCR amplification, and phylogenetic analysis based on 16S rRNA gene Sequences. Results showed the presence of 35 bacteria, among 400 initially heterotrophic isolates, that were able to remove ammonia. These 35 isolates were classified into 10 genetically different groups based on ITS pattern. Then, a collection of 10 isolates were selected because of their relatively high ammonia removal efficiencies （ARE≥ 80%） and their phylogenetic diversity. In conditions of mixotrophy, these strains were shown to be able to grow （increase of optical density OD660 during incubation with assimilation of nitrogen into cellular biomass） and to oxidize ammonia （important ammonia oxidation efficiencies, AOE between 79% and 87%）. Among these facultative mixotrophic AOB, four isolates were genetically related to Firmicutes （Bacillus and Exiguobacterium）, three isolates were affiliated to Actinobacteria （Arthrobacter） and three other isolates were associated with Proteobacteria （Pseudomonas, Ochrobactrum and Bordetella）.Autotrophic ammonia-oxidizing bacteria （AOB） have been widely studied in constructed wetlands systems, while mixotrophic AOB have been less thoroughly examined. Heterotrophic bacteria were isolated from wastewater and rhizospheres of macrophytes of constructed wetlands, and then cultivated in a mixotrophic medium containing ammonium and acetic acid. A molecular characterization was accomplished using ITS-PCR amplification, and phylogenetic analysis based on 16S rRNA gene Sequences. Results showed the presence of 35 bacteria, among 400 initially heterotrophic isolates, that were able to remove ammonia. These 35 isolates were classified into 10 genetically different groups based on ITS pattern. Then, a collection of 10 isolates were selected because of their relatively high ammonia removal efficiencies （ARE≥ 80%） and their phylogenetic diversity. In conditions of mixotrophy, these strains were shown to be able to grow （increase of optical density OD660 during incubation with assimilation of nitrogen into cellular biomass） and to oxidize ammonia （important ammonia oxidation efficiencies, AOE between 79% and 87%）. Among these facultative mixotrophic AOB, four isolates were genetically related to Firmicutes （Bacillus and Exiguobacterium）, three isolates were affiliated to Actinobacteria （Arthrobacter） and three other isolates were associated with Proteobacteria （Pseudomonas, Ochrobactrum and Bordetella）.

关 键 词：ammonia-oxidizing bacteria mixotroph constructed wetlands ammonia oxidation macrophytes＇ rhizosphere 

分 类 号：X172[环境科学与工程—环境科学]