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关键词： Time scale analysis   Characteristic times   Modeling-based design   Microscale-based technology  

摘要： Time-Scale Analysis and Characteristics Times are suggested as a novel and useful tool for analyzing the performance of microscale-based bioreactors with immobilized bioactive material (e.g. enzymes or microbial species), and plant flow-sheet diagrams of chemical processes. Transport rates, reaction kinetics, and phase contacting can be easily represented by unique time constants, which facilitate understanding and representation of these processes via the ?heat-map tableau? of Characteristic Times. Details related to the development and the origin of Characteristic Times are presented in Part I of this paper;Jovanovic et al. (2020). Time Scale Analysis & Characteristic Times is a technical approach germane to process improvement, where it facilitates the discovery of areas in need of process intensification. The feasibility and usefulness of this novel tool is demonstrated by considering a microbial biochemical reaction process performed in a traditional bioreactor vs. performance in a microscale-based bioreactor design and evaluating the balance of characteristic times associated with each technology. We believe that this technical approach will confidently find its place in the toolbox of practicing chemical reaction engineers. ? 2021 Elsevier Ltd. All rights reserved.

关键词： Flat membrane bioreactor   volatile organic compounds (VOCs)   xylene   biodegradation   activated sludge  

摘要： The xylene is an important hydrophobic volatile organic compound (VOC) widely used as a solvent in different industries. Compared to the conventional bioreactors, the membrane bioreactor is more efficient for the degradation of hydrophobic VOCs. In this work, the degradation of gaseous xylene in a flat composite membrane bioreactor inoculated with activated sludge under different operating conditions was investigated. The maximum elimination capacities, ECv of 289 g/(m(3) h) and ECm of 0.145 g/(m(2) h) were obtained at the gas residence time of 20 s and the loading rate of 475 g/(m(3) h). Moreover, the membrane bioreactor is stable enough to suffer weak shock loading and short intermittent process shutdown. These results indicate that the membrane biotechnology shows great potentials in practical applications for xylene removal.

关键词： Bioreactors  

摘要： Acoustofluidics, by combining acoustics and microfluidics, provides a unique means to manipulate cells and liquids for broad applications in biomedical sciences and translational medicine. However, it is challenging to standardize and maintain excellent performance of current acoustofluidic devices and systems due to a multiplicity of factors including device-to-device variation, manual operation, environmental factors, sample variability, etc. Herein, to address these challenges, we propose "intelligent acoustofluidics" - an automated system that involves acoustofluidic device design, sensor fusion, and intelligent controller integration. As a proof-of-concept, we developed intelligent acoustofluidics based mini-bioreactors for human brain organoid culture. Our mini-bioreactors consist of three components: (1) rotors for contact-free rotation via an acoustic spiral phase vortex approach, (2) a camera for real-time tracking of rotational actions, and (3) a reinforcement learning-based controller for closed-loop regulation of rotational manipulation. After training the reinforcement learning-based controller in simulation and experimental environments, our mini-bioreactors can achieve the automated rotation of rotors in well-plates. Importantly, our mini-bioreactors can enable excellent control over rotational mode, direction, and speed of rotors, regardless of fluctuations of rotor weight, liquid volume, and operating temperature. Moreover, we demonstrated our mini-bioreactors can stably maintain the rotational speed of organoids during long-term culture, and enhance neural differentiation and uniformity of organoids. Comparing with current acoustofluidics, our intelligent system has a superior performance in terms of automation, robustness, and accuracy, highlighting the potential of novel intelligent systems in microfluidic experimentation.

关键词： Manure composting   Biochar   Arsenic methylation   Arsenic volatilization   Microbial community  

摘要： Biochar is widely used as an amendment to optimize the composting process. In this study, we firstly investigated the effects of biochar amendment on methylation and volatilization of arsenic (As), and the microbial communities during manure composting. Biochar amendment was found to increase the concentrations of monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) during mesophilic (days 0?10) and early thermophilic (days 11?15) phases, and promote As volatilization during the maturing phase (days 60?80) of composting. In addition, the abundances of As(V) reductase (arsC) and As(III) S-adenosyl-L-methionine methyltransferase (arsM) genes were higher in the biochar treatment than that in the control. Moreover, biochar amendment influenced the microbial communities by promoting As methylation and volatilization via Ensifer and Sphingobium carrying arsC genes, and Rhodopseudomonas and Pseudomonas carrying arsM genes. This study emphasized the considerable role of biochar on methylation and volatilization of As during manure composting and provided an overall characterization of the community compositions of arsC and arsM genes during manure composting. It will broaden our insights in As biogeochemical cycle during manure composting with biochar amendment, which will facilitate the regulation of As during manure composting and its application in agricultural soil.

关键词： Microplastics (MPs)   Sequencing batch membrane bioreactor (SB-MBR)   Floc characteristics   Microbial community   Biofilm structure  

摘要： Issues associated with accumulating microplastic (MP) in sewage sludge during wastewater treatment in a membrane bioreactor (MBR) system have not been studied in detail. Here, we investigated the microplastic?s effects on floc characteristics, microbial community compositions, and fouling behavior inside sequencing-batch MBRs. MBRs were operated with 0, 7, 15, and 75 MPs/L of feed for 124-days. Results indicated that MP presence decreased sludge floc size, floc hydrophobicity, and extracellular polymeric substance (EPS) molecular size, and increased EPS concentration and the floc?s negative zeta potential. These results were attributed to the facilitation of divalent cation (Ca2+ and Mg2+) uptake by MPs that weakened ion-bridging interactions within the sludge flocs. MPs accumulation slightly affected microbial structure and diversity. Relative abundances of dominant phyla, Actinobacteria, also decreased substantially. MPs also acted like a scouring material on membrane surfaces, inducing transformation of matured biofilm structures where protein content was substantially lower than nucleic acid content, in contrast to the control. Overall, MPs? negative effects on sludge flocs were counteracted by their scouring effect;consequently, SB-MBRs operated up to 4 months did not suffer from severe cake fouling, compared to control.

关键词： 厌氧膜生物反应器   厌氧氨氧化   甲烷回收   自养脱氮  

摘要： 本研究构建了厌氧膜生物反应器(AnMBR)-部分亚硝化/厌氧氨氧化(PN/Anammox)污水处理工艺,以探究AnMBR-PN/A工艺处理效果最佳的水力停留时间(HRT).AnMBR将厌氧生物处理与膜分离技术相结合实现有机物去除,AnMBR出水NH^(+)_(4)-N通过PN部分转化为NO^(-)_(2)-N,最终通过NO^(-)_(2)-N氧化剩余NH^(+)_(4)-N去除.实验结果表明:在HRT=11.2 h时,AnMBR-PN/A工艺化学需氧量(COD)去除率稳定在97%以上,COD转化为CH_4效率超过77.5%,总氮(TN)去除率为78%,出水COD和TN浓度分别低于14和11 mg·L^(-1).AnMBR段COD去除率达到95%,平均甲烷产率为0.39 L·L^(-1)·d^(-1).PN段实现了NO^(-)_(2)-N的高效积累,其出水中NO^(-)_(2)/NH^(+)_(4)为0.91±***段出水中的NO^(-)_(2)-N、NH^(+)_(4)-N和NO^(-)_(3)-N浓度分别低于1.0、4.9和5.1 mg·L^(-1).高通量测序结果表明PN段氨氧化菌主要为Nitrosomonas,丰度为7.09%,Anammox段主要微生物为Candidatus Brocadia,丰度高达21.01%.本研究构建的AnMBR-PN/A工艺实现了污水处理过程的高效能源回收和深度自养脱氮,研究成果为工程应用提供了理论支撑.

关键词： bioreactor   organoid   stem cell   tissue engineering  

摘要： Owing to the paucity of donor organs and their acute rejection by the immune system after transplantation,advanced organ failure is one of the major challenges faced by the medical *** culturing used for synthesising tissues and organs cannot simulate the in vivo mechanical and biochemical signals;therefore,such artificial organs fail to maintain effective functional activity following *** engineering can overcome these hurdles by successfully enabling regeneration of tissues and organs in *** are pivotal in the development and generation of engineered biological *** simulate the in vivo microenvironment of tissue growth while also providing various mechanical stimuli and biochemical signals to stem cells to effectively generate transplantable organs or *** designs and types of bioreactors,their applications,and future research prospects are summarised,which promote functional tissue engineering.

关键词： 错流管式膜   污堵原因   处理方法  

摘要： 本文以某垃圾电厂实际应用为例,介绍了外置式错流管式超滤膜在垃圾渗滤液处理过程中出现的污堵原因及相应处理方法,并期望在实际应用中不断总结经验,更好地提高膜的使用效率。

关键词： Streptokinase   Pichia pastoris   AOX1 promoter   Nitrogen supplementation   Proteolytic degradation   High cell density cultivation  

摘要： Streptokinase is a well-established cost-effective therapeutic molecule for thrombo-embolic complications. In the current study, a tag-free variant of streptokinase with a native N-terminus (N-rSK) was developed using the Pichia expression system. A three-copy clone was screened that secreted 1062 mg/L of N-rSK in the complex medium at shake flask level. The biologically active (67,552.61 IU/mg) N-rSK recovered by anion exchange chro-matography was predicted to contain 15.43% alpha-helices, 26.43% beta-sheets. The fermentation run in a complex me-dium yielded a poor quality product due to excessive N-rSK degradation. Therefore, modified basal salt medium was also employed during fermentation operations to reduce the proteolytic processing of the recombinant product. The concomitant feeding of 1 g/L/h soya flour hydrolysate with methanol during the protein synthesis phase reduced the proteolysis and yielded 2.29 g/L of N-rSK. The fermentation medium was also supplemented with urea during growth and induction phases. The combined feeding approach of nitrogen-rich soya flour hy-drolysate and urea during bioreactor operations showed significant improvement in protein stability and re-sulted in a 4-fold increase in N-rSK concentration to a level of 4.03 g/L over shake flask. Under optimized conditions, the volumetric productivity and specific product yield were 52.33 mg/L/h and 33.24 mg/g DCW, respectively.& nbsp;(c) 2021 Elsevier B.V. All rights reserved.

关键词： 成果转化   生物反应器   生物技术产业   药物开发   发展新模式   人才培养   教育部工程研究中心   交叉与融合  

摘要： 生物反应器与药物开发教育部工程研究中心(以下简称"中心")于2006年6月获教育部批复立项,2012年1月通过验收,并获得优秀。中心以构建高校产、学、研一体化创新模式为目标,全面推进科技创新、人才培养及成果转化,为生物技术产业和社会发展做出贡献。同时,以生物反应器及其产品开发的基础研究、工程转化为主,构建农学、医学和药学相结合的新的学科领域,实现农业、医药、工业等领域的交叉与融合,探索并建立生物反应器开发的内涵和外延发展新模式。