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关键词： LED illumination   PBR   Chlamydomonas reinhardtii   Lipid production  

摘要： Silver tinted multi-folded reflector sheet was additionally used in the newly designed LED-PBR setup to study the growth performances and resultant lipid production in Chlamydomonas reinhardtii. The experiment was also carried out to compare the algal growth under various LED light qualities with a white fluorescent lamp (FLs). The synergistic effect of the direct and reflected light provided more efficiency and light penetration that improved the cell concentration (77.5 x 10(6) cells mL(-1)), specific growth rate (0.514 d(-1)), total pigments (12.876 +/- 0.673 mg L-1) and lipid content (39A%) of C. reinhardtii under blue illumination than FLs. Interestingly, green light exhibited remarkable changes in lipid content (27.9%) on the 10 d of cultivation than white, red and FLs. Nile red analysis of neutral accumulation and FTIR analysis of fatty acid contents of C. reinhardtii under different light condition significantly varied. This modified RC-PBR setup can be utilized to increase the light intensity in algal culture and thereby minimize energy consumption and culture duration compared to FLs.

关键词： Adsorption   MBR   Particle size   PPCPs   SRT  

摘要： Removals of 10 pharmaceutical compounds by microbial sludge in membrane bioreactors (MBR) operated under infinite and limited solid retention time (SRT) were investigated. High removal ( > 80%) of DCF, TMP, NPX, IBP, and TCS were achieved but CBZ removals were low ( < 20%). The residual pharmaceutical compounds leftover from the biodegradation in different sludge particle size fractions was quantified through physical separation and filtration in series. The results revealed that hydrophobic compounds were mainly adsorbed onto the coarse particles ( > 0.45 mu m) where majority of adsorption site was available. Meanwhile, hydrophilic and moderate hydrophobic compounds were less associated with particles and they were retained in fine particles and gel-like substances (1 kDa-0.45 mu m). Most of the studied pharmaceutical compounds associated with fine particles and gel-like substances was subsequently rejected by membrane filtration in the MBRs. The operation of the MBR at high mixed liquor suspended solids concentration under long sludge age conditions could enhance the removals of pharmaceutical compounds through increased adsorption site on the sludge particles.

关键词： Suspended growth bioreactors   Recirculating aquaculture system   Water quality   Carbon/nitrogen rations  

摘要： In situ suspended growth aquaculture systems for oligotrophic species suffer from excess total suspended solids, low dissolved oxygen, and other associated problems. To address these disadvantages, this study designed and tested a closed recirculating aquaculture system containing 3 pilot-scale suspended growth bioreactors (SGBRs) for the water treatment of pollutants. These SGBRs were designed to control extra carbon addition at carbon/ nitrogen ratios of 12, 8, and 4, respectively. It was determined that the culture tanks removed total ammonia nitrogen (TAN) and nitrite (NO2--N) by nitrification, and the SGBRs removed nitrate (NO3--N) by denitrification and also soluble reactive phosphate (SRP). Concentrations of NO3--N and SRP in the effluent decreased, as the controlled carbon/nitrogen ratio of the SGBR increased. When carbon was controlled at a carbon/nitrogen ratio of 12, the influent concentrations of NO3--N (35.41 +/- 1.22 mg.L-1) and SRP (4.60 +/- 0.67 mg.L-1) were reduced to 7.70 +/- 3.58 mg.L-1 and 0.30 +/- 0.16 mg.L-1, respectively. Thus, this proposed system had the ability to control simultaneously TAN, NO2--N, NO3--N and SRP. The survival rate of Anguilla marmorata was 98.00 +/- 1.41%, with a final stocking density of 56.46 +/- 0.51 kg.m(-3). We suggest that various adjustments in the carbon/nitrogen ratios of SGBRs can be practically controlled according to the concentrations of pollutants in the culture tanks.

关键词： bioreactors   cardiac diseases   cardiac tissue engineering   electrical stimulation   mechanical stimulation   tissue engineering   vascularization  

摘要： The advances in biotechnology, biomechanics, and biomaterials can be used to develop organ models that aim to accurately emulate their natural counterparts. Heart disease, one of the leading causes of death in modern society, has attracted particular attention in the field of tissue engineering. To avoid incorrect prognosis of patients suffering from heart disease, or from adverse consequences of classical therapeutic approaches, as well as to address the shortage of heart donors, new solutions are urgently needed. Biotechnological advances in cardiac tissue engineering from a bioreactor perspective, in which recapitulation of functional, biochemical, and physiological characteristics of the cardiac tissue can be used to recreate its natural microenvironment, are reviewed. Detailed examples of functional and preclinical applications of engineered cardiac constructs and the state-of-the-art systems from a bioreactor perspective are provided. Finally, the current trends and future directions of the field for its translation to clinical settings are discussed.

关键词： Nitritation   FNA shock   Membrane bioreactor ( MBR)   Long solids retention time   N2O emission  

摘要： This study investigated the initiation and maintenance of nitritation in a membrane bioreactor (MBR) with long solids retention time (SRT) of 43.8 days. Nitritation was initiated within 65 days in the MBR via dissolved oxygen (DO) limitation (< 0.5 mg/L). However, nitrite oxidizing bacteria (NOB) (Nitrospira and Nitrobacter) acclimated to the low DO environment and proliferated from day 81, leading to nitrate accumulation. Thereafter, the combined strategy of DO limitation and in-situ generated free nitrous acid (FNA) shock successfully restored and maintained stable nitritation for > 70 days. Quantitative polymerase chain reaction (qPCR) results showed that cell abundances of Nitrospira and Nitrobacter decreased by between 50.0 to 68.9% and 60.6 to 96.4%, respectively following the FNA shocks. The maximum ammonium loading rate achieved was 1.81 kg N/(m(3) day) with ammonium removal ratio and nitrite accumulation ratio of over 0.97 and 0.96, respectively. Average emission rate of N2O from the MBR was 2.1 +/- 0.72% of ammonium removed. FNA shock on day 195 reduced the N2O emission by 13.6%. The strategy developed in this study verified that spiked FNA shock together with DO limitation can be used for maintaining nitritation in MBRs with long SRTs. This method can potentially allow for maintaining nitritation at relatively low capital and operating expenditure when treating high concentration ammonium wastewater. (C) 2019 Elsevier B.V. All rights reserved.

关键词： Laccases   Peroxidases   White-rot basidiomycete   Lignin   Copper sulphate   Induction  

摘要： Testing different pHs, dissolved oxygen concentrations and temperatures, plus the addition of inducers, to optimize ligninolytic enzyme activity, resulted in increased production of laccases, total peroxidases and manganese peroxidases on the order of 2.1-fold, 4.6-fold and 10-fold, respectively;laccases reached 6588 U/mL, total peroxidases reached 3533 U/mL and manganese peroxidase achieved 60 U/mL. Furthermore, an increase in laccase volumetric productivity and in its specific activity was verified. The addition of inducers, such as copper sulphate and manganese sulphate, improved enzymatic activity. In addition, a new previously unidentified laccase isoform was documented by zymography. The present work successfully increased the production of ligninolytic enzymes.

关键词： Bioreactor   wastewater   sulfamethazine   LC-MS/MS   removal kinetic  

摘要： The use of anaerobic biomass attached to a support has been recently presented as a good prospect in the treatment of wastewater containing recalcitrant compounds, such as sulfamethazine (SMZ). SMZ has been found in swine wastewater and sewage treatment plants, which motivates assessing their degradation by new wastewater treatment technologies. Thus, this paper describes the use of a continuous fixed structured bed bioreactor for the purpose of evaluating SMZ removal kinetics present in lab-made wastewater. The analysis of SMZ used online solid-phase extraction coupled to liquid chromatography/tandem mass spectrometry (SPE online-LC-MS/MS). Chemical oxygen demand (COD) was also monitored to evaluate the organic matter removal. The bioreactor was operated under mesophilic conditions (30C), with a hydraulic retention time of 24 h. In order to evaluate SMZ removal, four different concentration levels were studied: 200, 400, 600, and 800 ng L-1. COD removal efficiency obtained for filtered effluent kept at 91.01% and there was no interference due to the increase of SMZ concentration. For SMZ, the removal efficiencies were of for 200 ng L-1 concentration level;for 400 ng L-1;for 600 ng L-1, and for 800 ng L-1. COD removal kinetics presented a first-order apparent removal rate constant () of h(-1). SMZ also showed a first-order apparent removal rate constant of h(-1) for the following concentrations levels: 200, 400, 600, and 800 ng L-1.

关键词： Membrane fouling reduction   poly dimethyldiallylammonium chloride (PDMDAAC)   flocs-to-flocs aggregation   zeta potential   soluble microbial products (SMP)  

摘要： Poly dimethyldiallylammonium chloride (PDMDAAC) was applied in a membrane bioreactor (MBR) to study its effects on mitigation of MBR membrane fouling. Floc size, zeta potential, soluble microbial substances (SMP) and extracellular polymeric substances (EPS) secretion were studied with respect to PDMMAAC-dosing operations. Results demonstrated that a sustainable filtration cycle extended 3.3 times with the optimal PDMDAAC dosage of 90 mg L-1. The addition of PDMDAAC could increase zeta potential of sludge floc, which led to the decrease in repulsive electrostatic interactions between flocs, as well as the facilitation of flocs-to-flocs aggregation. With the optimal dosage of PDMDAAC, the mean size of sludge was 3.23 +/- 0.55 times higher than the control group, resulting in higher impact resistance and better adaptive capacity to the changing environment, which led to less SMP secretion. Moreover, a high contaminants removal rate was achieved in the reactor that was dosed with PDMDAAC. The average effluent concentrations of chemical oxygen demand and total nitrogen were less than 45.6 +/- 2.85 and 5.23 +/- 0.61 mg L-1, respectively, and the corresponding removal rates were 93.1 +/- 5.81% and 89.1 +/- 9.61%.

关键词： activated sludge   biological treatment   endocrine disrupting compounds   trace organic compounds   water reuse  

摘要： Direct potable reuse of wastewater is attractive as the demand for potable water increases. However, the presence of organic micropollutants in industrial and domestic wastewater is a major health and environmental concern. Conventional wastewater treatment processes are not designed to remove these compounds. Further many of these emerging pollutants are not regulated. Membrane bioreactor based biological wastewater treatment has recently become a preferred method for treating municipal and other industrial wastewaters. Here the removal of five selected micropollutants representing different classes of emerging micropollutants has been investigated using a membrane bioreactor. Acetaminophen, amoxicillin, atrazine, estrone, and triclosan were spiked into wastewaters obtained from a local wastewater treatment facility prior to introduction to the membrane bioreactor containing both anoxic and aerobic tanks. Removal of these compounds by adsorption and biological degradation was determined for both the anoxic and aerobic processes. The removal as a function of operating time was investigated. The results obtained here suggest that removal may be related to the chemical structure of the micropollutants.

关键词： Biofilms   Antibiotic resistance   Antimicrobial agents   Membranes   Biomass  

摘要： Anaerobic membrane bioreactors (AnMBRs) are an emerging technology with potential to improve energy efficiency and effluent reuse in mainstream wastewater treatment. However, their contribution to the proliferation of contaminants of emerging concern, such as antibiotic resistance genes (ARGs), remains largely unknown. The purpose of this study was to determine the effect of select influent antibiotics at varying concentrations on the presence and abundance of ARGs in an AnMBR system and its effluent. Quantification of targeted ARGs revealed distinct profiles in biomass and effluent, with genes conferring resistance to different antibiotic classes dominating in biomass (macrolides) and effluent (sulfonamides). Effluent sul1 gene abundance was strongly correlated with abundance of intl1, signifying the potential importance of mobile genetic elements in ARG release from AnMBR systems. The addition of specific antibiotics also affected normalized abundances of their related ARGs, exemplifying the potential impact of selective pressures at both low (10 mu g/L) and high (250 mu g/L) influent antibiotic concentrations.