• 한국미생물·생명공학회지
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• 제21권4호
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• pp.348-353
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• 1993

The optimal conditions for operating a moving-aeration bioreactor were determined as 30rpm and 150 (ml/min) of air flow rate, which can yield ca. 7.3 (l/h)of maximum mass transfer coefficient. It was also found that the agitation speed played much much important role than air input rate in oxgen transfer into the medium. $2.6{\times}10^6$ (cells/ml) and 0.6 (ml/l) of maximum cell denisty and IL-2 production were observed in batch cultivation of IL-2 producing BHK cell line. 0.53 (mM/l/h) of oxygen uptake rate was also estimated. The performance of a moving-aeration bioreactor (specific growth rate and oxygen uptake rate, etc.) was superior to other culture systems, such as cell-life and static membrane aeration bioreactors. Ii must be useful to apply this reactor to many culture processes by improving structural limitations in scaling-up the system.

• 한국정밀공학회지
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• 제26권3호
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• pp.137-143
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• 2009

It has been reported that mechanical stimulation takes a role in improving eel/ growth in skeletal system. Various research groups have been showed their own bioreactors which stimulate cell-seed three-dimensional scaffold. In this study, we hypothesized that the various conditions of mechanical stimulation would affect cell growth and proliferation. To prove our hypothesis, we designed a custom-made bioreactor capable of applying controlled compression to cell-encapsulated scaffolds. This device consisted of a circulation system and a compression system. Each parts of the bioreactor was fabricated using the rapid prototyping technology By using the rapid prototyping technology, we can modify and improve the bioreactor very rapidly For dynamic cell-culture, cell-encapsulated agarose gel was fabricated in 2% concentration. We performed dynamic cell-culture using this agarose gel and developed bioreactor in 3 days.

• 멤브레인
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• 제17권2호
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• pp.112-117
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• 2007

The application of membrane bioreactors for the depuration of wastewater coming from the washing of mineral oil storage tanks is described. Microfiltration hollow-fibre membranes were used in the submerged configuration. Filtration tests were carried out with a biomass concentration of about 15 g/L in order to assess the critical flux of the hollow fibre membrane used. Then particular care was taken in carrying out the performance runs in the sub-critical flux region. The reactor performance was very high, with removal efficiencies ranging between 93% and 97% also when the concentration of hydrocarbon was very high. Some kinetic parameters for the COD and the hydrocarbon removal were estimated.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권4호
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• pp.264-268
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• 2001

Aggregates of specific cells are often regarded as better from in artificial organs and mammalian cell bioreactors in terms of cell-specific functionality. In this study, the morphology and liver specific functions of freshly harvested primary rat hepatocytes, which were cultivated as spheroids and entrapped in a synthetic thermo-reversible extracellular matrix, were examined and compared to a control (hepatocytes in single cell form). A copolymer of N-isopropylacrylamide(98 mole % in feed) and acrylic acid (poly (NiPAAm-co-AAC)), a thermo- reversible copolymer gel ma- trix, was used to entrap hepatocytes either in spheroids or single cells. During a 7-day culture pe-riod, the spheroids maintained higher viability and produced albumin and urea at a relatively con-stant rate, while, the single cell culture showed a slight increase in cell numbers and a reduction in albumin secretion Hepatocytes cultrured as spheroids present a potentially useful three-dimensional cell culture system for application in bioartificial liver device.

• 한국환경보건학회지
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• 제39권5호
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• pp.474-481
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• 2013

Objectives: This study was conducted to investigate the application of microbial fuel cells (MFCs) to the wastewater treatment systems employed in the Living Building Challenge. Methods: I reviewed a range of information on decentralized wastewater treatment technologies such as composting toilets, constructed wetlands, recirculating biofilters, membrane bioreactors, and MFCs. Results: The Living Building Challenge is a set of standards to make buildings more eco-friendly using renewable resources and self-treating water systems. Although there are various decentralized wastewater treatment technologies available, MFCs have been considered an attractive future option for a decentralized system as used in the Living Building Challenge. MFCs can directly convert substrate energy to electricity with high conversion efficiency at ambient and even at low temperatures. MFCs do not require energy input for aeration if using open-air cathodes. Moreover, MFCs have the potential for widespread application in locations lacking water and electrical infrastructure Conclusions: This paper demonstrated the feasibility of MFCs as a novel decentralized wastewater treatment system employed in the Living Building Challenge.

• BMB Reports
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• 제49권3호
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• pp.149-158
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• 2016

Plants have evolved a vast chemical cornucopia to support their sessile lifestyles. Man has exploited this natural resource since Neolithic times and currently plant-derived chemicals are exploited for a myriad of applications. However, plant sources of most high-value natural products (NPs) are not domesticated and therefore their production cannot be undertaken on an agricultural scale. Further, these plant species are often slow growing, their populations limiting, the concentration of the target molecule highly variable and routinely present at extremely low concentrations. Plant cell and organ culture constitutes a sustainable, controllable and environmentally friendly tool for the industrial production of plant NPs. Further, advances in cell line selection, biotransformation, product secretion, cell permeabilisation, extraction and scale-up, among others, are driving increases in plant NP yields. However, there remain significant obstacles to the commercial synthesis of high-value chemicals from these sources. The relatively recent isolation, culturing and characterisation of cambial meristematic cells (CMCs), provides an emerging platform to circumvent many of these potential difficulties.

• Journal of Plant Biotechnology
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• 제37권3호
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• pp.243-249
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• 2010

Molecular farming is production of pharmaceutically and industrially important proteins in plants. Plants and plant cell culture systems have been used as bio-factory to produce recombinant proteins such as monoclonal antibodies, enzymes, vaccines, hormones, interleukins, commercial enzymes and etc. The terms molecular farming, biofarming, molecular pharming, phytomanufacturing, recombinant or plant-made industrials, planta-pharma, plant bioreactors, plant biofactory, and pharmaceutical gardening are used interchangeably. Molecular farming can provide safe and inexpensive pharmaceutical proteins as well as commercial ones. In spite of several advantages of molecular farming such as safety and inexpensive cost, there are also a couple of drawbacks in the existing technology. One of them is low expression level of target gene in plants, which has been improved by optimizing gene-based codon usage, screening of strong promoters, expression of transcription factors, subcellular targeting of target proteins, chloroplast transformation, and transient expression using viral expression system (magnifection). Some plant-based commercial proteins have already been in markets and more than twenty plant-based pharmaceuticals have been in clinical trials, from that we can expect that several plant-based pharmaceutical proteins will be seen in the markets in the near future.

• ALGAE
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• 제26권1호
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• pp.3-20
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• 2011

The physiology of the unicellular green alga Dunaliella salina in response to abiotic stress has been studied for several decades. Early D. salina research focused on its remarkable salinity tolerance and ability, upon exposure to various abiotic stresses, to accumulate high concentrations of $\beta$-carotene and other carotenoid pigments valued highly as nutraceuticals. The simple life cycle and growth requirements of D. salina make this organism one of the large-scale commercially exploited microalgae for natural carotenoids. Recent advances in genomics and proteomics now allow investigation of abiotic stress responses at the molecular level. Detailed knowledge of isoprenoid biosynthesis mechanisms and the development of molecular tools and techniques for D. salina will allow the improvement of physiological characteristics of algal strains and the use of transgenic algae in bioreactors. Here we review D. salina isoprenoid and carotenoid biosynthesis regulation, and also the biotechnological and genetic transformation procedures developed for this alga that set the stage for its future use as a production system.

• Environmental Engineering Research
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• 제23권2호
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• pp.216-222
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• 2018

The growth characteristics of Spirulina platensis were investigated using four photo-bioreactors with $CO_2$-mixed air flows. Each reactor was operated under a specific condition: 3% $CO_2$ at 50 mL/min, 3% $CO_2$ at 150 mL/min, 6% $CO_2$ at 50 mL/min, and 6% CO2 at 150 mL/min. The 3% $CO_2$ at 150 mL/min condition produced the highest algal growth rate, while the 6% $CO_2$ at 150 mL/min conditioned produced the lowest. The algal growth performance was suitably assessed by the linear growth curve rather than the exponential growth. The medium pH decreased from 9.5 to 8.7-8.8 (3% $CO_2$) and 8.4-8.5 (6% $CO_2$), of which trends were predicted only by the pH-carbonate equilibrium and the reaction kinetics between dissolved $CO_2$ and $HCO_3{^-}$. Based on the stoichiometry between the nutrient amounts and cell elements, it was predicted that depleted nitrogen (N) at the early stage of the cultivation would reduce the algal growth rates due to nutrient starvation. In this study, use of the photobioreactors capable of good light energy distribution, proper ranges of $CO_2$ in bubbles and medium pH facilitated production of high amounts of algal biomass despite N limitation.

• Journal of Microbiology and Biotechnology
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• 제25권11호
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• pp.1928-1935
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• 2015

Microbial growth kinetics is often used to optimize environmental processes owing to its relation to the breakdown of substrate (contaminants). However, the quantification of bacterial populations in the environment is difficult owing to the challenges of monitoring a specific bacterial population within a diverse microbial community. Conventional methods are unable to detect and quantify the growth of individual strains separately in the mixed culture reactor. This work describes a novel quantitative PCR (qPCR)-based genomic approach to quantify each species in mixed culture and interpret its growth kinetics in the mixed system. Batch experiments were performed for both single and dual cultures of Pseudomonas putida and Escherichia coli K12 to obtain Monod kinetic parameters (μ_max and K_s). The growth curves and kinetics obtained by conventional methods (i.e., dry weight measurement and absorbance reading) were compared with that obtained by qPCR assay. We anticipate that the adoption of this qPCR-based genomic assay can contribute significantly to traditional microbial kinetics, modeling practice, and the operation of bioreactors, where handling of complex mixed cultures is required.