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关键词： SMBR   Pharmaceuticals   HRT   Bacterial community   High throughput sequencing  

摘要： The pharmaceuticals are biologically active compounds used to prevent and treat diseases. These pharmaceutical compounds were not fully metabolized by the human body and thus excreted out in the wastewater stream. Thus, the study on the treatment of synthetic hospital wastewater containing pharmaceuticals (ibuprofen, carbamazepine, estradiol and venlafaxine) was conducted to understand the variation of the bacterial community in a submerged membrane bioreactor (SMBR) at varying hydraulic retention time (HRT) of 6, 12 and 18 h. The variation in bacterial community dynamics of SMBR was studied using high throughput sequencing. The removal of pharmaceuticals was uniform at varying HRT. The removal of both ibuprofen and estradiol was accounted for 90%, whereas a lower removal of venlafaxine (< 10%) and carbamazepine (> 5%) in SMBR was observed. The addition of pharmaceuticals alters the bacterial community structure and result in increased abundance of bacteria (e.g., Flavobacterium, Pedobacter, and Methylibium) reported to degrade toxic pollutant.

关键词： High concentration organic wastewater   Granular sludge   Organic loading   Kinetics simulation   Time-space characteristics  

摘要： It is a technical barrier to efficiently treat traditional Chinese pharmaceutical (TCP) wastewater, due to its high chemical oxygen demanding (COD) concentration (>5000 mg/L). This study proposed and employed a spiral symmetry stream anaerobic bioreactor (SSSAB) to treat TCP wastewater. Results showed that a pilot-scale SSSAB (150 L) could achieve COD removal efficiency of 94.8% and volumetric removal rate (VRR) of 19.7 +/- 0.7 kg COD.(m(3).d)(-1) under room temperature, which were much higher than operation performance in internal circulation (IC) anaerobic reactor (COD removal efficiency and VRR were 85% and 113 +/- 0.8 kg COD.(m(3).d)(-1), respectively). The maximum COD volume removal rate could attain 43.4 kg COD.(m(3).d)(-1). The characteristics of granular sludge in SSSAB were investigated from both temporal and spatial scales. During the operation period, the anaerobic granular sludge in SSSAB was of higher concentration and superior properties compared to the IC anaerobic reactor. The sludge concentration exhibited a spatially decline trend, decreasing from 61 g L-1 in the bottom to 34 g.L-1 at the top of the bed, yet the average biomass concentration was still higher than that in IC reactor. According to shock tests with fluctuated real wastewater, the resistance of SSSAB to hydraulic and loading shock was up to 4.3 m h(-1) and 42 (kg COD.h).(m(3))(-1), respectively. The study demonstrated the proposed SSSAB is a promising reactor to treat high-concentration TCP wastewater. (C) 2019 Published by Elsevier Ltd.

关键词： Life cycle assessment   Membrane bioreactor   Wastewater treatment   Fruit processing industry   LCA   Water reuse  

摘要： Life-cycle assessment (LCA) was conducted to quantitatively assess the total environmental impacts of membrane bioreactor (MBR) and tertiary technologies treating wastewater in the fruit processing sector, allowing comparisons on the impacts of different treatment options, including impacts without on-site treatment. The system boundaries for all scenarios comprise raw materials extraction and processing, transportation, construction, operation and waste disposal. SimaPro 8.***.4.26 was used as the software tool, and two impact assessment methods (ReCiPe v1.11 and TRACI v2.1) were applied. Results showed that MBR combined with RO and UV contributed the least damage to the ecosystem, and minimized eutrophication impacts from the sewage when compared to the non-treatment scenario. Treating wastewater in municipal wastewater treatment plants (WWTP) would mitigate eutrophication effects, but it resulted in more environmental impacts from categories such as climate change and human health compared with implementing on-site treatment systems.

关键词： Multi soil layering bioreactor   synthetic domestic wastewater   pollutants removal   hydraulic loading rate   biofilm  

摘要： In this study, a multi soil layering (MSL) bioreactor was constructed to treat synthetic domestic wastewater. Effects of hydraulic loading rate (HLR) on the performance of the MSL bioreactor for synthetic domestic wastewater treatment were investigated. Results showed that the MSL bioreactor exhibited a strong adaptability on the variation of HLR, when the HLR was adjusted to 400 L center dot m(-2)center dot d(-1), average removal efficiencies of chemical oxygen demand (COD), ammonia, total nitrogen (TN), and total phosphorus (TP) reached 93.4%, 94.9%, 80.4%, and 94.7%, respectively, which meet to the 1A discharge standard of the Discharge standard of pollutants for municipal wastewater treatment plant (GB 18918-2002). In the treatment process by the MSL bioreactor, biological decomposition and biotransformation processes of microorganisms was the most important pathway for COD, ammonia, and TN removal, while TP was removed by the chemical reaction with ferric ion. Nitrobacteria, ciliate, rotifer and epistylis were in large numbers in the operating phase, indicated that the biofilm was matured with a high quality and the MSL bioreactor was effective for domestic wastewater treatment.

关键词： graphene   carbon-based nanomaterial   intestinal bacteria   microbiome   toxicity   next-generation sequencing   short chain fatty acids (SCFA)  

摘要： The increased use of graphene in consumer products such as food contact materials requires a thorough understanding of its effects on the gastrointestinal commensal bacterial population. During the first phase of study, three representative commensal bacterial species (L. acidophilus, B. longum, and E. coli) were exposed to different concentrations (1, 10, and 100 mu g/mL) of pristine graphene for 3, 6, and 24 h in the Bioreactor Rotary Cell Culture System (BRCCS) which allowed a continuous interaction of intestinal microbiota with the pristine graphene without precipitation of test material. The results showed that pristine graphene had dose dependent effects on the growth of selective bacteria. To study the interaction of graphene with more diverse consortia of intestinal microbiota, fresh fecal samples from laboratory rats were used. Rat fecal slurry (3%) was maintained in an anaerobic environment and treated with different concentrations (1, 10, and 100 mu g/mL) of pristine graphene for 3, 6, and 24 h. Counts of viable aerobic and anaerobic bacteria were assessed and fecal slurries were also collected for microbial population shift analysis using quantitative real-time PCR, as well as 16s rRNA sequencing. The results showed a significant two-fold increase in both aerobic and anaerobic bacterial counts (expressed as colony forming unit;CFU) during the first 3 h of exposure to all pristine graphene concentrations. However, 24 h of continuous exposure resulted in a 120% decrease in the CFU of aerobic bacteria at the highest concentration and the anaerobic bacteria CFU remained unchanged. Multivariate analysis of the q-PCR data showed that the exposure time, as well as the graphene concentrations, impacted the bacterial population abundance. Community analysis of graphene-treated fecal samples by 16S sequencing revealed significant alteration of 15 taxonomic groups, including 9 species. The increased abundance of butyrate producing bacteria (Clostridium fimetarium,

关键词： Genetic algorithm   Experimental design   Bioprocess   Mammalian cells   CHO   Recombinant protein  

摘要： Recombinant proteins produced by mammalian cell culture technology represent an important segment of therapeutic molecules. Development of their manufacturing processes is a time- and resource-consuming task. A wide array of process conditions, e.g. physico-chemical parameters, medium composition, feeding strategy, needs to be optimized to design a commercially feasible process with the desired productivity and product characteristics. Traditionally, statistical experimental designs, i.e. design-of-experiments methodology, have been used for such optimizations. However, statistical design approach has several limitations related to high dimensionality of the explored parameter space originating from the complexity of the mammalian cell culture processes. An alternative is therefore desired to overcome these limitations. In this study, we have successfully used a simple genetic algorithm as a method of experimental design for optimization of mammalian cell culture processes for two recombinant cell lines, one expressing a monoclonal antibody and one an Fc-fusion protein. Harnessing the automation capability of a robotically driven micro-bioreactor system to execute the genetic algorithm-derived experiments, a set of 14 process parameters was optimized within 132 experiments per cell line (six generations of 22 experiments), showing the feasibility of this approach as an alternative to classical statistical experimental designs.

关键词： Natamycin   Catabolite repression   Degradation   Streptomyces natalensis   Feeding   Bioreactor  

摘要： BackgroundNatamycin is an antifungal polyene macrolide antibiotic with wide applications in health and food industries. Currently, it is the only antifungal food additive with the GRAS status (Generally Regarded as Safe).ResultsNatamycin production was investigated under the effect of different initial glucose concentrations. Maximal antibiotic production (1.580.032g/L) was achieved at 20g/L glucose. Under glucose limitation, natamycin production was retarded and the produced antibiotic was degraded. Higher glucose concentrations resulted in carbon catabolite repression. Secondly, intermittent feeding of glucose improved natamycin production due to overcoming glucose catabolite regulation, and moreover it was superior to glucose-beef mixture feeding, which overcomes catabolite regulation, but increased cell growth on the expense of natamycin production. Finally, the process was optimized in 7.5L stirred tank bioreactor under batch and fed-batch conditions. Continuous glucose feeding for 30h increased volumetric natamycin production by about 1.6- and 1.72-folds in than the batch cultivation in bioreactor and shake-flasks, *** is a crucial substrate that significantly affects the production of natamycin, and its slow feeding is recommended to alleviate the effects of carbon catabolite regulation as well as to prevent product degradation under carbon source limitation. Cultivation in bioreactor under glucose feeding increased maximal volumetric enzyme production by about 72% from the initial starting conditions.

关键词： Membrane bioreactor   Membrane foulants   In-situ cleaning   Interactions energy   Extracellular polymeric substances  

摘要： In this study, the fate of sodium hypochlorite (NaClO) and detached membrane foulants and their impacts on the thermodynamic properties of raw sludge were investigated in a membrane bioreactor (MBR). It was found that about 20.3% of the total NaClO was potentially released into the bulk sludge, which significantly altered the raw sludge surface properties, such as a reduction in the number of surface electron donor components (gamma(-)) and an increase in surface hydrophobicity. After exposure to NaClO, the treated sludge had a higher adhesive and cohesive propensity compared to the raw sludge. Based on the extended Derjaguin-Landau-Verwey- Overbeek (XDLVO) theory and the batch filtration test results, the detached foulants potentially aggregated with the treated sludge and form the reconstructed sludge. The reconstructed sludge had a high protein (PN) level in the extracellular polymeric substances (EPS), with a higher membrane fouling potential compared with the raw sludge.

关键词： Haloalkaliphilic   SRB   16S rRNA sequencing   Bacterial communities  

摘要： Efficient removal of high concentration sulfate from wastewater with high sodium concentration and pH is a challenge to date. In this study, a bench-scale haloalkaliphilic bioreactor was continuously operated for high-efficiency treatment of high concentration sulfate in simulation wastewater. It was found that up to 70% of sulfate was removed within hydranlic retention time of 24 h when sulfate concentration in influent was as high as 3000 mgl(-1) at 1.0 M Na+ and pH 9.5. Sulfate removal rate reached 2.12 gl(-1) d(-1), which was much higher than results in literatures. The bottom region of bioreactor contributed approximate sulfate removal of 40% to total sulfate reduction. Then, the rate decreased gradually with the reduction of depth. Moreover, the composition of organic acids was closely related to depth of the bioreactor. According to microbial community analysis, Desulfonatronovibrio might play the most important role in sulfate removal, and its relative abundance was the highest at bottom region. The abundance decreased gradually as reduction of the depth of bioreactor. In addition, these results revealed a dynamic process of sulfate removal and variety of bacterial communities in whole bioreactor. The identification of many microorganisms by 16S rRNA sequencing deepened the insight of SRB interaction with non-SRB in sulfate-removal process. The high-efficiency process offered a great biotechnological penitential for sulfate removal of industrial wastewater.

关键词： Woodchip bioreactor   Climate change   Denitrification   Nitrous oxide   Methane   Dissolved greenhouse gases   Hydraulic residence time   Bioreactor management  

摘要： Denitrifying bioreactors remove nitrate (NO3-) from agricultural drainage and are slated to be an integral part of nitrogen reduction strategies in the Mississippi River Basin. However, incomplete denitrification can result in nitrous oxide (N2O) production and anaerobic conditions within bioreactors may be conducive to methane (CH4) production via methanogenesis. Greenhouse gas production has the potential to trade excess NO3- in surface water with excess greenhouses gases in the atmosphere. Our study examined N2O and CH4 production from pilot scale (6.38 m(3)) bioreactors across three hydraulic residence times (HRTs), 2, 8, and 16 h. Production was measured from both the surface of the bioreactors and dissolved in the bioreactor effluent. Nitrous oxide and CH4 was produced across all HRTs, with the majority dissolved in the effluent. Nitrous oxide production was significantly greater (P < 0.05) from 2h HRTs (478.43 mg N2O m(-3) day(-1)) than from 8 (29.95 mg N2O m(-3) day(-1)) and 16 (36.61 mg N2O m(-3) day(-1)) hour HRTs. Methane production was significantly less (P < 0.05) from 2 h HRTs (0.51 g C m(3) day(-1)) compared to 8 (1.50 g C m(3) day(-1)) and 16 (1.69 g C m(3) day(-1)) hour HRTs. The 2 h HRTs had significantly greater (P = 0.05) impacts to climate change compared to 8 and 16 h HRTs. Results from this study suggest managing HRTs between 6 and 8 h in field bioreactors could minimize total greenhouse gas production and maximize NO3- removal.