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关键词： Microchaete sp. NCCU-342   Silver nanoparticles   Optimization   TEM   DLS  

摘要： The green synthesis of metallic nanoparticles has paved the way for improving and protecting the environment by decreasing the use of toxic chemicals and eliminating biological risks in biomedical applications. Biological synthesis of metal nanoparticles is gaining more importance due to simplicity, rapid rate of synthesis and ecofriendliness. In the present investigation cyanobacterial (Microchaete NCCU-342) cell free aqueous extract has been used for optimizing biosynthesis of silver nanoparticles (AgNP). The optimized reaction parameters for efficient synthesis of AgNP were: biomass quantity of 80 mu g/ml, pH 5.5, 60 degrees C temperature, duration of 60 min UV light exposure and 1 mM AgNO3 concentration. AgNP was characterized by UV-Visible Spectrophotometery, Transmission Electron Microscopy and Dynamic light scattering. The smallest nanoparticles (obtained from biomass parameter were spherical, polydisperessed and in the range of 60-80 nm) were characterized further in a degradation study of azo dye methyl red. Degradation of methyl red within 2 h was more with AgNP (84.60%) as compared to cyanobacterial extract (49.80%).

关键词： biomanufacturing   bioreactor   environment control   perfusion   tissue engineering  

摘要： Bioreactors are crucial tools for the manufacturing of living cell-based tissue engineered products. However, to reach the market successfully, higher degrees of automation, as well as a decreased footprint still need to be reached. In this study, the use of a benchtop bioreactor for in vitro perfusion culture of scaffold-based tissue engineering constructs is assessed. A low-footprint benchtop bioreactor system is designed, comprising a single-use fluidic components and a bioreactor housing. The bioreactor is operated using an in-house developed program and the culture environment is monitored by specifically designed sensor ports. A gas-exchange module is incorporated allowing for heat and mass transfers. Titanium-based scaffolds are seeded with human periosteum-derived cells and cultured up to 3 weeks. The benchtop bioreactor constructs are compared to benchmark perfusion systems. Live/Dead stainings, DNA quantifications, glucose consumption, and lactate production assays confirm that the constructs cultured in the benchtop bioreactor grew similarly to the benchmark systems. Manual regulation of the system set points enabled efficient alteration of the culture environment in terms of temperature, pH, and dissolved oxygen. This study provides the necessary basis for the development of low-footprint, automated, benchtop perfusion bioreactors and enables the implementation of active environment control.

关键词： Anaerobic membrane bioreactor   Novel configurations   Membrane fouling   Energy recovery   Wastewater treatment  

摘要： Water shortage, public health and environmental protection are key motives to treat wastewater. The widespread adoption of wastewater as a resource depends upon development of an energy-efficient technology. Anaerobic membrane bioreactor (AnMBR) technology has gained increasing popularity due to their ability to offset the disadvantages of conventional treatment technologies. However there are several hurdles, yet to climb over, for wider spread and scale-up of the technology. This paper reviews fundamental aspects of anaerobic digestion of wastewater, and identifies the challenges and opportunities to the further development of AnMBRs. Membrane fouling and its implications are discussed, and strategies to control membrane fouling are proposed. Novel AnMBR configurations are discussed as an integrated approach to overcome technology limitations. Energy demand and recovery in AnMBRs is analyzed. Finally key issues that require urgent attention to facilitate global penetration of AnMBR technology are highlighted.

关键词： In vitro   Mutagenesis   Plant metabolites   Saccharum sp.   Plant breeding  

摘要： Chemical mutagens such as sodium azide (NaN3) have been widely used to increase genetic variability in crops, but the undirected mutations induced can have undesirable effects, which need to be characterized. This study investigated the effects of in vitro NaN3 (0-0.45 mM) exposure (30 days) on the micropropagation of sugarcane within temporary immersion bioreactors (TIB). Shoot multiplication rate and cluster fresh weight, and aldehyde, phenolic, carotenoid, and chlorophyll levels were measured on in vitro produced shoots. The soluble phenolic content of the culture medium was also assessed. NaN3 concentration was negatively correlated with sugarcane shoot multiplication rate and fresh weight;at 0.45 mM NaN3, these parameters were only 20% and 39% that of the untreated control, respectively. Shoot multiplication rate and fresh weight, and chlorophyll a and b levels were negatively correlated with NaN3 concentration. In contrast, malondialdehyde, other aldehyde, carotenoid, and exuded phenol levels were positively correlated with NaN3 concentration. Statistical comparisons suggest that shoot multiplication rate and the biochemical parameters that were positively correlated with NaN3 concentration may be the most suitable indicators of stress when optimizing the concentration of NaN3 for sugarcane explants. An interpolated 50% reduction of multiplication rates at 0.23 mM NaN3 suggests that this concentration to be suitable for TIB-based induction of mutagenesis in shoots and eventual production of agriculturally useful mutants.

关键词： Anaerobic fluidized bed membrane bioreactor   Granular activated carbon   Micropollutants   Biodegradation   Sorption  

摘要： This study applied a laboratory-scaled, staged anaerobic fluidized bed membrane bioreactor (SAF-MBR) added with granular activated carbon (GAC) as fluidized media to treat a synthetic wastewater containing 0.1 mg/L of three different pharmaceutical micropollutants. Diclofenac, ibuprofen, and sulfamethoxazole were selected as target micropollutants to investigate their removal efficiency during SAF-MBR operation. More than 96% of overall COD removal efficiency was achieved at 8.7 h of total HRT with 288 mg/L of bulk VSS concentration. Transmembrane pressure (TMP) from membrane remained less than 0.3 bar during operational period. After the SAF-MBR was introduced with the micropollutants at 5 Lm(-2) h(-1) of permeate flux, they were removed completely within 3 days of operation. Our batch experiments supported that the removal of micropollutants in reactor bulk was immensely pronounced by adsorption to GACs, sorption and biodegradation due to the biofilm formed on GACs fluidized in SAF-MBR system. (C) 2019 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.

关键词： scale-down   scale-up   miniaturized stirred bioreactor   high throughput   fermentation   process development  

摘要： Miniaturized stirred bioreactors (MSBRs) are gaining popularity as a cost-effective approach to scale-down experimentation. However, realizing conditions that reflect the large-scale process accurately can be challenging. This article highlights common challenges of using MSBRs for scale-down. The fundamental difference between oxygen mass transfer coefficient (k(L)a) and oxygen transfer rate scaling is addressed and the difficulty of achieving turbulent flow and industrially relevant tip speeds is described. More practical challenges of using MSBR systems for scale-down are also discussed, including the risk of vortex formation, changed volume dynamics, and wall growth. By highlighting these challenges, the article aims to create more awareness of these difficulties and to contribute to improved design of scale-down experiments.

关键词： Chlorophenols   Pentachlorophenol   Bioreactors   Remediation   Microbial communities   16S rRNA gene  

摘要： Chlorophenols (CPs), including pentachlorophenol (PCP), are chemicals of concern due to their toxicity and persistence. Here we describe a successful reactor-based remediation of CP-contaminated soil and assess changes in the toxicity patterns and bacterial communities during the remediation. The remediation consisted of separating half of the contaminated soil to be ground (samples M) in order to test whether the grinding expedited the remediation, the other half was left unground (samples P). Both soils were mixed with wastewater treatment sludge to increase their bacterial diversity and facilitate the degradation of CPs, and the resultant mixtures were placed in 2 bioreactors, M and P, operated for 16 months under anaerobic conditions to favor dehalogenation and for an additional 16 months under aerobic conditions to achieve complete mineralization. Samples were taken every 4 months for toxicity and microbial analyses. The results showed a 64% removal of total CPs (Sigma CPs) in reactor P after just 18 months of remediation, whereas similar depletion in reactor M occurred after similar to 25 months, indicating that the grinding decelerated the remediation. By the end of the experiment, both reactors achieved 93.5 -95% removal. The toxicity tests showed a decrease in toxicity as the remediation progressed. The succession of bacterial communities over time was significantly associated with pH, anaerobic/aerobic phase and the concentration of the majority of CP congeners. Our data indicate that the supplementation of contaminated soil with sludge and further incubation in pilot-scale bioreactors under consecutive anaerobic-aerobic conditions proved to be effective at the remediation of CP-contaminated soil. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Spirulina   Zarrouk's medium   Reuse   Biomolecules  

摘要： The objective was to evaluate the effect of reusing Zarrouk's medium on a Spirulina sp. LEB 18 culture by determining kinetic parameters, chemical composition, biofuels, and thermal characterization. Cultivation was performed in a raceway bioreactor for 7 days, the supernatant was reused for four cycles. Culturing the microalga in the reused medium resulted in a cellular yield of 2.30 g L-1 (control) and 2.04, 1.89, 1.73, and 1.15 g L-1 for four cycles with no influence on cell growth and productivity. Biomass with high contents of carbohydrates (58.00%, 3rd cycle), phycocyanin (2.47 mg mL(-1), 1st cycle), and saturated fatty acids (60.13%, 4th cycle) were obtained with an increase in the profiles of C16:0 (45.85%) and C18:2n6 (47.40%) in the 1st cycle. The reuse of Zarrouk's medium allowed obtaining biomass with reduced cost and differentiated characteristics, allowing the exploration of commercially important biomolecules by the completion of up to four cycles.

关键词： Domestic wastewater treatment   Ultrafiltration membrane bioreactor   Hydraulic retention time   Aeration rate   Pollution removal  

摘要： This work presents the performance of an ultrafiltration membrane bioreactor (UF-MBR) system used as a means of removing pollution from domestic wastewater. Considering the technical performances of the process under different operational conditions, influence of hydraulic retention time (HRT), aeration rate and transmembrane pressure were observed. The evaluation of permeate quality, calculated by the removal efficiencies for various water quality indicators: chemical oxygen demand, biological oxygen demand, total suspended solids, total nitrogen (TN) and total phosphorous (TP). The best results obtained on the system (pressure p = 1.27 bar), HRT (15 h) showed removal efficiencies up to 90% in terms of organic compounds removal, 100% in terms of suspended solids presence and up to 80% reduction of TN and TP. The overall results suggest that the performance of the UF-MBR are likely to impact on the operation and maintenance of the system. However, the MBR process might be successfully applied as a treatment for the removal of pollution from domestic wastewater.

关键词： 3D culture   bioreactor culture   cell expansion   human-induced pluripotent stem cells   inoculum density  

摘要： Objective For optimized expansion of human-induced pluripotent stem cells (hiPSCs) with regards to clinical applications, we investigated the influence of the inoculum density on the expansion procedure in 3D hollow-fibre bioreactors. Materials and Methods Analytical-scale bioreactors with a cell compartment volume of 3 mL or a large-scale bioreactor with a cell compartment volume of 17 mL were used and inoculated with either 10 x 10(6) or 50 x 10(6) hiPSCs. Cells were cultured in bioreactors over 15 days;daily measurements of biochemical parameters were performed. At the end of the experiment, the CellTiter-Blue (R) Assay was used for culture activity evaluation and cell quantification. Also, cell compartment sections were removed for gene expression and immunohistochemistry analysis. Results The results revealed significantly higher values for cell metabolism, cell activity and cell yields when using the higher inoculation number, but also a more distinct differentiation. As large inoculation numbers require cost and time-extensive pre-expansion, low inoculation numbers may be used preferably for long-term expansion of hiPSCs. Expansion of hiPSCs in the large-scale bioreactor led to a successful production of 5.4 x 10(9) hiPSCs, thereby achieving sufficient cell amounts for clinical applications. Conclusions In conclusion, the results show a significant effect of the inoculum density on cell expansion, differentiation and production of hiPSCs, emphasizing the importance of the inoculum density for downstream applications of hiPSCs. Furthermore, the bioreactor technology was successfully applied for controlled and scalable production of hiPSCs for clinical use.