Accumulibacter” is the most studied PAO, with a primary role in biological nutrient removal. However, the species-level taxonomy of this lineage is convoluted due to the use of different phylogenetic markers or genome sequencing approaches. Here, we redefined the phylogeny of these organisms, proposing a comprehensive approach which could be used to address the classification of other diverse and uncultivated lineages.
Recent advances in sequencing technology promoted the blowout discovery of super tiny microbes in the
(DPANN) superphylum. However, the unculturable properties of the majority of microbes impeded our investigation of their behavior and symbiotic lifestyle in the corresponding community.
Ammonia tolerance of AOA is usually much lower than that of the AOB, which makes the AOB rather than AOA a predominant ammonia oxidizer in agricultural soils, contributing to global N
O emission. Recently, some AOA species from the genus “
Nitrosocosmicus” were also found to have high ammonia tolerance.
Microbiology is in a new age in which sequence databases are primary sources of information about many microbes. However, in-depth analysis of environmental genomes thus retrieved is essential to substantiate the new knowledge.
Accumulibacter phosphatis” is widely found in full-scale wastewater treatment plants, where it has been identified as the key organism for biological removal of phosphorus. Since aeration can account for 50% of the energy use during wastewater treatment, microaerobic conditions for wastewater treatment have emerged as a cost-effective alternative to conventional biological nutrient removal processes. Our report provides strong genomics-based evidence not only that “
. Accumulibacter phosphatis” is the main organism contributing to phosphorus removal under microaerobic conditions but also that this organism simultaneously respires nitrate and oxygen in this environment, consequently removing nitrogen and phosphorus from the wastewater. Such activity could be harnessed in innovative designs for cost-effective and energy-efficient optimization of wastewater treatment systems.
-like bacteria are among the most diverse and widespread nitrifiers in natural ecosystems and the dominant nitrite oxidizers in wastewater treatment plants (WWTPs). The recent discovery of comammox-like
strains, capable of complete oxidation of ammonia to nitrate, raises new questions about specific traits responsible for the functional versatility and adaptation of this genus to a variety of environments. The availability of new
genome sequences from both nitrite-oxidizing and comammox bacteria offers a way to analyze traits in different
functional groups. Our comparative genomics analysis provided new insights into the adaptation of
strains to specific lifestyles and environmental niches.
Bacteria that directly use electrodes as metabolic electron donors (biocathodes) have been proposed for applications ranging from microbial electrosynthesis to advanced bioelectronics for cellular communication with machines. However, just as we understand very little about oxidation of analogous natural insoluble electron donors, such as iron oxide, the organisms and extracellular electron transfer (EET) pathways underlying the electrode-cell direct electron transfer processes are almost completely unknown. Biocathodes are a stable biofilm cultivation platform to interrogate both the rate and mechanism of EET using electrochemistry and to study the electroautotrophic organisms that catalyze these reactions. Here we provide new evidence supporting the hypothesis that the uncultured bacterium “
Tenderia electrophaga” directly couples extracellular electron transfer to CO
fixation. Our results provide insight into developing biocathode technology, such as microbial electrosynthesis, as well as advancing our understanding of chemolithoautotrophy.
. Pelagibacter ubique” is a key driver of marine biogeochemistry cycles and a model for understanding how minimal genomes evolved in free-living anucleate organisms. This study explores the unusual sulfur acquisition strategy that has evolved in these cells, which lack assimilatory sulfate reduction and instead rely on reduced sulfur compounds found in oxic marine environments to meet their cellular quotas. Our findings demonstrate that the sulfur acquisition systems are constitutively expressed but the enzymatic steps leading to the essential sulfur-containing amino acid methionine are regulated by a unique array of riboswitches and genes, many of which are encoded in a rapidly evolving genome region. These findings support mounting evidence that streamlined cells have evolved regulatory mechanisms that minimize transcriptional switching and, unexpectedly, localize essential sulfur acquisition genes in a genome region normally associated with adaption to environmental variation.