Molecular characterization of bacterial community in aerobic granular sludge stressed by pentachlorophenol

To characterize the effects of pentachlorophenol (PCP) on the performance and microbial community of aerobic granular sludge in sequencing batch reactor (SBR), the web-based terminal restriction fragment length polymorphism (T-RFLP) and real-time PCR (RT- PCR) techniques were used to explore the bacterial community structure. When PCP increased from 0 to 50 mg/L, the COD removal rate changed little, while the ammonia removal rate dropped from 100% to 64.9%. The results of molecular characterization showed t...

Comparison of Bacterioplankton Communities in Three Heavily Polluted Streams in China

Objective To compare the bacterioplankton communities in streams exposed to pollution of different types. Methods The bacterioplankton communities in three selected heavily polluted streams were investigated by using terminal‐restriction fragment length polymorphism （T‐RFLP） analysis in combination with 16S rRNA gene clone library analysis. Results Both T‐RFLP and 16S rRNA gene clone library revealed a great difference in bacterioplankton community composition in the different streams. Conclusion This work might provide some new insights into bioremediation of heavily polluted streams.

Spatial and seasonal variations in bacterial communities of the Yellow Sea by T-RFLP analysis

Four typical coastal sites(rocky shore,sandy shore,mud flat shore,and artificial harbor)at the Yellow Sea were chosen to investigate the spatial and seasonal variations in bacterial communities.This was accomplished by using terminal restriction fragment length polymorphism(T-RFLP)analysis of PCR amplified 16S rDNA fragments.Two kinds of tetrameric restriction enzymes,HhaI and MspI,were used in the experiment to depict the bacterial community diversity in different marine environments.It was found that the community compositions digested by the two enzymes separately were different.However,the results of bacterial community diversity derived from them were similar.The MDA analysis results of T-RFLP profiles coming from HhaI and MspI both exhibited a significant seasonal community shift for bacteria and a relatively low spatial variation among the four locations.With HhaI as the sample,the pair wise Ttests also revealed that variations were minor between each pair of marine environments,with R ranging from 0.198 to 0.349.However,the bacterial community structure in the mud flat site depicted a larger difference than each of the other three sites(R ranging from 0.282 to 0.349).

Community dynamics of ammonia oxidizing bacteria in a fullscale wastewater treatment system with nitrification stability

To determine whether the functional stability of nitrification was correlated to a stable community structure of ammonia oxidizing bacteria(AOB)in a fullscale wastewater treatment plant,the AOB community dynamics in a wastewater treatment system was monitored over one year.The community dynamics were investigated using specific PCR followed by terminal restriction fragment length polymorphism(T-RFLP)analysis of the amoA gene.The T-RFLP results indicated that during the period of nitrification stability,the AOB community structure in the full-scale wastewater treatment system was relatively stable,and the average change rate every 15 d of the system was 6.6%±5.8%.The phylogenetic analysis of the cloned amoA gene showed clearly that the dominant AOB in the system was Nitrosomonas spp.The results of this study indicated that throughout the study period,the AOB community structure was relatively stable in the full-scale wastewater treatment system with functional stability of nitrification.

Diversity and vertical distributions of sediment bacteria in an urban river contaminated by nutrients and heavy metals

The aim of this study was to investigate the benthic bacterial communities in different depths of an urban river sediment accumulated with high concentrations of nutrients and metals. Vertical distributions of bacterial operational taxonomic units （OTUs） and chemical para- meters （nutrients： NH4＋, NO3, dissolved organic carbon, and acid volatile sulfur; metals： Fe, Zn, and Cu） were characterized in 30 cm sediment cores. The bacterial OTUs were measured using the terminal restriction fragment length polymorphism analysis. Biodiversity indexes and multivariate statistical analyses were used to characterize the spatial distributions of microbial diversity in response to the environmental parameters. Results showed that concentrations of the nutrients and metals in this river sediment were higher than those in similar studies. Furthermore, high microbial richness and diversity appeared in the sediment. The diversity did not vary obviously in the whole sediment profile. The change of the diversity indexes and the affiliations of the OTUs showed that the top layer had different bacterial community structure from deeper layers due to the hydrological disturbance and redox change in the surface sediment. The dominant bacterial OTUs ubiquitously existed in the deeper sediment layers （5-27 cm） corresponding to the distributions of the nutrients and metals. With much higher diversity than the dominant OTUs, the minor bacterial assemblages varied with depths, which might be affected by the sedimentation process and the environmental competition pressure.