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关键词： Para-coumarate   Bioreactor   RB-TnSeq   Pseudomonas putida   Metabolic engineering  

摘要： Pseudomonas putida KT2440 is an emerging biomanufacturing host amenable for use with renewable carbon streams including aromatics such as para-coumarate. We used a pooled transposon library disrupting nearly all (4,778) non-essential genes to characterize this microbe under common stirred-tank bioreactor parameters with quantitative fitness assays. Assessing differential fitness values by monitoring changes in mutant strain abundance identified 33 gene mutants with improved fitness across multiple stirred-tank bioreactor formats. Twentyone deletion strains from this subset were reconstructed, including GacA, a regulator, TtgB, an ABC transporter, and PP_0063, a lipid A acyltransferase. Thirteen deletion strains with roles in varying cellular functions were evaluated for conversion of para-coumarate, to a heterologous bioproduct, indigoidine. Several mutants, such as the Delta gacA strain improved fitness in a bioreactor by 35 fold and showed an 8-fold improvement in indigoidine production (4.5 g/L, 0.29 g/g, 23% of maximum theoretical yield) from para-coumarate as the carbon source.

关键词： Articular cartilage   Perfusion-based bioreactor   Decellularization   Tissue engineering  

摘要： Current decellularization methods for articular cartilages require many steps, various and high amounts of detergents, and a relatively long time to produce decellularized scaffolds. In addition, such methods often damage the essential components and the structure of the tissue. This study aims to introduce a novel perfusion-based bioreactor (PBB) method to decellularize bovine articular cartilages efficiently while reducing the harmful physical and chemical steps as well as the duration of the process. This leads to better preservation of the structure and the essential components of the native tissue. Firstly, a certain number of channels (o 180 mu m) were introduced into both sides of cylindrical articular bovine cartilage disks (5 mm in diameter and 1 mm in thickness). Next, the disks were decellularized in the PBB and a shaker as the control. Using the PBB method resulted in -90% reduction of DNA content in the specimens, which was significantly higher than those of the shaker results with -60%. Also, -50% sulfated glycosaminoglycan (sGAG) content and -92% of the compression properties were maintained implying the efficient preservation of the structure and components of the scaffolds. Moreover, the current study indicated that the PBB specimens supported the adherence and proliferation of the new cells effectively. In conclusion, the results show that the use of PBB method increases the efficiency of producing decellularized cartilage scaffolds with a better maintenance of essential components and structure, while reducing the chemicals and steps required for the process. This will pave the way for producing close-to-natural scaffolds for cartilage tissue engineering.

关键词： Lymphocyte   T cells   Bioreactor   Clinical scale   Expansion   Proliferation   Automation   Scale-up  

摘要： Cell therapies based on T cell have gathered interest over the last decades for treatment of cancers, becoming recently the most investigated lineage for clinical trials. Although results of adoptive cell therapies are very promising, obtaining large batches of T cell at clinical scale is still challenging nowadays. We propose here a review study focusing on how bioreactor systems could increase expansion rates of T cell culture specifically towards efficient, reliable and reproducible cell therapies. After describing the specificities of T cell culture, in particular activation, phenotypical characterization and cell density considerations, we detail the main objectives of bioreactors in this context, namely scale-up, GMPcompliance and reduced time and costs. Then, we report recent advances on the different classes of bioreactor systems commonly investigated for non-adherent cell expansion, in comparison with the current "gold standard" of T cell culture (flasks and culture bag). Results obtained with hollow fibres, G-Rex (R) flasks, Wave bioreactor, multiple-step bioreactors, spinner flasks as well as original homemade designs are discussed to highlight advantages and drawbacks in regards to T cells' specificities. Although there is currently no consensus on an optimal bioreactor, overall, most systems reviewed here can improve T cell culture towards faster, easier and/or cheaper protocols. They also offer strong outlooks towards automation, process control and complete closed systems, which could be mandatory developments for a massive clinical breakthrough. However, proper controls are sometimes lacking to conclude clearly on the features leading to the progresses regarding cell expansion, and the field could benefit from process engineering methods, such as quality by design, to perform multi parameters studies and face these challenges.

关键词： biological treatment   membrane technology   nitrogen removal   resource recovery   wastewater treatment  

摘要： Anaerobic membrane bioreactors (AnMBRs) have become a new mature technology and entered into the wastewater market, but there are several challenges to be addressed for wide applications. In this review, we discuss challenges and potentials of AnMBRs focusing on wastewater treatment. Nitrogen and dissolved methane control, membrane fouling and its control, and membrane associated cost including energy consumption are main bottlenecks to facilitating AnMBR application in wastewater treatment. Accumulation of dissolved methane in AnMBR permeate decreases the benefit of methane energy and contributes to methane gas emissions to atmosphere. Separate control units for nitrogen and dissolved methane add system complexity and increase capital and operating and maintenance (O & M) costs in AnMBR-centered wastewater treatment. Alternatively, methane-based denitrification can be an ideal nitrogen control process due to simultaneous removal of nitrogen and dissolved methane. Membrane fouling and energy associated with membrane fouling control are major limitations, in addition to membrane cost. More efforts are required to decrease capital and O & M costs associated with the control of dissolved methane nitrogen and membrane fouling to facilitate AnMBRs for wastewater treatment. Practitioner points AnMBRs can accelerate anaerobic wastewater treatment including dilute wastewater. Nitrogen and dissolved methane control is detrimental for AnMBR application to wastewater treatment. Membrane biofilm reactors using gas-permeable membranes are suitable for simultaneous nitrogen and dissolved methane control. High capital and O & M costs from membranes are a major bottleneck to wide application of AnMBRs. Dynamic membranes could be an option to reduce capital and O & M costs for AnMBRs.

关键词： MASM   new model for membrane activated sludge system   super-fast membrane activated sludge   particle size distribution   modified COD fractionation   captured COD fractions  

摘要： The structure of existing activated models is inherently deficient in reflecting the major role of the membrane filtration. The study developed a novel model, MASM, for the membrane activated process. The effective filtration size imposed by the membrane module, entrapping larger particles, was adopted as the basis of the proposed model. The model defines a modified form of COD fractionation that accounts for the captured COD fractions as additional model components and utilizes related mass-balance relationships. It was implemented to test the fate of soluble hydrolyzable COD and the system performance of super-fast membrane activated sludge based on real data for the characterization and process kinetics of domestic sewage and denim processing effluents. Model evaluation was carried out for parallel systems with gravity settling and membrane filtration operated at a sludge age range of 0.5-2.0 d. Results reflected significantly better performance by the super-fast membrane activated sludge system for both wastewaters, underlining that it was crucially important to account for the captured COD fractions to provide an accurate evaluation of system behavior and effluent quality. This should also be identified as the major shortcoming of the ASM models for evaluating and predicting the system performance of activated sludge configurations with membrane separation.

关键词： Rapid granulation   Automobile coating wastewater   Aerobic granular sludge   Phenol   Sequencing batch reactor   High-throughput sequencing  

摘要： In this study, by inoculating 65% activated sludge and 35% intact aerobic granular sludge (AGS), the rapid granulation of AGS was achieved to treat automobile coating wastewater (ACW). The results showed that after 15 d of operation, compact AGS which a clear shape was found in the sequencing batch reactor with the sludge volume index is 31 mL/g, and an average particle size of 1.2 mm. When the reactor was operated for about 50 d, the chemical oxygen demand, total nitrogen, total phosphorus, and phenol could be effectively removed from the ACW by AGS, with removal rates of 85%, 82%, 62%, and 90%, respectively. Furthermore, the microbial community dynamics were studied by high-throughput sequencing. The correlation between the pollutant removal efficiency and the level of the microbial community (phylum, class, order, family, and genus) was investigated. The results showed that the most abundant genus Thauera played an important role in phenol degradation. Moreover, the abundances of Zoogloea, Azoarcus, Stenotrophomonas, Sediminibacterium, Methyloversatilis, and Acidovorax gradually increased. These functional genera had a significant effect on the biodegradation of phenol and organic matter. This research provides new insights into the rapid start-up of AGS bioreactors and illustrates the practical application potential of AGS technology in the treatment of phenol-containing ACW.

关键词： fermentation   recombinant protein   cytochrome b5   bioreactor   bioprocess   scale up   partial least squares   PID controllers  

摘要： The production of recombinant proteins is gaining increasing importance as the market requests high quality proteins for several applications. However, several process parameters affect both the growth of cells and product yields. This study uses high throughput systems and statistical methods to assess the influence of fermentation conditions in lab-scale bioreactors. Using this methodology, it was possible to find the best conditions to produce cytochrome b5 with recombinant cells of Escherichia coli. Using partial least squares, the height-to-diameter ratio of the bioreactor, aeration rate, and PID controller parameters were found to contribute significantly to the final biomass and cytochrome concentrations. Hence, we could use this information to fine-tune the process parameters, which increased cytochrome production and yield several-fold. Using aeration of 1 vvm, a bioreactor with a height-to-ratio of 2.4 and tuned PID parameters, a production of 72.72 mg/L of cytochrome b5 in the culture media, and a maximum of product to biomass yield of 24.97 mg/g could be achieved.

关键词： Mass transfer   Bioreactor   Mixing   Multiphase   GPU  

摘要： The biomanufacturing processes that produce biologic drugs has become an extremely important area of study within the pharmaceutical industry. Within such processes, the drug substance is typically produced by living organisms within stirred tank bioreactors that require a continuous supply of sparged oxygen. The overall oxygen transfer rate to the fluid is a nonlinear convolution of the gas bubble size distribution, fluid properties, local fluid energy dissipation rates, and local dissolved oxygen concentrations. The complexity of this process presents challenges to process scale-up and intensification. In this work, we propose, implement, and validate a mechanistic transport model for predicting oxygen transfer rates within stirred tank bioreactors. To begin, we describe the relevant conservation laws and key principles from turbulence theory that govern mass transfer. Next, we present a physics-based modeling approach for solving these equations in tandem and in real-time. We then systematically validate the model against experimental data at operating scales ranging from 5 L to 2000 L. By running the algorithm on graphics processing units (GPUs), the approach is shown to solve at timescales practical for industrial application. CO 2021 Elsevier Ltd. All rights reserved.

关键词： Anaerobic membrane bioreactor   Real domestic wastewater   Hydraulic retention times   Sustainable flux   Biogas composition   Mass balance  

摘要： A 20 L hollow-fiber submerged anaerobic membrane bioreactor (SAnMBR) was used to treat real domestic wastewater at 25 degrees C with hydraulic retention times (HRTs) ranging from 4 to 12 h. The process performance was evaluated by organic removal efficiency, biogas production, sludge yield, and filtration behaviors during one-year's operation. For HRTs ranging between 6 and 12 h, the AnMBR showed good organic removal efficiency with chemical oxygen demand (COD) and biochemical oxygen demand (BOD) removal efficiencies of about 89% and 93%, respectively. The biogas yield was 0.26 L-gas/g-CODfed, with approximately 80% methane content, and the sludge yield was 0.07-0.11 g-VSS/g-CODrem. While at an HRT of 4 h, with the higher wastewater treatment capacity and organic loading rate (OLR), the biogas production was lower (0.17 L-gas/g-CODfed), and the sludge production was higher (0.22 g-VSS/g-CODrem). The organic removal performance (COD 84% and BOD 89%) at HRT of 4 h was acceptable due to the effective separation effect of the membrane filtration process. According to COD balance analysis, the low biogas yield and high sludge yield at HRT of 4 h were due to insufficient biodegradation under an OLR of 2.05 g-COD/L-reactor/d. Theoretical calculations based on Henry's law indicate that the ideal methane content in the biogas should be 82-85% when the operational temperature was 25 degrees C. To achieve a high flux and sustainable AnMBR operation, the impact of mixed liquor suspended solid (MLSS) and gas sparging velocity (GSV) on the filtration performance was analyzed. The critical flux increased with increase in the GSV from 24.2 to 174.3 m/h, but decreased with increase in the MLSS concentration from 8.2 to 20.2 g/L. Therefore, decreasing fouling rate to 0.8-1.2 kPa/d by efficiently controlling GSV and MLSS, sustainable operation could be achieved at a flux of 0.34 m/d. (C) 2021 Elsevier B.V. All rights reserved.

关键词： Domestic sewage   OMBR-MD   Pharmaceutical active compounds   Submerged module   Water reuse  

摘要： A novel configuration of an osmotic anaerobic membrane bioreactor coupled with membrane-assisted distillation (OMBR-MD) in a single submerged module was proposed for domestic sewage treatment and potabilization. A steady permeate flux was achieved after the 22nd day of monitoring, in which the draw solution (DS) was diluted by the forward osmosis (FO) permeate at the same rate in which it was concentrated by the membrane distillation (MD). Salinity build-up inside the bioreactor contributed to fouling in the FO membrane since it increases the production of soluble microbial products and extracellular polymeric substances. In addition, organic matter accumulated in DS, due to the closed-loop system, may be the main cause for fouling in MD membranes at the latter stages. The OMBR-MD presented great removal for organic matter (91%), phosphorous (95%) and ammonium nitrogen (71%). Alkalinity accumulation within the bioreactor prevented a significant change in bulk solution pH (8.0 ? 8.4), reducing the effects of volatile fatty acids production on methanogenic performance. The OMBR-MD removal efficiencies were higher than 96% for all 7 selected pharmaceutical drugs. Additionally, the MD distillate attained eight out of the nine parameters assessed for potable water standards established in Brazilian legislations and recommendations from US EPA, including Escherichia coli. Therefore, the novel OMBRMD proved to be a feasible alternative for treating municipal wastewater, generating a high-quality distillate.