• Journal of Microbiology and Biotechnology
• /
• v.31 no.7
• /
• pp.967-977
• /
• 2021

A total of 37 bacterial isolates were obtained from dye-contaminated soil samples at a textile processing factory in Nakhon Ratchasima Province, Thailand, and the potential of the isolates to decolorize and biotransform azo dye Reactive Red 141 (RR141) was investigated. The most potent bacterium was identified as Paenibacillus terrigena KKW2-005, which showed the ability to decolorize 96.45% of RR141 (50 mg/l) within 20 h under static conditions at pH 8.0 and a broad temperature range of 30-40℃. The biotransformation products were analyzed by using UV-Vis spectrophotometry and Fourier-transform infrared spectroscopy. Gas chromatography-mass spectroscopy analysis revealed four metabolites generated from the reductive biodegradation, namely sodium 3-diazenylnaphthalene-1,5-disulfonate (I), sodium naphthalene-2-sufonate (II), 4-chloro-1,3,5-triazin-2-amine (III) and N¹-(1,3,5-triazin-2-yl) benzene-1,4-diamine (IV). Decolorization intermediates reduced phytotoxicity as compared with the untreated dye. However, they had phytotoxicity when compared with control, probably due to naphthalene and triazine derivatives. Moreover, genotoxicity testing by high annealing temperature-random amplified polymorphic DNA technique exhibited different DNA polymorphism bands in seedlings exposed to the metabolites. They compared to the bands found in seedlings subjected to the untreated dye or distilled water. The data from this study provide evidence that the biodegradation of Reactive Red 141 by P. terrigena KKW2-005 was genotoxic to the DNA seedlings.

• Korean Journal of Agricultural Science
• /
• v.47 no.4
• /
• pp.1011-1020
• /
• 2020

Efficient management systems of facilities make it possible to manage environmental conditions properly, such as the temperature, humidity and light source required for the best growth of the crops, as well as for the mass production of fruit and vegetables with high quality every year through an advanced and protected cultivation system. Powdery mildew is a type of chronic disease that is difficult to control during the production of Korean melons under a protected cultivation system, the use of which is increasing in production areas in Korea. Two Bacillus strains isolated from soil samples showed antagonistic activities against several pathogens, specifically Botrytis cinerea, Colletotrichum gloeosporioides, and Fusarium oxysporum f.sp. melonis; they were identified as Bacillus velezensis M2 and B. amyloliquefaciens M3 in a molecular biological test of the nucleotide sequences of gyrase subunit A (gyrA). The treatment was given three times at intervals of five days with 400-fold diluted cultures of B. velezensis M2 and B. amyloliquefaciens M3. This led to the inhibition of the incidence of powdery mildew disease in Korean melon leaves, which resulted in effective control efficiency against the incidence of powdery mildew disease with control values of 87% and 65%, respectively. Cultures of antagonistic microbes tested in this study can be used to increase the efficiency as part of an environmentally friendly management scheme to prevent powdery mildew disease during the protected cultivation of crops, including Korean melons.

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

• Mass Spectrometry Letters
• /
• v.13 no.4
• /
• pp.166-176
• /
• 2022

Banana peels are also widely used as bio-adsorbent in the removal of chemicals contaminants and heavy metals from water and soil. GC-MS plays an essential role in the phytochemical analysis and chemo taxonomic studies of medicinal plants containing biologically active components. Intrinsically, with the use of the flame ionization detector and the electron capture detector which have very high sensitivities, Gas chromatography can quantitatively determine materials present at very low concentrations and most important application is in pollution studies. In the present study banana peels were used as bio-adsorbent to remediate the heavy metal contaminated water taken from three different stations located around the industrial belts of Ranipet, Tamilnadu, India. The AAS analysis of the samples shows a decrement of chromium concentration of 98.93%, 96.16% and 96.5% in Station 1, 2 and 3 respectively which proves the efficiency of the powdered peels of Musa paradisiaca. The GC-MS analysis of the control and treated peels of Musa paradisiaca reveals the presence of phytochemicals like Acetic Acid, 1-Methylethyl Ester, DL-Glyceraldehyde Dimer, N-Hexadecanoic Acid, 3-Decyn-2-Ol, 26-Hydroxy, Cholesterol, Ergost-25-Ene-3,5,6,12-Tetrol, (3.Beta.,5.Alpha.,6.Beta.,12.Beta.)-, 1-Methylene-2b-Hydroxymethyl-3, and 3-Dimethyl-4b-(3-Methylbut-2-Enyl)-Cyclohexane in the control banana peels. The banana peels which were used for the treatment reveals the changes and alteration of the phytochemicals. It is concluded that the alteration in phytochemicals of the experimental banana peels were due to adsorption of chromium heavy metal from the sample.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.11
• /
• pp.1435-1446
• /
• 2022

Zinc-solubilizing bacteria can convert the insoluble form of zinc into soluble forms available to plants. This study was conducted to isolate and screen zinc-solubilizing actinobacteria from rhizosphere soils and to assess their effect on vegetable soybean growth. In total, 200 actinobacteria strains belonging to 10 genera were isolated from rhizosphere soil samples. Among these isolates, four showed zinc solubilization with solubilizing index values ranging from 3.11 to 3.78 on Bunt and Rovira agar supplemented with 0.1% zinc oxide. For the quantitative assay, in broth culture, strains CME34 and EX51 solubilized maximum available zinc contents of 529.71 and 243.58 ㎍/ml. Furthermore, indole-3-acetic acid (IAA) and ammonia were produced by these two strains, the strain CME34 produced the highest amount of IAA 4.62 ㎍/ml and the strain EX51 produced the highest amount of ammonia 361.04 ㎍/ml. In addition, the phosphate-solubilizing abilities in Pikovskaya's medium of CME34 and EX51 were 64.67 and 115.67 ㎍/ml. Based on morphological and biochemical characterization and 16S rDNA sequencing, the strains CME34 and EX51 were closely related to the genus Streptomyces. In a greenhouse experiment, single-strain inoculation of Streptomyces sp. CME34 or EX51 significantly increased the shoot length, root length, plant dry weight, number of pods per plant and number of seeds per plant of vegetable soybean plants compared to the uninoculated control. These findings facilitated the conclusion that the two Streptomyces strains have potential as zinc solubilizers and can be suggested as bioinoculants to promote the growth and yield of soybean.

• Journal of the Korean Geotechnical Society
• /
• v.24 no.11
• /
• pp.133-141
• /
• 2008

In this study, a new method for estimating the undrained shear strength $s_u$ of saturated clays using piezocone penetration test (CPTu) result is proposed. This is to develop more effective CPTu-based $s_u$ estimation method at lower cost with less uncertainty. For this purpose, a marine clay deposit is selected and tested through extensive experimental testing program including both in-situ and fundamental laboratory tests. The proposed method is based on a correlation between the undrained shear strength $s_u$ and the cone resistance $q_t$, without introduction of the total overburden stress into the $s_u-q_t$ correlation. As a result, no additional testing procedure for collecting undisturbed soils samples is required, which can reduce overall testing cost. To verify the proposed method, 4 test sites, which consist of a variety of soil conditions, are selected and used for comparison between measured and predicted undrained shear strength. From comparison, it is seen that predicted values of $s_u$ using the proposed method match well those from measured results.

• Journal of the Korean Geotechnical Society
• /
• v.25 no.11
• /
• pp.5-15
• /
• 2009

Dynamic shear properties of Nak-Dong river sand were investigated to build a soil property database for Nak-Dong delta region. Samples were taken from the estuary and the midstream of the river. Laboratory specimens were prepared by air pluviation method, and were tested by using RC/TS apparatus at various confining stresses, relative densities and numbers of cycles. Shear modulus reduction and damping curves were developed using Ramberg-Osgood and Modified Hyperbolic Models. The developed curves, compared to those reported by other investigators, show only a slight difference. The outcome of this RC/TS experiments can be very important resources when accessing the dynamic response of sandy soils in Nak-Dong delta region in the future.

• The Plant Pathology Journal
• /
• v.39 no.2
• /
• pp.207-219
• /
• 2023

Soft rot is a widespread, catastrophic disease caused by Pectobacterium carotovorum subsp. carotovorum (Pcc) that severely damages the production of Amorphophallus spp. This study evaluated the rhizosphere bacterial and fungal communities in Pcc-infected and uninfected plants of two species of Amorphophallus, A. muelleri and A. konjac. Principal component analysis showed that the samples formed different clusters according to the Pcc infection status, indicating that Pcc infection can cause a large number of changes in the bacterial and fungal communities in the Amorphophallus spp. rhizosphere soil. However, the response mechanisms of A. muelleri and A. konjac are different. There was little difference in the overall microbial species composition among the four treatments, but the relative abundances of core microbiome members were significantly different. The relative abundances of Actinobacteria, Chloroflexi, Acidobacteria, Firmicutes, Bacillus, and Lysobacter were lower in infected A. konjac plants than in healthy plants; in contrast, those of infected A. muelleri plants were higher than those in healthy plants. For fungi, the relative abundances of Ascomycota and Fusarium in the rhizosphere of infected A. konjac plants were significantly higher than those of healthy plants, but those of infected A. muelleri plants were lower than those of healthy plants. The relative abundance of beneficial Penicillium fungi was lower in infected A. konjac plants than in healthy plants, and that of infected A. muelleri plants was higher than that of healthy plants. These findings can provide theoretical references for further functional research and utilization of Amorphophallus spp. rhizosphere microbial communities in the future.

• The Journal of Engineering Geology
• /
• v.32 no.1
• /
• pp.143-155
• /
• 2022

In this study, the response acceleration amplification according to different conditions was analyzed by changing the boundary condition of the soil called LSB (Laminar Shear Box), which is placed on a 1 g shaking table for earthquake simulation experiments. Experiments were carried out with different boundary conditions by fixing both sides of the LSB, and two samples were tested by installing an accelerometer at the same location. In addition, using DEEPSOIL v7 program, a one-dimensional ground response analysis was performed to compare and analyze with the free field condition. As a result, it was confirmed that the acceleration was amplified as it went from the lower layer to the upper layer, and as a result of comparing it with the ground response analysis, it was confirmed that it appeared similar to the analysis under the free field condition. As a result of the SA (Spectrum acceleration) analysis, a result similar to that of the ground response analysis was obtained, and in the case of fixing, it was confirmed that the PSA (Peak Spectral Acceleration) was further amplified.