• Journal of Microbiology and Biotechnology
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• v.10 no.1
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• pp.111-114
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• 2000

Streptomyces are widespread in nature and play a very important role in the biosynthesis as well as biodegradation of natural and unnatural aromatic compounds. Both qualitatively and quantitatively through TLC and UV spectrophotometric assays, it was observed that the thermophilic soil bacteria S. setonii (ATCC 39116), which can utilize a benzoate as a sole carbon and energy source in a minimal liquid culture, was not very sensitive to the benzoate concentation and to the culture conditions such as the pH and temperature. The in vitro conversion of a catechol to a cis, cis-muconic acid by a crude S. setonii lysate implies that the aromatic ring cleavage by S. setonii is initiated by a thermostable catechol-1,2-dioxygenase, the key enzyme in the ortho-cleavage pathway of aromatic compound biodegradation. Unlike non-degrading S. lividans, S.setonii was also highly resistant to other similar hazardous aromatic compounds, exhibiting almost no adverse effect on its growth in a complex liquid culture.

• Safety and Health at Work
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• v.2 no.3
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• pp.229-235
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• 2011

Objectives: In this study, we summarized the External Quality Assessment Scheme (EQAS) for the biological monitoring of occupational exposure to toxic chemicals which started in 1995 and continued until a $31^{st}$ round robin in the spring of 2010. The program was performed twice per year until 2009, and this was changed to once a year since 2010. The objective of the program is to ensure the reliability of the data related to biological monitoring from analytical laboratories. Methods: One hundred and eighteen laboratories participated in the $31^{st}$ round robin. The program offers 5 items for inorganic analysis: lead in blood, cadmium in blood, manganese in blood, cadmium in urine, and mercury in urine. It also offers 10 items for organic analysis, including hippuric acid, methylhippuric acid, mandelic acid, phenylglyoxylic acid, N-methylformamide, N-methylacetamide, trichloroacetic acid, total trichloro-compounds, trans,trans-muconic acid, and 2,5-hexanedione in urine. Target values were determined by statistical analysis using consensus values. All the data, such as chromatograms and calibration curves, were reviewed by the committee. Results: The proficiency rate was below 70% prior to the first round robin and improved to over 90% for common items, such as PbB and HA, while those for other items still remained in the range of 60-90% and need to be improved up to 90%. Conclusion: The EQAS has taken a primary role in improving the reliability of analytical data. A total quality assurance scheme is suggested, including the validation of technical documentation for the whole analytical procedure.

• Journal of Microbiology and Biotechnology
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• v.33 no.1
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• pp.1-14
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• 2023

Polyethylene terephthalate (PET) is a plastic material commonly applied to beverage packaging used in everyday life. Owing to PET's versatility and ease of use, its consumption has continuously increased, resulting in considerable waste generation. Several physical and chemical recycling processes have been developed to address this problem. Recently, biological upcycling is being actively studied and has come to be regarded as a powerful technology for overcoming the economic issues associated with conventional recycling methods. For upcycling, PET should be degraded into small molecules, such as terephthalic acid and ethylene glycol, which are utilized as substrates for bioconversion, through various degradation processes, including gasification, pyrolysis, and chemical/biological depolymerization. Furthermore, biological upcycling methods have been applied to biosynthesize value-added chemicals, such as adipic acid, muconic acid, catechol, vanillin, and glycolic acid. In this review, we introduce and discuss various degradation methods that yield substrates for bioconversion and biological upcycling processes to produce value-added biochemicals. These technologies encourage a circular economy, which reduces the amount of waste released into the environment.

• Journal of Microbiology and Biotechnology
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• v.10 no.5
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• pp.643-650
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• 2000

A new aniline-utilizing microorganism, strain HY1 obtained from an orchard soil, was characterized by using the BIOLOG system, an analysis of the total cellular fatty acids, and a 16S rDNA sequence. Strain HY1 was identified as a Burkholderia species, and was designated Burkholderia sp. HY1. GC and HPLC analyses revealed that Burkholderia sp. HY1 was able to degrade aniline to produce catechol, which was subsequently converted to cis,cis-muconic acid through an ortho-ring fission pathway under aerobic conditions. Strain HY1 exhibited a drastic reduction in the rate of aniline degradation when glucose was added to the aniline media. However, the addition of peptone or nitrate to the aniline media dramatically accelerated the rate of aniline degradation. A fatty acid analysis showed that strain HY1 was able to produce lipids 16:0 2OH, and 11 methyl 18:1 ${\omega}7c$ approximately 3.7-, 2.2-, and 6-fold more, respectively, when grown on aniline media than when grown on TSA. An analysison the alignment of a 1,435 bp fragment. A phylogenetic analysis of the 16S rDNA sequence based on a 1,420 bp multi-alignment sowed of the 16s rDNA sequence revealed that strain HY1 was very closely related to Burkholderia graminis with 95% similarity based that strain HY1 was placed among three major clonal types of $\beta$-Proteobacteria, including Burkholderia graminis, Burkholderia phenazinium, and Burkholderia glathei. The sequence GAT(C or G)${\b{G}}$, which is highly conserved in several locations in the 16S rDNA gene among the major clonal type strains of $\beta$-Proteobacteria, was frequently replaced with GAT(C or G)${\b{A}}$ in the 16S rDNA sequence from strain HY1.

• Journal of Environmental Health Sciences
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• v.50 no.1
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• pp.25-35
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• 2024

Background: There are concerns about the health effects of various environmental pollution exposures among residents living near coal-fired power plants (CFPP). Objectives: This study attempted to compare the concentrations of heavy metals in blood and urine and those of urinary volatile organic compound (VOC) metabolites according to the residential separation distance. Methods: Participants in the study totaled 334 people who have lived for more than 10 years in areas within 10 km of a CFPP. The separation distance was analyzed in quartiles by dividing it into Q1 (88 people), Q2 (89 people), Q3 (89 people), and Q4 (68 people). We explained the purpose of this study to the participants and collected blood and urine after obtaining signatures on a participation agreement. Results: The study participants were 102 males (30.5%) and 232 females (69.5%), with an average age of 71. The average length of residence and distance were 43.8 years and 4,800 meters. The geometric mean concentrations of Pb, Cd, and Hg in blood and As and Cd in urine were respective 1.35 ㎍/dL, 1.43 ㎍/L, 3.16 ㎍/L. They were 167.88 ㎍/g for creatinine and 1.58 ㎍/g creatinine. The metabolite concentrations of VOCs were 50.67 ㎍/g creatinine in t, t-muconic acid (t, t-MA), 10.73 ㎍/g creatinine in benzyl mercapturic acid, 317.05 ㎍/g creatinine in phenylglyoxylic acid, 123.55 ㎍/g creatinine in methylhippuric acid, and 190.82 ㎍/g creatinine in mandelic acid. The concentration of Pb in the blood and Cd and t, t-MA in the urine of residents within affected area of the CFPP showed statistically significant differences among distance groups. Conclusions: The concentration of urinary VOCs metabolites, especially t, t-MA, differed according to the distance groups of residents within the affected area of CFPP (p<0.05).

• Journal of environmental and Sanitary engineering
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• v.14 no.3
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• pp.54-62
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• 1999

2,4-Dichlorophenol was known pollutants caused by the endocrine disruptor into the refractory substances of environment and this is difficult to be degradable by conventional methods. Therefore, a considerable interest has been devoted to developing new process where 2,4-Dichlorophenol can easily decomposed. In this study, the series of ultrasonic irradiation for removal of 2,4-Dichlorophenol has been selected as a model reaction in the batch reactor system in order to obtain the basic data investigate the influence of various experimental parameters such as concentration, pH, reaction temperature, acoustic intensity. The products obtained form the ultrasonic irradiation were analysed by GC/MS and HPLC. The formation of $H_2O_2$, a well-known the strong oxidant was found proportionally to increase with irradiation time. The intermediates of ultrasonic irradiation of 2,4-Dichlorophenol were identified as HCl, catechol, hydroquinone, o,p-benzoquinone, muconic acid, and maleic acid. The final products of this was $CO_2$ and $H_2O$. As the decomposition of 2,4-Dichlorophenol proceeds by the ultrasonic irradiation, the pH of 2,4-Dichlorophenol containing aqueous solution increases slowly, The decomposition of 2,4-Dichlorophenol was found to be occured fast in the basic medium. In general, the rate of reaction is proportional to the reaction temperature obeying the Arrhenius' law. However, in the ultrasonic irradiation, this suggests as the reaction temperature increase the decomposition rate of the reactant decreases. This result meant that the increase of reaction temperature due to the increase of vapor pressure of water accelerated the decrease of acoustic intensity which was can be proportional to the decomposition rae of these compounds. It was found that more than 80% of phenol solution was removed within hours in all reaction conditions. The reaction order in the degradation of the 2,4-Dichlorophenol compounds was verified as the Pseude-first order. From the fore-mentioned results, it can be concluded that the refractory organic compounds caused by endocrine disruptor as 2,4-dichlorophenol could be removed by the ultrasonic irradiation with radicals, such as $H{\;}{\cdot}{\;}and{\;}OH{\;}{\cdot}$ radical causing the high increase of pressure and temperature. Finally, it apeared that the technology using ultrasonic irradiation can be applied to the treatment of refractory substances caused by endocrine disruptor which are difficult to be decomposed by the conventional methods.

• Proceedings of the Korean Environmental Health Society Conference
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• 2003.06a
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• pp.187-191
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• 2003

In this study, biomonitoring methods were developed to measure BTEXs exposure level in the air, metabolites of benzene and toluene in human urine, individual susceptibility markers in human blood for evaluation of the health effects about environmental pollution. We have also performed a small-scaled molecular epidemiology study on residents in Chuncheon and workers in workplace for these method applications. The workers in workplace were surveyed as study areas, and the residents in Chuncheon which is in the suburban area were surveyed as comparative areas in this study. Actually, 31 workers in as target group and 33 residences in as control group this epidemiological study. The results obtained from this study were as follows: 1. Benzene is a well-known carcinogen, it's median concentrations were 0.00024∼0.02057ppm at suburban area and 0.002∼00.654ppm at work place, These benzene concentrations were not exceed the OSHA(Occupational Safety and Health Administration) threshold benzene level of 1ppm in the states. 2. Metabolites product of benzene(t,t-Muconic Acid) and toluene(Hippuric Acid) were not significant both in suburban and workplace area. The median concentration of t,t-MA and HA were 0.0122, 1.44277g/g creatinine, respectively. 3. In the case of individual susceptibility markers as CYPlAl, 41.8% of them has homozygous wild type(W) and who has heterozygous variant type(H) was 35.4% and 22.8% of homozygous variant type(M) genetic type. In the case of CYP2E1, 62.82% of them has homozygous wild type(D) type, 34.62% of each has heterozygous variant type (DC) and 2.56% of them has homozygous variant type (CC). Who doesn't have GSTM1 gene was 46.25% and who has GSTM1 gene was 53.75％. Who doesn't have GSTT1 gene was 40.0％ in study groups and who has GSTT1 gene was 60.0%. Who has W genetic type, which is homozygous wild type of GSTP1, was 69.18% and H genetic type, which is heterozygous variant type was 28.4%. M genetic type which is homozygous variant type was 2.4%. 4. Concentration differences of metabolites such as t,t-MA and HA in urine, which is generated by individual susceptibility marker of GSTM1, GSTT1, GSTP1 gene of Phase I and CYP1A1, CYP2E1 gene of Phase II, was examined. As a result, GSTP1 and GSTM1 indicate slight differences depend on the amount of metabolites in urine, it was not statistically significant.

• Journal of Environmental Health Sciences
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• v.45 no.5
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• pp.529-540
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• 2019

Objectives: The aim of this study is to compare exposure levels of PAHs and benzene metabolites in the urine of nationally representative adults in Korea and identify exposure factors in relation to questionnaire results. Methods: The study analyzed PAHs and benzene metabolites in the urine of adults aged 19 and older recruited in Cycles 1-3 of the Korean National Environmental Health Survey (KoNEHS). Participants were administered questionnaires on demographic characteristics, lifestyle, and dietary habits to identify the association with exposure levels to environmental chemicals. Results: 1-hydroxypyrene and t,t-muconic acid levels in this study were higher than those in large-scale biomonitoring conducted in other countries (the US and Canada), while 2-hydroxynaphthalene levels were lower. Most environmental chemicals exhibited significant differences depending on gender and age, and exposure levels tended to increase with grilled food intake. In addition, variables such as smoking, distance between home and a road, travelling on public transportation, and ventilation time had a significant effect on exposure to environmental chemicals. Conclusions: The importance of this study lies in utilizing the representative results of KoNEHS, large scale biomonitoring conducted in Korea over roughly ten years. Variables including smoking and roasted food intake were found to affect exposure to PAHs and benzene, which can be used to establish baseline exposure levels of environmental chemicals in Korea.

• Journal of Environmental Health Sciences
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• v.49 no.6
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• pp.344-352
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• 2023

Background: With its developed port and related industries, the concentration of fine dust is high in Busan compared to other cities in South Korea. Many studies have reported the health effects of fine dust, but there has been a lack of information regarding concentrations of volatile organic compounds among those who exposed to high levels of fine dust. Objectives: This study aimed to define an area with high concentrations of particulate matter and perform biomonitoring surveys among the residents of the area. Methods: Air quality data was collected and the mean level of each district in Busan was derived. We then defined the area with the highest concentrations of PM₁₀ as a target site. Urine samples were collected from the 400 participants and analyzed for VOCs metabolites - trans,trans-Muconic Acid (t,t-MA) and N-AcetylS-(benzyl)-L-cysteine (BMA). Interviews were conducted by trained investigators to examine demographic information. The levels of t,t-MA and BMA were compared with representative South Korean population data (Korean National Environmental Health Survey). The association of the VOC metabolites and fine dust were analyzed by general linear regression analysis. Results: The mean of PM₁₀ in the target site was 42.50 ㎍/m³ from 2018 to 2020. Among the 400 participants in the target site, 74.8% were female and the average age of the participants was 66 years. The geometric mean of t,t-MA was 71.15 ㎍/g creatinine and the BMA was 7.00 ㎍/g creatinine among the residents. The levels were higher than the geometric mean from the 4th KoNEHS. The levels of t,t-MA showed significance in BMI, smoking status, and household income. BMA showed significance in gender and age. Conclusions: Compared to the general population of South Korea, the target site's residents had higher biomonitoring levels. Based on this study, continuous screening for high risk areas, including the target site, and biomonitoring of the residents are required.