[Effect of Thermal Hydrolysis Pretreatment Time on Microbial Community Structure in Sludge Anaerobic Digestion System].

To evaluate the effect of thermal hydrolysis pretreatment time on the sludge anaerobic digestion system of wastewater treatment plants (WWTPs) in Daxing district, Beijing, the structure and diversity of microbial communities in primary sludge and an activated sludge anaerobic digestion system with different thermal hydrolysis pretreatment times (15 min, 30 min, and 45 min) were analyzed using Illumina MiSeq high-throughput sequencing. The results showed that the dominant groups of digested sludge were mainly distributed in Firmicutes, Cloacimonadota, Chloroflexi, and Synergistota, with W5 being the most common genus. The sum of relative abundance of the dominant phylum was greater than 60%, and W5 accounted for 20.8%-54.5%, showing a high abundance of a few dominant species. During the anaerobic digestion of thermo-hydrolyzed sludge, the relative abundance of acetogenic methanogens decreased due to high levels of volatile fatty acids (VFAs) and ammonia nitrogen (NH4+-N) concentrations, which suggested that the hydrogenophilic methanogenic pathway was more than that of the acetogenic methanogenic pathway. Correlation analysis showed that the soluble protein and pH of thermo-hydrolyzed sludge, NH4+-N of digested sludge, and thermal hydrolysis pretreatment time were the four main environmental factors affecting microbial community structure, and NH4+-N of digested sludge had the largest negative correlation with methanogens. The thermal hydrolysis pretreatment time was negatively correlated with both the Chao index and Shannon index, so longer thermal hydrolysis pretreatment time was not conducive to microbial flora during anaerobic digestion.

4-Octyl itaconate alleviates renal ischemia reperfusion injury by ameliorating endoplasmic reticulum stress via Nrf2 pathway.

Renal ischemia-reperfusion injury (IRI) is a common clinical complication of multiple severe diseases. Owing to its high mortality and the lack of effective treatment, renal IRI is still an intractable problem for clinicians. Itaconate, which is a metabolite of cis-aconitate, can exert anti-inflammatory and antioxidant roles in many diseases. As a derivative of itaconate with high cell membrane permeability, 4-octyl itaconate (4-OI) could provide a protective effect for various diseases. However, the role of 4-OI in renal IRI is still unclear. Herein, we examined whether 4-OI afforded kidney protection through attenuating endoplasmic reticulum stress (ERS) via nuclear factor erythroid-2-related factor 2 (Nrf2) pathway. To observe the effects of 4-OI on alleviating renal pathologic injury, improving renal dysfunction, decreasing inflammatory cytokines, and reducing oxidative stress, we utilized C57BL/6J mice with bilateral renal pedicle clamped and HK-2 cells with hypoxia/reoxygenation (H/R) exposure in our study. In addition, through western blot assay, we found 4-OI ameliorated renal IRI-induced ERS, and activated Nrf2 pathway. Moreover, Nrf2-knockout (KO) mice and Nrf2 knockdown HK-2 cells were used to validate the role of Nrf2 signaling pathway in 4-OI-mediated alleviation of ERS caused by renal IRI. We demonstrated that 4-OI relieved renal injury and suppressed ERS in wild-type mice, while the therapeutic role was not shown in Nrf2-KO mice. Similarly, 4-OI could exert cytoprotective effect and inhibit ERS in HK-2 cells after H/R, but not in Nrf2 knockdown cells. Our in vivo and in vitro studies revealed that 4-OI protected renal IRI through attenuating ERS via Nrf2 pathway.

Deciphering the fate of osmotic stress priming on enhanced microorganism acclimation for purified terephthalic acid wastewater treatment with high salinity and organic load.

Osmotic stress priming (OSP) was an effective management strategy for improving microbial acclimation to salt stress. In this study, the interaction between pollutants and microbiota, and microbial osmoregulation were investigated triggered by OSP (alternately increasing salinity and organic loading). Results showed that OSP significantly improved COD removal from 31.53 % to 67.99 % and mitigated the terephthalate inhibition produced by toluate, decreasing from 1908.08 mg/L to 837.16 mg/L compared with direct priming. Due to an increase in salinity, Pelotomaculum and Mesotoga were enriched to facilitate terephthalate degradation and syntrophic acetate oxidation (SAO). And organic load promoted acetate formation through syntrophic metabolism of Syntrophorhabdus/Pelotomaculum and SAO-dependent hydrogenotrophic methanogenesis. K+ absorbing, proline and trehalose synthesis participated in osmoregulation at 0.5 % salinity, while only ectoine alleviated intracellular osmolarity under 1.0 % salinity with OLR of 0.44 kg COD /m3. This study provided in-depth insight for microbial acclimation process of anaerobic priming of saline wastewater.

Temperature-regulated and starvation-induced refractory para-toluic acid anaerobic biotransformation.

Little research was focused on the anerobic degradation of refractory para-toluic acid at present. Thus, temperature-regulated anaerobic system of para-toluic acid fed as sole substrate was built and investigated via microbiota, metabolism intermediates, and function prediction in this study. Results showed that low methane yield was produced in para-toluic acid anaerobic system at alkaline condition. And the causes were owing to anaerobic methane oxidation and potentially H2S production at 37 °C, N2 production by denitrification before starvation and propionic acid occurrence after starvation at 27 °C, and production of N2 and free ammonia, and accumulation of acetic acid at 52 °C. Simultaneously, hydrogenotrophic methanogenesis dependent on syntrophic acetate oxidation (SAO) was predominant, facilitating the removal of para-toluic acid at 52 °C. Moreover, the key intermediate changed from phthalic acid of 37 °C and 27 °C before starvation to terephthalic acid of 52 °C. Starvation promoted removal of para-toluic acid through benzoyl-CoA pathway by Syntrophorhabdus, enrichment of syntrophic propionate degraders of Bacteroidetes and Ignavibacteriaceae, and increase of methylotrophic methanogens.

Evaluation of the Effect of Food on the Pharmacokinetics of SHR6390, An Oral CDK4/6 Inhibitor, in Healthy Volunteers.

BACKGROUND AND INTRODUCTION: SHR6390 is a new developed highly effective and selective small-molecule oral CDK4/6 inhibitor. We aimed to evaluate the effect of food on the pharmacokinetics of SHR6390 tablets. METHODS: In an open-label two-way crossover study, 24 healthy Chinese volunteers were randomly divided into Group A and Group B, and 12 volunteers in each group received a single oral dose of a SHR6390 150-mg tablet under fasting and high-fat conditions. Blood samples were collected and determined for pharmacokinetic analyses. A liquid chromatography-tandem mass spectrometry method was developed and validated for determining the SHR6390 concentration. RESULTS: The time to maximum plasma concentration was not significantly affected by a high-fat diet. Compared with the fasting group, maximum plasma concentration, i.e., the area under the concentration-time curve (AUC0-t and AUC0-∞) was altered significantly, as evidenced by an increase of 56.9%, 38.6%, and 37.5% respectively. We identified seven metabolites of SHR6390 from the plasma samples, and we found no sex differences in metabolic pathways. All treatment-emergent adverse events were Grade 1 or 2. CONCLUSIONS: Food intake increased the maximum plasma concentration, AUC0-t, and AUC0-∞ significantly compared with the fasting condition. Meanwhile, single-dose SHR6390 for two treatment cycles is safe. SHR6390 was administered in a fasting status in the pivotal phase III study (NCT03927456) and chosen for the final drug label.

The fate and behavior mechanism of antibiotic resistance genes and microbial communities in anaerobic reactors treating oxytetracycline manufacturing wastewater.

In this study, two parallel-operated expanded granular sludge bed (EGSB) reactors, one used to treat oxytetracycline (OTC) manufacturing wastewater with gradual increase of OTC concentration as experimental reactor and the other fed with the same wastewater without OTC as control reactor, were operated to investigate the behavior of antibiotics resistance genes (ARGs) and mobile genetic elements (MGEs) and their possible relationships with bacterial community among influent, sludge and effluent environments. Though the average absolute abundance of ARGs slightly decreased (0.26 - log), the ARGs' relative abundance normalized to 16S-rRNA gene copy numbers showed a significant upward trend in effluent (2 multiples - increase) and the absolute and relative abundances both extremely increased in anaerobic sludge, indicating that anaerobic treatment process cannot reduce ARGs efficiently, inversely can increase the risk of ARGs through the proliferation of antibiotics resistance bacteria (ARB) under the suppression of OTC. MGEs, bacterial communities and OTC concentration mainly impacted the ARGs profiles, which contributed 88.4% to the variation of ARGs. The differences and correlations of hosts in influent, effluent and sludge were further confirmed by network analysis. Overall, this study enhanced the understanding of the prevalence and transfer of ARGs in OTC production effluents during anaerobic treatment.

Characteristics of microbial community in EGSB system treating with oxytetracycline production wastewater.

In order to realize the efficient and stable operation of anaerobic digestion for oxytetracycline (OTC) production wastewater which contains high concentration refractory organic matters and antibiotic residues, two laboratory-scale EGSB reactors (the experimental reactor and the control reactor) were constructed for pre-treating OTC production wastewater and the complex characteristics and connections among anaerobic fermentative bacteria, methanogens and fungi were analyzed. The experimental reactor gradually increased OTC doses of 0-200 mg/L by four phases compared with the control reactor which was fed without OTC addition during 280 days' operation. The average COD removal efficiency of 91.44% with the average OTC removal efficiency of 27.90% was achieved at OTC concentration of 200 mg/L. The addition of OTC did not affect the preponderant methanogen type, and Methanosaeta, a strict aceticlastic methanogen genus, was dominant both in working and controlling reactors on day 280. Redundancy analysis revealed that OTC and VFAs were the main environmental factors affecting the microbial communities and molecular ecological networks analysis indicated that the key genera principally belonged to Methanosaeta, Proteobacteria and Apiotrichum. Additionally, the fungi genus Apiotrichum might be related to the degradation of complex organic contaminants in OTC production wastewater treatment system.

Impact of salinity on anaerobic microbial community structure in high organic loading purified terephthalic acid wastewater treatment system.

To investigate the effect of salinity (1% sodium chloride) on anaerobic microbial community structure in high strength telephthalic wastewater treatment system, the performances of anaerobic-aerobic process and the shifts of microbial community in anaerobic tank were studied and determined. Results showed that the chemical oxygen demand (COD) removal in the whole process remained above 90%. And the effluent concentrations of targeted pollutants were lower than 10 mg/L, other than para-toluic acid (PT, 38.09 mg/L). However, methane production significantly decreased compared to no salinity situation. This might be due to the inhibition of salinity on methanogens, which hindered the conversion of acetate to methane. Furthermore, the dominant genus in bacterial level changed from Tepidisphaera to Syntrophus, which facilitated the syntrophic association with hydrogenotrophic methanogens. The prevailed archaea remained acetoclastic Methanothrix above 90%. Therefore, the salinity on anaerobic microbial community structure mainly reflects in the methanogen process, remarkably decreasing methane production.

Influence of organic loading rate on purified terephthalic acid wastewater treatment in a temperature staged anaerobic treatment (TSAT) system: Performance and metagenomic characteristics.

In this study, a temperature staged anaerobic treatment (TSAT) system featured by thermophilic reactor (R1)-mesophilic reactor (R2) co-digestion was introduced to treat PTA wastewater. The process was successively conducted at three organic loading rates (OLRs): 3.34, 4.45, 6.68 kg COD/(m³·d), respectively (OLRs were R1 basis). The results indicated that TSAT system was highly efficient in PTA wastewater treatment at OLR lower than 4.45 kg COD/(m³·d). Miseq sequencing analysis demonstrated that R1 and R2 were predominated by hydrogenotrophic Methanolinea and acetotrophic Methanosaeta, separately. In addition, TA06, Caldisericia and Acetothermia associated groups were highly abundant in R1, whereas Chlorobiaceae and Syntrophobacteraceae were largely observed in R2. Tax4Fun analysis suggested that the important functional capabilities were significantly different between R1 and R2 (P < 0.05). The pathways related to aromatic compounds degradation mainly occurred in mesophilic stage, while the biosynthesis and metabolism pathways were more favored in thermophilic stage.

The long-term impact of cefalexin on organic substrate degradation and microbial community structure in EGSB system.

In order to investigate long-term effect of cefalexin (CFX) on the performance of expanded granular sludge bed (EGSB) system and microbial community structure, two 1.47 L EGSB reactors E1 and E2 were designed and run for 224 days treating with synthetic antibiotic wastewater. For the purpose of comparison, E1 was fed with synthetic antibiotic industry wastewater with CFX added as the test reactor, while, E2 was fed without any CFX added as the control reactor (E2). The addition of CFX resulted in the continual increasing of soluble COD (sCOD) and accumulation of VFAs in the effluent of E1 system. Besides, it was found that the accumulation of CFX by-products D-1, D-2 and D-3 was negative correlation with sCOD removal efficiency. Furthermore, the microbial community structures were also investigated. For the bacterial community, Gelria and Syntrophorhabdus which can ferment propionate and other organic pollutants as their substrate were obviously enriched in E1 system. For the archaea, there was more functional diversity in E1 system than in E2 system. Furthermore, fungi also played an important role on the removal of complex organics in E1 system.

Establishment of thermophilic anaerobic terephthalic acid degradation system through one-step temperature increase startup strategy - Revealed by Illumina Miseq Sequencing.

Over recent years, thermophilic digestion was constantly focused owing to its various advantage over mesophilic digestion. Notably, the startup approach of thermophilic digester needs to be seriously considered as unsuitable startup ways may result in system inefficiency. In this study, one-step temperature increase startup strategy from 37 °C to 55 °C was applied to establish a thermophilic anaerobic system treating terephthalic acid (TA) contained wastewater, meanwhile, the archaeal and bacterial community compositions at steady periods of 37 °C and 55 °C during the experimental process was also compared using Illumina Miseq Sequencing. The process operation demonstrated that the thermophilic TA degradation system was successfully established at 55 °C with over 95% COD reduction. For archaea community, the elevation of operational temperature from 37 °C to 55 °C accordingly increase the enrichment of hydrogenotrophic methanogens but decrease the abundance of the acetotrophic ones. While for bacterial community, the taxonomic analysis suggested that Syntrophorhabdus (27.40%) was the dominant genus promoting the efficient TA degradation under mesophilic condition, whereas OPB95 (24.99%) and TA06 (14.01%) related populations were largely observed and probably take some crucial role in TA degradation under thermophilic condition.

454-Pyrosequencing Reveals Microbial Community Structure and Composition in a Mesophilic UAFB System Treating PTA Wastewater.

To well understand the community structure and composition of mesophilic microorganisms in anaerobic system fed with PTA wastewater, an up-flow anaerobic fixed bed reactor was continuously run at 33 and 37 °C for 75 and 60 days, respectively. Both fluorescence in situ hybridization analysis and 454-pyrosequencing were applied to investigate the microbial distinction within mesophilic ranges. A preferable performance was achieved at 37 than 33 °C. The taxonomic complexities of two samples were further compared at phylum, class, and genus levels. Notably, microbial diversity differed a lot and the change of populations was observed mainly in the shared OTUs. Genus level analysis showed that when temperature was increased to 37 °C, the abundance of Thauera and Hydrogenophaga (ß-Proteobacteria) decreased by 93.75 and 61.47 %, respectively, whereas that of Syntrophorhabdus (δ-Proteobacteria) increased from 4.93 to 16.01 %. Furthermore, the dominant archaeal Methanobacterium at both temperatures indicated the prevailing contribution of hydrogenotrophic methanogens in mesophilic anaerobic system.

Performance and microbial community profiles in an anaerobic reactor treating with simulated PTA wastewater: from mesophilic to thermophilic temperature.

Performance and microbial community profiles in a hybrid anaerobic reactor treating synthetic PTA wastewater (contained the major pollutants terephthalate and benzoate) were studied over 220 days from 33 °C to 52 °C. Results indicated that PTA treatment process was highly sensitive to temperature variations in terms of COD removal. Operation at 37 °C showed the best performance as well as the most diverse microbial community revealed by 16S rRNA gene clone library and T-RFLP (terminal restriction fragment length polymorphism). Finally, the anaerobic process achieved a total COD removal of 77.4%, 91.9%, 87.4% and 66.1% at 33, 37, 43 and 52 °C. While the corresponding TA removal were 77.6%, 94.0%, 89.1% and 60.8%, respectively. Sequence analyses revealed acetoclastic Methanosaeta was preponderant at 37 °C, while hydrogenotrophic genera including Methanobrevibacter and Methanofollis were more abundant at other temperatures. For bacterial community, 16 classes were identified. The largely existent Syntrophorhabdus members (belonging to δ-Proteobacteria) at 37 °C was likely to play an important role in mesophilic anaerobic wastewater treatment system contained terephthalate. Meanwhile, ß-Proteobacteria seemed to be favored in an anaerobic system higher than 43 °C.

[Influence of alkalinity and DO on ANAMMOX bioreactor at normal temperature and low substrate concentration].

A lab-scale up-flow ANAMMOX bioreactor with ceramics as biomass carrier was started up. The influence of alkalinity and dissolved oxygen on ANAMMOX reaction at normal temperature and low substrate concentration was investigated. The results showed that, at (20 ± 2) degrees C and an HRT of 3 h, when the alkalinity was between 44 mg x L(-1) and 350 mg x L(-1), the ammonia removal efficiency was decreased from 97.2% to 75.6% and the TN removal efficiency was decreased from 89.7% to 75.1% as the alkalinity reduced. Meanwhile, the nitrite removal efficiency was stabilized at 99.7%. When the alkalinity was 0 mg x L(-1), the effluent nitrite concentration was increased to 4.9 mg x L(-1). Ammonia removal efficiency was decreased by 12.3% because of light. When the HRT was 1.5 h, the DO value was < 3 mg x L(-1), the average removal efficiencies of ammonia and nitrite were 99.7% and 100%, respectively, the nitrogen removal rate was 1.0 kg x (m3 x d)(-1). 16S rRNA phylogenic analysis was applied to analyze the microbial community structure. Results revealed that Candidatus Jettenia asiatica and Candidatus Brocadia sp. were adapted to normal temperature.

Molecular characterization of microbial populations in full-scale biofilters treating iron, manganese and ammonia containing groundwater in Harbin, China.

In iron and manganese-containing groundwater treatment for drinking water production, biological filter is an effective process to remove such pollutants. Until now the exact microbial mechanism of iron and manganese removal, especially coupled with other pollutants, such as ammonia, has not been clearly understood. To assess this issue, the performance of a full-scale biofilter located in Harbin, China was monitored over four months. Microbial populations in the biofilter were investigated using T-RFLP and clone library technique. Results suggested that Gallionella, Leptothrix, Nitrospira, Hyphomicrobium and Pseudomonas are dominant in the biofilter and play major roles in the removal of iron, manganese and ammonia. The spatial distribution of microbial populations along the depth of the biofilter demonstrated the stratification of the removal of iron, manganese and ammonia. Additionally, the absence of ammonia-oxidizing bacteria in the biofilter implicated that ammonia-oxidizing archaea might be responsible for the oxidation of ammonia to nitrite.

[Fingerprint analysis of Glehniae Radix by TLC].

OBJECTIVE: To establish TLC fingerprint of Glehniae Radix for the identification and quality control of the drug. METHODS: 10 batches of Glehniae Radix commercial drugs collected from different gathering areas and 3 batches from Laiyang, Shandong were used as qualitative identification samples. Falcarindiol, scopoletin umbelliferone and isoimperatorin were used as the chemical reference substances. Double wavelength TLCS was performed with petroleum and ethyl acetate (4:1) as developer,detection wavelength at 300 nm and reference wavelength at 260 nm. RESULTS: TLC chromatogram of 13 samples had 8 well-resolved characteristic peaks, in which 4 peaks were falcarindiol, umbelliferone, scopoletin and isoimperatorin, respectively. CONCLUSION: The method is accurate and simple, and can be used for the quality control of Glehniae Radix.

Phosphorus accumulation by bacteria isolated from a continuous-flow two-sludge system.

In this article, polyphosphate-accumulating organisms (PAOs) from a lab-scale continuous-flow two-sludge system was isolated and identified, the different phosphorus accumulation characteristics of the isolates under anoxic and aerobic conditions were investigated. Two kinds of PAOs were both found in the anoxic zones of the two-sludge system, one of them utilized only oxygen as electron acceptor, and the other one utilized either nitrate or oxygen as electron acceptor. Of the total eight isolates, five isolates were capable of utilizing both nitrate and oxygen as electron acceptors to uptake phosphorus to some extent. And three of the five isolates showed good phosphorus accumulative capacities both under anoxic or aerobic conditions, two identified as Alcaligenes and one identified as Pseudomonas. Streptococcus was observed weak anoxic phosphorus accumulation because of its weak denitrification capacity, but it showed good phosphorus accumulation capacity under aerobic conditions. One isolates identified as Enterobacteriaceae was proved to be a special species of PAOs, which could only uptake small amounts of phosphorus under anoxic conditions, although its denitrification capacity and aerobic phosphorus accumulation capacity were excellent.

Simultaneous phosphorus and nitrogen removal in a continuous-flow two-sludge system.

The ability of simultaneous biological phosphorus and nitrogen removal was investigated in a lab-scale continuous-flow two-sludge system. Alternating anaerobic and anoxic conditions were combined with contact oxidation stage for treating raw municipal wastewater. Long-term experiments showed that the contradiction of competing for the organic substrate between denitrifying bacteria and PAOs (phosphorus accumulating organisms) in traditional phosphorus and nitrogen removal system has been resolved. The system can adapt to low influent COD/TN ratio (C/N). Furthermore the SRT (sludge retention time) of nitrifying sludge and denitrifying phosphorus removal sludge can be controlled at optimal conditions respectively. The removal efficiency of COD, TP, TN, and NH4-N was 81.78%, 92.51%,75.75%, and 84.47% respectively. It was also found that the appropriate influent C/N should be controlled at the range of 3.8-6, while the optimal C/N to the system ranged between 4-5, and the BFR (bypass sludge flow rate) should be controlled at 0.35 around.