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关键词： Algal-sludge membrane bioreactor   Soluble extracellular polymeric substance   Bound extracellular polymeric substance   Fouling potential   Interaction energy  

摘要： This study focused on the effect of algae on the fouling potential and dynamic fouling variation of foulants in an innovative algal-sludge membrane bioreactor (AS-MBR). Filtration experiments revealed that the soluble extracellular polymeric substance (S-EPS) released by the algal-sludge flocs showed a slower diminishing rate of flux than that released by the sludge flocs. The intermediate blocking and cake filtration models demonstrated the major mechanisms, which implied a reduction in the driving force of pore blocking and fouling layer formation induced by the algal-bacterial S-EPS. Furthermore, the relative flux decrements of loosely bound EPS (LBEPS) and tightly bound EPS (TB-EPS) in the AS-MBR were lower than those of the control without algae, indicating a reduction in the fouling potential of the bound EPS (B-EPS) in the algal-sludge flocs compared to the control. This could be attributed to the reduction in the membrane intercepts for LB- and TB-EPS, respectively. Specifically, S-EPS and B-EPS released by algal-sludge flocs had a lower free energy of cohesion (Delta G(coh)) than those released by sludge flocs (decreased of 19.14%, 45.93%, and 43.34% for the S-EPS, LB-EPS, and TB-EPS, respectively). Furthermore, these changes could contribute to the decrease in the relative abundance of adsorbed polysaccharide- and protein-like substances in the B-EPS (released by algal-sludge flocs) filtration membrane, leading to the formation of less rough peaks and valleys in the fouling layer in the AS-MBR. Accordingly, the lower fouling propensity and weaker cohesion energy of S-EPS and B-EPS tend to decrease the hydrophobicity and the free energy of the floc surface and further provide less driving force to adhere to the membrane, resulting in significant mitigation of membrane fouling in the AS-MBR. Therefore, the overall fouling behavior caused by S-EPS, B-EPS and flocs should be comprehensively considered to achieve an underlying understanding of the algal effect

关键词： Effluent treatment plant sludge   Municipal solid waste   Bioreactor landfill   Co-disposal   Bioenergy generation  

摘要： The study aims to investigate the feasibility of anaerobic co-landfilling of effluent treatment plant sludge (ETPS) from paper mill and municipal solid waste (MSW) in prismoidal shaped simulated anaerobic landfill bioreactors. Both ETPS and MSW were co-disposed in 0:100 (R1), 25:75 (R2), 50:50 (R3) and 75:25 (R4) ratios. Periodic assessments of leachate characteristics and biomethane production were carried out for 300 days. ETPS codisposal with MSW showed considerable reduction in biochemical oxygen demand of leachate (R2: 95.9%, R3: 97.5% and R4: 93.2%). Moreover, cumulative methane gas generations were 2.974, 6.085 and 4.653 times more in R2, R3 and R4 bioreactors as compared to R1. Gompertz growth model was found in well-fitting for methane generation with the observed data. Correlogram plotted among leachate parameters exhibited exclusive relationships and justified leachate trends. This simulation of co-landfilling could be baseline study for the implementation of technology at pilot scale.

关键词： Disinfection   Virus removal   Electrochemical membrane bioreactor   Wastewater treatment  

摘要： Wastewater treatment facilities play pivotal roles in preventing the transmission of water-borne viruses and protecting human health. In this study, a new electrochemical membrane bioreactor (EMBR) was proposed to achieve a long-lasting and efficient removal of virus from wastewater. Results showed that applying a low electric field (2.0 V) in EMBR system could achieve similar to 100% removal efficiency at both batch tests and continuous flow experiments. In contrast, the control MBR, without the exertion of electric field, exhibited a very low removal efficiency (19.8% on average). Moreover, the fouling in EMBR was significantly mitigated, which enabled its operation duration almost 3 times longer than that of the control. Further explorations suggested that the reactive oxidants generated on electrodes in the EMBR system were mainly responsible for MS2 removal. This study demonstrated the potential of utilizing the EMBR process to achieve an enhanced virus disinfection efficiency during the wastewater treatment process.

关键词： decellularization and recellularization   disease modeling   EVLP systems   lung‐   on‐   a‐   chip   monitoring bioreactors   stem cells  

摘要： Lung bioengineering has emerged to resolve the current lung transplantation limitations and risks, including the shortage of donor organs and the high rejection rate of transplanted lungs. One of the most critical elements of lung bioengineering is bioreactors. Bioreactors with different applications have been developed in the last decade for lung bioengineering approaches, aiming to produce functional reproducible tissue constructs. Here, the current status and advances made in the development and application of bioreactors for bioengineering lungs are comprehensively reviewed. First, bioreactor design criteria are explained, followed by a discussion on using bioreactors as a culture system for scalable expansion and proliferation of lung cells, such as producing epithelial cells from induced pluripotent stem cells (iPSCs). Next, bioreactor systems facilitating and improving decellularization and recellularization of lung tissues are discussed, highlighting the studies that developed bioreactors for producing engineered human-sized lungs. Then, monitoring bioreactors are reviewed, showing their ability to evaluate and optimize the culture conditions for maturing engineered lung tissues, followed by an explanation on the ability of ex vivo lung perfusion systems for reconditioning the lungs before transplantation. After that, lung cancer studies simplified by bioreactors are discussed, showing the potentials of bioreactors in lung disease modeling. Finally, other platforms with the potential of facilitating lung bioengineering are described, including the in vivo bioreactors and lung-on-a-chip models. In the end, concluding remarks and future directions are put forward to accelerate lung bioengineering using bioreactors.

摘要： Membrane fouling remains a challenging issue which is the main obstacle of wider applications of anaerobic membrane bioreactors (AnMBRs). This is because the cake layer in AnMBRs is thicker and less removable than that in aerobic membrane bioreactors due to the different sludge characteristics. Pretreatment of feed wastewater can efficiently control membrane fouling by altering the feed water properties with the addition of fouling reduction enhancers, such as adsorbents and flocculants. Activated carbon, such as powdered activated carbon (PAC), which is comparatively simple and effective adsorbent, has been largely applied as an adsorbent to aerobic membrane bioreactors for membrane fouling mitigation. However, only a limited amount of research has focused on the application of PAC to AnMBRs. Although some studies have reported the effects of PAC addition on pollutants removal performance and fouling control of AnMBR system, few studies discussed the overall nutrient and organics removal performance as well as detailed membrane fouling behaviour regarding PAC addition at an ambient temperature. In addition, no study has been carried out on the effect of PAC on microbial community in AnMBR. The long-term effects of the optimal PAC dosage, which was found to be 5 g/L from the short-term experiments, on conventional AnMBR performance with a hollow fiber membrane were investigated in this study. The optimal one-off PAC dosing could increase average COD and total organic carbon (TOC) removal rates up to 15.71% and 15.69%, respectively. The PAC addition exhibited not only lower transmembrane pressure (TMP) increase rate, but also reduction of soluble microbial product (SMP) and extracellular polymeric substances (EPS). High protein fraction of SMP as well as increased zeta potential in AnMBR with PAC addition could enhance hydrophobicity, which improved the flocculation ability of sludge. In addition, lower total membrane resistance and pore blocking resistance indicated

关键词： Anaerobic membrane bioreactor   Biochar   Sewage   Digestion efficiency   Membrane fouling  

摘要： The enhancement effects of biochar to an anaerobic membrane bioreactor (AnMBR) treating sewage at low temperatures was investigated in this study through analyzing organics removal, digestion performance, mixed liquor properties, membrane resistance, and foulant compositions. The chemical oxygen demand (COD) removal efficiency and the COD converted to methane rate increased by more than 12.5% at 10 ?C, mainly because of the promotion of biochar to volatile fatty acids degradation. Although biochar caused higher dissolved organic matter (DOM) concentration in the AnMBR, it improved the filtration property of the bulk sludge and absorbed the hydrophobic DOM. The decreased filtration resistance assisted by biochar leads to a prolonged membrane operation duration over 200%. Surface foulants, especially cake foulants, were largely mitigated by the enhanced scouring intensity of mixed liquor at the membrane surface, and hence, decreasing the cake/gel foulants ratio.

关键词： Bioreactor   Chemostat   Dynamic system   Mathematical model   Hopf bifurcation   Stability analysis  

摘要： Bioeactors with various configuration are used for the biodegradation of industrial and municipal wastes. In this article we study dynamic performance of a nonlinear bioreactor model for the aerobic biodegradation of wastes. The proposed model accounts for oxygen transfer, cells decay, Contois growth kinetics for cells decay, while the biomass yield coefficient is assumed to depend on the substrate. Some key properties of time evolution of the solutions, sensitivity of parameters and controllability of the proposed model have been rigorously examined here. Unsteady behavior of solutions have been studied both analytically and numerically. It is confirms in this study that the proposed model is able to capture a range of solution behavior including bistability and oscillations. The steady state solutions and their stability has been evaluated with the bioreactor residence time. Here a few specific mathematical conditions are studied to describe the number of different steady states and their stability. Performance analysis of the bioreactor model has also been studied to validate the model. Periodicity of solutions within a physically meaningful parameter regions for are also investigated. (c) 2021 Elsevier Ltd. All rights reserved.

关键词： Acclimatization   Auxins   Cytokinins   Ex vitro rooting  

摘要： Corema album is one of the two species of flowering plants in the Corema genus, from family Ericaceae, and is also known for its common name Camarinha or Portuguese crowberry. It has a restricted distribution, being confined to the western Atlantic coast of the Iberian Peninsula and Aquitaine in France, in dune systems or in low pine forests. The shrub is exploited because of its food, ornamental and medicinal value and the regeneration rate in the natural habitat is very low. For the first time, an in vitro propagation protocol has been developed from nodal segments obtained from adult plants in the field. Several nutrient formulations were tested for the establishment and the best results, in terms of highest bud break frequency (6.7%), were achieved with the woody plant medium (WPM) basal salts, supplemented with 2.0 mg l(-1) 2iP at pH 5.6. WPM was then used for sub-culturing of shoots every 8 weeks and to perform an assay to test the effect of different cytokinins (BA, Kin 2iP and mT) combinations in the multiplication phase. Of all the combinations tested, 2.0 mg l(-1) 2iP with 1.0 mg l(-1) Kin is the most beneficial with 100% bud break, 6.8 new shoots, with 14.2 mm average length and the shoots regenerated were healthy. A study with a temporary immersion bioreactor (SETIS (TM)) was performed, with promises results, where more than double the multiplication rate was achieved compared with the previous semisolid medium. However, in this system, vitrification processes have occurred which may compromise the viability of the shoots. Rooting, which proved to be a difficult process, was best induced ex vitro by dipping of the microshoots in a 2.0 g l(-1) IBA solution for 10 s, followed by placement in jiffy-7C pellets, with 20% of rooting and an average of 5.3 roots and 43.8 mm long. The microplants were potted and acclimatized, showed 100% survival. Key message Corema album, exploited because of its food, ornamental and medicinal value, has a restricted distributio

关键词： Escherichia coli   L-phenylalanine   metabolic engineering   large-scale cultivation  

摘要： As an essential aromatic amino acid, L-phenylalanine (L-Phe) has a lot of applications as precursors for pharmaceuticals, artificial sweetner, etc. Previously, through metabolic engineering, we developed an Escherichia coli strain (YHP05) capable of overproducing L-Phe. In this study, we further engineered E. coli strain to develop an economic bioprocess for L-Phe production in large scale bioreactor. First, we developed E. coli YHP06 harboring pYHP which cultivation does not require supplementation of amino acids for cell growth. Next, the strong and constitutive gene expression systems for L-Phe biosynthesis were sequentially introduced into chromosome of E. coli, which allowed the antibiotic-free and inducer-free cultivation. Among the engineered strains, the H-02 strain showed the highest production of L-Phe (3.6 g/L) in the flask cultivation. The production of L-Phe in the engineered H-02 strain was also evaluated in lab-scale (5 L), and L-Phe as high as 30.7 g/L could be produced with 0.81 g/L/h of productivity. Finally, the pilot-scale (30 L) fed-batch cultivation was performed, and we could achieve the production of L-Phe as high as 38.6 g/L with 1.07 g/L/h of productivity.

关键词： 生物膜反应器  

ISBN: (纸本)9787122388063

摘要： 本书全面阐述和分析了MBR全系统设计和运行的各个环节，理论与工程实践相结合；提出了很多新的技术观点和实验新发现，并对系统安装与设备的制造细节等做了详实的论述。详细论述了膜生物反应器各个生化段的反应机理，对各项工艺参数的选定方法进行了探讨并根据工程实践提供了实用数据，对膜生物反应器的通用生化系统提供了工艺计算方法和计算示例，对膜生物反应器系统的设计、制造、安装、调试及配套等各个细节进行了细致的讲解。