• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.692-700
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• 1996

The objective of this study is to develop a systematic purification plant using the metabolism of aerobic microorganisms. This system is subsequently aerated and continuously removes suspended solids and settling sludges caused by aerating pressure at the bottom of a lower pipe (i.e., Continuous Removal of Suspended solids and Settling sludges, CRSS). The CRSS plants are brought out by introducing fine air bubbles into the liquid phase of a lower pipe in the bio-reactor. These plant uses aeration pipe, with multiple inlets to sweep the floor of bio-reactor tank, instead of the conventional scraper mechanisms. The principal advantage of this system is that it can continuously remove very small or light particles that settles completely within a short time. Once the particles have been floated to the surface, they can be moved into the pipe and collected in the settling tank by sequently aerated pressure. The experimental results shows that about 99.0% of the biochemical oxygen demand(BOD), 99.3% of the suspended solid(SS), 92.3% of the total nitrogen(T-N), 99.0% of the turbidity(TU), 100% of the total coliform(TC)and ammonia was respectively removed during aerobic digestion for 9 days. These result indicates that the CRS S plants are very effective for reduction and deodorization of swine wastewater contaminants, and the efflux from CRS S can either be discharged in the river or used as nutrient solution of formulation for plant growth factories. The developed CRSS plant proved to be flexible and it can simply be adapted to any type of biological waste treatment problem.roblem.

• Journal of Bio-Environment Control
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• v.14 no.4
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• pp.298-301
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• 2005

Potato (Solamum tuberosum 'Dejima') plantlets were investigated on culture type and initial quantity of inoculation in bioreactor and survival rate by hydroponics for mass production. rode stems (1 to 1.5cm in length) of potato plantlets multiplied in vitro were grown for 3 weeks in liquid Murashige and Skoog (MS) medium with sucrose $30 g\; L^{-1}$. When plantlets (80-node inoculation) were raised in 10L balloon type bubble (BB) bioreactor, the healthiest growth of plantlets was obtained from explants cultured in ebb & flow culture with medium supplied periodically 12 times per day. The suitable inoculation quantity of 20L BB bioreactor was 120 pieces of stem segments (mean 2.2g fresh weight) in ebb & flow culture. Number of nodal shoot was eight on the average. In controlled culture room, survival rate of plantlets at 7 days after stem cutting was above $70\%$ when they were acclimatized by hydroponics grown in deep flow and solid medium culture. The highest survival rate of the stem cutting plantlets was in nutrient solution adjusted to EC $1.4dS{\cdot}m^{-1}$. Stem cutting plantlets through one culture could be obtained $670\~900$, when plantlets were grown in ebb & flow culture during 3 weeks using a 20L bioreactor with initial 120 pieces of nodal segments. 11 is possible In do mass production of seedlings cultured in bioreactor and hydroponics.

• Macromolecular Research
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• v.17 no.11
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• pp.856-862
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• 2009

This study examined the effects of liquid and solid additives on the morphological, mechanical and thermal insulating properties of rigid polyurethane foams (PUFs). The PUFs synthesized with tetramethylsilane (TEMS) as a liquid-type additive showed a smaller average cell size and lower thermal conductivity than those with the aerosil 200 and clay 30B as solid-type additives. When TEMS was added, the average cell size of the PUF became more uniform and finer due to the reduced surface tension of the polymer solution, which increased the nucleation rate and number of bubbles produced and reduced cell size. The PUFs with TEMS showed the highest closed cell contents among the PUFs prepared using TEMS, aerosil 200 and clay 30B. This suggests that the insulation properties of PUF can be determined by both the size of the cell structure and the amount of closed cell contents in the system. The compression and flexural strengths of the PUF increased slightly when the aerosil 200, clay 30B and TEMS were added compared those of the neat PUF. The reaction profiles of the PUFs showed a similar gel and tack tree time with the reaction time among the PUFs synthesized with three different additives and neat PUF. This suggests that the nucleating additives used in this study do not affect the bubble growth of the chemical reaction, and the additives may act as nucleating agents during the formation of PUF. From the above results of the cell size, thermal conductivity, closed cell contents and reaction profile of the PUFs, liquid-type nucleating agent, such as TEMS, is more effective in decreasing the thermal conductivity of the PUF than solid-type nucleating agent, such as aerosil 200 and clay 30B.

• Journal of Plant Biology
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• v.39 no.1
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• pp.63-69
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• 1996

A hairy root clone of Panax ginseng C.A. Meyer, HRB-15 was cultured iu various conditions with 3 L bubble type bioreactor to enhance both growth and ginsenoside production. The hairy roots were more rapidly grown under the dark condition than under the light condition. However, total amount of ginsenoside of hairy roots cultured under the light for 30 days increased 2 folds as compared with the dark condition and was 1.10% based on 6 ginsenosides. Especially, ginsenoside-Re was significantly increased and some ginsenosides except for ginsenoside-Re was slightly reduced. Also, the growth of hairy roots decreased about 30% as compared with the dark condition. In contrast, addition of sodium acetate led to decreased production of ginsenoside and growth of hairy roots under light condition. The influence of potassium dihydrogenphosphate concentration was examined in MS medium and a 1.25 mM concentration was found to be the most appropriate for growth and ginsenoside production under light condition. Two-step process of hairy roots culture with yeast elicitation or without ammonia in culture medium was developed to enhance growth and giusenoside synthesis. $50\;\mu\textrm{g}$ of yeast elicitor per g of fresh weight showed a synergistic effect on the ginsenoside synthesis of hairy roots on 20 days after culture. At that time, the content of total ginsenoside was 1.15%, while the growth of hairy roots decreased 21 % as compared with the dark condition. In addition, when elimination of ammonia on 20 days after culture, the content of total ginsenoside was 1.26% with significant increment of ginsenoside-Rd (0.27%) in addition to ginsenoside-Re and the growth of hairy roots decreased 10% as compared with the dark condition. In this system, we have demonstrated a unique two-step process of hairy root cultures to maximize biomass and secondary metabolites. It has found possibility to enhance ginsenosides production by growing hairy roots in this method.

• The Korean Journal of Mycology
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• v.2 no.1
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• pp.1-6
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• 1974

1. The mycelial growth and sporulation of Mycogone perniciosa was compared on modified Czapek's media deficient in carbon source, nitrogen source, K,Mg, P or the heavy metal elements. The mycelial growth was significantly reduced in solution cultures lacking Mg, K or P and only a trace of growth occurred in solutions lacking carbon source or nitrogen source. Most sparse sporulation and smaller chlamydospores than on any of deficient agar media occurred on agar media dificient in carbon source or nitrogen source. 2. In both potato dextrose agar and malt extract solution, growth of the fungus was optimum at $25^{\circ}C$, and undetectable at $10^{\circ}C$ and $35^{\circ}C$. 3. Optimum pH for growth of this fungus was 7.0. 4. This fungus was killed in soil when exposed to $50^{\circ}C$ or higher for 20 minutes or more.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.12
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• pp.1846-1853
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• 2010

The storage attributes of green juice prepared by washing Angelica keiskei with various washing solutions using air bubble method were investigated. The washing solutions were distilled water (DW), sodium hypochlorite electrolyzed water (SHEW), and slightly acidic electrolyzed water (SAEW). During storage at $4^{\circ}C$, the number of bacteria after 1 day was $>10^5$ CFU/mL when DW was used, whereas bacterial growth was $<10^5$ CFU/mL after 4 days when SHEW or SAEW was used. The pH and color were not changed, and the polyphenol content, electron donating ability and total antioxidant ability were decreased slowly with the increase of storage time. No significant difference in any of the measured properties was found among washing methods (p<0.05). Consequently, these results suggest the possible use of electrolyzed water for washing to enhance the shelf life of green juice with A. keiskei because SHEW and SAEW decreased bacterial growth without affecting other properties of the green juice.

• Journal of agriculture & life science
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• v.45 no.3
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• pp.81-88
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• 2011

In this study, we investigated effect of washing with brine on quality characteristics of strawberries during storage at 4 or $20^{\circ}C$. The strawberry samples were prepared with brine-washing (BW), brine-washing and removing moisture on surface (BWR), or without brine-washing and removing moisture (control). The samples were tested for total aerobic bacteria, pH, color, firmness. BWR affected the microbial change, resulting in retarding the growth of total aerobic bacteria, compared with the control and BW. The initial microbial and exponential growth phase of BWR at $4^{\circ}C$ was not detected. For pH, there wasn't dramatical change on BWR at $4^{\circ}C$ and $20^{\circ}C$. In addition, there was dramatically in decreased on control and BW. A-value was increased over storage time on control and BWR except BW. For firmness, there wasn't dramatical change on all sample when stored at $4^{\circ}C$. The results suggest that storage of strawberry stored after washing and moisture removal from the surface should be applied to maintain quality and shelf-life during storage of strawberries.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.4
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• pp.128-135
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• 2022

The inside of a quartz glass crucible for semiconductor processing, called a transparent layer, is manufactured using synthetic silica powder. Bubbles existing in the transparent layer of the crucible cause a problem of reducing the quality of the crucible as well as the yield of the silicon ingot. Therefore, the main goal of the synthetic silica powder, which is the raw material of the transparent layer, is to minimize the bubble generation factor. For this purpose, in the case of synthetic silica powder, it is necessary to minimize silanol groups, carbon and pores. In this study, synthetic silica gel was prepared using the sol-gel method, and changes in carbon content and specific surface area were investigated according to calcination temperature and dwelled time in a two-stage calcination process. The first-stage calcination process was performed between 500℃ and 600℃ and the second-stage calcination process was performed between 1000℃ and 1100℃. The dwelled time was carried out from 10 minutes to a maximum of 12 hours. The carbon content of the powder calcined at 1000℃ for 1 hour was 0.0031 wt.%, and the specific surface area of the powder calcined at 1100℃ for 12 hours was 16.6 m²/g.

• Microbiology and Biotechnology Letters
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• v.29 no.4
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• pp.240-247
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• 2001

The effect of microsparged aeration in mammalian cell bioreactor on the oxygen transfer rate and cell viability was studied. The microspargers with differ- ent micron-sized pores were used to supply oxygen to the medium. The oxygen transfer coefficients (k$_{L}$a) measured in the bioreactor were markedly increased, which is due to the increase of the contacting area between air bubbles and liquid medium when the pore size of microsparger decreases. When the impellers of two different types (square-pitch marine impeller and $45^{\circ}$ pitched flat blade impeller) were used for agitation, the k$_{L}$a values were slightly higher with the marine impeller than with the blade impeller. The detrimental effect of direct gas sparging with microsparger on mammalian cells was investigated in bubble columns with various air flow rates and different pore sized microspargers. The first-order cell death rate constant ($k_{d}$ /7) was shown to be directly proportional to the air flow rate and inversely proportional to the pore size. During the cultivation of hybridoma cells using microsparger with the pore size of $0.57\mu$m in the mammalian cell culture bioreactor, the continuous sparging caused the cell death and suppressed the cell growth. However, cells grew normally and cell viability was maintained above 90% in the logarithmic phase when the air was intermittently sparked in order to maintain the dissolved oxygen level above 20%.

• Microbiology and Biotechnology Letters
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• v.48 no.3
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• pp.328-336
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• 2020

Parachlorella sp. is an efficient fatty acid producer that can be used in the production of biofuels, feeds, and fertilizers. Microalgae show varying responses to culture conditions, even those within the same species. In this study, growth and fatty acid composition of a newly isolated Parachlorella sp. from the Nakdong river of Korea in different culture media were investigated. The microalga was cultivated in 400 ml bubble column photobioreactors using BG-11, BBM, TAP, and modified TAP (MTAP) media. It was shown that using BBM led to greater fatty acid accumulation (34%), while using TAP medium led to greater biomass productivity (0.34 g/l/day). Composition of the TAP medium was modified to have the N:P ratio of BBM while also varying concentrations of N and P to improve fatty acid productivity. One of the modified TAP media, MTAP-1 (104.8 mgN/l, 135.2 mgP/l, N:P ratio = 0.77), showed the highest fatty acid concentration of 0.69 ± 0.04 g/l, while those from TAP and BBM were 0.48 ± 0.06 g/l and 0.40 ± 0.02 g/l, respectively. The results showed that microalgal fatty acid productivity could be enhanced by changing the N:P ratio and concentrations.