The co-existence of anammox genera in an expanded granular sludge bed reactor with biomass carriers for nitrogen removal

The internal environment of the gallbladder has been considered extremely unfavorable for bacterial growth, and the microbial profile of the gallbladder still unknown. By high-throughput sequencing of the bacterial 16S rRNA gene, we studied the microbial profile of the gallbladder from healthy rabbits before and after weaning. Moreover, we investigated the difference of microbiota between the gallbladder and gut. Our results showed that the gallbladder was dominantly populated by Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria in the phylum throughout the developmental stages of rabbits. The adult rabbits showed higher species richness and exhibited higher bacterial diversity than rabbits before weaning based on the results of alpha diversity. Beta diversity analyses indicated differences in the bacterial community composition between different developmental stages. In the comparison of the gallbladder and feces, Firmicutes and Bacteroidetes were dominant in the phylum, as they were present in about 61% and 21% of the feces, respectively. Conversely, in the gallbladder, Firmicutes was the most dominant (about 41%), and Bacteroidetes and Proteobacteria were present in about 16% and 22% of the gallbladder, respectively. The Unweighted UniFrac Principal Coordinate Analysis results illustrated samples clustered into 2 categories: the gallbladder and feces. Our study might provide a foundation for knowledge on gallbladder microbiota for the first time and a basis for further studies on gallbladder and intestinal health.

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“…When the number of samples (groups) was less than 5, the Venn Graph was drawn. The microbial function was predicted by FAPROTAX [29].…”

Section: Methodsmentioning

confidence: 99%

Dynamic distribution of gallbladder microbiota in rabbit at different ages and health states

Xing

Liu

et al. 2019

PLoS ONE

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“…On day 36, the ammonium and nitrite removal efficiencies of R2 were stable at 94.8% and 90.3%, respectively, indicating the successful start-up of anammox. 37,38 However, the same phenomenon appeared in R1 until 21 days later. The assorted infrared EMFs shortened the start-up period of the anammox process from 57 to 36 days and realized a 36.8% time saving.…”

Section: ■ Resultsmentioning

confidence: 60%

Utilizing Infrared Electromagnetic Fields to Increase Anammox Activity and Growth Rates

Wang

Cui

et al. 2021

ACS EST Water

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Achieving a rapid start-up of the anammox process is still full of challenges and obstacles due to the slow growth of anammox bacteria. In this study, a new physical energy, infrared electromagnetic fields (EMFs) generated from a widely used traditional Chinese medicine apparatus by accelerating charged particles through thermal excitation, proved to be a “bioactivity enhancer” for the anammox process. Short-term batch tests indicated that the specific anammox activity [26.6 mg of N (g of MLSS)−1 h–1] was increased by 76% after the treatment with infrared EMFs. The long-term effect of the EMFs on anammox was studied in upflow column reactors, and a 36.8% start-up time saving, a 17.7% total nitrogen removal increase, and a 22.5% acceleration of the anammox bacteria growth rate were achieved. The reactor that included EMFs also had better resistance to performance deterioration and shock loading. The high-throughput sequencing results showed that the existence of the EMFs increased the relative abundance of Candidatus Kuenenia and Candidatus Jettenia. Furthermore, the evaluation of the community functions based on the Kyoto Encyclopedia of Genes and Genomes indicated infrared EMFs stimulated anammox bacteria by controlling the metabolism of c-di-GMP. Taken together, infrared EMFs are, therefore, considered to be an efficient “bioactivity enhancer” for promoting the anammox process.

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“…The entire system was maintained in a 37°C water bath. Mixed liquor volatile suspended solids (MLVSS) mass (0.9 g) of seed anammox sludge was sourced from a laboratory-scale anammox MBR; these anammox sludges were inoculated from an expanded granular sludge bed with carriers initially ( Wu et al, 2019 ). The condition of this laboratory-scale anammox MBR was described as follows: the influent nitrite concentration of laboratory-scale anammox MBR was 1,550 mg N L –1 , and the ammonia nitrogen concentration was 1,350 mg N L –1 ; the corresponding nitrogen removal rate was 1.5 g N L –1 day –1 ; MLVSS was approximately 3 g/L; the main AnAOB was Ca.…”

Section: Methodsmentioning

confidence: 99%

Specific Denitrifying and Dissimilatory Nitrate Reduction to Ammonium Bacteria Assisted the Recovery of Anammox Community From Nitrite Inhibition

et al. 2022

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The anaerobic ammonium oxidation (anammox) by autotrophic anaerobic ammonia-oxidizing bacteria (AnAOB) is a biological process used to remove reactive nitrogen from wastewater. It has been repeatedly reported that elevated nitrite concentrations can severely inhibit the growth of AnAOB, which renders the anammox process challenging for industrial-scale applications. Both denitrifying (DN) and dissimilatory nitrate reduction to ammonium (DNRA) bacteria can potentially consume excess nitrite in an anammox system to prevent its inhibitory effect on AnAOB. However, metabolic interactions among DN, DNRA, and AnAOB bacteria under elevated nitrite conditions remain to be elucidated at metabolic resolutions. In this study, a laboratory-scale anammox bioreactor was used to conduct an investigation of the microbial shift and functional interactions of AnAOB, DN, and DNRA bacteria during a long-term nitrite inhibition to eventual self-recovery episode. The relative abundance of AnAOB first decreased due to high nitrite concentration, which lowered the system’s nitrogen removal efficiency, but then recovered automatically without any external interference. Based on the relative abundance variations of genomes in the inhibition, adaptation, and recovery periods, we found that DN and DNRA bacteria could be divided into three niche groups: type I (types Ia and Ib) that includes mainly DN bacteria and type II and type III that include primarily DNRA bacteria. Type Ia and type II bacteria outcompeted other bacteria in the inhibition and adaptation periods, respectively. They were recognized as potential nitrite scavengers at high nitrite concentrations, contributing to stabilizing the nitrite concentration and the eventual recovery of the anammox system. These findings shed light on the potential engineering solutions to maintain a robust and efficient industrial-scale anammox process.

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The co-existence of anammox genera in an expanded granular sludge bed reactor with biomass carriers for nitrogen removal

Cited by 20 publications

References 49 publications

Dynamic distribution of gallbladder microbiota in rabbit at different ages and health states

Dynamic distribution of gallbladder microbiota in rabbit at different ages and health states

Utilizing Infrared Electromagnetic Fields to Increase Anammox Activity and Growth Rates

Specific Denitrifying and Dissimilatory Nitrate Reduction to Ammonium Bacteria Assisted the Recovery of Anammox Community From Nitrite Inhibition

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