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关键词： Advanced Oxidation Processes   Bacillus Subtilis   Toxicity sensor  

摘要： Wastewater streams contain a large number of contaminants, part of which can be quite toxic for the working bacteria in bioreactors, thus hampering its efficiency. In such cases, pretreatment by an Advanced Oxidation Process (AOP) might be needed. Since, in general, biotreatment is more economic than AOP, it is sensible to design the integrated system in a manner that would reduce the load on the AOP as much as possible. This is a very challenging task, since the type and the concentration of the toxic compounds constantly varies over time. The problem is aggravated by lack of inexpensive and fast technologies that are able to evaluate the toxicity under conditions in which the nature of the toxic compounds is *** we report on the developing of a unit that automatically measures the extent by which polluted water might put at risk a biological treatment unit. The sensing unit monitors in real time the viability of the reporting bacteria Bacillus Subtilis, using resazurin. The toxic compounds were modelled by three antibiotics (chloramphenicol, tetracycline and ciprofloxacin). The potential of embedding the sensing unit in a multi-technology system (AOP-biological) was demonstrated by connecting the sensing unit to a photocatalytic reactor and controlling the number of operating lamps in the photocatalytic reactor autonomously according to predetermined toxicity setpoint. The approach can be easily applied to almost any AOP-biotreatment tandem system, while altering any controllable parameter (residence time, light, etc.) of the AOP unit according to needs.

关键词： 厌氧膜生物反应器   膜污染   主成分分析   BP神经网络  

摘要： 膜污染是厌氧膜生物反应器运行中不可避免的问题,制约了工艺技术的推广应用,分析膜污染的形成过程是控制膜污染的重要内容。基于主成分分析(PCA)和反向传播神经网络(BPNN)的理论,提出了一种采用主成分分析优化BP神经网络的膜污染预测模型。以反应器连续运行试验数据为样本,利用相关性分析确定模型的输入变量,并基于输入变量间存在信息重叠问题,采用主成分分析法对输入因素进行降维处理,提取贡献率为70.4%的第一主成分和贡献率为17.7%的第二主成分作为输入特征。结合模型的贡献度分析和主成分分析发现,反应器内的污泥浓度是膜污染影响因素中最主要的特征变量,贡献度为34.9%。对比分析优化模型和单一模型的预测结果,发现PCA-BPNN模型的拟合效果更好,平均相对误差仅为3.8%,可用于膜污染分析研究,为后续研究提供参考。

关键词： orbitally shaken bioreactors   CFD   liquid wave   hydrodynamic stress   cell cultivation  

摘要： BACKGROUND For several years, orbitally shaken cylindrical bioreactors (OSRs) have become a new approach for propagation of mammalian cells cultivated under suspension. With new commercial cell culture media available today, allowing exceptionally high cell densities, the identification of suitable operating conditions presents a special challenge. Balancing hydrodynamic stress and other factors in reactors, this is particularly true for gas transfer rates providing sufficient oxygen (O-2) to cultures that can attain ten-fold greater biomasses than just a decade ago. This challenge is more profound the larger the working volume of the reactor becomes. RESULT For 10-L working volume cylindrical OSRs, we established a computational fluid dynamics model to evaluate the impacts of different operational conditions. Both fluid velocity distributions and O-2 transfer coefficients (k(L)a) were calculated for different filling volumes and shaking speeds. Also, hydrodynamic stress parameters were investigated considering the most critical working conditions. CONCLUSION The fluid velocity decreased with larger working volumes and, as expected, was found to increase with higher shaking frequency. Gas transfer rates between 10 and 54 h(-1) were found in working volumes from 2.5 to 10 L and under shaking frequencies from 100-160 rpm. Critically assessing the obtained data, with no liquid-submerged gas supply, we conclude that an air flow into the head-space of a disposable bag appears to be satisfactory under certain operating conditions to support the culture of the most sensitive mammalian or insect cell cultures towards high cell density, presently in fed-batch cultures achieving <= 30 x 10(6) cells mL(-1). Shear stress parameters were found to be exceptionally low. (c) 2021 Society of Chemical Industry (SCI).

关键词： 生物膜反应器  

ISBN: (纸本)9787560392967

摘要： 膜生物反应器 (MBR) 是高效膜分离技术与生物处理技术相结合的新型水处理技术, 在污水处理和回用方面被广泛应用, 被誉为21世纪最具有发展前途的水处理新技术之一。本书主要介绍了膜与膜材料特征、膜生物反应器及其原理、城市污水处理MBR系统及其效能与影响因素、膜污染行为与机理、膜污染控制技术及MBR的工程应用案例。在新型膜材料、新型膜生物反应器及其处理效能、膜污染物质识别与控制等方面进行了重点论述。

关键词： biodegradation   butachlor   mass transfer coefficient   packed bed bioreactor  

摘要： In the present study, the effect of external mass transfer on the rate of butachlor biodegradation was studied using calcium alginate immobilized microbial consortium SMC1 in a re-circulated up-flow packed bed bioreactor in a batch scale. By assuming the biodegradation kinetics to be first order, the effect of various operational parameters such as feed flow rate, substrate concentration, and the external mass transfer on the bio-removal of butachlor from the aqueous medium has been explored. Using external film diffusion models and Colburn analogy, the mass transfer correlations at several feed rates were worked out. The correlational analysis obtained in the form of J(D) = 1.341 NRe-0.3 was found to predict the experimental data precisely.

关键词： Rhamnolipids   Acinetobacter calcoaceticus   Bioreactor fermentation   Wound healing   TGF-S1  

摘要： Rhamnolipids are predominantly produced from the opportunistic pathogen Pseudomonas aeruginosa, which restricts their scaled-up production and biomedical applications. Moreover, the wound healing property of rhamnolipids is mainly focused on either mono- or di-rhamnolipid congeners, which are obtained after extensive and costly purification procedures. Here, crude rhamnolipids from non-pathogenic Acinetobacter calcoaceticus BU-03 have been prepared and characterized and their wound healing potency evaluated in vitro and in vivo. Rhamnolipid extract was produced in a bioreactor by batch fermentation at a concentration of 12.7 +/- 1.4 g/L. Characterization of the extract by Fourier Transform Infrared spectroscopy and mass spectrometry revealed characteristic rhamnolipid peaks. Rha-C10-C10 and Rha-Rha-C10-C10 appeared as the predominant congeners along with minor quantities of six more congeners. The rhamnolipid extract obtained from A. calcoaceticus had no toxicity against mouse fibroblast L929 cells and accelerated their migration. Transforming growth factor beta 1 (TGF-S1) has been shown to promote fibroblast migration by activating Smad3. It was found that the rhamnolipid extract enhanced Smad3 phosphorylation in L929 cells. In vivo studies showed that it promoted wound healing in mice with excisional wounds. The protein levels of TGF-S1 and alpha smooth muscle actin (a-SMA), a highly contractile protein, were significantly increased by 2.56- and 1.51-fold, respectively, in extract-treated compared with vehicle control-treated wounds, indicating that the activation of TGF-S1 signaling is possibly involved in the wound healing effect. These results suggest that a rhamnolipid extract obtained from A. calcoaceticus has potential as a wound healing material for topical application in cutaneous wound treatment.

关键词： Phytosterol esters   Continuous-flow   Immobilized lipase   Enzymatic esterification   Food additives  

摘要： In this study, a continuous-flow bioreactor packed with well-organized lipase microarrays was developed for the sustainable synthesis of functional lipid-phytosterol esters (PEs). Hollow mesoporous silicon spheres with a suitable pore size were prepared for lipase immobilization, and the hydrophobic modification endowed the lipase with excellent catalytic activity and stability. The results showed that the condensely packed lipase microarrays offered large specific surface areas and guaranteed the thorough interaction between the lipase and substrates in the continuous-flow bioreactor. Meanwhile, the substrate could pass through the reactor at 1 mL/min with a high conversion of 93.6% due to the hollow structure of the packing spheres. Moreover, the reactors were able to produce 1564 g PEs/g catalyst in a continuous 30-day processing period, which set the highest records for PEs synthesis. This sustainable and highly-converting flow system provided a feasible path for scale-up production of PEs in the food processing area.

关键词： Acid mine drainage   Sulfate-reducing bacteria   Bioremediation   Spent brewing grains   Sugarcane bagasse   Lignocellulose  

摘要： Lignocellulosic sulfate-reducing bioreactors are an inexpensive passive approach for treatment of mininginfluenced water (MIW). Typically, microbial community acclimation to MIW involves bioreactor batch-mode operation to initiate lignocellulose hydrolysis and fermentation and provide electron donors for sulfatereducing bacteria. However, batch-mode operation could significantly prolong bioreactor start-up times (up to several months) and select for slow-growing microorganisms. In this study we assessed the feasibility of bioreactor continuous-mode acclimation to MIW (pH 2.5, 6.5 mM SO42-, 18 metal(loid)s) as an alternate start-up method. Results showed that bioreactors with spent brewing grains and sugarcane bagasse achieved acclimation in continuous mode at hydraulic retention times (HRTs) of 7-12-d within 16-22 days. During continuousmode acclimation, extensive SO42- reduction (80 +/- 20% -91 +/- 3%) and > 98% metal(loid) removal was observed. Operation at a 3-d HRT further yielded a metal(loid) removal of 97.5 +/- 1.3 -98.8 +/- 0.9% until the end of operation. Sulfate-reducing microorganisms were detected closer to the influent in the spent brewing grains bioreactors, and closer to the effluent in the sugarcane bagasse bioreactors, giving insight as to where SO(4)(2- )reduction was occurring. Results strongly support that a careful selection of lignocellulose and bioreactor operating parameters can bypass typical batch-mode acclimation, shortening bioreactor start-up times and promoting effective MIW metal(loid) immobilization and treatment.

关键词： BHK-21细胞   禽偏肺病毒   悬浮培养   生物反应器  

摘要： 目的对生物反应器悬浮培养禽偏肺病毒(avian metapneumovirus,aMPV)制备弱毒疫苗的工艺进行优化。方法采用分批培养的方法优化悬浮BHK-21细胞在生物反应器内培养及aMPV增殖工艺,并对制备的疫苗进行动物安全性及攻毒保护试验。结果采用1.0×10^(6)cells/mL的初始接种密度培养BHK-21悬浮细胞,细胞能快速度过延滞期进入对数生长期,培养72 h细胞密度可达1.6×10^(7)cells/mL。调整细胞密度为3.0×10^(6)cells/mL,按照感染复数MOI=0.1的剂量接种病毒,病毒含量可达10^(8.67)TCID_(50)/mL。制备的疫苗安全性良好,可有效保护番鸭,保护率为100%。结论优化了生物反应器培养aMPV的工艺,可获得较高的病毒效价,为aMPV疫苗的规模化生产提供了参考。

关键词： Membrane fouling   Microbial community   Membrane bioreactors   Ecological network   Biofilm   Mixed liquor  

摘要： This work examined fouling-associated microbial community in a carefully controlled laboratory-scale membrane bioreactor (MBR) at different fouling stages. In agreement with the literature, fouling severity was positively correlated with bound polysaccharide and protein content (indicators) in the mixed liquor. UPGMA clustering analysis with different indices indicated that although the biofouling layer (biofilm) and mixed liquor possessed highly similar microbial identity, important differences between the two communities' structures were also observed. This appears to be the first comprehensive study to apply differential abundance analysis (ANCOM) to identify microbial taxa driven the divergence in microbial structure including Victivallales, Coxiellales, unassigned Microgenomatia and Blastocatellia 11-24 (all presented at 1% abundance). Network analysis also identified Victivallales and Blastocatellia 11-24 among the few key players in the mixed liquor and biofilm community, respectively. Despite their low abundances, key players in both communities positively correlated (Pearson's correlation coefficient 0.6) with fouling indicators, confirming their important contributions to fouling propensity. The biofilm community exhibited a more complex structure with higher level of inter-species interaction and prevalence of positive connections (74.6%) compared to the mixed liquor community (42.2%), reflecting higher stability and synergy between microbial taxa in the biofilm. Results from this comprehensive investigation can support the development of new fouling control strategies.