• Journal of Korean Society on Water Environment
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• v.20 no.3
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• pp.197-205
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• 2004

Batch test methods have developed for a long time to measure kinetic and stoichiometric parameters which are required to perform steady state design and mathematical modelling of activated sludge processes. However, at various So/Xo ratios, abnormal behaviors of ordinary heterotrophic organism in batch tests have been reported in many researches. Thus, in this research, abnormal behaviors of heterotrophs in batch tests were investigated at various So/Xo conditions by measuring and interpreting oxygen utilization rate. As So/Xo ratio increased, the calculated values of maximum specific growth rates, ${\mu}_{H,max}$ and $K_{MP,max}$, increased. However, at a certain point of So/Xo (around 10mgCOD/mgMLAVSS), ${\mu}_{H,max}$ and $K_{MP,max}$ values started to decrease. According to this observation, three prominent behaviours of heterotrophs were identified at various So/Xo conditions. (1) At low So/Xo region (below 5 mgCOD/mgMLAVSS), the oxygen utilization rate of heterotrophs in batch tests were almost stable and consequently yielded lower maximum specific growth rate. (2) At high So/Xo region (up to 5~10 mgCOD/mgMLAVSS), oxygen utilization rate incresed sharply with time and indicated more upward curvature than the predicted OUR with conventional activated sludge model, which consists of single hetetrotrophs group. Thus, in this region, competition model of two organisms, fast-grower and slow-grower, seemed to be appropriate. (3) At extremely high So/Xo region (over 10mgCOD/mgMLAVSS), significant oxygen utilization rate was still observed even after depletion of readily biodegradable COD. This might be caused by retarded utilization of intermediates which were generated by self inhibition mechanism in the process of RBCOD uptake.

• Journal of Korean Society of Water and Wastewater
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• v.13 no.1
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• pp.81-94
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• 1999

This study aims at a proposal of the plan that can improve raw water quality by an experimental study using influent water of Nak-dong river, which has been used as raw water for drinking in U-city, through the establishment of the submerged biofilter process PILOT PLANT of media packing channel method. From the analysis of removal efficiency for each water quality item of the collected sample, following results are obtained. First of all, the removal rate of suspended material, BOD, COD, T-N, TOC, turbidity, and $NH_3$ -N appear 82%, 78%, 42%, 15%, 57%, 43%, 54%, and 55% respectively and it is known that the submerged biofilter process of media packing channel method takes effects on water quality improvement from the above analysis results of water treatment efficiency. And the analyzed results for water temperature, residence time, and activities of microorganism, which can be the factors affect on water quality improvement, are as follows. 1) The removal rate variation of SS, BOD, and COD attendant on water temperature change is examined and it is known that the removal rate increases at $13^{\circ}C$ or above. 2) The removal rate of SS, BOD, and COD attendant on residence time is most active in the range of 0~18hr, 0~1.8hr, 0~2.7hr respectively, so it is found that the removal rate becomes smaller after 2.7hr. 3) From the examination of microorganism activity with the abundance of normal bacteria, it is found that the floating bacteria decrease as the flow distance from raw water inflow point of PILOT PLANT increases, and the adhesive bacteria have no concern with the flow distance. And it its known that the biomass of fine algae decreases as the flow distance from the raw water inflow point of PILOT PLANT increases from the examination with Chl-a.

• Advances in environmental research
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• v.5 no.1
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• pp.19-35
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• 2016

The phytoextraction of some toxic heavy metals from municipal waste dump soil by castor plant (Ricinus communis) was tested under natural and single or mixed chelant-assisted scenarios in pot microcosms. A sandy loam with total metal contents (mg/kg): Cd (84.5), Cu (114.5), Ni (70.3), Pb (57.8), and Zn (117.5), was sampled from an active dumpsite in Calabar, Nigeria and used for the study. Castor (small seed variety) was grown under natural phytoextraction or single/binary chelant (citric acid, oxalic acid, and EDTA) applications (5-20 mmol/kg soil) for 63 days. Castor exhibited no visual phytotoxic symptoms with typically sigmoid growth profiles at the applied chelant doses. Growth rates, however, decelerated with increase in chelant dose. Post-harvest biomass yields were higher under chelant application than for natural phytoextraction. Both root and shoot metal concentrations (mg/kg) increased quasilinearly and significantly ($p{\leq}0.05$) with increase in chelant dose, furnishing maximum levels as: Cd (55.6 and 20.9), Cu (89.5 and 58.4), Ni (49.8 and 19.6), Pb (32.1 and 12.1), and Zn (99.5 and 46.6). Ranges of translocation factors, root and shoot bioaccumulation factors were 0.21-3.49, 0.01-0.89 and 0.01-0.51, respectively. Overall, the binary chelant treatments were less toxic for R. communis growth and enhanced metal accumulation in shoots to a greater extent than the single chelant scenarios, but more so when EDTA was present in the binary combination. This suggests that the mixed chelants could be considered as alternative treatments for enhanced phytoextraction and revegetation of degraded waste dump soils.

• Journal of Microbiology and Biotechnology
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• v.31 no.8
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• pp.1123-1133
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• 2021

Biodegradation is the key process involved in natural lignocellulose biotransformation and utilization. Microbial consortia represent promising candidates for applications in lignocellulose conversion strategies for biofuel production; however, cooperation among the enzymes and the labor division of microbes in the microbial consortia remains unclear. In this study, metagenomic analysis was performed to reveal the community structure and extremozyme systems of a lignocellulolytic microbial consortium, TMC7. The taxonomic affiliation of TMC7 metagenome included members of the genera Ruminiclostridium (42.85%), Thermoanaerobacterium (18.41%), Geobacillus (10.44%), unclassified_f__Bacillaceae (7.48%), Aeribacillus (2.65%), Symbiobacterium (2.47%), Desulfotomaculum (2.33%), Caldibacillus (1.56%), Clostridium (1.26%), and others (10.55%). The carbohydrate-active enzyme annotation revealed that TMC7 encoded a broad array of enzymes responsible for cellulose and hemicellulose degradation. Ten glycoside hydrolases (GHs) endoglucanase, 4 GHs exoglucanase, and 6 GHs β-glucosidase were identified for cellulose degradation; 6 GHs endo-β-1,4-xylanase, 9 GHs β-xylosidase, and 3 GHs β-mannanase were identified for degradation of the hemicellulose main chain; 6 GHs arabinofuranosidase, 2 GHs α-mannosidase, 11 GHs galactosidase, 3 GHs α-rhamnosidase, and 4 GHs α-fucosidase were identified as xylan debranching enzymes. Furthermore, by introducing a factor named as the contribution coefficient, we found that Ruminiclostridium and Thermoanaerobacterium may be the dominant contributors, whereas Symbiobacterium and Desulfotomaculum may serve as "sugar cheaters" in lignocellulose degradation by TMC7. Our findings provide mechanistic profiles of an array of enzymes that degrade complex lignocellulosic biomass in the microbial consortium TMC7 and provide a promising approach for studying the potential contribution of microbes in microbial consortia.

• Textile Coloration and Finishing
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• v.31 no.1
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• pp.1-13
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• 2019

In this study, eco-friendly functional leather was developed by recycling wastes such as eel skin, marigold(Tagetas erecta l.), hinoki cypress(Chamaecyparis obtusa). The hot water extracts of marigold and hinoki cypress leaves were freeze-dried at $-80^{\circ}C$ to prepare colorant powder. The dyeing of eel leather with marigold was carried out to investigate the effects of dyeing conditions, mordanting on dye uptake, color, morphological change, and color fastness. Considering shrinkage of eel leather caused by dyeing, the optimum dyeing conditions were $60^{\circ}C$ of dyeing temperature and 60 min of dyeing time at 1:100 of bath ratio, and color of the dyed eel leather was Y to YR Munsell series. In order to prevent the degradation of leather from microbe, we conducted combination dyeing with marigold and hinoki cypress leave colorants. In this case, the combination dyed eel leathers showed excellent antimicrobial activity with above 99% bacterial reduction rate against S. aurieus and K. pneumoniae. It was confirmed that all of the dyed eel leathers were sufficient to meet the Korean Standard for color fastness of leather products. It can be applied practically for the development of eco-friendly functional leather by utilizing some useful active components extracted from plant resources and by recycling food wastes.

• Journal of Korea Society of Waste Management
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• v.35 no.7
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• pp.587-599
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• 2018

The coffee grounds generated during the coffee extraction process contain several resources, but the technology for their recycling has not been commercialized yet, causing various environmental problems. Due to the recent increase in coffee consumption worldwide, the amount of coffee grounds produced has been continuously increasing, reaching more than 750 million tons. In Korea, about 120,000 tons of coffee waste are annually generated; however, most of them are landfilled or incinerated. Although there is still a shortage of coffee waste recycling technologies compared to the amount of coffee grounds produced, various recycling approaches are being actuated in many countries including Korea. In this study, the generation of coffee grounds at home and abroad, the status of coffee grounds recycling, and the associated technology development trends were investigated. The coffee grounds recycling has been studied in the fields of energy, adsorbent, construction, agriculture, and bio-foods. Research is most active in the energy and biotechnology areas; in particular, since the oil in the coffee grounds is valuable as a feedstock for biomass energy, the technology related to energy recovery is currently under development worldwide. Removed because confusing and unnecessary.

• Journal of Microbiology and Biotechnology
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• v.32 no.1
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• pp.117-125
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• 2022

Until recently, four types of cellobiose-fermenting Saccharomyces cerevisiae strains have been developed by introduction of a cellobiose metabolic pathway based on either intracellular β-glucosidase (GH1-1) or cellobiose phosphorylase (CBP), along with either an energy-consuming active cellodextrin transporter (CDT-1) or a non-energy-consuming passive cellodextrin facilitator (CDT-2). In this study, the ethanol production performance of two cellobiose-fermenting S. cerevisiae strains expressing mutant CDT-2 (N306I) with GH1-1 or CBP were compared with two cellobiose-fermenting S. cerevisiae strains expressing mutant CDT-1 (F213L) with GH1-1 or CBP in the simultaneous saccharification and fermentation (SSF) of cellulose under various conditions. It was found that, regardless of the SSF conditions, the phosphorolytic cellobiose-fermenting S. cerevisiae expressing mutant CDT-2 with CBP showed the best ethanol production among the four strains. In addition, during SSF contaminated by lactic acid bacteria, the phosphorolytic cellobiose-fermenting S. cerevisiae expressing mutant CDT-2 with CBP showed the highest ethanol production and the lowest lactate formation compared with those of other strains, such as the hydrolytic cellobiose-fermenting S. cerevisiae expressing mutant CDT-1 with GH1-1, and the glucose-fermenting S. cerevisiae with extracellular β-glucosidase. These results suggest that the cellobiose-fermenting yeast strain exhibiting low energy consumption can enhance the efficiency of the SSF of cellulosic biomass.

• The Korea Journal of Herbology
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• v.33 no.4
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• pp.95-100
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• 2018

Objectives : Ligustri Fructus has been used since ancient times as a medicinal usages in folk medicines against antitumor purpose. Many biological active constituents have been identified from this biomass such as several terpenoids and lignans. In current study, the properties of antioxidant and anti-diabetic complications using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)($ABTS^+$) radicals scavenging, and advanced glycation end products (AGEs) inhibition assays were evaluated by different extraction methods of Ligustri Fructus. Methods : In present continuing research for development of bioactive natural ingredients, antioxidant and AGEs formation inhibitory capacities of Ligustri Fructus extracts using different organic solvents were prepared and the biological potentials were investigated using in vitro bioassays. Antioxidant properties were evaluated employing radical scavenging assays using DPPH and $ABTS^+$ radicals. In addition, the anti-diabetic complications effects of Ligustri Fructus extracts were tested via AGEs formation inhibitory assay. The total phenolic contents were determined using a spectrophotometric method. Results : All the tested extracts exhibited dose-dependent radical scavenging and AGEs formation inhibitory activities. Among the tested samples, hot water extract of Ligustri Fructus was showed the most potent activity with $IC_{50}$ value of $494.8{\pm}6.7{\mu}g/m{\ell}$ against DPPH radical scavenging assay. Also, $ABTS^+$ radical scavenging activity of hot water extract was higher than those of other extracts. In addition, AGEs formation inhibitory effects of each extacts and total phenolic contents were evaluated. Conclusions : These results suggested that Ligustri Fructus can be considered as a new effective source of natural antioxidant and anti-diabetic complications resources.

• Journal of Applied Biological Chemistry
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• v.65 no.1
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• pp.1-6
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• 2022

Urea is one of the most common nitrogen fertilizer, but nitrogen use efficiency by crop is low because of rapid hydrolysis of urea and loss of nitrogen in environments. Therefore, it is important to control the nitrogen release from nitrogen fertilizers. In this study, pyroligneous acid (PA) was used as a mean to inhibit urease in soil and prevent excessive nitrogen release from urea. Active ingredient in PA (AI) inhibited ammonification of urea in soil by reducing extracted ammonium nitrogen at 79.7% compared to the soil without PA. In order to evaluate the effect of PA on fertilization efficiency of urea, Chinese cabbage (Brassica campestris var. Pekinensis) was cultivated in soil treated with urea and PA both in pot and field. For PA treatment, half amount of urea was used compared to the amount of urea conventionally applied to Chinese cabbage. The PA treatment with half amount of urea resulted in similar Chinese cabbage biomass to the conventional urea application. Nitrogen concentration in Chinese cabbage was less in PA treatment indicating that Chinse cabbage effectively used nitrogen. Consequently, fertilization of urea with PA will reduce amount of fertilizer and frequency of application.

• Korean Journal of Remote Sensing
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• v.40 no.1
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• pp.45-56
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• 2024

Faced with aging populations, declining resources, and limited agricultural productivity, rural areas in South Korea require innovative solutions. This study investigated the potential of drone-based vegetation indices (VIs) to analyze soybean growth patterns in open-field smart agriculture in Goesan-gun, Chungbuk Province, South Korea. We monitored multi-seasonal normalized difference vegetation index (NDVI) and the normalized difference red edge (NDRE) data for three soybean lots with different irrigation methods (subsurface drainage, conventional, subsurface drip irrigation) using drone remote sensing. Combining NDVI (photosynthetically active biomass, PAB) and NDRE (chlorophyll) offered a comprehensive analysis of soybean growth, capturing both overall health and stress responses. Our analysis revealed distinct growth patterns for each lot. LotA(subsurface drainage) displayed early vigor and efficient resource utilization (peaking at NDVI 0.971 and NDRE 0.686), likely due to the drainage system. Lot B (conventional cultivation) showed slower growth and potential limitations (peaking at NDVI 0.963 and NDRE 0.681), suggesting resource constraints or stress. Lot C (subsurface drip irrigation) exhibited rapid initial growth but faced later resource limitations(peaking at NDVI 0.970 and NDRE 0.695). By monitoring NDVI and NDRE variations, farmers can gain valuable insights to optimize resource allocation (reducing costs and environmental impact), improve crop yield and quality (maximizing yield potential), and address rural challenges in South Korea. This study demonstrates the promise of drone-based VIs for revitalizing open-field agriculture, boosting farm income, and attracting young talent, ultimately contributing to a more sustainable and prosperous future for rural communities. Further research integrating additional data and investigating physiological mechanisms can lead to even more effective management strategies and a deeper understanding of VI variations for optimized crop performance.