• Journal of Microbiology and Biotechnology
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• v.32 no.9
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• pp.1195-1208
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• 2022

Silver nanoparticles (AgNPs) have potential applications in medicine, photocatalysis, agriculture, and cosmetic fields due to their unique physicochemical properties and strong antimicrobial activity. Here, AgNPs were synthesized using actinobacterial SL19 strain, isolated from acidic forest soil in Poland, and confirmed by UV-vis and FTIR spectroscopy, TEM, and zeta potential analysis. The AgNPs were polydispersed, stable, spherical, and small, with an average size of 23 nm. The FTIR study revealed the presence of bonds characteristic of proteins that cover nanoparticles. These proteins were then studied by using liquid chromatography with tandem mass spectrometry (LC-MS/MS) and identified with the highest similarity to hypothetical protein and porin with molecular masses equal to 41 and 38 kDa, respectively. Our AgNPs exhibited remarkable antibacterial activity against Escherichia coli and Pseudomonas aeruginosa. The combined, synergistic action of these synthesized AgNPs with commercial antibiotics (ampicillin, kanamycin, streptomycin, and tetracycline) enabled dose reductions in both components and increased their antimicrobial efficacy, especially in the case of streptomycin and tetracycline. Furthermore, the in vitro activity of the AgNPs on human cancer cell lines (MCF-7, A375, A549, and HepG2) showed cancer-specific sensitivity, while the genotoxic activity was evaluated by Ames assay, which revealed a lack of mutagenicity on the part of nanoparticles in Salmonella Typhimurium TA98 strain. We also studied the impact of the AgNPs on the catalytic and photocatalytic degradation of methyl orange (MO). The decomposition of MO was observed by a decrease in intensity of absorbance within time. The results of our study proved the easy, fast, and efficient synthesis of AgNPs using acidophilic actinomycete SL19 strain and demonstrated the remarkable potential of these AgNPs as anticancer and antibacterial agents. However, the properties and activity of such particles can vary by biosynthesized batch.

• Journal of People, Plants, and Environment
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• v.24 no.6
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• pp.585-593
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• 2021

Background and objective: Illegal open-air incineration, which is criticized as a leading source of air pollutants among agricultural activities, currently requires constant effort and attention. Countries around the world have been undertaking studies on the emission of heavy metal substances in fine dust discharged during the incineration process. A precise analytical method is required to examine the harmful effects of particulate pollutants on the human body. Methods: In order to simulate open-air incineration, the infrastructure needed for incineration tests complying with the United States Environmental Protection Agency (EPA) Method 5G was built, and a large-area analysis was conducted on particulate pollutants through automated scanning electron microscopy (SEM)-energy-dispersive X-ray spectroscopy (EDS). For the test specimen, high-density polyethylene (HDPE) waste collected by the DangJin Office located in Choongcheongnam-do was used. To increase the identifiability of the analyzed particles, the incineration experiment was conducted in an incinerator three times after dividing the film waste into 200 g specimens. Results: Among the metal particulate matters detected in the HDPE waste incineration test, transition metals included C (20.8-37.1 wt%) and O (33.7-37.9 wt%). As for other chemical matters, the analysis showed that metal particulate matters such as metalloids, alkali metals, alkaline earth metals, and transition metals reacted to C and C-O. Si, a representative metalloid, was detected at 14.8-20.8 wt%, showing the highest weight ratio except for C and O. Conclusion: In this study, the detection of metal chemicals in incinerated particulate matters was effectively confirmed through SEM-EDS. The results of this study verified that HDPE waste adsorbs metal chemicals originating from soil due to its own properties and deterioration, and that when incinerated, it emits particulate matters containing transition metals and other metals that contribute to the excessive production and reduction of reactive oxygen species.

• Journal of People, Plants, and Environment
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• v.24 no.2
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• pp.195-207
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• 2021

Background and objective: While response measures to particulate matters in rural areas are limited due to poor inventory record keeping in the agricultural sector, it is necessary to control agricultural waste vinyl and the emission of precursors released from open burning and the secondary generation of particulate matters. Currently, the open burning emission calculation method uses the definition prescribed in CAPSS by the National Institute of Environmental Research. Methods: This study presented an open burning emission calculation formula for agricultural waste vinyl, which is included as agricultural waste. As for activity data, the open burning ratio of agricultural waste vinyl, and the annual incineration volume provided in the Status Survey by the Ministry of Agriculture, Food, and Rural Affairs were applied. The emission factor was generated through incineration tests on three agricultural plastic film samples collected by the Korea Environment Corporation. Results: Among precursors, SOx and NOx were selected and their emission features were monitored with incineration experiment infrastructure based on the EPA 5G method. The highest emission concentration by agricultural waste type was concentrated in the first and second quarters. As for emission factor of SO₂, it was calculated at 98.25 g/kg for mulching-use LDPE, 52.31 g/kg for greenhouse-use LDPE, and 14.40 g/kg for HDPE. As for NOx, it was calculated at 18.21 g/kg for mulching-use LDPE, 16.49 g/kg for greenhouse-use LDPE, and 10.67 g/kg for HDPE. Conclusion: This test confirmed the incineration features of PE-based plastics, ascertained the SOx emission factor that had not been included in open burning in the past, and established that low NOx emission concentration is interfered by soil mixed with livestock excretions. The findings from this study are expected to contribute to improving the system for controlling air pollutants in rural environments.

• The Korean Journal of Applied Statistics
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• v.36 no.6
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• pp.619-629
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• 2023

Fertilizers are crucial for increasing crop yield, but using too much of them without taking into account the nutrients that the crops need can increase costs for farm management and have a negative impact on the environment. Through smart agriculture, fertilizers can be applied as needed at the right time to reflect the growth characteristics of crops, reducing the burden of fertilizer losses and providing economical nutrient management. In this study, we use the total dry weight of field-cultivated red pepper and green onion grown in various growing environments to fit a nonlinear model-based crop growth model using different growth curves (logistic, Gompertz, Richards, and double logistic curve), and we propose a fertilizer distributed algorithm based on crop growth rate.

• Korean Journal of Plant Resources
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• v.36 no.6
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• pp.588-596
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• 2023

Long-term culture of cell lines is an important issue in in vitro culture and in plant science. In this study, the regeneration ability and ex vitro acclimatization of regenerants were evaluated. The ploidy level of regenerants derived from long-term cultured cell lines was measured in Imperata cylindrica 'Rubra', Poaceae. Adventitious buds (shoots) were successfully induced from five-year-cultured calli on MS medium containing 0.1 mg/L BA or 2.0 mg/L TDZ, combined with 0.01 mg/L auxins (IAA, IBA, NAA and 2,4-D), respectively. Adventitious roots were also induced on MS medium containing 0.01 mg/L auxins (IBA, NAA and 2,4-D), respectively. Interestingly, regenerants with both red and green leaf were successfully obtained when regenerants were cultured on MS medium with 9% sucrose. Regenerants derived from long-term cultured calli were transferred to pots using an optimal acclimatization process and successfully adapted to both pot and soil conditions. Moreover, the ploidy level was measured using calli and regenerants that had been kept on MS medium containing various kinds of plant growth regulators (PGRs).

• Resources Recycling
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• v.33 no.1
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• pp.48-57
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• 2024

This study aimed to improve utilization of the Class C vinyl waste generated in rural areas based on a preliminary investigation on the use of eco-powder, generated through pyrolysis, as a raw material for plastic. The efficiency of pre-processing treatments in controlling ash content of the generated eco-powder and its effect on the basic properties of manufactured plastic were evaluated. The basic properties included ash content of the compressed eco-powder at different levels of ash content, impact strength, flexural strength, and tensile strength. The experimental results confirmed that pre-processing improved the separation efficiency of soil particles and vinyl waste through physical impact. The eco-powder with ash content of less than or equal to 26% was found to satisfy the target performance during impact strength, flexural strength, and tensile strength evaluation. Thus, it was confirmed that the Class C vinyl waste, having low utilization and recovery rates, could be effectively utilized as a plastic raw material after optimum thermal treatment and physical processing using the eco-powder.

• Animal Bioscience
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• v.37 no.7
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• pp.1196-1203
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• 2024

Objective: A study was conducted to quantify the performance differences of the near-infrared spectroscopy (NIRS) calibration models developed with different degrees of hay sample preparations. Methods: A total of 227 imported alfalfa (Medicago sativa L.) and another 360 imported timothy (Phleum pratense L.) hay samples were used to develop calibration models for nutrient value parameters such as moisture, neutral detergent fiber, acid detergent fiber, crude protein, and in vitro dry matter digestibility. Spectral data of hay samples prepared by milling into 1-mm particle size or unground were separately regressed against the wet chemistry results of the abovementioned parameters. Results: The performance of the developed NIRS calibration models was evaluated based on R², standard error, and ratio percentage deviation (RPD). The models developed with ground hay were more robust and accurate than those with unground hay based on calibration model performance indexes such as R² (coefficient of determination), standard error, and RPD. Although the R² of calibration models was mainly greater than 0.90 across the feed value indexes, the R² of cross-validations was much lower. The R² of cross-validation varies depending on feed value indexes, which ranged from 0.61 to 0.81 in alfalfa, and from 0.62 to 0.95 in timothy. Estimation of feed values in imported hay can be achievable by the calibrated NIRS. However, the NIRS calibration models must be improved by including a broader range of imported hay samples in the modeling. Conclusion: Although the analysis accuracy of NIRS was substantially higher when calibration models were developed with ground samples, less sample preparation will be more advantageous for achieving rapid delivery of hay sample analysis results. Therefore, further research warrants investigating the level of sample preparations compromising analysis accuracy by NIRS.

• Journal of Food Hygiene and Safety
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• v.39 no.3
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• pp.191-208
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• 2024

The peptide-type hepatotoxins microcystins (MCs) and nodularin (NOD) are secondary metabolites produced by cyanobacteria. MCs and NOD can bioaccumulate in agricultural products through toxin-contaminated water, soil, and manure and can cause human health risks through the consumption of agricultural products. As interest in the contamination of agricultural products by MCs or NOD has recently emerged, occurrence studies based on various analysis methods for agricultural products have been conducted. However, studies on agricultural products are still insufficient compared to research on drinking water and seafood. In addition, research is primarily conducted on agricultural products grown in areas where green algae occur, but not on marketed products. In the present study, we review the physicochemical properties, toxicity, analysis methods, occurrence studies, and management status of MCs and NOD in agricultural products to build a foundation for systematic monitoring and safety management.

• Journal of Environmental Impact Assessment
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• v.26 no.2
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• pp.93-104
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• 2017

CCS (Carbon Capture and Storage) is a technical process to capture $CO_2$ from industrial and energy-based sources, to transfer and sequestrate impressed $CO_2$ in geological formations, oceans, or mineral carbonates. However, potential $CO_2$ leakage exists and causes environmental problems. Thus, this study was conducted to analyze the spatial and temporal variations of $CO_2$ fluxes and concentrations after artificial $CO_2$ release. The Environmental Impact Evaluation Test Facility (EIT) was built in Eumseong, Korea in 2015. Approximately 34kg $CO_2$ /day/zone were injected at Zones 2, 3, and 4 among the total of 5 zones from October 26 to 30, 2015. $CO_2$ fluxes were measured every 30 minutes at the surface at 0m, 1.5m, 2.5m, and 10m from the $CO_2$ releasing well using LI-8100A until November 13, 2015, and $CO_2$ concentrations were measured once a day at 15cm, 30cm, and 60cm depths at every 0m, 1.5m, 2.5m, 5m, and 10m from the well using GA5000 until November 28, 2015. $CO_2$ flux at 0m from the well started increasing on the fifth day after $CO_2$ release started, and continued to increase until November 13 even though the artificial $CO_2$ release stopped. $CO_2$ fluxes measured at 2.5m, 5.0m, and 10m from the well were not significantly different with each other. On the other hand, soil $CO_2$ concentration was shown as 38.4% at 60cm depth at 0m from the well in Zone 3 on the next day after $CO_2$ release started. Soil $CO_2$ was horizontally spreaded overtime, and detected up to 5m away from the well in all zones until $CO_2$ release stopped. Also, soil $CO_2$ concentrations at 30cm and 60cm depths at 0m from the well were measured similarly as $50.6{\pm}25.4%$ and $55.3{\pm}25.6%$, respectively, followed by 30cm depth ($31.3{\pm}17.2%$) which was significantly lower than those measured at the other depths on the final day of $CO_2$ release period. Soil $CO_2$ concentrations at all depths in all zones were gradually decreased for about 1 month after $CO_2$ release stopped, but still higher than those of the first day after $CO_2$ release stared. In conclusion, the closer the distance from the well and the deeper the depth, the higher $CO_2$ fluxes and concentrations occurred. Also, long-term monitoring should be required because the leaked $CO_2$ gas can remains in the soil for a long time even if the leakage stopped.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.460-466
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• 2009

Carbon fixation and density of crops are important to estimate carbon uptake or emission by agricultural production activities and to establish life cycle inventory of crops for assessment of climate change impact. In this study, regional carbon fixation and density in each part of 14 crops, harvest index, and ratio of aboveground to underground were investigated to estimate biomass of 14 crops in Korea by using agricultural statistics data. Biomass yield of potato was $16.5ton\;ha^{-1}$, which was the highest, and those of rice, sweet potato, and garlic were $10.5ton\;ha^{-1}$, $8.7ton\;ha^{-1}$, and $7.5ton\;ha^{-1}$ respectively. Biomass yield of Green onion was the lowest as $2.8ton\;ha^{-1}$. Carbon density of 14 crops were in the order of potato ($6.4ton\;ha^{-1}$), rice ($4.2ton\;ha^{-1}$), sweet potato ($3.4ton\;ha^{-1}$), rape ($2.9ton\;ha^{-1}$) and garlic ($2.8ton\;ha^{-1}$). Regional distribution of carbon contents for each crop mapped revealed that carbon fixation of rice, soybean, sesame, garlic, and green onion were the highest in Jeonnam province, barley, red pepper, and watermelon in Gyeongnam, perilla in Chungnam, peanut in Gyeongbuk, rape and carrot in Jeju, sweet potato in Gyeonggi, potato in Gangwon. The results can be applied for assessing life cycle inventory of crops and crop productivity using remotely sensed data.