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关键词： 膜曝气生物反应器   同步硝化反硝化   无泡曝气  

摘要： 膜曝气生物反应器(MABR)是一种将传统的生物膜工艺与膜曝气的供氧方式联合起来而诞生的新型污水处理工艺。阐述了MABR的原理和特点,通过膜材料、影响因素和应用现状的综述,指出当前MABR应用中需要进一步研究的问题,展望了其在未来的发展趋势。

关键词： Bioreactor   Rotation seeding   Lung tissue engineering   Decellularized scaffold  

摘要： Bioreactors for the reseeding of decellularized lung scaffolds have evolved with various advancements, including biomimetic mechanical stimulation, constant nutrient flow, multi-output monitoring, and large mammal scaling. Although dynamic bioreactors are not new to the field of lung bioengineering, ideal conditions during cell seeding have not been extensively studied or controlled. To address the lack of cell dispersal in traditional seeding methods, we have designed a two-step bioreactor. The first step is a novel system that rotates a seeded lung every 20 min at different angles in a sequence designed to anchor 20% of cells to a particular location based on the known rate of attachment. The second step involves perfusion-ventilation culture to ensure nutrient dispersion and cellular growth. Compared to statically seeded lungs, rotationally seeded lungs had significantly increased dsDNA content and more uniform cellular distribution after perfusion and ventilation had been administered. The addition of this novel seeding system before traditional culture methods will aid in recellularizing the lung and other geometrically complex organs for tissue engineering.

关键词： Articular Cartilage   Soft Matter   Microindentation   Stiffness   Biotribology  

摘要： Background Microindentation is a technique with high sensitivity and spatial resolution, allowing for measurements at small-scale indentation depths. Various methods of indentation analysis to determine output properties exist. Objective Here, the Oliver-Pharr Method and Hertzian Method were compared for stiffness analyses of articular cartilage at varying length-scales before and after bioreactor loading. Methods Using three different conospherical tips with varying radii (20, 100, 793.75 mu m), a bioreactor-indenter workflow was performed on cartilage explants to assess changes in stiffness due to articular loading. For all data, both the Oliver-Pharr Method and Hertzian Method were applied for indentation analysis. Results The reduced moduli calculated by the Hertzian Method were found to be similar to those of the Oliver-Pharr Method when the 20 mu m tip size was used. The reduced moduli calculated using the Hertzian Method were found to be consistent across the varying length-scales, whereas for the Oliver-Pharr Method, adhesion/suction led to the largest tip exhibiting an increased average reduced modulus compared to the two smaller tips. Loading induced stiffening of articular cartilage was observed consistently, regardless of tip size or indentation analysis applied. Conclusions Overall, geometric linearity is preserved across all tip sizes for the Hertzian Method and may be assumed for the two smaller tip sizes using the Oliver-Pharr Method. These findings further validate the previously described stiffening response of the superficial zone of cartilage after articular loading and demonstrate that the finding is length-scale independent.

关键词： Bioreactors   Impedance spectroscopy   Bacillus thuringiensis   Operating conditions   Cole–   Cole   Zarc circuit  

摘要： The most important parameter in bioprocesses is biomass, where not only the quantity produced in a culture but also the behavior that is presented are important concerns. It is clear that conditions of operation in a bioreactor affect biomass production, but how operation conditions affect the measurement of biomass on-line is of special interest. We studied the effect of bioreactor operating condition variations on model parameters using impedance spectroscopy for biomass monitoring. The model parameters analyzed were capacitance, resistance, alpha (alpha), conductivity delta ( increment sigma) and critical frequency (fc). These model parameters were obtained by fitting data from impedance measurements to an equivalent circuit model and Cole-Cole conductivity model. The effect of operating conditions on the medium with no cells was estimated by the percentage of change in each model parameter. The operating conditions with the most significant percentage of change were determined, by comparing to the percentage of change of the same model parameters obtained, during a fermentation of Bacillus thuringiensis as a cellular model. Equivalent circuit parameters were mainly affected by variation in pH, temperature and aeration, whereas Cole-Cole parameters were affected by variation in agitation, aeration, temperature and pH. Therefore, any variation in these operating conditions (within the test interval) during a fermentation may generate changes in monitoring parameters, which will not be a direct consequence of any change in the properties of the biomass.

关键词： anammox bacteria   free‐   living cells   growth rate   membrane bioreactor   rapid cultivation  

摘要： The low growth rate of anammox bacteria is one of the main obstacles to its broad use in removing biological nitrogen in sewage treatment. Free cells show the characteristics of relatively rapid growth. To increase the growth rate, this study cultivated free-living anammox bacteria using a membrane bioreactor. The particle size distributions showed that more than 95.48% of biomass was less than 50 mu m in size, and the growth rate of free-living anammox bacteria was shortened to 5.68 days after cultivation. Candidatus Brocadia was the most important anammox genus, with a relative abundance of 8.83%. The key functional genes, including hzs, hdh, and hao, were identified and expressed using metagenomic and metaproteomic analyses. After the rapid cultivation of the free-living anammox bacteria, a potential method shortening the start-up time was proposed to rapidly form anammox biofilm by attaching to carriers. Practitioner points The free-living anammox bacteria are cultivated in a membrane bioreactor. More than 95.48% of biomass size is less than 50 mu m. The doubling time of these free anammox bacteria was 5.68 days. The key functional genes of anammox bacteria were identified and expressed. A novel method is proposed to rapidly form anammox biofilm.

关键词： Intermittent aeration   ASM1   Nitrification rate   Oxygen transfer rate (OTR)   Cascade control   Aeration energy cost  

摘要： The aim of this study was to apply the ASM1 model to predict the aeration cost of an intermittently aerated and fed bioreactor (IAFB) treating domestic wastewater at dissolved oxygen (DO) set points of 1-4 mg/L. In this work, the energy efficiency from the use of a classical Proportional-Integral (PI) DO controller installed in the IAFB system was compared to that of a DO cascade controller. In comparison to classical PI DO controller, a DO cascade controller set at 3 mg/L could reduce energy consumption by up to 16 %, decreasing the nitrification rate by only 5%. Moreover, a DO cascade controller at set point of 2.5 mg/L could lead to less energy consumption compared to a set point of 4.0 mg/L (by 41 %), reducing nitrification rate by only 7%. In particular, DO concentration higher than 3 mg/L can result in a higher air flow rate, which, however, does not drastically improve nitrification rate, causing an overaerated mode of operation, thus significantly increasing the aeration cost. These results indicate that the IAFB system can be accurately simulated through the use of ASM1 model within OpenModelica software, evaluating energy saving consumption scenarios during IAFB system operation.

关键词： Organic loading rate   Acidogenic fermentation   Fungal community   Immersed membrane bioreactor   Volatile fatty acids  

摘要： In this study, the influence of distinct hydraulic retention times (HRT) and organic loading rates (OLRs) on fungal dynamics during food waste anaerobic digestion in immersed membrane-based bio-reactors (iMBR) were investigated. The organic loading rate 4-8 g VS/L/d (R1) and 6-10 g VS/L/d (R2) were set in two iMBR. T1 (1d), T2 (15d) and T3 (34d) samples collected from each bioreactor were analyzed fungal community by using 18s rDNA. In R2, T2 had the most abundant Ascomycota, Basidiomycota, Chytridiomycota and Mucoromycota. As for R1, T3 also had the richest Cryptomycota except above four kinds of fungi. Subsequently, the Principal Component Analysis (PCA) and Non-Metric Multi-Dimensional Scaling (NMDS) indicated that fungal diversity was varied among the all three phases (T1, T2, and T3) and each treatment (R1 and R2). Finally, the results showed that different OLRs and HRT have significantly influenced the fungal community.

关键词： Temporary immersion bioreactors   Photomixotrophic cultures   Phenylpropanoids   ABA   Aristotelia chilensis  

摘要： Key message For the first time maqui micropropagation has been established in TIBs followed by elicitation of phenylpropanoids metabolites. Contents of metabolites from maqui in TIBs do not differ from those of wild fruits, while antioxidant capacity of phenylpropanoids was preserved during the study. A biotechnological system for the production of plants biomass and phenylpropanoids of maqui was developed in photomixotrophic TIBs. The in vitro maqui multiplication was evaluated using combinations of TDZ and BAP in TIBs 1L capacity. Treatment of MS basal supplemented with TDZ 1 mg/L shows the best results for the variables fresh weight and multiplication rate. Photomixotrophic conditions were standardized in media with 3%, 2%, 1%, 0% sucrose at a light intensity of 100 mu M m(-2) s(-1). The treatments reduced in sucrose (1 and 2%) and air supplemented with 0.4 MPa CO2 do not differ significantly in biomass production (fresh weight per cluster of plants) compared to the control treatment with sucrose 3% and standard air. Treatment with ABA (1 m/l) induced the production and accumulation of phenylpropanoids metabolites in maqui cultures bioreactors. Phenylpropanoids in in vitro biomass of maqui and culture medium from TIBs were determined in parallel with control samples from wild plants and mature fruits. After the third day of analysis, not significant differences in polyphenols and anthocyanin contents were verified between the treatments of maqui in TIBs + ABA and controls. The non-significant differences in the contents of polyphenols and anthocyanin were maintained until the 15 days of analysis. The antioxidant capacity comparing samples of maqui in bioreactors and wild plants showed no significant differences by the ORAC test from day 5 to day 15 of the study. Results originate an optimized methodology that was scale to SETIS (TM) bioreactors of 5L capacity.

关键词： Biofilm bioreactor   Acid mine drainage   Arsenite-oxidizing bacteria   Acidophilic bacteria   aioAgene diversity   As(III)-contaminated acidic wastewater  

摘要： Arsenite (As(III)) was considered to be of great concern in acid mine drainage (AMD). A promising approach for cleaning up of arsenite from AMD is microbial oxidation of As(III) followed by adsorptions. However, there is virtually no research about the acidophilic bioreactor for As(III) oxidation so far. In this study, we formed a new biofilm bioreactor with a consortium of acidophilic As(III) oxidation bacteria. It is totally chemoautotrophic, with no need to add any carbon or other materials during the operations. It works well under pH 3.0-4.0, capable of oxidizing 1.0-20.0 mg/L As(III) in 3.0-4.5 h, respectively. A continuous operation of the bioreactor suggests that it is very stable and sustainable. Functional gene detection indicated that the biofilms possessed a unique diversity of As(III) oxidase genes. Taken together, this acidophilic bioreactor has great potential for industrial applications in the cleaning up of As(III) from AMD solution.

关键词： Oxygen transfer coefficient   Mass transfer   Hydrocarbon-based bioprocess   Bubble column   Multiphase system  

摘要： This study investigates the overall volumetric oxygen transfer coefficient (K(L)a) in multiphase hydrocarbon-based bioprocess under a range of hydrocarbon concentrations (H-C), solid loadings (deactivated yeast) (S-L) and superficial gas velocities (U-G) in a bubble column reactor (BCR). K(L)a increased with increasing U-G in the air-water system;due to an increase in the number of small bubbles which enhanced gas holdup. In air-water-yeast systems, the initial addition of yeast increased K(L)a significantly. Further increases in S-L reduced K(L)a, due to increases in the bubble size with increasing S-L. K(L)a decreased when H-C was added in air-water-hydrocarbon systems. However, U-G, S-L and H-C affected K(L)a differently in air-water-yeast-hydrocarbon systems: an indication of the complex interactions between the yeast and hydrocarbon phases which changed the system's hydrodynamics and therefore affected K-L. This work illustrates the effect of the operating conditions (S-L, H-C and U-G) on oxygen transfer behaviour in multiphase systems.