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Based on long-term systematic sampling, information is currently limited regarding the impacts of different air pollution levels on variations of bacteria, fungi and ammonia-oxidizing microorganisms (AOMs) in fine particulate matter (PM 2.5 ), especially their interactions. Here, PM 2.5 samples were weekly collected at different air pollution levels in Beijing, China during one-year period. Microbial composition was profiled using Illumina sequencing, and their interactions were further investigated to reveal the hub genera with network analysis. Diversity of bacteria and fungi showed obvious seasonal variations, and the heavy- or severe-pollution levels mainly affected the diversity and composition of bacteria, but not fungi. While, the community structure of both bacteria and fungi was influenced by the combination of air pollution levels and seasons. The most abundant bacterial genera and some genera with highest abundance in heavy- or severe-pollution days were the hub bacteria in PM 2.5 . Whereas, only the dominant fungi in light-pollution days in winter were the hub fungi in PM 2.5 . The complex positive correlations of bacterial or fungal pathogens would aggravate the air pollution effects on human health, despite of their low relative abundances. Moreover, the strong co-occurrence and co-exclusion patterns of bacteria and fungi in PM 2.5 were identified. Furthermore, the hub environmental factors (e.g., relative humidity and atmospheric pressure) may play central roles in the distributions of bacteria and fungi, including pathogens. Importantly, AOMs showed significant co-occurrence patterns with the main bacterial and fungal genera and potential pathogens, providing possible microbiological evidences for controlling ammonia emissions to effectively reduce PM 2.5 pollution. These results highlighted the more obvious air pollution impacts on bacteria than fungi, and the complex bacterial-fungal interactions, as well as the important roles of AOMs in airborne microbial interactions webs, improving our understanding of bioaerosols in PM 2.5 ., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Aerobic granular sludge (AGS) was cultivated in a sequencing batch reactor (SBR). In this study, AGS was broken during the formation process and then mature AGS formed again. The microbial community dynamics during two sludge granulation processes were investigated using high-throughput sequencing to reveal the dominant bacteria beneficial to AGS formation. The abundance dynamics of nitrifying microorganisms were analyzed by a quantitative polymerase chain reaction (qPCR). The results showed that the amount of extracellular protein and polysaccharides increased during two sludge granulation processes. The abundance of ammonia oxidizing archaea (AOA) increased during the first AGS formation process and during the process of AGS maturation. The abundance of ammonia oxidizing bacteria (AOB) decreased during the first AGS formation process, while it maintained a higher abundance than AOA during AGS cultivation. Microbial diversity decreased with AGS formation. The relative abundance of Proteobacteria increased by 12.29% and 5.90% during two sludge granulation processes, respectively. Candidatus Competibacter belonging to Proteobacteria was enriched during two sludge granulation processes, accounting for 14.20% in mature AGS. Overall, extracellular protein and polysaccharides may have contributed to the sludge granulation. Both AOA and AOB might have been involved in ammonia oxidation. This study indicated that Ca. Competibacter might contribute to AGS formation.

In this study, the short-term effect of roxithromycin(ROX) on the abundance and diversity of ammonia-oxidizing archaea(AOA) and ammonia-oxidizing bacteria(AOB) based on amoA gene in activated sludge were investigated by high-throughput sequencing and quantitative real-time PCR(qPCR). High-throughput sequencing overcomes the drawbacks of low sequencing depth, significant randomness and great bias of traditional Sanger sequencing. This approach can provide enough sequencing depth to comprehensively investigate the sensitive and insensitive ammonia-oxidizing microorganisms under ROX selective pressure. Lab-scale reactors were operated under ten different ROX levels. The results indicated that the environmental(0.3-30 μg·L -1 ) and medium(300 μg·L -1 and 3000 μg·L -1 ) levels of ROX did not affect ammonia oxidation, while the higher concentration(5000-12000 μg·L -1 ) of ROX showed a significant negative effect on ammonia oxidation. The environmental and medium levels of ROX stimulated the growth of AOA, however, the higher level of ROX decreased the abundance of AOA. In addition, different levels of ROX(except 0.3 μg·L -1 ) caused the decrease of the abundance of AOB, which suggested that AOA was less sensitive than AOB under ROX selective pressure. The results of high-throughput sequencing showed that ROX selective pressure caused the decrease of the numbers of OTUs for AOA and increase of that for AOB. The insensitive AOA, accounting for 57.70%-97.81% of the total sequences, were Candidatus Nitrososphaera gargensis and Candidatus Nitrosoarchaeum koreensis. The insensitive AOB were Nitrosomonas oligotropha, Nitrosospira multiformis, Nitrosomonas watsonii and Nitrosomonas halophilus , accounting for 0.76%-5.10% of the total sequences. These results also indicated that AOA was insensitive to ROX, but AOB was sensitive to ROX. RDA analyses showed that AOA Ca . Nitrososphaera gargensis, Ca . Nitrosoarchaeum koreensis and AOB N. oligotropha, N. watsonii, N. halophilus were positively correlated with ROX concentrations.

Increasing ammonia emissions could exacerbate air pollution caused by fine particulate matter (PM 2.5 ). Therefore, it is of great importance to investigate ammonia oxidation in PM 2.5 . This study investigated the diversity, abundance and activity of ammonia oxidizing archaea (AOA), ammonia oxidizing bacteria (AOB) and complete ammonia oxidizers (Comammox) in PM 2.5 collected in Beijing-Tianjin-Hebei megalopolis, China. Nitrosopumilus subcluster 5.2 was the most dominant AOA. Nitrosospira multiformis and Nitrosomonas aestuarii were the most dominant AOB. Comammox were present in the atmosphere, as revealed by the occurrence of Candidatus Nitrospira inopinata in PM 2.5 . The average cell numbers of AOA, AOB and Ca. N. inopinata were 2.82 × 10 4 , 4.65 × 10 3 and 1.15 × 10 3 cell m -3 air, respectively. The average maximum nitrification rate of PM 2.5 was 0.14 μg (NH 4 + -N) [m 3 air·h] -1 . AOA might account for most of the ammonia oxidation, followed by Comammox, while AOB were responsible for a small part of ammonia oxidation. Statistical analyses showed that Nitrososphaera subcluster 4.1 was positively correlated with organic carbon concentration, and Nitrosomonas eutropha showed positive correlation with ammonia concentration. Overall, this study expanded our knowledge concerning AOA, AOB and Comammox in PM 2.5 and pointed towards an important role of AOA and Comammox in ammonia oxidation in PM 2.5 .

Acute toxicity of wastewater from 5 nodes of technological process in the pharmaceutical factory sewage treatment station was studied by luminescent bacteria tests. The EC50, TUa and LID of the wastewater in underground regulating tanks was 3.44%, 29 and 625, respectively, indicating the water was extremely/highly toxic; for the wastewater in surface regulating tanks, the EC50, TUa and LID was 2.46%, 41 and 244, respectively, also extremely/highly toxic; for the wastewater in middle sediment tanks, the EC50 > 100% and LID was 10, which was moderately toxic; for the wastewater in secondary sediment tanks and the final effluents, the EC50 was above 100% and LID was 1, with no observed toxicity. The results indicated that the existing treatment process effectively reduced the acute toxicity of the pharmaceutical wastewater to luminescent bacteria, the effluents showed no observed toxicity to luminescent bacteria, which was lower than the relative effluent limits of pharmaceutical wastewater. The wastewater in lower concentration did not inhibit the luminosity, but enhanced the luminosity.

This study investigated the diversity and abundance of AOA and AOB amoA genes in eight full-scale wastewater treatment plants (WWTPs). Although the process principles and system operations of the eight WWTPs were different, quantitative real-time PCR measurements showed that AOB amoA genes outnumbered AOA amoA genes with the ratio varying from 2.56 to 2.41×10(3), and ammonia may be partially oxidized by AOA. Phylogenetic analyses based on cloning and sequencing showed that Nitrososphaera cluster was the most dominant AOA species and might be distributed worldwide, and Nitrosopumilis cluster was few. Statistical analysis indicated that there might be versatile AOA ecotypes and some AOA might be not obligate autotrophic. The Nitrosomonas europaea cluster and Nitrosomonas oligotropha cluster were the two most dominant AOB species, and AOB species showed higher diversity than AOA species., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The contributions of loosely bound extracellular polymeric substances (LB-EPS), tightly bound EPS (TB-EPS), residual sludge (the sludge left after EPS extraction) and functional groups such as amine, carboxyl, phosphate and lipid on aerobic granules on biosorption of four different dyes (Reactive Brilliant Blue KN-R (KN-R), Congo Red (CR), Reactive Brilliant Red K-2G (RBR) and Malachite Green (MG)) were investigated. EPS may be responsible for biosorption of cationic dyes. However, residual sludge always made greater contribution than that of EPS. The biosorption mechanisms were dependent on the functional groups on aerobic granules and dyes' chemical structures. The lipid and phosphate groups might be the main binding sites for KN-R biosorption. Amine, carboxyl, phosphate and lipid were all responsible for the binding of CR. The lipid fractions played an important role for RBR biosorption. For MG, the phosphate groups gave the largest contribution., (Copyright © 2010 Elsevier Ltd. All rights reserved.)