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关键词： Hybrid carrousel   Chemical oxygen demand   Ammonia   Nitrite   Methane  

摘要： Nowadays, there are several wastewater treatment systems for treating industrial wastewater, but most of them require big areas for the construction, complex operation and high energy, elevating the costs. The goal of this study was to evaluate the effectiveness of the hybrid carrousel reactor, a multi-modular system, for coupling several biological processes in the same reaction unit, in order to remove nitrogenous and carbonaceous compounds from synthetic and industrial wastewater. The industrial wastewater used was coming from the raw influent entering the Wastewater Treatment Plant located in Lerma, Mexico. The hybrid carrousel reactor was of 21.5 L composed mainly of 4 modules: activated sludge module, secondary settler module and two facultative-anaerobic modules. With industrial wastewater, two organic loading rates were evaluated, 611 and 1025mg CODs/L-d, achieving 60-80% of ammonia removal. The biodegradability index of this kind of industrial wastewater was 0.5, so hybrid bioreactor was indeed effective for removing all the biodegradable organic matter. The kinetic studies showed that the presence of toxic compounds contained in the industrial wastewater strongly inhibited the nitrite-oxidizing step. The experimental results showed that the combination of aerobic, facultative and anaerobic modules was effective for the biotransformation of ammonia to N-2 and organic matter to CH4. This novel hybrid bioreactor might be a feasible technology for coupling biological processes in order to treat complex industrial wastewaters.

摘要： 360

关键词： Nitric oxide (NO)   Hollow fiber membrane   Denitrification   Microbial community   Electron acceptor   Waste treatment  

摘要： Nitric oxide (NO) removal from a gas stream containing 500ppm NO was studied in a hollow fiber membrane (HFM) bioreactor. Compared to other biological NO removal methods the HFM bioreactor achieved NO removal rates that were as good if not better, of up to 92% NO removal, under comparable loadings and reactor size. Results showed that a wastewater stream containing organic carbon can be used as the electron donor to reduce the NO. Hence, combining biological NO treatment with treatment of a wastewater containing organic carbon has may be an effective overall cost-reducing strategy. The effect of different nitrate (NO- loading regimes and the NO removal rate as well as the microbial denitrifier community in the reactor was tracked. Specifically, the relevant genes responsible for each denitrification step were tracked during each different NO:NOloading regime to the reactor. Results showed that the denitrifying microbial community adjust rapidly to changes in the different N loadings, but overall the performance of the reactor is robust and can withstand such variability in terms of NO, Nnd organic carbon removal.

关键词： integrated powder activated carbon   activated sludge bioreactor   saline wastewater   halotolerant bacteria   biokinetic coefficient   industrial wastewater treatment  

摘要： The halotolerant bacteria including Pseudomonas stutzeri strain Ahv-S12, Bacillus vietnamensis strain Ahv-Q1 and Brevibacterium sediminis strain Ahv-Z20 were used as inoculums in an integrated powder activated carbon/activated sludge bioreactor. The influence of organic loading rates (OLRs) and total dissolved solids (TDS) concentrations on chemical oxygen demand (COD) removal efficiency was evaluated. Furthermore, biokinetic coefficient was evaluated under TDS variation. Results showed that the COD removal value of 68.32% was observed in OLR of 0.4 kg COD m(-3) day(-1) and TDS concentrations of 20,000 mg L-1. Higher OLR and TDS concentration led to lower COD removal efficiency. On the other hand, the biodegradation function of isolated salt tolerant strains was much more affected by salinity rather than OLR. Results of biokinetic coefficient determination showed that yield value (Y), k(d), K, and mu(max) were 0.199-0.274 mgVSS mg COD-1, 0.016-0.038 day(-1), 0.48-0.922 day(-1) and 0.097-0.244 day(-1), respectively. (c) 2018 American Institute of Chemical Engineers Environ Prog, 38:e13088, 2019

关键词： Spray-drying   microgel   immobilization   laccase   pH-dependence   radicals   cytotoxicity   oxidative stress   cancer cell targeting   microparticles  

摘要： The lack of specificity of traditional cytostatics and increasing resistance of cancer cells represent important challenges in cancer therapy. One of the characteristics of cancer cells is their intrinsic oxidative stress caused by higher metabolic activity, mitochondrial malfunction, and oncogene stimulation. This feature can be exploited in the pursuit of more selective cancer therapy, as there is increasing evidence that cancer cells are more sensitive to elevated concentrations of reactive oxygen species than normal cells. In this study, we demonstrate a new concept for cancer cell targeting by in situ production of radicals under physiological conditions. The biologically active radicals are produced in the milieu of cancer cells by enzymatic conversion from an inactive precursor, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)diammonium salt, by using miniature bioreactors represented by cell-sized microgels containing immobilized laccase. We utilize the pH-dependent activity of laccase to generate radicals only at a lower pH (5.7-6.1) that is characteristic of the tumor microenvironment. The composition of the microgels was optimized so as to allow sufficient substrate and radical diffusion, high enzyme activity, and stability under physiological conditions. The functionality of this system was evaluated on three cancer cell lines (HeLa, HT-29, and DLD1) and the cytotoxicity of in situ-produced radicals was successfully proven in all cases. These results demonstrate that cancer cell targeting by in situ-generated radicals using miniature enzymatic reactors may represent an alternative to traditional cytostatics. In particular, the pH-dependence of radical generation and their short-lived nature can ensure localized functionality in the tumor microenvironment and thereby reduce systemic side-effects.

关键词： Volatile fatty acids   Anaerobic   Wastewater   pH   Fouling  

摘要： This study investigated the production of major volatile fatty acid (VFA) components in an anaerobic membrane bioreactor (AnMBR) to treat low-strength synthetic wastewater. No selective inhibition was applied for methane production and solvent-extraction method was used for VFA extraction. The results showed acetic and propionic acid were the predominant VFA components at pH 7.0 and 6.0 with concentrations of 1.444 +/- 0.051 and 0.516 +/- 0.032 mili-mol/l respectively. At pH 12.0 isobutyric acid was the major VFA component with a highest concentration of 0.712 +/- 0.008 mili-mol/l. The highest VFA yield was 48.74 +/- 1.5 mg VFA/100 mg CODfeed at pH 7.0. At different pH, AnMBR performance was evaluated in terms of COD, nutrient removal and membrane fouling rate. It was observed that the membrane fouled at a faster rate in both acidic and alkaline pH conditions, the slowest rate in membrane fouling was observed at pH 7.0.

关键词： cellulose breakdown   Corbicula japonica   environmental cellulase   invertebrate cellulase   wetland  

摘要： Recently, numerous species of aquatic invertebrates inhabiting wetlands have been shown to possess endogenous cellulase, following the discovery that termites have cellulase genes encoded in their own genome rather than relying on symbiotic bacteria for decomposing cellulose. Wetlands have been empirically shown to play an important role in the decomposition of land-originating hard-to-degrade polysaccharides such as cellulose. However, the mechanism that connects the cellulase producer and the wetlands remains unknown, which makes it very difficult to evaluate the ecological function of wetlands. Here we found that a macrobenthic bivalve, Corbicula japonica, secretes its cellulase to the wetland sediment. Secreted cellulases are immobilized in the components of the sediment. Moreover, adding cellulose or glucose to C. japonica could trigger its cellulase secretion level. These findings suggest a novel wetland cellulose decomposition mechanism. The decomposition ability of wetlands was previously ascribed only to microbes and/or invertebrates that contain cellulases. Our findings suggest that benthic animals supply wetlands with their enzymes as decomposition agents, while wetland sediments serve as immobilization scaffolds for the enzymes. This system, which was named by us an "environmental bioreactor system," could provide a key function in wetlands.

关键词： membrane bioreactor   transmembrane pressure   membrane foulants   aggregation   extracellular polymeric substances  

摘要： In this study, the characteristics of membrane foulants were analyzed with regard to morphology, composition, and aggregation ability during the three stages of transmembrane pressure (TMP) development (fast-slow-fast rise in TMP) in a steady operational membrane bioreactor (MBR). The results obtained show that the fouling layer at the slow TMP-increase stage possessed a higher average roughness (71.27 nm) and increased fractal dimension (2.33), which resulted in a low membrane fouling rate (0.87 kPa/d). A higher extracellular DNA (eDNA) proportion (26.12%) in the extracellular polymeric substances (EPS) resulted in both higher zeta potential (-23.3 mV) and higher hydrophobicity (82.3%) for initial foulants, which induced and increased the protein proportion in the subsequent fouling layer (74.11%). Furthermore, the main composition of the EPS shifted from protein toward polysaccharide dominance in the final fouling layer. The aggregation test confirmed that eDNA was essential for foulant aggregation in the initial fouling layer, whereas ion interaction significantly affected foulant aggregation in the final fouling layer.

关键词： quality by design   vaccine   cell culture   batch processing   biotechnology  

摘要： Quality by design (QbD) principle has been established as a guideline to emphasize the understanding of the relationship of product quality with process control. Vaccine product have characteristics of security and high efficiency, but it also has features such as complexity and rigorous regulatory for production. This case study describes an example of QbD-driven process development for manufacturing a veterinary vaccine produced with baby hamster kidney-21 cells. The study revealed that cell culture duration was the most significant factor affecting 50% tissue culture infectious doses (TCID50) and antigenic titer, and the factors of culture temperature and pH at infection phase exhibited less effect. Culture temperature at infection phase was the only significant factor for total protein. Through the Monte Carlo simulation, the design spaces of process parameters were determined. Meanwhile, the excellent and robust performance in manufacturing scale (4000-L) validated the effectiveness of this strategy. A reliable and robust multivariate process parameter range, that is, design space, was identified by this systematic approach. Our investigation presents a successful case of QbD principle, which encourages other researchers to combine the methodology into other biopharmaceutical manufacturing process. (c) 2019 American Pharmacists Association (R). Published by Elsevier Inc. All rights reserved.

关键词： Biological treatment   MBR   Styrene removal   Real petrochemical wastewater  

摘要： In this study, real petrochemical wastewater treatment was investigated at four hydraulic retention times (HRTs) of 30, 18, 12 and 6h, using membrane bioreactor. Initial evaluation confirmed the presence of styrene and more than 30 different types of compounds in petrochemical wastewater. Laboratory tests and gas chromatography-mass spectrometry (GC-MS) studies indicated that at all HRTs, styrene and chemical oxygen demand (COD) removal efficiencies are higher than 99 and 95%, respectively. Further investigations also revealed that HRT decreasing, not only does not reduce the COD removal efficiency, but also improves the effluent COD by increasing mixed liquor suspended solids. Also GC-MS analysis indicated that styrene as the major pollutant was removed over 99%. Transmembrane pressure was monitored for determining membrane fouling. Data showed severe membrane fouling occurred at HRT of 6h which was attributed to increase in soluble microbial products.