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关键词： Swine manure   Heavy metals   Cytotoxicity   Estrogenic hormones   Algal-bacterial bioreactor   Hydrothermal liquefaction   Catalytic hydrothermal gasification  

摘要： An integrated manure treatment system, including a mixed algal-bacterial bioreactor (MABB) and hydrothermal processing of biomass solids, was found to remove 76.4-97.0% of the total estrogenic hormones (estrone (E1), 17-estradiol (E2), and estriol (E3)) from the liquid portion of animal manure (LPAM). The mixed biomass was converted into either biocrude oil with a yield up to 40% via hydrothermal liquefaction (HTL) or syngas with a yield up to 54% yield via catalytic hydrothermal gasification (CHG). Adding granular activated carbon (GAC) in the MABB enhanced the removal of estrogenic hormones (+ 7.2%), cytotoxicity (+ 58%), and heavy metals (+ 10.5%). After the integrated system with the MABB, HTL, and CHG processes, the overall percent removal of heavy metals from the LPAM ranged from 27.1 to 40.3%. The concentrations of potentially toxic heavy metals (lead (Pb), copper (Cu), zinc (Zn), cadmium (Cd), nickel (Ni), chromium (Cr)) in the aqueous phase after HTL and CHG tests ranged from 0.01 to 25.3 mg/L.

关键词： Dendrobium nobile Lindl.   Temporary Immersion Bioreactor   Immersion Time   Semi-Solid Culture   Growth Index  

摘要： A protocol for culturing D. nobile shoots by temporary immersion bioreactor (TIB) in liquid medium was developed. The influences of immersion frequency, immersion time, sucrose concentration and culture methods were investigated for micropropagation of D. nobile using TIB with 10 g of explants and 1000 mL of liquid medium. The immersion frequency of 6 h and immersion time of 5 min were found to substantially promote the development of plantlet. Plantlet growth and polysaccharide accumulation showed differences with different sucrose concentrations, and the optimum concentration was 1.5%. In contrast to different methods of culture, we found the growth state of shoots obtained in the TIB was better than that in semi-solid medium and the rate of survival was improved when shoots obtained in the TIB were acclimatized to greenhouse. This is the first demonstration of the production of D. nobile plantlets cultured in liquid medium, and the protocol presented here shows good potential for application in large-scale propagation.

关键词： Tissue engineering   Perfusion bioreactor   Cell expansion   Wall shear stress  

摘要： BACKGROUND: Tissue engineering represents a promising approach for the production of bone substitutes. The use of perfusion bioreactors for the culture of bone-forming cells on a three-dimensional porous scaffold resolves mass transport limitations and provides mechanical stimuli. Despite the recent and important development of bioreactors for tissue engineering, the underlying mechanisms leading to the production of bone substitutes remain poorly understood. METHODS: In order to study cell proliferation in a perfusion bioreactor, we propose a simplified experimental set-up using an impermeable scaffold model made of 2 mm diameter glass beads on which mechanosensitive cells, NIH-3T3 fibroblasts are cultured for up to 3 weeks under 10 mL/min culture medium flow. A methodology combining histological procedure, image analysis and analytical calculations allows the description and quantification of cell proliferation and tissue production in relation to the mean wall shear stress within the bioreactor. RESULTS: Results show a massive expansion of the cell phase after 3 weeks in bioreactor compared to static control. A scenario of cell proliferation within the three-dimensional bioreactor porosity over the 3 weeks of culture is proposed pointing out the essential role of the contact points between adjacent beads. Calculations indicate that the mean wall shear stress experienced by the cells changes with culture time, from about 50 mPa at the beginning of the experiment to about 100 mPa after 3 weeks. CONCLUSION: We anticipate that our results will help the development and calibration of predictive models, which rely on estimates and morphological description of cell proliferation under shear stress.

关键词： SSF   Computational fluid dynamics   ANSYS fluent   Biotechnology   Transport phenomena  

摘要： In recent years, Solid-State Fermentation (SSF) has shown much promise for the development of bioprocesses and products. SSF involves the growth of microorganisms within a bed of moist solid particles permeated by a continuous gas phase and a minimum of visible water. SSF offers potential advantages over submerged culture: since the concentrations of products are often higher, smaller bioreactors can be used, reducing operational costs. However, there is a major challenge in obtaining adequate heat and mass transfer when this fermentation method is used at large scales. Mathematical models and computer simulations are useful tools for designing strategies to overcome this challenge;use of these tools can reduce costs of experimental development programs at pilot-scale and production scale, by reducing the number of fermentation experiments required. In the current work, we used the commercial CFD software ANSYS FLUENT (R) 16.0 to develop a mathematical model for heat and mass transfer in a pilot-scale packed-bed bioreactor. The model was used to simulate two different experiments that had been carried out previously in the bioreactor: first, the cooling of a bed of soybeans and, second, the heating of a bed composed of a mixture of wheat bran and sugarcane bagasse. The simulations considered the dynamics of airflow in the porous substrate bed and the non-equilibrium transfer of heat and moisture between the solid and gas phases. The second simulation considered a heterogeneous distribution of porosity within the substrate bed. Even though the two experiments were quite different, the same mathematical model was able to represent the temperature profiles observed experimentally. In the second simulation, the average temperature difference between the experimental and predicted values was 0.07 degrees C. A third simulation was done for the growth of the filamentous fungus Aspergillus niger in SSF, with the predictions being compared to the results of a traditional mat

关键词： biofilm membrane bioreactor   complex   thermodynamic stability   membrane fouling mitigation   computational thermodynamic analysis   multivariate statistics  

摘要： The membrane bioreactor (MBR) and the biofilm membrane bioreactor (BF-MBR) are among key solutions to water scarcity;however, membrane fouling is the major bottleneck for any expansion of these technologies. Prepolymerized aluminum coagulants tend to exhibit the greatest extent of fouling alleviation, with the reduction of soluble microbial products (SMPs) being among the governing mechanisms, which, nevertheless, has been poorly understood. This current study demonstrates that the investigation of the chemical coordination of monosaccharides, which are the major foulants in MBR and BF-MBR, to the main hydrolysis species of the prepolymerized aluminum coagulant, is among the key approaches to the comprehension of the fouling mitigation mechanisms in BF-MBR. Quantum chemical and thermodynamic calculations, together with the multivariate chemometric analysis, allowed the team to determine the principal mechanisms of the SMPs removal, understand the thermodynamic patterns of fouling mitigation, develop the model for the prediction of the fouling mitigation based on the thermodynamic stability of the inorganic-organic complexes, and classify these complexes into thermodynamically stable and less stable species. The results of the study are practically significant for the development of plant surveillance and automated process control with regard to MBR and BF-MBR systems.

关键词： Membrane fouling   Membrane bioreactor   Interface interaction   XDLVO theory   Artificial neural network  

摘要： It is of great importance to propose effective methods to quantify interfacial interaction since it directly determines foulant adhesion and membrane fouling process in membrane bioreactors (MBRs). This study developed a radial basis function (RBF) artificial neural network (ANN) to predict the interfacial interactions with randomly rough membrane surface. The interaction data quantified by the advanced extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) approach were used as the training samples for the RBF networks. It was found that, the computing time consumption for the RBF network prediction was only about 1/50 of that for the advanced XDLVO approach under same conditions, indicating the high efficiency of the RBF ANN method. Meanwhile, the calculation accuracy of the method was acceptable to get reliable results. This study demonstrated the breakthrough of the fundamental methodology related with membrane fouling. The proposed RBF ANN method has broad application prospects in membrane fouling and interface behavior research.

关键词： Anaerobic membrane bioreactor   Ambient temperature   Biogas   Agricultural irrigation   Pathogens  

摘要： A 496 L pilot scale anaerobic submerged membrane bioreactor (AnSMBR) for the treatment of municipal wastewater was evaluated during a year of stable operation at ambient (28-10 degrees C) temperature, and inoculated with mesophilic inoculum. The temperature was the main parameter affecting the process performance. The chemical oxygen demand (COD) of the effluent was around 150 mg O-2/L in the summer period, operating with a volumetric loading rate (VLR) of 5 kg COD/m(3) d and hydraulic retention time (HRT) of 8-10 h, with a specific methane production between 0.09 and 0.14 Nm(3)/kg CODremoved. However, during the winter season, an important increase of effluent COD was observed, and therefore the VLR was decreased to values around 1 kg COD/m(3) d in order to recover the quality of the effluent. Biogas production was negligible in this period. The effluent complies with the parameters stipulated by Spanish law regarding the use of treated wastewater for agricultural irrigation.

关键词： Vitellogenin promoter   Avian bioreactors   Recombinant proteins   Tissue-specific Promoters   Transgenic Chicken   LMH cells   Hepatocytes  

摘要： Transgenic chickens are of great interest for the production of recombinant proteins in their eggs. However, the use of constitutive strong promoters or the tissue-specific ovalbumin promoter for the generation of the transgenic chickens have different drawbacks that have to be overcome in order to make chicken bioreactor an efficient production system. This prompted us to investigate the use of an alternative tissue-specific promoter, the vitellogenin promoter, which could overcome the difficulties currently found in the generation of chicken bioreactors. In the present work we establish and characterize a DNA construct consisting of a fragment of the 5 '-flanking region of the chicken vitellogenin II gene cloned in a reporter vector. This construct is capable of showing the ability of the promoter to drive expression of a reporting gene in a tissue-specific manner and in a way that closely resembles physiologic regulation of vitellogenin, making it an ideal candidate to be used in the future for generation of avian bioreactors. Besides, we validate an in vitro culture system to test the performance of the DNA construct under study that could be used as a practical tool before generating any transgenic chicken. These results are important since they provide the proof of concept for the use of the vitellogenin promoter for future genetic modification of chickens bioreactors with improved characteristics in terms of quality of the recombinant protein produced.

关键词： Wastewater   Pathogens   Metagenomic sequence   Virulent factors   Size-fractionated flocs  

摘要： The size nature of sludge flocs could affect the occurrence and distribution of bacterial pathogens in wastewater treatment plants (WWTPs). In this study, the floc-size dependence of bacterial pathogens in the activated sludge of a WWTP was investigated using high-throughput metagenomic sequencing approaches. The results showed that a total of 423 pathogenic species belonging to 123 genera were identified in the three size-fractionated flocs. Also, we found that all the pathogens on the WHO's global priority pathogens list were detected in the size-fractionated flocs, with relative abundance of 0.4%, 0.3% and 0.3% for large-size, medium-size and small-size flocs, respectively, indicating the severe human and environmental health risks of activated sludge. Importantly, our results revealed that the pathogenic species showed a clear floc-size dependent distribution manner, leading to significant differences (P < 0.05) of pathogenic communities among the size-fractionated flocs. Additionally, by partitioning pathogens based on the occurrence and significant difference in abundances, we suggested the following distribution features: 1) large flocs-associated pathogens, such as Borrelia recurrentis, Actinobacillus ureae and Campylobacter gracilis;2) medium flocs-associated pathogens, such as Mycobacterium szulgai and Ureaplasma urealyticum;and 3) small flocs-associated pathogens, such as Rickettsia akari, Staphylococcus anginosus and Helicobacter cinaedi. Overall, this study provides a comprehensive understanding of pathogens in activated sludge, which is expected to aid in assessment and management of pathogen risks.

关键词： Fed-batch bioreactor   Sulfur-oxidizing bacteria   Toxicity test   Heavy metals   Electrical conductivity  

摘要： A fed-batch bioreactor based on sulfur-oxidizing bacteria (SOB) was tested for rapid detection of heavy metal-induced toxicity in water. For this evaluation, SOB were exposed to water contaminated by selenium, mercury, hexavalent chromium, arsenic, cyanide, cadmium, and lead for 2 h and their inhibition rates were analyzed based on changes in electrical conductivity (EC). The results demonstrate that SOB were highly inhibited by selenium, mercury, hexavalent chromium, and arsenic but not by cyanide, cadmium, and lead. The 2 h half maximum effective concentrations (EC50) of SOB for selenium, mercury, hexavalent chromium, and arsenic were estimated to be 0.33, 0.89, 1.18, and 0.24 mg/L, respectively, which are comparable or lower than earlier reports in the literature. However, the EC50 or EC20 values of SOB for cyanide, cadmium, and lead were notably higher compared to findings from previous toxicity tests that employed other microorganisms. The findings from the current study suggest that the fed-batch SOB bioreactor is suitable for rapid detection of toxicity induced by selenium, mercury, hexavalent chromium, and arsenic in water.