• Microbiology and Biotechnology Letters
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• v.31 no.1
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• pp.83-89
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• 2003

2,4-Dichlorophenoxyacetic acid (2,4-D) as a widely used herbicide has caused serious environmental problems because of its difficult decomposition in nature. We isolated the strain capable of metabolizing 2,4-D as sole carbon and energy source by an enrichment culture technique from the 2,4-D contaminated soil collected at orchard in Gwangju, Korea. This strain was identified tentatively as Aeromonas sp. NOH2. With this strain, we established the response surface methodology (Box-Behnken Design) to optimize the principle parameters for maximizing biodegradation of 2,4-D such as culture pH, temperature, and nutrient concentration in liquid batch culture. The ranges of parameters were obtained from preliminary works done at our laboratory and chosen as 5.5, 6.5, and 7.5 for pH, 25, 30, and $35^{\circ}C$ for temperature, and 5, 20, and 35 g/1 nutrient concentration. Initial concentration of 2,4-D was 500 ppm and nutrient source was tryptic soy broth. The experimental data were significantly fitted to a second order polynomial equation using multiple regression. The most important parameter influencing 2,4-D degradation and biomass production was nutrient concentration. For 2,4-D degradation, the optimum values of pH and temperature, and nutrient concentration were obtained at pH (6.5), temperature (31.8 to $32.1^{\circ}C$), and nutrient concentration (29.6 to 30.1.0 g/1).

• Clean Technology
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• v.20 no.4
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• pp.349-353
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• 2014

Succinic acid is an important precursor in industries producing biopolymers, pharmaceutical and food additives and green solvents. However, due to the high price of petroleum and the global $CO_2$ emission, the biological production of succinic acid from renewable biomass is a novel process due to the fixation of $CO_2$ into succinate during fermentation. In this study, aqueous two phase systems based on imidazolium ionic liquids/$K_2HPO_4$ were used as an effective separation and concentration process for succinic acid. Experimental results show that aqueous two phase systems can be formed by adding appropriate amount of imidazolium ionic liquids to aqueous $K_2HPO_4$ solutions in the presence of succinic acid. It can be found that the ability of imidazolium ionic liquids for phase separation followed the order [HMIm][Br]${\fallingdotseq}$[OMIm][Br]>[BMIm][Br]>[EMIm][Br]. The maximum value of extraction efficiency for succinic acid was about 90% and the amount of coextracted water into top phase is proportional to the chain length of cation in imidazolium ionic liquids. It was concluded that the aqueous two phase systems composed of imidazolium ionic liquids/$K_2HPO_4$ was effective for the selective extraction and concentration of succinic acid.

• Korean Chemical Engineering Research
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• v.51 no.3
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• pp.335-341
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• 2013

Ammonia circulation reactor (ACR) was devised for the effective pretreatment of corn stover. This method is designed to circulate aqueous ammonia continuously so that it can reduce the chemical and water consumption during pretreatment. In this study, ammonia pretreatment with various reaction conditions such as reaction time (4~12 hour), temperature ($60{\sim}80^{\circ}C$), and solid:liquid ratio (1:3~1:8) was tested. Chemical compositions including solid remaining after reaction, lignin and carbohydrates were analyzed and enzymatic digestibility was also measured. It was observed that as reaction conditions become more severe, lignin removal was significantly affected, which was in the range of 47.6~70.6%. On the other hands, glucan and xylan losses were not substantial as compared to that of lignin. At all tested conditions, the glucan loss was not changed substantially, which was between 4.7% and 15.2%, while the xylan loss varied, which was between 7.4% and 25.8%. With (15 FPU-GC220+30 CBU)/g-glucan of enzyme loading, corn stover treated using ammonia circulation reactor for 8~12 hours resulted in 90.1~94.5% of 72-h glucan digestibility, which was higher than 92.7% of $Avicel^{(R)}$-101. In addition, initial hydrolysis rate (at 24 hour) of this treated corn stover was 73.0~79.4%, which was shown to be much faster than 69.5% of $Avicel^{(R)}$-101. As reaction time increased, more lignin removal and it was assumed that the enhanced enzymatic digestibility of treated biomass was attributed to the lignin removal.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.523-531
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• 2018

The purpose of this paper is to derive priorities and implications for the organic resource conservation policy in the livestock sector. We conducted a survey on the importance-performance of the organic waste resource reclamation of livestock sector using a 5-point Likert scale. The importance average for the resource recycling of livestock organic waste was 3.63 and the average of performance was 3.04. As a result of the IPA on livestock manure recycling measures, it is necessary to improve feed quality, establish a local recycling system, increase demand for compost and liquid, enhance customer linkages, and develop cost reduction technologies. It requires intensive support for promoting the spread of odor reduction technologies and integrated management of biomass. It is necessary to introduce mid- and long-term measures such as the revival of feed in tariff, promote by-product feeding, establish solid fuel process management standards, create hygiene safety standards, develop eco-beads and promotion of feed conversion. It is required to strengthen support for the development of odor reduction technologies and prepare consultative organizations among related departments, develop eco-friendly solid fuel technology, and support policies for renewable energy certification.

• Journal of Life Science
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• v.26 no.11
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• pp.1330-1335
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• 2016

Sasa species leaves have been used in traditional medicine for their anti-inflammatory, antipyretic, and diuretic properties. Sasa quelpaertensis Nakai is a small bamboo grass that grows only on Mt. Halla on Jeju Island, Republic of Korea. This small bamboo grass has recently been the focus of much attention due to its potential biomass as well as its beneficial health effects. In this study, to promote the efficient utilization of the S. quelpaertensis leaf, we established a simple preparation method for phytochemical-rich extract (PRE) by comparing phytochemical contents and biological activities according to extraction methods. high performance liquid chromatography (HPLC) analysis revealed that the contents of two major phytochemicals such as, tricin (5.35 mg/g) and p-coumaric acid (44.10 mg/g) contained in PRE were higher than those in fresh hot water extract (SQH, p-coumaric 23.39 mg/g, tricin 0.18 mg/g) and ethanol extract (SQE, p-coumaric 10.8 mg/g, tricin 0.38 mg/g). The antioxidant activities [1,1-diphenyl-2-picrylhydrazy (DPPH) radical scavenging activity, 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging activity, nitric oxide (NO) scavenging activity, and xanthine oxidase inhibitory activity] of PRE were higher than those of SQH and SQE. PRE effectively inhibited NO production in LSP- stimulation RAW 264.7 cells, and the growth of human promyelocytic leukemia (HL-60) cells. These results suggest that PRE has a potential as a promising antioxidant and anti-inflammatory agent.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.8
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• pp.852-859
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• 2006

The novel microbial process such as Anammox(anaerobic ammonium oxidation) and Canon(completely autotrophic nitrogen removal over nitrite) processes is promising biotechnology to remove nitrogen from ammonium-rich wastewater like anaerobic sludge digester liquid. In this research, a new Canon-type nitrogen removal process adopting upflow granular sludge bed type configuration was investigated on its feasibility and process performance, using synthetic wastewater and sludge digester liquids. Air as an oxygen source was provided in an external aeration chamber with flow recirculation. In the first experiment using the synthetic wastewater(up to 110 mg $NH_4$-N $L^{-1}$), the ammonium removal was about 95%(92% for T-N) at effective hydraulic retention time(HRT) for 3.8 days. In the second experiment using the sludge digester liquids($438{\pm}26$ mg $NH_4$-N $L^{-1}$), the total nitrogen removal was $94{\pm}1.7%$ at HRT for 5.4 days and $76{\pm}1.5%$ at HRT for 3.8 days, respectively. Little nitrite and nitrate were observed in the effluent of both experiments. The process revealed quite a lower oxygen($0.29{\sim}0.59$ g $O_2$ $g^{-1}N$) and less alkalinity($3.1{\sim}3.4$ g $CaCO_3$ $g^{-1}N$) consumption as compared to other new technology in microbial nitrogen removal. The process also offers the economical compact reactor configuration with excellent biomass retention, resulting in lower cost for investment and maintenance.

• KSBB Journal
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• v.20 no.6
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• pp.458-463
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• 2005

[ $H_2$ ] from CO and water was continuously produced in a trickle bed reactor(TBR) using Citrobacter amalonaticus Y19. When the strain C. was cultivated in a stirred-tank reactor under a chemoheterotrophic and aerobic condition, the high final cell concentration of 13 g/L was obtained at 10 hr. When the culture was switched to an anaerobic condition with the continuous supply of gaseous CO, CO-dependent hydrogenase was fully induced and its hydrogen production activity approached 16 mmol/g cell/hr in 60 hr. The fully induced C. amalonaticus Y19 cells were circulated through a TBR packed with polyurethane foam, and the TBR was operated for more than 20 days for $H_2$ production. As gas retention time decreased or inlet CO partial pressure increased, $H_2$ production rate increased but the conversion from CO to $H_2$ decreased. The maximum $H_2$ production rate obtained was 16 mmol/L/hr at the gas retention time of 25 min and the CO inlet partial pressure of 0.4 atm. The high $H_2$ production rate was attributed to the high cell density in the liquid phase circulating the TBR as well as the high surface area of polyurethane foam used as packing material of the TBR.

• Journal of Energy Engineering
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• v.20 no.1
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• pp.36-43
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• 2011

Plant biomass has been proposed as an alternative source of petroleum-based chemical compounds. Especially, aromatic chemical compounds can be obtained from lignin by depolymerization processes because the lignin consist of complex aromatic materials. In this study, kraft lignin, the largest emitted substance among several kinds of lignin in Korea, was used as a starting material and was characterized by solid-state $^{13}C$-Muclear Magnetic Resonance($^{13}C$-NMR), Fourier Transform Infrared Spectroscopy(FT-IR), Elemental Analysis(EA). The depolymerization of kraft lignin was studied at water-phenol mixture solvent in near critical region and the experiments were conducted using a batch type reactor. The effects of water-to-phenol ratio and reaction temperature($300-400^{\circ}C$) were investigated to determine the optimum operating conditions. Additionally, the effects of formic acid as a hydrogen-donor solvent instead of $H_2$ gas were examined. The chemical species and quantities in the liquid products were analyzed using gas chromatography-mass spectroscopy(GC-MS), and solid residues(char) were analyzed using FT-IR. GC-MS analysis confirmed that the aromatic chemicals such as anisole, o-cresol(2-methylphenol), p-cresol(4-methylphenol), 2-ethylphenol, 4-ethylphenol, dibenzofuran, 3-methyl cabazole and xanthene were produced when phenol was added in the water as a co-solvent.

• Journal of Plant Biotechnology
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• v.1 no.1
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• pp.1-7
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• 1999

Large-scale cultures of plant cell, tissue, and organ have been achieved by using BTBB. When different sized BTBBs (5 L, 20 L, 100 L, 300 L, and 500 L) were tested for the culture of yew cells (Taxus cuspidata Sieb. et Zucc.), cell growth increment reached to 94.5% in SCV after 24 days of culture with 30% of inoculation cell density. However, there were some variations in the production of taxol and its derivatives among the BTBBs of different size. Approximate 4 ㎎/l of taxol and 84 ㎎/l of total taxanes were obtained by using a 500L BTBB after 6 weeks of culture. With a 20L BTBB, about 20,000 cuttings of virus-free potatoes (cv. Dejima) could be obtained by inoculating 128 explants and maintaining 8 weeks under 16 hr light illumination. The frequency of ex vitro rooting of the cuttings revealed as more than 99% under 30% shade. By incorporating two-stage culture process consisting of multiple bulblet formation in solid medium and bulblet development in liquid medium, mass propagation of lily through bioreactor seemed to be possible. In the case of 'Marcopolo', the growth of mini-bulblets in BTBB was nearly 10 folds faster than that of the solid medium. Time course study revealed that maximum MAR yield of ginseng (Panax ginseng C. A. Meyer) in a 5 L and 20 L BTBB after 8 weeks of culture was 500 g and 2.2 ㎏, respectively. By cutting the MAR once and/or twice during the culture, the yield of root biomass could be increased more than 50% in fresh weight at the time of harvest. With initial inoculum of 500 g of sliced MAR in a 500 L BTBB, 74.8 ㎏ of adventitious root mass was obtained after 8 weeks of culture. The average content of total ginseng saponin obtained from small-scale and/or pilotscale BTBBs was approximately 1% per gram dry weight. Based on our results, we suggest that large-scale cultures of plant cell, tissue, and organ using BTBB system should be quite a feasible approach when compared with conventional method of tissue culture.

• Journal of the Korean Wood Science and Technology
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• v.40 no.6
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• pp.424-430
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• 2012

In this study, laccase activity, rate of weight loss and degree of lignin degradation of pine wood chips were determined during the liquid and solid state incubation with Polyporus brumalis. The results showed that laccase enzyme activity at untreated wood chip was gradually decreased after 20 days, but enzyme activity with wood chip treatment showed 10 times higher than untreated ones at 60 incubation days. Rate of weight losses of pine chip and rate of lignin loss were 23.4% and 6.3% by P. brumalis during 80 incubation days. Gene expression of pblac1 from P. brumalis was 3 times increased under pine chip treatment at 40 incubation days. Consequently, laccase activity of white rot fungi, P. brumalis, was increased at incubation with wood chip and pblac1 gene was important factor of lignin degradation. Therefore, to regulate lignin degrading enzyme gene expression by using the tools of biotechnology will be able to develop superior strains and it will be useful for pretreatment of lignocellulosic biomass at bioethanol production.