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The studies related to a mixed culture dechlorinating 1,2-dichloroethane (1,2-DCA) to ethene which was enriched from groundwater and subjected to long-term contamination is presented.

The tdnQ gene that degrades aniline and related compounds in the Comamonadaceae is very diverse. The tdnQ sequences of I2, LME1, B8c, and CA28 are closely related but the sequences of BN3.1 and Pseudomonas putida UCC22 are only 83% similar to the other sequences.

Research has been conducted on the Comamonas testosteroni 12 strain. Results indicate that this strain can mineralize 3-chloroaniline.

The impact of the mesophilic and thermophilic anaerobic digestion of pig slurry on the inactivation of the murine norovirus 1 is discussed. The temperature and matrix are shown to have various effects on the viral titler of the compounds.

Several molecular techniques are employed for the characterization of different communities of anodes that are obtained from the sediment microbial fuel cells. The various effects of electrical circuitry and sediment matrix on the development of these anodes are also discussed.

The relationship between oxygen-limited autotrophic nitrification-denitrification (OLAND) aggregate size, aerobic ammonium-oxidizing bacteria (AerAOB) and anoxic ammonium-oxidizing bacteria (AnAOB) abundance and the activity balance is studied. New pathways are proposed for aggregation and granulation by relating (dis)similarities in aggregate size distribution, morphology and architecture to differences in reactor inoculation and operation.

Lactobacillus fermentum has served as a reducing agent and bacterial carrier matrix for zerovalent silver nanoparticles (biogenic [Ag.sup.0]). The analysis has shown the antiviral efficacy of extracellular biogenic [Ag.sup.0] and its promising opportunities for continuous water disinfection.

An experimental study is performed with three rumen-fistulated dairy cows receiving a concentrate containing algae for 20 days to relate the accumulation of biohydrogenation intermediates with shifts in Butyrivibrio spp. in the rumen dairy cows. The clones associated with altered DGGE bands indicated that dietary algae affected noncultivated species, which cluster between the genus Butyrivibrio and the genus Pseudobutyrivibrio and hence as-yet-uncultivated bacteria are involved in [C.sub.18:0] production.

The in vitro conversion of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) into its microbial derivative by fecal samples from human volunteers is examined. Abiotic synthesis of PhIP-M1 and quantification of the glycerol metabolite 3-hydroxypropionaldehyde (3-HPA) has shown that the anaerobic fermentation of glycerol via 3-HPA is the critical bacterial transformation process responsible for the formation of PhIP-M1.

The bacterial reactor dynamics are characterized by a rate of change as a function of time and the internal community structure is evaluated by Pareto-Lorenz evenness distribution curves. The studies have shown that only a small group of AOB species have played a numerically dominant role in the nitritation of both reactors, a sequential batch reactor (SBR) and a membrane bioreactor (MBR).

An evolutionary algorithm is applied to study the complex interactions between medium parameters and their effects on the isolation of denitrifying bacteria, both in number and in diversity. One hundred ninety-nine denitrifiers are isolated, the majority of which belonged to the Betaproteobacteria (50.4%) and the Alphaproteobacteria (36.8%).

A study was conducted to investigate the feasibility of a slow-release inoculation approach as a bioaugmentation strategy for the degradation of lindane (gamma-hexacholorocyclohexane). It was observed that a slow-release inoculation approach can enhance the pollutant removal and can prolong the degrading activity in comparison with traditional inoculation strategies.

The analyses of whether a bacterial community, either suspended or attached to an electrode, can evolve in a microbial fuel cell to bring about higher power output and to identify species responsible for the electricity generation are described. The enrichment procedure, irrespective of whether only attached or suspended bacteria were examined, selected for organisms capable of mediating the electron transfer either by direct bacterial transfer or by excretion of redox components.

The authors have investigated microbial calcium carbonate preciptation. They report that bacterial isolates precipitate different crystal aggregates in a repeatable manner when cultivated on semisolid media under the same growth conditions, and that primary mechanisms responsible for the diversity in crystal aggregate morphology have been characterized.

Results indicate that a single isolate, Variovorax sp. strain WDL1 can degrade linuron, which is enhanced by synergistic interaction with the other strains forming the bacterial consortium. Data show that Variovorax sp. strain WDL1 uses linuron as its sole source of carbon, nitrogen, and energy.

Research shows bioaugmentation of wastewater reactors with the 3-chloroaniline degrading bacteria protects the nitrifying bacterial community leading to faster recoveries from 3-chloroaniline toxic shock. The inoculated bacteria help degrade the toxic chlorinated organics coming to the wastewater streams from industrial discharges.

Biofilms within drinking water distribution systems serve as a habitat for drinking water microorganisms. However, biofilms can negatively impact drinking water quality by causing water discoloration and deterioration and can be a reservoir for unwanted microorganisms. In this study, we investigated whether indicator organisms for drinking water quality, such as coliforms, can settle in mature drinking water biofilms. Therefore, a biofilm monitor consisting of glass rings was used to grow and sample drinking water biofilms. Two mature drinking water biofilms were characterized by flow cytometry, ATP measurements, confocal laser scanning microscopy, and 16S rRNA sequencing. Biofilms developed under treated chlorinated surface water supply exhibited lower cell densities in comparison with biofilms resulting from treated groundwater. Overall, the phenotypic as well as the genotypic characteristics were significantly different between both biofilms. In addition, the response of the biofilm microbiome and possible biofilm detachment after minor water quality changes were investigated. Limited changes in pH and free chlorine addition, to simulate operational changes that are relevant for practice, were evaluated. It was shown that both biofilms remained resilient. Finally, mature biofilms were prone to invasion of the coliform, Serratia fonticola . After spiking low concentrations (i.e., ±100 cells/100 mL) of the coliform to the corresponding bulk water samples, the coliforms were able to attach and get established within the mature biofilms. These outcomes emphasize the need for continued research on biofilm detachment and its implications for water contamination in distribution networks., Importance: The revelation that even low concentrations of coliforms can infiltrate into mature drinking water biofilms highlights a potential public health concern. Nowadays, the measurement of coliform bacteria is used as an indicator for fecal contamination and to control the effectiveness of disinfection processes and the cleanliness and integrity of distribution systems. In Flanders (Belgium), 533 out of 18,840 measurements exceeded the established norm for the coliform indicator parameter in 2021; however, the source of microbial contamination is mostly unknown. Here, we showed that mature biofilms, are susceptible to invasion of Serratia fonticola . These findings emphasize the importance of understanding and managing biofilms in drinking water distribution systems, not only for their potential to influence water quality, but also for their role in harboring and potentially disseminating pathogens. Further research into biofilm detachment, long-term responses to operational changes, and pathogen persistence within biofilms is crucial to inform strategies for safeguarding drinking water quality., Competing Interests: The authors declare no conflict of interest.

There is an urgent need for sustainable protein supply routes with low environmental footprint. Recently, the use of hydrogen oxidizing bacteria (HOB) as a platform for high quality microbial protein (MP) production has regained interest. This study aims to investigate the added value of using conditions such as salt and temperature to steer HOB communities to lower diversities, while maintaining a high protein content and a high quality amino acid profile. Pressure drop and hydrogen consumption were measured for 56 days to evaluate autotrophy of a total of six communities in serum flasks. Of the six communities, four were enriched under saline (0.0, 0.25, 0.5 and 1.0 mol NaCl l -1 ) and two under thermophilic conditions (65°C). Five communities enriched for HOB were subsequently cultivated in continuously stirred reactors under the same conditions to evaluate their potential as microbial protein producers. The protein percentages ranged from 41 to 80%. The highest protein content was obtained for the thermophilic enrichments. Amino acid profiles were comparable to protein sources commonly used for feed purposes. Members of the genus Achromobacter were found to dominate the saline enrichments while members of the genus Hydrogenibacillus were found to dominate the thermophilic enrichments. Here we show that enriching for HOB while steering the community toward low diversity and maintaining a high quality protein content can be successfully achieved, both in saline and thermophilic conditions. IMPORTANCE Alternative feed and food supply chains are required to decrease water and land use. HOB offer a promising substitute for traditional agricultural practice to produce microbial protein (MP) from residual materials and renewable energy. To safeguard product stability, the composition of the HOB community should be controlled. Defining strategies to maintain the stability of the communities is therefore key for optimization purposes. In this study, we use salt and temperature as independent conditions to stabilize the composition of the HOB communities. Based on the results presented, we conclude that HOB communities can be steered to have low diversity using the presented conditions while producing a desirable protein content with a valuable amino acid profile., (Copyright © 2020 American Society for Microbiology.)