Gradients in the taxonomic composition of different microbial systems: comparison between biofilms for advanced waste treatment and lake sediments

Abstract

The application of in situ hybridization with group specific oligonucleotide probes detected by epifluorescence microscopy and confocal laser scanning microscopy was tested to identify spatial gradients in the distribution of bacteria in biofilms of plug flow reactors and in the bottom sediment layer of a drinking water reservoir. The two tubular biofilm reactors were fed with the effluent from a full scale biological wastewater treatment plant to which were added the chlorophenols whole degradation was being investigated. One was operated as a continuous-flow reactor and the other as a sequencing batch reactor. The vertical gradients in the microbial colonization of the sediment were analyzed by means of glass slides exposed to the sediment. In the biofilms of both reactors the beta-Proteobacteria dominated. The Cytophaga-Flavobacterium group and the Gram-positive bacteria were also abundant. Only small amounts of gamma-bacteria could be detected. This is contrary to findings using traditional cultivation methods. Unlike the biofilms in the reactor, the bacterial Aufwuchs on the glass slides in the sediment presented a surprising diversity of morphological types and size classes of bacteria.

Characterization and performance of constructed nitrifying biofilms during nitrogen bioremediation of a wastewater effluent

“…It is accepted that boundary layers protect the microorganisms of biofilms against losses by flushing, shear stress, and inhibitory substances. That is why microorganisms structured in support matrix are preferred than in a system with suspended biomass and a high flow-through rate [5,28]. Biofilm systems allow slow growing nitrifying bacteria to remain in the reactors by their attached growth, which improves nitrogen removal from wastewater [24].…”

“…Although extensive studies through a combination of microcopy, selective culture, microprobes, and molecular methods have been carried out on nitrifying biofilms in different supports [6,10,28], little information is available on the molecular characterization and performance of constructed nitrifying biofilms on low-density polyester Dacron support during the bioremediation of a wastewater effluent.…”

Effects of temperature on nutrient removal performance of a pilot-scale ABR/MBR combined process for raw wastewater treatment

“…For in situ hybridization, the eight samples were taken from the MBR tank and treated as described by Roske et al [11]. All in situ hybridizations were performed according to the standard hybridization protocol [12].…”

Mechanism of efficient nutrient removal and microbial analysis of a combined anaerobic baffled reactor–membrane bioreactor process

“…For in situ hybridization, the samples were taken from each compartment and treated as described by Röske et al (1998). All in situ hybridizations were performed according to the standard hybridization protocol (Amann 1995).…”