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1.
Cureus ; 14(10): e30331, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36407234

RESUMEN

Pulmonary sequestration is a congenital disease formed by embryogenic separation of the lung parenchyma, halting development and function. It has an aberrant blood supply and can provide a nidus for infection and respiratory compromise. It can be diagnosed prenatally with surgical resection after delivery reserved as the best mode of treatment. In literature, six to twelve months is the most optimal time for elective surgical repair giving time for some maturation to withstand single lung ventilation and operation before the risk of infection heightens after 12 months. We present a case of an infant that had an elective repair at four months of age with no postoperative sequelae highlighting that surgeons can perform elective repair sooner than six months of age and that surgical decision-making should be on a case-by-case basis.

2.
J Immunother Cancer ; 10(10)2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36192086

RESUMEN

BACKGROUND: Current immunotherapies still have limited successful rates among cancers. It is now recognized that T cell functional state in the tumor microenvironment (TME) is a key determinant for effective antitumor immunity and immunotherapy. In addition to exhaustion, cellular senescence in tumor-infiltrating T cells (TILs) has recently been identified as an important T cell dysfunctional state induced by various malignant tumors. Therefore, a better understanding of the molecular mechanism responsible for T cell senescence in the TME and development of novel strategies to prevent effector T cell senescence are urgently needed for cancer immunotherapy. METHODS: Senescent T cell populations in the TMEs in mouse lung cancer, breast cancer, and melanoma tumor models were evaluated. Furthermore, T cell senescence induced by mouse tumor and regulatory T (Treg) cells in vitro was determined with multiple markers and assays, including real-time PCR, flow cytometry, and histochemistry staining. Loss-of-function strategies with pharmacological inhibitors and the knockout mouse model were used to identify the potential molecules and pathways involved in T cell senescence. In addition, melanoma mouse tumor immunotherapy models were performed to explore the synergistical efficacy of antitumor immunity via prevention of tumor-specific T cell senescence combined with anti-programmed death-ligand 1 (anti-PD-L1) checkpoint blockade therapy. RESULTS: We report that both mouse malignant tumor cells and Treg cells can induce responder T cell senescence, similar as shown in human Treg and tumor cells. Accumulated senescent T cells also exist in the TME in tumor models of lung cancer, breast cancer and melanoma. Induction of ataxia-telangiectasia mutated protein (ATM)-associated DNA damage is the cause for T cell senescence induced by both mouse tumor cells and Treg cells, which is also regulated by mitogen-activated protein kinase (MAPK) signaling. Furthermore, blockages of ATM-associated DNA damage and/or MAPK signaling pathways in T cells can prevent T cell senescence mediated by tumor cells and Treg cells in vitro and enhance antitumor immunity and immunotherapy in vivo in adoptive transfer T cell therapy melanoma models. Importantly, prevention of tumor-specific T cell senescence via ATM and/or MAPK signaling inhibition combined with anti-PD-L1 checkpoint blockade can synergistically enhance antitumor immunity and immunotherapy in vivo. CONCLUSIONS: These studies prove the novel concept that targeting both effector T cell senescence and exhaustion is an effective strategy and can synergistically enhance cancer immunotherapy.


Asunto(s)
Neoplasias de la Mama , Inmunoterapia , Neoplasias Pulmonares , Melanoma , Linfocitos T , Animales , Neoplasias de la Mama/inmunología , Neoplasias de la Mama/terapia , Senescencia Celular , Femenino , Humanos , Neoplasias Pulmonares/inmunología , Neoplasias Pulmonares/terapia , Melanoma/inmunología , Melanoma/terapia , Ratones , Proteínas Quinasas Activadas por Mitógenos , Linfocitos T/citología , Microambiente Tumoral
3.
J Hazard Mater ; 407: 124348, 2021 04 05.
Artículo en Inglés | MEDLINE | ID: mdl-33144005

RESUMEN

Produced water is a major waste problem in oil production yet it also represents a potential water source if treated properly, especially in arid regions. In this study, we investigate the anaerobic treatability of an oil-produced water with extremely high chemical oxygen demand (COD) and total dissolved organic carbon (TOC) from Wyoming's Greater Green River Basin using anaerobic microcosms inoculated with a microbial consortium derived from a brewery wastewater treatment facility. The results demonstrate that for this water and an appropriate microbial inoculation, high-COD/TOC can be effectively removed with concomitant energy recovery as a form of methane. 93% and 89% of the COD and TOC were removed with a final high methane yield of 33.9 mmol/g carbon (848 µmol/g carbon/day). Chemical analyses showed that the ethylacetate-extractable compounds were much more amenable to biodegradation than the CH2Cl2 extractable compounds. Furthermore, compounds that were added during drilling and completion remained in the water and contributed significantly to the COD and anaerobic degradability. This study demonstrates that produced waters are amenable to anaerobic biological treatment and also that thorough chemical analyses are necessary to fully understand the potential for treatment.


Asunto(s)
Petróleo , Purificación del Agua , Anaerobiosis , Reactores Biológicos , Metano , Aguas Residuales , Agua
4.
J Hazard Mater ; 399: 123017, 2020 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-32521313

RESUMEN

Visible light-responsive tetradecahedral ZnO-SnO2-Zn2SnO4 photocatalysts possessing double Z-scheme mechanism were prepared via a hydrothermal pathway and subsequent annealing treatment. Due to its enhanced optical absorption ability and effective charge separation, the sample with a Zn/Sn atom ratio of 3:2 (Z32) exhibited superior degradation of the antibiotics ciprofloxacin and sulfamonomethoxine under visible light irradiation and also degraded bisphenol A. Furthermore, five-cycle experiments confirmed that Z32 also exhibited satisfactory photostability. The trapping experiment and electron spin resonance data demonstrated that both OH and O2- play important roles in the photocatalytic system, where electron transfer coincides with the double Z-scheme mechanism. Photo-generated electrons in the conduction band (CB) of ZnO can transfer to the valence band (VB) of Zn2SnO4, while electrons in the CB of SnO2 transfer to the VB of ZnO, as a result of the intimate-contact, chemically-bound interface. Therefore, the reduction and oxidation reactions occur at higher reduction and oxidation potentials, producing reactions that can successfully eliminate the biotoxicity of antibiotics to Escherichia coli DH5a after photocatalytic degradation by Z32.


Asunto(s)
Óxido de Zinc , Antibacterianos/toxicidad , Catálisis , Oxidación-Reducción , Zinc , Óxido de Zinc/toxicidad
5.
Water Res ; 93: 179-186, 2016 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-26905796

RESUMEN

N-Nitrosodimethylamine (NDMA) is a disinfection by-product (DBP) with many known precursors such as amine-containing pharmaceuticals that can enter the environment via treated wastewater. Reverse osmosis and tight nanofiltration membranes (MW cutoff < 200 Da) are treatment technologies that demonstrate high removal of many compounds, but at relatively high energy costs. Looser membranes (>200 Da) may provide sufficient removal of a wide range of contaminants with lower energy costs. This study examined the rejection of pharmaceuticals that are known NDMA precursors (∼300 Da) using nanofiltration (MW cutoff ∼350 Da). MQ water was compared to two raw water sources, and results illustrated that NDMA precursors (as estimated by formation potential testing) were effectively rejected in all water matrices (>84%). Mixtures of pharmaceuticals vs. single-spiked compounds were found to have no impact on rejection from the membranes used. The use of MQ water vs. surface waters illustrated that natural organic matter, colloids, and inorganic ions present did not significantly impact the rejection of the amine-containing pharmaceuticals. This study illustrates that NDMA formation potential testing can be effectively used for assessing NDMA precursor rejection from more complex samples with multiple and/or unknown NDMA precursors present, such as wastewater matrices.


Asunto(s)
Dimetilnitrosamina/química , Profármacos/química , Aguas Residuales/química , Contaminantes Químicos del Agua/química , Purificación del Agua/métodos , Cloraminas/química , Dimetilnitrosamina/aislamiento & purificación , Desinfección/instrumentación , Desinfección/métodos , Filtración/instrumentación , Filtración/métodos , Membranas Artificiales , Filtros Microporos , Preparaciones Farmacéuticas/química , Preparaciones Farmacéuticas/aislamiento & purificación , Profármacos/aislamiento & purificación , Factores de Tiempo , Contaminantes Químicos del Agua/aislamiento & purificación , Purificación del Agua/instrumentación
6.
Chemosphere ; 117: 170-7, 2014 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-25016429

RESUMEN

This study examined the rejection of selected pharmaceutically active (PhAC) and endocrine disrupting compounds (EDCs) when using nanofiltration as a function of naturally occurring dissolved organic matter (DOM), colloidal particles, cations and their interactions. Lake Ontario water served as a source of natural DOM and colloidal particles. PhAC/EDC rejection experiments were conducted using raw Lake Ontario water and Lake Ontario water that was pre-treated with either ultrafiltration to remove colloidal particles, or fluidized ion exchange resins to remove DOM. Additionally, the concentration of cations (Ca(2+), Mg(2+), and Na(+)) in the raw and pre-treated water matrices was varied. While ionic PhACs and EDCs exhibited high rejections from all the water matrices examined, neutral compounds were most effectively rejected in water containing DOM and no colloids, and least effectively rejected from colloid-containing water with increased cations but no DOM. The presence of DOM significantly improved compound rejection and the increase in cation concentration significantly decreased rejection. The presence of colloids had comparatively little effect except to mitigate the impact of increased cation concentration, apparently providing some cation-buffering capacity. The sequence in which constituents are removed from waters during treatment may significantly impact PhAC and EDC removal, especially of neutral compounds.


Asunto(s)
Disruptores Endocrinos/análisis , Sustancias Húmicas , Preparaciones Farmacéuticas/análisis , Eliminación de Residuos Líquidos , Aguas Residuales/análisis , Contaminantes Químicos del Agua/análisis , Cationes/química , Coloides/química , Filtración , Lagos , Peso Molecular , Ontario , Material Particulado/química
7.
Biotechnol Adv ; 30(4): 817-58, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22306168

RESUMEN

The bioeconomy, and in particular, biorefining and bioenergy production, have received considerable attention in recent years as a shift to renewable bioresources to produce similar energy and chemicals derived from fossil energy sources, represents a more sustainable path. Membrane technologies have been shown to play a key role in process intensification and products recovery and purification in biorefining and bioenergy production processes. Among the various separation technologies used, membrane technologies provide excellent fractionation and separation capabilities, low chemical consumption, and reduced energy requirements. This article presents a state-of-the-art review on membrane technologies related to various processes of biorefining and bioenergy production, including: (i) separation and purification of individual molecules from biomass, (ii) removal of fermentation inhibitors, (iii) enzyme recovery from hydrolysis processes, (iv) membrane bioreactors for bioenergy and chemical production, such as bioethanol, biogas and acetic acid, (v) bioethanol dehydration, (vi) bio-oil and biodiesel production, and (vii) algae harvesting. The advantages and limitations of membrane technologies for these applications are discussed and new membrane-based integrated processes are proposed. Finally, challenges and opportunities of membrane technologies for biorefining and bioenergy production in the coming years are addressed.


Asunto(s)
Biocombustibles , Biomasa , Reactores Biológicos , Biotecnología/métodos , Membranas Artificiales , Etanol/química , Lignina/química , Metano/química , Polisacáridos/química
8.
Bioresour Technol ; 101(2): 654-67, 2010 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-19762231

RESUMEN

Lignocellulosic ethanol holds promise for addressing climate change and energy security issues associated with personal transportation through lowering the fuel mixes' carbon intensity and petroleum demand. We compare the technological features and life cycle environmental impacts of near- and mid-term ethanol bioconversion technologies in the United States. Key uncertainties in the major processes: pre-treatment, hydrolysis, and fermentation are evaluated. The potential to reduce fossil energy use and greenhouse gas (GHG) emissions varies among bioconversion processes, although all options studied are considerably more attractive than gasoline. Anticipated future performance is found to be considerably more attractive than that published in the literature as being achieved to date. Electricity co-product credits are important in characterizing the GHG impacts of different ethanol production pathways; however, in the absence of near-term liquid transportation fuel alternatives to gasoline, optimizing ethanol facilities to produce ethanol (as opposed to co-products) is important for reducing the carbon intensity of the road transportation sector and for energy security.


Asunto(s)
Etanol/química , Lignina/química , Electricidad , Fermentación , Hidrólisis , Modelos Químicos , Método de Montecarlo
9.
Philos Trans A Math Phys Eng Sci ; 367(1904): 3923-39, 2009 Oct 13.
Artículo en Inglés | MEDLINE | ID: mdl-19736228

RESUMEN

The detection of organic micropollutants, such as endocrine-disrupting compounds, pharmaceuticals and personal care products, in wastewater and the aquatic environment has brought increasing concern over their potential adverse ecological and human impacts. These compounds are generally present at trace levels (ng l(-1)) and in complex water matrices, such as wastewaters and surface waters, making their analysis difficult. Currently, no standardized analytical methods are available for the analysis of organic micropollutants in environmental waters. Owing to the diversity of physico-chemical properties exhibited by the various classes of organic micropollutants, the majority of established analytical methods described in the literature focus on a specific class of compounds, with few methods applicable to multi-class compound analysis. As such, analytical challenges and limitations contribute to the lack of understanding of the effectiveness of drinking water and wastewater treatment processes to remove organic micropollutants. This paper provides a practical overview of current analytical methods that have been developed for the analysis of multiple classes of organic micropollutants from various water matrices and describes the challenges and limitations associated with the development of these methods.


Asunto(s)
Técnicas de Química Analítica/métodos , Disruptores Endocrinos/análisis , Monitoreo del Ambiente/métodos , Purificación del Agua/métodos , Abastecimiento de Agua/análisis , Ecología , Preparaciones Farmacéuticas/análisis , Preparaciones Farmacéuticas/química , Eliminación de Residuos Líquidos/métodos , Agua/análisis , Contaminantes Químicos del Agua/efectos adversos , Contaminantes Químicos del Agua/análisis
10.
Water Res ; 43(3): 613-22, 2009 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19046596

RESUMEN

The impact of natural organic matter (NOM) and cations on the rejection of five endocrine disrupting compounds (EDCs) and pharmaceutically active compounds (PhACs) (acetaminophen, carbamazepine, estrone, gemfibrozil, oxybenzone) by nanofiltration (NF) was examined. The water matrices included membrane bioreactor (MBR) effluent, Lake Ontario water and laboratory-prepared waters modelled to represent the characteristics of the Lake Ontario water. The impact of cations in natural waters on compound rejection was also examined by doubling the natural cation concentration (calcium, magnesium, sodium) in both the Lake Ontario water and the MBR effluent. The presence of Suwannee River NOM spiked into laboratory-grade water was found to cause an increase in compound NF rejection. In addition, the presence of cations alone in laboratory-grade water did not have a significant impact on rejection with the exception of the polar compound gemfibrozil. However, when cation concentration in natural waters was increased, a significant decrease in the rejection of EDCs and PhACs was observed. This suggests that the presence of cations may result in a reduction in the association of EDCs and PhACs with NOM.


Asunto(s)
Disruptores Endocrinos/aislamiento & purificación , Filtración/métodos , Nanotecnología/métodos , Compuestos Orgánicos/química , Preparaciones Farmacéuticas/aislamiento & purificación , Análisis de Varianza , Cationes , Membranas Artificiales , Presión , Agua/química
11.
Bioresour Technol ; 99(3): 540-6, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17336058

RESUMEN

Biosolids pellets produced from anaerobically digested municipal wastewater sludge by drying to greater than 90% total solids at 110-115 degrees C for at least 75 min, were tested for their suitability as an inoculum source for fermentative hydrogen production. The hydrogen recoveries (mg gaseous H(2) produced as COD/mg added substrate COD) for glucose-fed batch systems were equal, 20.2-21.5%, between biosolids pellets and boiled anaerobic digester sludge as inoculum sources. Hydrogen recoveries from primary sludge were 2.4% and 3.5% using biosolids pellets and boiled sludge, respectively, and only 0.2% and 0.8% for municipal wastewater. Biosolids pellets should be a practical inoculum source for fermentative hydrogen reactors, although the effectiveness will depend on the wastewater treated.


Asunto(s)
Fermentación , Hidrógeno/metabolismo , Aguas del Alcantarillado , Anaerobiosis , Glucosa , Metano/metabolismo , Especificidad por Sustrato , Eliminación de Residuos Líquidos
12.
Biotechnol Lett ; 29(5): 685-95, 2007 May.
Artículo en Inglés | MEDLINE | ID: mdl-17279447

RESUMEN

Efforts to increase H(2) yields from fermentative H(2) production include heat treatment of the inoculum, dissolved gas removal, and varying the organic loading rate. Although heat treatment kills methanogens and selects for spore-forming bacteria, the available evidence indicates H(2) yields are not maximized compared to bromoethanesulfonate, iodopropane, or perchloric acid pre-treatments and spore-forming acetogens are not killed. Operational controls (low pH, short solids retention time) can replace heat treatment. Gas sparging increases H(2) yields compared to un-sparged reactors, but no relationship exists between the sparging rate and H(2) yield. Lower sparging rates may improve the H(2) yield with less energy input and product dilution. The reasons why sparging improves H(2) yields are unknown, but recent measurements of dissolved H(2) concentrations during sparging suggest the assumption of decreased inhibition of the H(2)-producing enzymes is unlikely. Significant disagreement exists over the effect of organic loading rate (OLR); some studies show relatively higher OLRs improve H(2) yield while others show the opposite. Discovering the reasons for higher H(2) yields during dissolved gas removal and changes in OLR will help improve H(2) yields.


Asunto(s)
Fermentación , Hidrógeno/metabolismo , Bacterias/metabolismo , Calor , Solubilidad
13.
Biotechnol Lett ; 28(18): 1485-91, 2006 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16955354

RESUMEN

Dissolved H(2) and CO(2) were measured by an improved manual headspace-gas chromatographic method during fermentative H(2) production with N(2) sparging. Sparging increased the yield from 1.3 to 1.8 mol H(2)/mol glucose converted, although H(2) and CO(2) were still supersaturated regardless of sparging. The common assumption that sparging increases the H(2) yield because of lower dissolved H(2) concentrations may be incorrect, because H(2) was not lowered into the range necessary to affect the relevant enzymes. More likely, N(2) sparging decreased the rate of H(2) consumption via lower substrate concentrations.


Asunto(s)
Reactores Biológicos , Dióxido de Carbono/análisis , Cromatografía de Gases/métodos , Fermentación , Hidrógeno/análisis , Hidrógeno/metabolismo , Nitrógeno/farmacología , Biomasa , Solubilidad
14.
Water Environ Res ; 77(4): 390-403, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-16121507

RESUMEN

Municipal wastewater treatment may lead to the emission of greenhouse gases. The current Intergovenmental Panel on Climate Change (Geneva, Switzerland) approach attributes only methane emissions to wastewater treatment, but this approach may overestimate greenhouse gas emissions from the highly aerobic processes primarily used in North America. To better estimate greenhouse gas emissions, a procedure is developed that can be used either with plant-specific data or more general regional data. The procedure was evaluated using full-scale data from 16 Canadian wastewater treatment facilities and then applied to all 10 Canadian provinces. The principal greenhouse gas emitted from municipal wastewater treatment plants was estimated to be carbon dioxide (CO2), with very little methane expected. The emission rates ranged from 0.005 kg CO2-equivalent/m3 treated for primary treatment facilities to 0.26 kg CO2-equivalent/m3 for conventional activated sludge, with anaerobic sludge digestion to over 0.8 kg CO2-equivalent/m3 for extended aeration with aerobic digestion. Increasing the effectiveness of biogas generation and use will decrease the greenhouse gas emissions that may be assigned to the wastewater treatment plant.


Asunto(s)
Contaminación del Aire/análisis , Reactores Biológicos , Efecto Invernadero , Metano/análisis , Eliminación de Residuos Líquidos/métodos , Amoníaco/análisis , Bacterias Aerobias , Bacterias Anaerobias , Canadá , Dióxido de Carbono/análisis , Volatilización
15.
Water Res ; 39(16): 3982-90, 2005 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16112164

RESUMEN

A membrane bioreactor and reverse osmosis (MBR-RO) system was developed to assess potential reuse applications of municipal wastewater. The objective of the study was to examine the water quality throughout the system with a focus on waterborne pathogens, disinfection by-products (DBPs) and nitrate. This paper will discuss the presence of these contaminants in MBR effluent and focus on their subsequent removal by RO. This study has shown that high quality reuse water can be produced from municipal wastewater through the use of an MBR-RO system. The water meets California Title 22 reuse regulations for non-potable applications and US EPA drinking water limits for trihalomethanes (THM) (80 microg/L), haloacetic acids (HAA) (60 microg/L), chlorite (1.0 mg/L), total coliform (not detectable), viruses (not detectable), and nitrate/nitrite (10 mg N/L). However, THM formation (182-689 microg/L) attributed to cleaning of the MBR with chlorine and incomplete removal by subsequent RO treatment resulted in reuse water with THM levels (40.2+/-19.9 microg/L) high enough to present a potential concern when considering drinking water applications. Nitrate levels of up to 3.6 mg N/L, which resulted from incomplete removal by the RO membrane, are also a potential concern. A denitrification step in the MBR should be considered in potable water applications.


Asunto(s)
Reactores Biológicos , Ósmosis , Eliminación de Residuos Líquidos/métodos , Adhesión a Directriz , Membranas Artificiales , Nitratos/aislamiento & purificación , Control de Calidad , Microbiología del Agua , Contaminantes del Agua/aislamiento & purificación
16.
Environ Sci Technol ; 39(10): 3819-25, 2005 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-15952391

RESUMEN

The effects of effluent recycle were examined in a two-phase anaerobic system where the first phase was operated for fermentative hydrogen production and the second for methanogenesis. The hydrogen reactor was operated as a chemostat at 35 degrees C and pH 5.5 with a 10 h hydraulic retention time, and the methane reactor was operated as an up-flow reactor at 28 degrees C and pH between 6.9 and 7.2. Two recycle ratios were examined: 0 and 0.98. Effluent recycle reduced the required alkalinity for pH control by approximately 40%. The H2 productivity metric, with a basis in electrons and incorporating both gaseous and dissolved H2, was developed as a more fundamental reporting method than the molar H2 yield. Without recycle, the H2 productivity was 0.115 g of H2 COD/g of feed COD, but decreased to 0.015 q of H2 COD/g of feed COD with recycle (COD = chemical oxygen demand). Mass balances indicated the lower H2 productivity during recycle was due to electrons being partitioned to methane and less-oxidized soluble constituents such as propionic acid, ethanol, and butanol. The results indicated that achieving high H2 productivity with nonsterile wastewaters will be challenging and membrane filtration of the recycle liquid may be required to exclude the return of hydrogen-consuming organisms.


Asunto(s)
Reactores Biológicos , Conservación de los Recursos Naturales , Hidrógeno/metabolismo , Metano/metabolismo , Eliminación de Residuos Líquidos/métodos , 1-Butanol/análisis , Bacterias Anaerobias/metabolismo , Etanol/análisis , Ácidos Grasos Volátiles/análisis , Fermentación , Concentración de Iones de Hidrógeno , Aguas del Alcantarillado/microbiología
17.
Water Res ; 36(13): 3307-13, 2002 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12188129

RESUMEN

The effects of linoleic (C18:2), oleic (C18:1), and stearic (C18:0) acids on glucose, butyrate and hydrogen degradation were investigated at 21 degrees C using a culture unacclimated to long-chain fatty acids (LCFAs). Diethyl ether was used to facilitate precise addition of LCFAs and provide adequate dispersion in cultures. Butyrate degradation was affected by diethyl ether but minimal effects were observed on hydrogen and glucose consumption. In the presence of oleic and stearic acids, the glucose consumption rate was similar but was approximately 50% lower in the presence of linoleic acid. The effect of a mixture of 100 mg l(-1) of each individual LCFA (300 mg l(-1) total LCFA) was approximately the same as 100 mg l(-1) linoleic acid alone, suggesting no synergistic inhibition of glucose degradation. Butyric acid degradation was more severely inhibited by the LCFAs with inhibition becoming more severe with the addition of double bonds to the LCFA. Furthermore, mixtures of LCFAs synergistically inhibited butyric acid degradation compared to the results with individual LCFAs. In contrast, although lower hydrogen consumption rates were observed in cultures receiving oleic and linoleic acids compared to cultures receiving stearic acid, inhibition by all three acids individually or in mixture was limited. The introduction of LCFAs into a system may severly inhibit intermediate acid degradation while having little effect on acid production.


Asunto(s)
Butiratos/metabolismo , Ácidos Grasos/metabolismo , Industria de Alimentos , Glucosa/metabolismo , Eliminación de Residuos Líquidos/métodos , Reactores Biológicos , Hidrógeno/química
18.
Water Res ; 36(1): 363-7, 2002 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11766815

RESUMEN

A lab-scale anaerobic sequencing batch reactor (ASBR) that had operated with glucose at an organic loading rate of 2.1 kg COD m(-3) d(-1) was stressed with an organic loading rate of 3.2 kg COD m(-3) (-1). Five different combinations of influent concentration, total cycle time, and fill time to cycle time ratio were examined. No external pH control was used. In all cases, acetate and propionate were the main constituents of the effluent. Larger fill time to cycle time ratios and lower initial substrate concentrations resulted in improved performance suggesting that ASBR operation may be improved by changing operational parameters.


Asunto(s)
Bacterias Anaerobias/fisiología , Eliminación de Residuos Líquidos/métodos , Reactores Biológicos , Diseño de Equipo , Glucosa/metabolismo , Concentración de Iones de Hidrógeno , Oxígeno/metabolismo , Control de Calidad , Movimientos del Agua
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