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Molecules (Basel, Switzerland) Aug 2019Biomass characteristics are regarded as particularly influential for fouling in Membrane Bio-Reactors (MBRs). They primarily include the Mixed Liquor Suspended Solids... (Review)
Review
Biomass characteristics are regarded as particularly influential for fouling in Membrane Bio-Reactors (MBRs). They primarily include the Mixed Liquor Suspended Solids (MLSS), the colloids and the Extracellular Polymeric Substances (EPS). Among them, the soluble part of EPS, which is also known as Soluble Microbial Products (SMP), is the most significant foulant, i.e., it is principally responsible for membrane fouling and affects all fundamental fouling indices, such as the Trans-Membrane Pressure (TMP) and the membrane resistance and permeability. Recent research in the field of MBRs, tends to consider the carbohydrate fraction of SMP (SMP) the most important characteristic for fouling, mainly due to the hydrophilic and gelling properties, which are exhibited by polysaccharides and allow them to be easily attached on the membrane surface. Other wastewater and biomass characteristics, which affect indirectly membrane fouling, include temperature, viscosity, dissolved oxygen (DO), foaming, hydrophobicity and surface charge. The main methods employed for the characterization and assessment of biomass quality, in terms of filterability and fouling potential, can be divided into direct (such as FDT, SFI, TTF, MFI, DFCM) or indirect (such as CST, TOC, PSA, RH) methods, and they are shortly presented in this review.
Topics: Biomass; Bioreactors; Membranes, Artificial; Research; Waste Disposal, Fluid; Wastewater
PubMed: 31394820
DOI: 10.3390/molecules24162867 -
The Science of the Total Environment Apr 2024Nitrate (NO) removal in denitrifying bioreactors is influenced by flow, water chemistry, and design, but it is not known how these widely varying factors impact the...
Nitrate (NO) removal in denitrifying bioreactors is influenced by flow, water chemistry, and design, but it is not known how these widely varying factors impact the production of nitrous oxide (NO) or methane (CH) across sites. Woodchip bioreactors link the hydrosphere and atmosphere in this respect, so five full-size bioreactors in Illinois, USA, were monitored for NO, NO, and CH to better document where this water treatment technology resides along the pollution swapping to climate smart spectrum. Both surface fluxes and dissolved forms of NO and CH were measured (n = 7-11 sampling campaigns per site) at bioreactors ranging from <1 to nearly 5 years old and treating subsurface drainage areas from between 6.9 and 29 ha. Across all sites, NO surface and dissolved volumetric production rates averaged 1.0 ± 1.6 mg NO-N/m-d and 24 ± 62 mg dNO-N/m-d, respectively, and CH production rates averaged 6.0 ± 26 mg CH-C/m-d and 310 ± 520 mg dCH-C/m-d for surface and dissolved, respectively. However, NO was consistently consumed at one bioreactor, and only three of the five sites produced notable CH. Surface fluxes of CH were significantly reduced by the presence of a soil cover. Bioreactor denitrification was relatively efficient, with only 0.51 ± 3.5 % of removed nitrate emitted as NO (n = 48). Modeled indirect NO emissions factors were significantly lower when a bioreactor was present versus absent (EF: 0.0055 versus 0.0062 kg NO-N/kg NO-N; p = 0.0011). While further greenhouse gas research on bioreactors is recommended, this should not be used as an excuse to slow adoption efforts. Bioreactors provide a practical option for voluntary water quality improvement in the heavily tile-drained US Midwest and elsewhere.
Topics: Nitrous Oxide; Nitrates; Greenhouse Gases; Bioreactors; Methane
PubMed: 38365030
DOI: 10.1016/j.scitotenv.2024.170956 -
Journal of Tissue Engineering and... Jan 2018In cellular, tissue-level or whole organ bioreactors, the level of dissolved oxygen is one of the most important factors requiring control. Hypoxic environments may lead...
In cellular, tissue-level or whole organ bioreactors, the level of dissolved oxygen is one of the most important factors requiring control. Hypoxic environments may lead to cellular apoptosis, while hyperoxic environments may lead to cellular damage or dedifferentiation, both resulting in loss of overall tissue function. This manuscript describes the creation, characterization and validation of a bioreactor system that can control oxygen delivery based on real-time metabolic demand of cultured whole lung tissue. A mathematical model describing and predicting gas exchange within the tunable bioreactor system is developed. In addition, the inherent gas exchange properties of the bioreactor and the inherent oxygen consumption rates of native rat lungs are determined, thereby providing a quantitative relationship between system parameters and levels of dissolved oxygen. Finally, the mathematical model is validated during whole lung culture under a range of system parameters. The system presented here provides a quantitative relationship between the concentration of dissolved oxygen, tissue oxygen consumption rates, and controllable system parameters that introduce gasses into the bioreactor. This relationship not only enables the maintenance of constant levels of dissolved oxygen throughout a culture period during which cells are replicating, but also provides noninvasive and real-time estimation of the metabolic and proliferative states of native or engineered lung tissue simply through dissolved oxygen measurements. Copyright © 2017 John Wiley & Sons, Ltd.
Topics: Animals; Bioreactors; Cell Count; DNA; Equipment Design; Gases; Image Processing, Computer-Assisted; Lung; Models, Biological; Oxygen Consumption; Rats, Sprague-Dawley; Reproducibility of Results
PubMed: 28083925
DOI: 10.1002/term.2408 -
Polish Journal of Microbiology Mar 2018Ureolysis-driven microbially induced carbonate precipitation (MICP) has recently received attention for its potential biotechnological applications. However, information...
Ureolysis-driven microbially induced carbonate precipitation (MICP) has recently received attention for its potential biotechnological applications. However, information on the enrichment and production of ureolytic microbes by using bioreactor systems is limited. Here, we report a low-tech down-flow hanging sponge (DHS) bioreactor system for the enrichment and production of ureolytic microbes. Using this bioreactor system and a yeast extract-based medium containing 0.17 M urea, ureolytic microbes with high potential urease activity (> 10 μmol urea hydrolyzed per min per ml of enrichment culture) were repeatedly enriched under non-sterile conditions. In addition, the ureolytic enrichment obtained in this study showed in vitro calcium carbonate precipitation. Fluorescence in situ hybridization analysis showed the existence of bacteria of the phylum Firmicutes in the bioreactor system. Our data demonstrate that this DHS bioreactor system is a useful system for the enrichment and production of ureolytic microbes for MICP applications.
Topics: Bioreactors; Calcium Carbonate; Chemical Precipitation; Firmicutes; In Situ Hybridization, Fluorescence; Urea; Urease
PubMed: 30015425
DOI: 10.5604/01.3001.0011.6144 -
Bioengineered Dec 2023This investigation is a review of the potential of aerobic granular sludge membrane bioreactor (AGMBR) in wastewater treatment due to the advantage of combination of... (Review)
Review
This investigation is a review of the potential of aerobic granular sludge membrane bioreactor (AGMBR) in wastewater treatment due to the advantage of combination of membrane and aerobic granules for reducing membrane fouling and enhancing removal performance. The AGMBR is the same as the membrane bioreactor (MBR), but the activated sludge is replaced by aerobic granular sludge. This technology combines the advantages of aerobic granular sludge, such as good settleability, strong ability to withstand shock-loadings and high organic loading rate, and capacity of simultaneous chemical oxygen demand (COD) and nitrogen removal, and advantages of membrane bioreactor (MBR) such as excellent effluent quality, high biomass content, low excess sludge production, and small land requirement. Therefore, it can be considered a promising option for efficient wastewater treatment. Most studies have shown that aerobic granules could control membrane fouling, which often occurs in MBR. The main fouling mechanism was determined to be surface fouling by floccular sludge in MBR but pore fouling by colloids and solutes in AGMBR. Aerobic granular sludge also removed COD and nitrogen simultaneously, with more than 60% total nitrogen removal efficiency. The formation and stability of aerobic granules in AGMBR with various operational modes are discussed in this study.
Topics: Sewage; Biomass; Bioreactors; Nitrogen; Technology
PubMed: 37732563
DOI: 10.1080/21655979.2023.2260139 -
Organogenesis Oct 2021Synergistic promotion of angiogenesis and osteogenesis in bone tissue-engineered constructs remains a crucial clinical challenge, which might be overcome by simultaneous...
Synergistic promotion of angiogenesis and osteogenesis in bone tissue-engineered constructs remains a crucial clinical challenge, which might be overcome by simultaneous employment of superior techniques including coculture systems, differentiation-stimulated factors, combinatorial scaffolds and bioreactors.Current study investigated the effect of flow perfusion along with coculture of human adipose stem cells (hASCs) and human umbilical vein endothelial cells (HUVECs) on osteogenic and angiogenic differentiation.Pre-treated hASCs with 1,25-dihydroxyvitamin D were seeded onto poly(lactic-co-glycolic acid)/β-tricalcium phosphate/polycaprolactone (PLGA/β-TCP/PCL) scaffold with/without HUVECs, and cultured for 14 days within a flask or modified perfusion bioreactor. Analysis of osteogenic and angiogenic gene expression, alkaline phosphatase (ALP) activity and ALP staining indicates a synergistic effect of perfusion flow and coculture system on osteogenic and angiogenic differentiation. The advantage of modified perfusion bioreactor is its five-branch flow distributor which directly connect to the porous PCL hollow fibers embedded in the 3D scaffold to improve flow and flow-induced shear stress uniformity.Dynamic coculture increased VEGF by 6-fold, VEGF by 2-fold, and Endothelin-1 by 4-fold, relative to dynamic monoculture. Static coculture enhanced osteogenic and angiogenic differentiation, compared with static monoculture. Although dynamic coculture is in preference to static coculture due to significant increase in ALP activity and promoted angiogenic marker expression. Our finding is the first to indicate that the modified perfusion bioreactor combined with the beneficial cell-cell crosstalk in pre-treated hASC/HUVEC cocultures provides a synergy between osteogenic and angiogenic differentiation of the accumulation of cells, suggesting that it represents a promising approach for regeneration of critical-sized bone defects.
Topics: Bioreactors; Cell Differentiation; Cells, Cultured; Coculture Techniques; Human Umbilical Vein Endothelial Cells; Humans; Osteogenesis; Perfusion; Stem Cells; Tissue Scaffolds
PubMed: 34323661
DOI: 10.1080/15476278.2021.1954769 -
Chemosphere Apr 2023Recovery of the energy contained in biogas will be essential in coming years to reduce greenhouse gas emissions and our current dependence on fossil fuels. The... (Review)
Review
Recovery of the energy contained in biogas will be essential in coming years to reduce greenhouse gas emissions and our current dependence on fossil fuels. The elimination of HS is a priority to avoid equipment corrosion, poisoning of catalytic systems and SO emissions in combustion engines. This review describes the advances made in this technology using fixed biomass bioreactors (FBB) and suspended growth bioreactors (SGB) since the first studies in this field in 2008. Anoxic desulfurization has been studied mainly in biotrickling filters (BTF). Elimination capacities (EC) up to 287 gS m h have been achieved, with a removal efficiency (RE) of 99%. Both nitrate and nitrite have been successfully used as electron acceptor. SGBs can solve some operational problems present in FBBs, such as clogging or nutrient distribution issues. However, they present greater difficulties in gas-liquid mass transfer, although ECs of up to 194 gS m h have been reported in both gas-lift and stirred tank reactors. One of the major disadvantages of using anoxic biodesulfurization compared to aerobic biodesulfurization is the need to provide reagents (nitrates and/or nitrites), with the consequent increase in operating costs. A solution proposed in this respect is the use of nitrified effluents, some ammonium-rich effluents nitrified include landfill leachate and digested effluent from the anaerobic digester have been tested successfully. Among the microbial diversity found in the bioreactors, the genera Thiobacillus, Sulfurimonas and Sedimenticola play a key role in anoxic removal of HS. Finally, a summary of future trends in technology is provided.
Topics: Hydrogen Sulfide; Biofuels; Filtration; Bioreactors; Nitrates; Nitrites
PubMed: 36775028
DOI: 10.1016/j.chemosphere.2023.138084 -
Current Opinion in Chemical Biology Aug 2007Widespread use of embryonic and adult stem cells for therapeutic applications will require reproducible production of large numbers of well-characterized cells under... (Review)
Review
Widespread use of embryonic and adult stem cells for therapeutic applications will require reproducible production of large numbers of well-characterized cells under well-controlled conditions in bioreactors. During the past two years, substantial progress has been made towards this goal. Human mesenchymal stem cells expanded in perfused scaffolds retained multi-lineage potential. Mouse neural stem cells were expanded as aggregates in serum-free medium for 44 days in stirred bioreactors. Mouse embryonic stem cells expanded as aggregates and on microcarriers in stirred vessels retained expression of stem cell markers and could form embryoid bodies. Embryoid body formation from dissociated mouse embryonic stem cells, followed by embryoid body expansion and directed differentiation, was scaled up to gas-sparged, 2-l instrumented bioreactors with pH and oxygen control.
Topics: Animals; Bioreactors; Cell Differentiation; Cell Proliferation; Humans; Oxygen; Perfusion; Stem Cells
PubMed: 17656148
DOI: 10.1016/j.cbpa.2007.05.034 -
Biotechnology Advances Nov 2013Stem cells hold promise to revolutionize modern medicine by the development of new therapies, disease models and drug screening systems. Standard cell culture systems... (Review)
Review
Stem cells hold promise to revolutionize modern medicine by the development of new therapies, disease models and drug screening systems. Standard cell culture systems have limited biological relevance because they do not recapitulate the complex 3-dimensional interactions and biophysical cues that characterize the in vivo environment. In this review, we discuss the current advances in engineering stem cell environments using novel biomaterials and bioreactor technologies. We also reflect on the challenges the field is currently facing with regard to the translation of stem cell based therapies into the clinic.
Topics: Animals; Bioreactors; Cell Engineering; High-Throughput Screening Assays; Humans; Mice; Models, Biological; Regenerative Medicine; Stem Cell Niche; Stem Cells
PubMed: 23531529
DOI: 10.1016/j.biotechadv.2013.03.007 -
Journal of Environmental Science and... 2012This review presents a general overview of physical, chemical and biological waste-gas treatment techniques such as adsorption, absorption, oxidation and biodegradation,... (Review)
Review
This review presents a general overview of physical, chemical and biological waste-gas treatment techniques such as adsorption, absorption, oxidation and biodegradation, focusing more extensively on combined processes. It is widely recognized that biological waste-gas treatment devices such as biofilters and biotrickling filters can show high performance, often reaching removal efficiencies above 90 % for pollutant concentrations below 5 g/m(3). However, for concentrations exceeding this limit and under transient shock-load conditions that are frequently encountered in industrial situations, a physicochemical gas cleaning process can sometimes be advantageously combined with a biological one. Besides improving the overall treatment efficiency, the non-biological, first-stage process could also serve as a load equalization system by reducing the pollutant load during periodic shock-loads, to levels that can easily be handled in the second-stage bioreactor. This article reviews the operational advantages of integrating different non-biological and biological processes, i.e., adsorption pre-treatment+bioreactor, bioreactor+adsorption post-treatment, absorption pre-treatment+bioreactor, UV pre-treatment+bioreactor, and bioreactor/bioreactor combinations, for waste-gas treatment, where different gas-phase pollutants have been tested.
Topics: Air Pollutants; Air Pollution; Bacteria; Biodegradation, Environmental; Bioreactors; Filtration; Fungi; Gases; Industrial Waste
PubMed: 22486662
DOI: 10.1080/10934529.2012.667289