• Journal of Environmental Health Sciences
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• v.24 no.3
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• pp.54-62
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• 1998

20 bacterial strains capable of growing on phenol minimal medium were isolated from soil and wastewater by the enrichment culture technique, and among them, one isolate which was the best in the cell growth was selected and identified as Bacillus sp. SH3 by its characteristics. Strain SH3 could grow with phenol as the sole carbon source up to 15 mM, but did not grow in minimal medium containing above 20 mM of phenol. The optimal conditions of temperature and initial pH for growth and phenol degradation were 30$^{\circ}$C and 7.5, respectively. This strain could grow on various aromatic compounds such as catechol, protocatechuic acid, gentisic acid, o-, m-, p-cresol, benzoic acid, p-hydroxybenzoic acid, anthranilic acid, phenyl acetate and pentachlorophenol, and the growth-limiting log P value of strain SH3 on organic solvents was 3.1. In batch culture, strain SH3 degraded 97% of 10 mM phenol in 48 hours. In continuous culture under the conditions of 20 mM of influent phenol concentration and 0.050 hr$^{-1}$ of dilution rate, the treatment rate of phenol was 94%.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.340-343
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• 2003

Soils contaminated by hazardous hydrophobic organic compounds, such as polycyclic aromatic hydrocarbons (PAHs), have become a major environmental issue due to toxic and carcinogenic properties of those compounds. In this work, we investigated effects of various metabolic inducers on phenanthrene biodegradation. Biodegradation tests were peformed with two different Pseudomonads: Pseudononrdia hydrocarboxydans (Gram positive) and Pseudomonas putida (Gram negative). Intermediates of phenanthrene metabolism (1-hydroxy-2-naphthoate, salicylate, catechol, phthalate and protocatechuate) were selected as inducers. The tests indicated that 1-hydroxy-2-naphthoate was the most effective inducer and enhanced the phenanthrene degradation rate up to 5.7 times, even though all the others also had induction ability to some extent. The effective induction could be achieved even at a low concentration of 1-hydroxy-2-naphthoate. Addition of metabolic inducers would be an attractive trick for the successful bioremediation of PAH-contaminated soil.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.257-258
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• 2022

In this study, as a part of the study to alleviate the durability degradation due to low tensile performance and cracking of concrete, two kinds of catechol functional chitosan (Cat-Chit) were replaced at a ratio of 5, 10, 15, 20% as a mixed water substitute to evaluate the fluidility and strength characteristics of mortar.

• Korean Journal of Microbiology
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• v.33 no.2
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• pp.92-96
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• 1997

The 6.8 kb Xhol fragment of chromosomal ONA of Pseudomonas sp. 0177 contains the phnDEFG genes involved in the degradation of polyaromatic hydrocarbons and chlorinated aromatics. Here, we report the nucleotide sequence of the ORF encoding a polypeptide consisted of 143 amino acids with a Mr of 13,859. The nucleotide sequence of the ORF is 99% and 68.6% identical to the downstream region of catE of Sphingomonas sp. strain HV3 and the ORF between xylE and xylG of Sphingomonas yanoikuyae Bl, respectively. The deduced amino acid sequence of the PhnF has 62.3% identity with the amino acid encoded hy orfY region of Citrobacter freundii DSM30040. We now confirm that the ORF is located between the catechol 2,3-dioxygenase (C230), phnE, and 2-hydroxymuconic semialdehyde dehydrogenase (2HMSO), phnG.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.393-399
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• 2004

Useful genes can be Screened from various environments by construction of metagenomic DNA libraries. In this study, water samples were collected from several lakes in mid Korea, and analyzed by T-RFLP to examine diversities of the microbial communities. The crude DNAs r were extracted by the SDS-based freezing-thawing method, and then further purified using an $UltraClean^{TM}$ kit (MoBio, USA). The metagenomic libraries were constructed with the DNAs partially digested with EcoR I, BamH I, and Sac II in Escherichia coli DH 10B using the pBACe3.6 vector. About 44.0 Mb of metagenomic libraries were obtained with average inserts 13-15 kb in size. The bphC genes responsible for degradation of aromatic hydrocarbons via mets-cleavage were identified from the metagenomic libraries by colony hybridization using the bphC specific sequence as a probe. The 2,3-dihydroxybiphenyl (2, 3-DHBP) dioxygenase gene (bphC ), capable of degradation of 2,3-DHBP, was cloned and its nucleotide Sequences analyzed. The genes consisted of 966 and 897 base pairs with an ATG initiation codon and a TGA termination codon. The activity of the 2,3-DHBP dioxygenase was highly expressed to 2,3-DHBP and Showed a broad substrate range to 2,3-DHBP, catechol, 3-methylcatechol and 4-methylcatechol. These results in-dicated that the bphC gene identified from the metagenomes derived from lake water might be useful in the development of a potent strain for degradation of aromatic pollutants.

• Journal of Life Science
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• v.21 no.11
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• pp.1511-1517
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• 2011

We isolated a potent phenanthrene-degrading bacterium from oil-contaminated soils of Suzhou, China, and assessed the potential use of these bacteria for bioremediation of soils contaminated by polycyclic aromatic hydrocarbons (PAHs) in a microcosm. Based on 16S rDNA sequencing, we identified this bacteria as Sphigobacterium sp. SW-09. By PCR amplification, we also identified catechol 2,3-dioxygenase genes (nahH genes) mediating PAH degradation. Staphylococcus sp. KW-07, which has been identified in our previous study, showed potential for use in bioremediation of oil-contaminated soils. In this experiment, we compared the rate of phenanthrene-degradation between Staphylococcus sp. KW-07 and Sphingobacterium sp. SW-09 in a microcosm condition. Newly isolated Sphingobacterium sp. SW-09 showed a higher phenanthrene-degradation rate than that of Staphylococcus sp. KW-07 in soil microcosms. Together, our results suggest that the Sphingobacterim sp. SW-09 strain isolated from the Suzhou area may also be useful in bioremediation of PAH-contaminated soils.

• Journal of Microbiology
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• v.35 no.1
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• pp.53-60
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• 1997

Pseudomonas sp. P20 and Pseudomonas sp. DJ-12 isolated from the polluted environment are capable of degrading biphenyl and 4-chlorobiphenyl (4CB) to produce benzoic acid and 4-chlorobenzoic acid (4CBA) respectively, by pcbABCD-encoded enzymes. 4CBA can be further degraded by Pseudomonas sp. DJ-12, but not by Pseudomonas sp P20. However, the meta-cleavage activities of 2, 3-dihydroxybiphenyl (2, 3-DHBP) and 4-chloro-2, 3-DHBP dioxygenases (2, 3-DHBD) encoded by pcbC in Pseudomonas sp. P20 were stronger than Pseudomonas sp. DJ-12. In this study, the pcbC gene encoding 2, 3-DHBD was cloned from the genomic DNA of Pseudomonas sp. P20 by using pKT230. A hybrid plasmid pKK1 was constructed and E. coli KK1 transformant was selected by transforming the pKK1 hybrid plasmid carrying pcbC into E. coli XL1-Blue. By transferring the pKK1 plasmide of E. coli KK1 into Pseudomonas sp. DJ-12 by conjugation, a recombinant strain Pseudomonas sp. P20, Pseudomonas sp. DJ-12, and the recombinant cell assay methods. Pseudomonas sp. DJ12-C readily degraded 4CB and 2, 3-DHBP to produce 2-hydroxy-6-oxo-6-phenylhexa-2, 4-dienoic acid (HOPDA), and the resulting 4CBA and benzoic acid were continuously catabolized. Pseudomonas sp. DJ12-C degraded 1 mM 4CB completely after incubation for 20 h, but Pseudomonas sp. P20 and Pseudomonas sp. DJ-12 showed only 90% and Pseudomonas sp. DJ-12 had, but its degradation activity to 2, 3-DHBP, 3-methylcatechol, and catechol was improved.

• Proceedings of the Microbiological Society of Korea Conference
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• 2001.11a
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• pp.157-163
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• 2001

Mycolic acid-containing gram-positive bacteria, so called nocardioform actinomycetes, have become a great interest to environmental microbiologists due to their metabolic versatility, multidegradative capacity and potential for bioremediation of priority pollutants. For example, Rhodococcus rhodochrous N75 was able to metabolize 4-methy1catechol via a modified $\beta$-ketoadipate pathway whereby 4-methylmuconolactone methyl isomerase catalyzes the conversion of 4-methylmuconolactone to 3-methylmuconolactone in order to circumvent the accumulation of the 'dead-end' metabolite, 4-methylmuconolactone. R. rhodochrous N75 has also shown the ability to transform a range of alkyl-substituted catechols to the corresponding muconolactones. A novel 3-methylmuconolactone-CoAsynthetase was found to be involved in the degradation of 3-methylmuconolactone, which is not mediated in a manner analogous to the classical $\beta$-ketoadipate pathway but activated by the addition of CoA prior to hydrolysis of lactone ring, suggesting that the degradative pathway for methylaromatic compounds by gram-positive bacteria diverges from that of proteobacteria. Mycobacterium sp. Strain PYR-l isolated from oil-contaminated soil was capable of mineralizing various polyaromatic hydrocarbons (PAHs), such as naphthalene, phenanthrene, pyrene, fluoranthrene, 1-nitropyrene, and 6-nitrochrysene. The pathways for degradation of PAHs by this organism have been elucidated through the isolation and characterization of chemical intermediates. 2-D gel electrophoresis of PAH-induced proteins enabled the cloning of the dioxygenase system containing a dehydrogenase, the dioxygenase small ($\beta$)-subunit, and the dioxygenase large ($\alpha$)-subunit. Phylogenetic analysis showed that the large a subunit did not cluster with most of the known sequences except for three newly described a subunits of dioxygenases from Rhodococcus spp. and Nocardioides spp. 2-D gel analysis also showed that catalase-peroxidase, which was induced with pyrene, plays a role in the PAH metabolism. The survival and performance of these bacteria raised the possibility that they can be excellent candidates for bioremediation purposes.

• 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.13 no.4
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• pp.487-494
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• 2003

2,3-Dihydroxybiphenyl 1,2-dioxygenase (23DBDO), an enzyme of the biphenyl biodegradation pathway encoded by the bphC gene of Comnmonas sp. SMN4, was expressed and purified using column chromatographies. SDS-PAGE of purified 23DBDO showed a single band with a molecular mass of 32 kDa, which was consistent with the data from the gel filtration chromatography (GFC). The purified enzyme exhibited a maximum 23DBDO activity at pH 9.0 and was stable at pH 8.0. The enzyme showed maximum activity at $40^{\circ}C$ and maintained activity at $30^{\circ}C$ for 24 h. Kinetic parameters represented by Michaelis-Menten constants such as $K_m\;and\;V_{max}$ values for various substrates were determined by Lineweaver-Burk plots: The purified enzyme 23DBDO from Comamonas sp. SMN4 had the highest catalytic activity for 2,3-dihydroxybiphenyl and 3-methylcatechol, and had very poor activity with catechol and 4-methylcatechol.