Chemodivergent Synthesis of Allylic Sulfones via Ligand-Controlled Coupling of Allenes with Sulfinic Acids.

Allylic sulfones are important building blocks in organic synthesis and pharmaceutical chemistry. Herein, we disclose a chemodivergent protocol for Pd-catalyzed and ligand-controlled coupling of allenes with sulfinic acids, providing straightforward and atom-economical access to branched allylic sulfones and linear allylic sulfones bearing a conjugated (Z,E)-1,3-diene scaffold in good yields with high selectivities. This strategy features mild conditions, an unprecedented substrate scope, and functional group compatibility.

Emergence and spread patterns of antibiotic resistance genes during two different aerobic granular sludge cultivation processes.

The prevalence and accumulation of antibiotic resistance genes (ARGs) were frequently detected in biological wastewater treatment processes, which might cause potential health crisis to human. In present study, the fates of ARGs during two different aerobic granular sludge (AGS) cultivation processes were investigated. The results showed that traditional AGS (T-AGS) cultivation process and enhanced AGS (E-AGS) cultivation process had significant differences (P < 0.005) in ARGs shift patterns. E-AGS process had higher average relative abundance (0.280 ± 0.079) of ARGs than T-AGS process (0.130 ± 0.041), while the intensity of ARGs enrichment during E-AGS (1.52-5.29 fold) was lower than T-AGS (3.79-75.31 fold) process. TnpA and intI1 as two different types of mobile genetic elements (MGEs) carrying ARGs, were observed to contribute significantly to the horizontal gene transfer (HGT) during T-AGS (r = 0.902, P < 0.050) and E-AGS (r = 0.823, P < 0.001) processes, respectively. Higher HGT level took place and more possible potential hosts (25 hosts) harboring ARGs were detected during E-AGS process comparing with T-AGS process (17 hosts). Meanwhile, over large AGS might increase the propagation of several antibiotic deactivation ARGs, so it was not advised. Overall, whether during T-AGS or during E-AGS process which was applied in a pilot-scale sequencing batch reactor treating municipal wastewater, the accumulation and spread of ARGs were inevitable. It should be valued that some suitable pre-treatments of seed sludge should be executed, meanwhile, advanced treatment for removing of ARGs in AGS should be conducted to maintain the relative abundances of ARGs at relatively low level.

A conjugated microporous polymer as a recyclable heterogeneous ligand for highly efficient regioselective hydrosilylation of allenes.

Pyridines containing adjacent C[triple bond, length as m-dash]C bonds were utilized as ligand units and integrated into the skeleton of conjugated microporous polymers. The resultant Pd-CMP-1 was first applied as a highly efficient heterogeneous catalytic system for Pd-catalyzed allene hydrosilylation towards a wide range of allenes to produce branched allylsilanes with high regioselectivity. The ligand units of the polymer, along with the confinement effect of the porous structure, jointly regulated the regioselectivity. The parts-per-million (ppm) levels of Pd, coordinated with the recyclable heterogeneous ligand, show promise for industrial applications. This work opens a new front of using CMP as an intriguing platform for developing highly efficient catalysts to control the regioselectivities in allene hydrosilylation.

Enhanced granulation process, a more effective way of aerobic granular sludge cultivation in pilot-scale application comparing to normal granulation process: From the perspective of microbial insights.

Aerobic granular sludge (AGS) could be cultivated from only flocs (called normal granulation (NG) process) or mixture of flocs and crushed AGS (called enhanced granulation (EG) process), which might lead to different system performances such as granulation speed and pollutants removal efficiencies. However, the differences of mechanisms between NG and EG processes at microbial community level are still unknown. In this study, the NG and EG processes were implemented successively in a pilot-scale sequencing batch reactor (SBR) with certain amounts of additional carbon sources. Illumina MiSeq sequencing and quantitative PCR were applied to investigate the dynamics of bacterial communities during NG and EG processes and explore the possible explanations for faster EG process. The results showed that significant distinctions in bacterial diversities and community structures were observed between NG and EG processes. The major contributor to NG process was bacterial communities with 32.04% contribution. While EG process was more dependent on the interactions (73.16% contribution) between the bacterial communities and environmental variables (operational parameters and self-adaptive variable). EG process had higher relative abundances of functional bacteria than NG process. Glycogen accumulating organisms (GAOs) related bacteria with a total relative abundance of maximum 65.43% might be mainly responsible for the faster EG process. This study provided microbial insights for practical application of AGS technology that inoculating crushed AGS might be an effective way to cultivate AGS.

The dominance of non-halophilic archaea in autotrophic ammonia oxidation of activated sludge under salt stress: A DNA-based stable isotope probing study.

Dynamics of nitrification activity, ammonia-oxidizing archaea (AOA) and bacteria (AOB) abundance and active ammonia oxidizers of activated sludge were explored under different salinities. Results showed that specific ammonium oxidation rates were significantly negative with increasing salinity. The responses of AOA and AOB populations to salt stress were distinct. AOA abundance decreased at moderate salinities (2.5, 5 and 7 g L-1) and increased at high salinities (10, 15, 20 and 30 g L-1), while AOB abundance showed opposite tendency. DNA-based stable isotope probing assays indicated AOA exclusively dominated active ammonia oxidation of test samples under different salinities. The active AOA communities retrieved were all non-halophilic and regulated by salinities. Candidatus Nitrosocosmicus exaquare and Ca. Nitrosocosmicus franklandus were the predominantly active AOA in both salt-free and salt-containing microcosms, while 13C-labeled Nitrososphaera viennensis and Ca. Nitrososphaera gargensis were only retrieved from the microcosms amended with 0 and 30 g L-1 salinity, respectively.

More obvious air pollution impacts on variations in bacteria than fungi and their co-occurrences with ammonia-oxidizing microorganisms in PM2.5.

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 (PM2.5), especially their interactions. Here, PM2.5 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 PM2.5. Whereas, only the dominant fungi in light-pollution days in winter were the hub fungi in PM2.5. 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 PM2.5 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 PM2.5 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 PM2.5.

Xantphos Doped POPs-PPh3 as Heterogeneous Ligand for Cobalt-Catalyzed Highly Regio- and Stereoselective Hydrosilylation of Alkynes.

A Co(acac)2 /POL-Xantphos@10PPh3 -catalyzed hydrosilylation of unsymmetrical internal alkynes with Ph2 SiH2 has been developed for the synthesis of highly selective syn-α-vinylsilane products. Furthermore, terminal alkynes were also used and gave the products with excellent regioselectivity and a wide functional group tolerance. Because this porous organic polymer combines the selectivity and activity merits of Xantphos with the stability advantage derived from the high concentration of PPh3 , the Co(acac)2 /POL-Xantphos@10PPh3 can be recycled multiple times without loss of activity and selectivity. This heterogeneous catalyst is expected to find promising applications in industrial synthesis.

The more important role of archaea than bacteria in nitrification of wastewater treatment plants in cold season despite their numerical relationships.

Nitrification failure of wastewater treatment plants (WWTPs) in cold season calls into investigations of the functional ammonia-oxidizing microorganisms (AOMs). In this study, we report the abundance of ammonia-oxidizing archaea (AOA), bacteria (AOB) and complete ammonia-oxidizing (comammox) Nitrospira in 23 municipal WWTPs in cold season, and explore the correlations between AOMs abundance and their relative contribution to nitrification. The copy numbers of AOA and AOB amoA gene ranged from 2.42 × 107 to 2.47 × 109 and 5.54 × 106 to 3.31 × 109 copies/g sludge, respectively. The abundance of amoA gene of Candidatus Nitrospira inopinata, an important strain of comammox Nitrospira, was stable with averaged abundance of 8.47 × 106 copies/g sludge. DNA-based stable isotope probing (DNA-SIP) assays were conducted with three typical WWTPs in which the abundance of AOA was lower than, similar to and higher than that of AOB, respectively. The results showed that considerable 13C-assimilation by AOA was detected during active nitrification in all WWTPs, whereas just a much lesser extent of 13C-incorporation by AOB and comammox Nitrospira was found in one WWTP. High-throughput sequencing with 13C-labeled DNA also showed the higher reads abundance of AOA than AOB and comammox Nitrospira. Nitrososphaera viennensis was the dominant active AOA, while Nitrosomonas oligotropha and Nitrosomonas europaea were identified as active AOB. The results obtained suggest that AOA, rather than AOB and comammox Nitrospira, dominate ammonia oxidation in WWTPs in cold season despite the numerical relationships of AOMs.

Highly Regio- and Stereoselective Heterogeneous Hydrosilylation of Terminal Alkynes over Cobalt-Metalated Porous Organic Polymer.

A cobalt/POL-PPh3 catalyzed ( E)-selective hydrosilylation of alkynes with PhSiH3 has been developed for the synthesis of ( E)-ß-vinylsilanes with high regio- and stereoselectivity and wide functional group tolerance. It is the first report of using porous organic polymer as a recyclable regio- and stereoselective and efficient ligand in hydrosilylation reactions in which the polymer could be recycled numerous times in a continuous flow system without loss of activity and selectivity. The earth-abundant base-metal catalyst, coordinated by heterogeneous recyclable ligand, shows promise for industrial application.

Functional genera, potential pathogens and predicted antibiotic resistance genes in 16 full-scale wastewater treatment plants treating different types of wastewater.

This study aimed to investigate the bacterial communities and antibiotic resistance genes (ARGs) in 16 wastewater treatment plants (WWTPs) treating municipal, industrial and mixed wastewater. Wastewater types showed obvious effects on bacterial communities and functions. Nitrosomonas, Nitrospira, Hyphomicrobium and Accumulibacter were the main functional genera. Mycobacterium was the dominant potential pathogens. A total of 69 ARGs were obtained, and the dominant ARGs subtypes were similar in different WWTPs. Efflux pumps were the most common resistance mechanisms. Copper and zinc resistance genes were the main metal resistance genes (MRGs). Wastewater types affected the distributions of ARGs and MRGs, and they were more similar in industrial and mixed wastewater. The co-occurrence of ARGs existed within or across ARG types, and they were also positively linked to MRGs, some functional and pathogenic genera or environmental factors. This study furthers the understanding of interactions between bacterial communities, ARGs and MRGs in different WWTPs.

Ammonia-oxidizing bacteria dominate ammonia oxidation in a full-scale wastewater treatment plant revealed by DNA-based stable isotope probing.

A full-scale wastewater treatment plant (WWTP) with three separate treatment processes was selected to investigate the effects of seasonality and treatment process on the community structures of ammonia-oxidizing archaea (AOA) and bacteria (AOB). And then DNA-based stable isotope probing (DNA-SIP) was applied to explore the active ammonia oxidizers. The results of high-throughput sequencing indicated that treatment processes varied AOB communities rather than AOA communities. AOA slightly outnumbered AOB in most of the samples, whose abundance was significantly correlated with temperature. DNA-SIP results showed that the majority of AOB amoA gene was labeled by 13C-substrate, while just a small amount of AOA amoA gene was labeled. As revealed by high-throughput sequencing of heavy DNA, Nitrosomonadaceae-like AOB, Nitrosomonas sp. NP1, Nitrosomonas oligotropha and Nitrosomonas marina were the active AOB, and Nitrososphaera viennensis dominated the active AOA. The results indicated that AOB, not AOA, dominated active ammonia oxidation in the test WWTP.

Shifts in bacterial community composition and abundance of nitrifiers during aerobic granulation in two nitrifying sequencing batch reactors.

Shifts in bacterial community composition and abundance of nitrifiers during aerobic granulation, and the effects of wastewater composition on them were investigated using Illumina sequencing and quantitative PCR. The bacterial diversity decreased sharply during the post-granulation period. Although cultivated with different wastewater types, aerobic granular sludge (AGS) formed with similar bacterial structure. The bacterial structure in AGS was completely different from that of seed sludge. The minor genera in seed sludge, e.g., Arcobacter, Aeromonas, Flavobacterium and Acinetobacter, became the dominant genera in AGS. These genera have the potential to secrete excess extracellular polymer substances. Whereas, the dominant genera in seed sludge were found in less amount or even disappeared in AGS. During aerobic granulation, ammonia-oxidizing archaea were gradually washed-out. While, ammonia-oxidizing bacteria, complete ammonia oxidizers and nitrite-oxidizing bacteria were retained. Overall, in this study, the bacterial genera with low relative abundance in seed sludge are important for aerobic granulation.

[Short-term Effect of Roxithromycin on Abundance and Diversity of Ammonia-Oxidizing Microorganisms in Activated Sludge].

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-1and 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.