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关键词： Peanut hairy root   Arachidin-1   Arachidin-3   Antimicrobial activity   Bioreactor  

摘要： Obtaining large-scale hairy root cultures is a major challenge to increasing root biomass and secondary metabolite production. Enhanced production of stilbene compounds such as trans-resveratrol, trans-arachidin-1 and trans-arachidin-3 was achieved using an elicitor treatment procedure. Two different hairy root inoculum densities were investigated and compared between shake flask and bioreactor cultures. The lowest growth index was observed using a 20 g/L inoculum size in the bioreactor, which differed significantly from bioreactor of 5 g/ L. Increasing the hairy root inoculum size from 5 g/L to 20 g/L in both the shake flask and bioreactor significantly improve antioxidant activity, phenolic content and stilbene compound levels. The highest ABTS and FRAP antioxidant activity, and levels of total phenolic compounds, trans-arachidin-1 and trans-arachidin-3 in the crude extract were demonstrated in shake flask cultures with a 20 mu g/L inoculum after elicitation for 72 h. The minimum inhibitory concentrations (MICs) of the crude extract to inhibit growth of foodborne microbes, S. aureus, S. typhimurium and E. coli, were 187.5, 250 and 500 mu g/mL, respectively. This was due to the ability of the crude extract to disrupt the cell membrane, as observed by scanning electron microscopy (SEM) showing ruptured pores on the S. aureus and S. typhimurium cell surfaces. Moreover, the E. coli cell division process could be inhibited by the crude extract, which promoted an increase in cell size. A DNA nicking assay indicated that a 50 mu g/mL concentration of the crude extract caused plasmid DNA damage that might be due to a genotoxic effect of the pro-oxidant activity of the crude extract.

关键词： Chlorella sp.   First principles model   Light specific absorptivity   Light intensity   Steady-state   Algal productivity   Biomass  

摘要： Algal productivity in steady-state cultivation systems depends on important factors such as biomass concentration, solids retention time (SRT), and light intensity. Current modeling of algal growth often ignores light distribution in algal cultivation systems and does not consider all these factors simultaneously. We developed a new algal growth model using a first principles approach to incorporate the effect of light intensity on algal growth while simultaneously considering biomass concentration and SRT. We first measured light attenuation (decay) with depth in an indoor algal membrane bioreactor (A-MBR) cultivating Chlorella sp. We then simulated the light decay using a multi-layer approach and correlated the decay with biomass concentration and SRT in model development. The modelwas calibrated by delineating specific light absorptivity and half-saturation constant to match the algal biomass concentration in the A-MBR operated at a target SRT. We finally applied the model to predict the maximum algal productivity in both indoor and outdoor A-MBRs. The predicted maximum algal productivities in indoor and outdoor A-MBRs were 6.7 g.m(-2).d(-1) (incident light intensity 5732 lx, SRT approximately 8 d) and 28 g.m(-2).d(-1) (sunlight intensity 28,660 lx, SRT approximately 4 d), respectively. The model can be extended to include other factors (e.g., water temperature and carbon dioxide bubbling) and such a modeling framework can be applied to full-scale, continuous flow outdoor systems to improve algal productivity. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Two-phase model   CFD   Non-Newtonian   Multiphase bioreactor   Biomass   Scale-up  

摘要： The application of Computational Fluid Dynamics to aerobic fermentations faces several issues, such as validation of multiphase models at high gas holdup and with complex liquids under turbulent condition. In this work, the Eulerian two-fluid model framework was adapted to simulate the enzyme production by the filamentous fungi T. reesei. Due to scarcity of data on turbulent mixing in complex fluids, every aspect of the numerical model (turbulence model, drag force law, rheology model, etc.) needed to be validated. First, the adequacy of the model was evaluated by the mean of comparison with new and previous exper-imental data in non-Newtonian aerated systems. Once coupled with an apparent oxygen and substrate uptake kinetics, the model was used to investigate the effect of scale-up on the enzyme productivity from biomass. Fully predictive results highlighted complex behaviors, such as: possible substrate heterogeneities, yield loss, and non-obvious interactions between mixing and oxygen transfer limitations. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Induced pluripotent stem cells   Megakaryocyte   Platelet   Acellular natural scaffold   Microfluidic system   3D bioreactor  

摘要： Background: Induced pluripotent stem cells (hiPSCs) are reprogrammed cells that can develop into all human cell types, including megakaryocytes. Extracellular matrix plays a crucial role in the differentiation of hiPSCs into megakaryocytes. Therefore, we aimed to prepare a suitable natural acellular scaffold, and 3D bioreactor for invitro proliferation, and differentiation of hiPSCs into megakaryocytes. Methods: The rat lung was extracted, and the decellularization process was performed in order to eradicate cellular and nuclear materials, and lung three-dimensional (3D) structure with the protein contents remained intact. Scanning electron microscopy (SEM), hematoxylin and eosin (H&E), and 4', 6-diamidino-2-phenylindole (DAPI) staining were used to verify tissue decellularization, and to ensure the integrity of the tissue structure. The 3D polydimethylsiloxane (PDMS) based bioreactor was designed, and the recellularization of the acellular lung was performed by hiPSCs. Decellularized rat lung vessels were used to deliver culture media as a microfluidic system. Differentiation of hiPSCs to megakaryocytes was assessed by RT-PCR and flow cytometry. Results: H&E, DAPI staining, and SEM analysis confirmed the integrity of the 3D lung structure. Flow cytometry and RT-PCR analysis revealed the presence of megakaryocyte markers in differentiated cells. Conclusion: It seems that natural acellular scaffold and microfluidic 3D bioreactor provides a suitable natural cost-benefit microenvironment for hiPSCs differentiation into megakaryocytes.

关键词： Biological process   Cake layer   F/M ratio   Filtration   Membrane bioreactor  

摘要： A lab-scale Self-Forming Dynamic Membrane BioReactor (SFD MBR) equipped with a nylon mesh was operated for the treatment of real municipal wastewater under a volumetric loading rate of 0.9-1.1 gCOD L-1 d(-1) and a flux of 61-68 L m(-2) h(-1). During an experimental period of more than 600 d, three runs were performed with different solids retention times (SRT of 15, 30, and 50 d). At the steady state, the system had always good biological and filtration performances, but the mesh clogging tendency and the solid removal observed varied with the SRT. Lower filtration performance, both in terms of permeate quality and productivity, was observed under unstable conditions for the biological processes, such as start-up and variations of the food-to-microorganism ratio. Higher SRT resulted in more stable biological process at the steady state, which positively affected the filtration performance even in front of organic load variations.

关键词： Anaerobic membrane bioreactor (AnMBR)   Confectionery wastewater   Membrane fouling mechanism   Sustainable organic loading rate (OLR)   Next generation sequencing analysis (NGS)  

摘要： An anaerobic membrane bioreactor (AnMBR) system treating confectionery wastewater was operated for 247 days at various organic loading rates (OLRs) of 1.1, 2.2, 4.4, 6.6 and 7.9 kg COD m-3 d-1 to determine sustainable OLR. In this study, up to 99% COD removal efficiency was obtained at all OLRs, and the maximum methane production of 0.26 m3 kg-1 CODremoved was achieved at OLR 7.9 kg COD m-3 d-1. Next Generation Sequencing (NGS) analysis showed that the dominance of hydrogenotrophic methanogens shifted to acetoclastic methanogens after OLR value of 4.4 kg COD m-3 d-1, which caused a decrease in the biogas methane composition. The increase in OLR, negatively affected the membrane filtration performance. After OLR value of 4.4 kg COD m-3 d-1, TMP, filtration resistance and EPS/SMP production increased sharply. These results indicated that the AnMBR system could be efficiently operated efficiently at OLR 4.4 kg COD m-3 d-1. Membrane fouling mechanism was evaluated using Fourier-transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy coupled with energy dispersive X-ray (SEM-EDX), and contact angle measurements after 247 days of operation. The results demonstrated that the membrane fouling mechanism can be attributed to cake layer formation which mainly consisted of protein and carbohydrate. In this study, the efficient treatment of confectionery wastewater showed that the AnMBR system could be applied to high strength organic wastewater such as industries of beverage, beer, dairy, and sugar product. Filtration performance should be enhanced with further investigations. Superscript/Subscript Available

关键词： Anaerobic sequencing batch reactor   Desulfovibrio   DNA sequencing   Microbial community structure   Sulfate-reducing bacteria  

摘要： This study evaluated the biological treatment efficiency and microbial communities of eight anaerobic sequencing batch reactors treating sulfate-rich wastewater using inocula of sewage and industrial origin, immobilized or not, operated in two phases, first using lactate, and then ethanol as an electron donor. Regardless of the inoculum origin and immobilization, the maximum percentage of sulfate removal in the lactate phase was 80 +/- 2%;the ethanol phase was 84 +/- 3%. A lag phase in the sulfate removal was observed at the beginning of the reactor operation (lactate phase) for both types of sludge-inoculated reactors. The maximum chemical oxygen demand removal in the lactate phase was 70 +/- 4%;the ethanol phase was 65 +/- 5%. Pyrosequencing analysis demonstrated an increased abundance of sulfate-reducing bacteria. Only the reactors inoculated with industrial sludge presented methanogenic Archaea abundance of 3.44 and 4.15% in the lactate and ethanol phases, respectively. The genus Desulfovibrio was found in an abundance of 25.21 and 34.06% with ethanol as a carbon source in the reactors with the immobilized inocula of industrial origin, demonstrating the ability of the microbial consortium to adapt to the substrate and microenvironment. Understanding the potential for the effects of electron donors, inoculum origin, and its immobilization in the sulfate reduction and development of the microbial community can facilitate the establishment of strategies for the bioremediation of acid mine drainage.

关键词： Membrane bioreactor (MBR)   micropollutants   in-situ ozonation   Membrane fouling   Microbial communities  

摘要： In this study, impacts of in-situ ozonation applied directly in the membrane tank of a ceramic MBR (Oz-MBR) were assessed to elucidate its implications on micropollutant removal, microbial taxa and membrane fouling. The basic effluent quality (i.e., bulk organics and nutrients) of the MBR without and with in-situ ozonation was comparable. Importantly, pollutant-specific (10-26%) improvement in micropollutant removal was achieved by the Oz-MBR, which could be attributed to the increase in the abundance of microbial taxa responsible for the removal of structurally complex pollutants and/or ozone-assisted oxidation. In-situ ozonation affected the abundance of denitrifying bacteria and functional genes but total nitrogen removal by the Oz-MBR was com-parable to that achieved by the control (C)-MBR. Improved mixed liquor properties, and the reduced accumulation of foulants on the membrane surface resulted in membrane fouling alleviation (53%) in the Oz-MBR. In addition, fouling models evaluated for the first time in the case of Oz-MBR indicated that the cake-complete model was suitable to explain membrane fouling mechanism. This comprehensive study demonstrates the performance of MBR coupled with in-situ ozonation, and the obtained results would serve as a useful reference for its implementation at pilotand/or full-scale.

关键词： Osmotic membrane bioreactor   Forward osmosis   Salinity build-up   Sodium dodecyl benzene sulfonate   Wastewater treatment  

摘要： This study investigated the effects of surfactant addition to the draw solution on the performance of osmotic membrane bioreactor (OMBR). Forward osmosis (FO) tests were conducted with the addition of sodium dodecyl benzene sulfonate (SDBS), a representative surfactant, to both inorganic and ionic organic draw solutions, including sodium chloride (NaCl), sodium acetate (NaOAc), and sodium propionate (NaPro), to determine the desirable draw solution for OMBR operation. Results show that SDBS impacts were more notable for inorganic draw solution in comparison to its ionic organic counterparts at the same osmotic pressure (60 bar) in FO operation. In specific, SDBS addition up to 5 mM considerably reduced the reverse diffusion of NaCl draw solute (approximately 69.7%) with insignificant impact on water flux. Thus, salinity build-up in the bioreactor could be effectively mitigated when SDBS was added to the NaCl draw solution in OMBR operation. This mitigation led to stable sludge characteristics and biological treatment to sustain OMBR performance regarding water production (approximately 10 L/m(2)h) and contaminant removal (e.g. over 90% for pharmaceutically active compounds).

关键词： Wastewater   Microalgal membrane bioreactor (MMBR)   Organic loading rate (OLR)   HRT   Removal efficiency   Membrane fouling  

摘要： Current microalgal based photobioreactors focus on the secondary treated effluent while limited researches attempted for treating the raw domestic wastewater. This study aimed to assess the microalgal biomass production, removal performance, and fouling characteristics of microalgal membrane bioreactors (MMBRs) for treating synthetic wastewater under different conditions of organic loading rate (OLR) and hydraulic residence time (HRT). The 12h/12 h dark/light cycle continuous experiments were performed for four MMBRs at different OLRs and three MMBRs at different HRTs. Results showed that microalgal biomass production rate (as TSS and chlorophyll-a) decreased with increasing OLR and increased with decreasing of HRT. Regardless of the OLR and HRT conditions, MMBRs can achieve up to 94% organic removal by bacterial oxidation without external aeration. Total nitrogen (TN) and total phosphorus (TP) removals were significantly decreased with increasing OLR. Highest TN removal (68.4%) achieved at the OLR of 0.014 kg/(m(3) d) which was reduced to 58.1% at 0.028 kg/(m(3) d). Removals of total phosphorous significantly decreased from 48.2% to 37.7% with an increase in OLR from 0.011 to 0.014 kg/(m(3) d). TN removal was reduced at shorten HRT (2 d), while, the effect of HRT was found insignificant at higher HRT. An effective removal of P can only be achieved at higher HRTs, i.e., 7 days. OLR up to 0.014 kg/(m(3) d) and 2 days HRT was found suitable for maintaining the fouling frequency at an optimal level of 0.016/d. Overall the OLR and HRT need to be carefully selected to achieve optimal efficiency of MMBR. The results of this study provide guidelines for designing the microalgal-based membrane bioreactors for the treatment of domestic wastewater.