• Journal of Soil and Groundwater Environment
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• v.10 no.4
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• pp.26-32
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• 2005

Surfactants can be used to enhance the mass transfer rate of hydrophobic compounds into the biologically active liquid phase, resulting in an increase in biodegradation rate of toluene. In this study, the mass transfer rate and the biocompatibility of toluene in the presence of various surfactants were evaluated. Four anionic and non ionic surfactants were tested: sodium dodecyl sulfate (SOS), TritonX-100, Tween 80, and BYK-345 (silicone surfactant). Experimental results showed that BYK-345 at the critical micelle concentration (CMC) enhanced the solubility of toluene. However, there was no increase in the solubility of toluene by SOS and TritonX-100 at their CMCs. With the addition of each surfactant into deionized water the mass transfer rate became faster than that of the case with no surfactant. A bottle study using toluene-degrading microorganisms showed that SOS seriously reduced toluene removal presumably due to the toxicity of the anionic surfactant and/or the substrate competition between the surfactant and toluene. In addition, the degradation rate of toluene was decreased in the presence of BYK-345, indicating that BYK-345 adversely affects the activity of microorganisms. However, TritonX-100 and Tween 80 did not decrease the degradation rate of toluene significantly. Rather, at the low concentration of TritonX-100 toluene degradation rate was even increased. Overall the experimental results suggest that TritonX-100 be the appropriate surfactant for enhanced biological degradation of toluene.

• Korean Journal of Microbiology
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• v.34 no.1_2
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• pp.37-42
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• 1998

The microorganisms degrading levan were screened from soil. The isolated strain produced levanase releasing single oligosacchride from levan. The optimum cultural medium for levanase production (g/l) was composed of 0.5% levan, 0.1% $K_2HPO_4$, 0.05% NaCl, 0.3% $NaNO_3$, 0.3% yeast extract (pH 8.0). The cultivation for levanase production was carried out in 500 ml shaking flask containing 50 ml of the optimum medium at $30^{\circ}C$ on a reciprocal shaker, and the highest levanase production was observed after 54 hours of cultivation. The levanase hydrolyzed levan into single oligosaccharide. The product purified by chilled EtOH precipitation and gel filtration was detected as a single peak on HPLC analysis. The oligosaccharides formed by enzyme reaction was identified as levanheptaose (DP7) by HPLC and by ESI-MASS.

• Journal of Environmental Science International
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• v.2 no.4
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• pp.271-278
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• 1993

Optimal biodegradation kinetics models to the initial nonylphenol ethoxylates-30 concentration were investigated and had been fitted by the linear regression. Microorganisms capable of degrading nonylphenol ethoxylates-30 were isolated from sewage near Ulsan plant area by enrichment culture technique. Among them, the strain designated as EL-10K had the highest biodegradability and was identified as Pseudomonas from results of taxonomical studies. The optimal conditions for the biodegradation were 1.0 g/ι of nonylphenol ethoxylates-30 and 0.02 g/ι of ammonium nitrate at pH 7.0 and 3$0^{\circ}C$. The highest degradation rate of nonylphenol ethoxylates-30 was about 89% for 30 hours incubation on the optimal condition. Biodegradation data were fit by linear regression to equations for 3 kinetic models. The kinetics of biodegradation of nonylphenol ethoxylates was best described by first order model for 0.1 $\mu\textrm{g}$/ι nonylphenol ethoxylates-30 ; by Monod no growth model and Monod with growth model for 0.5 $\mu\textrm{g}$/mι and 1.0, 5.0 $\mu\textrm{g}$/mι, respectively.

• Journal of Microbiology and Biotechnology
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• v.9 no.4
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• pp.422-428
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• 1999

Aromatic hydrocarbons can be utilized as carbon and energy sources by some microorganisms at lower concentrations. However, they can also act as stresses to these organisms at higher concentrations. Pseudomonas sp. DJ-12 is capable of degrading 0.5 mM concentration of benzoate and 4-chlorobenzoate (4CBA). In this study, the exposure of Pseudomonas sp. DJ-12 to the pollutant stresses of benzoate and 4CBA at various concentrations was comparatively studied for its cellular responses, including survival tolerance, degradability of the aromatics, and morphological changes. Pseudomonas sp. DJ-12 utilized 0.5 to 1.0mM benzoate and 4CBA as carbon and energy sources for growth. However, the organism could not degrade the aromatics at concentrations of 3 mM or higher, resulting in reduced cell viability due to the destruction of the cell envelopes. Pseudomonas sp. DJ-12 cells produced stress-shock proteins such as DnaK and GroEL when treated with benzoate and 4CBA at concentrations of 0.5mM, or higher as sublethal dosage; Yet, there were differing responses between the cells treated with either benzoate or 4CBA. 4CBA affected the degradability of the cells more critically than benzoate. The DnaK and GroEL stress-shock proteins were produced either by 1mM benzoate with 5 min treatment or by higher concentrations after 10min. The proteins were also induced by 0.5mM 4CBA, however, it needed at least 20min treatment or longer. These results indicate that the chlorination of benzoate increased the recalcitrance of the pollutant aromatics and changed the conditions to lower concentrations and longer treatment times for the production of stress-shock proteins. of stress-shock proteins produced by the aromatics at sublethal concentrations functioned interactively between the aromatics for survival tolerance to lethal concentrations.

• Journal of Microbiology and Biotechnology
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• v.12 no.4
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• pp.544-552
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• 2002

Several microorganisms from rat and human feces and lumen fluid of cows were screened for their ability to decolorize the synthetic dyes. Consequently, a novel dye-degrading strain AB&J was isolated. Taxonomic identification including 165 rDNA sequencing and phylogenetic analysis indicated that the isolate had 99.9% homology in its 165 rDNA base sequence with Clostridium perfringens. After 27 h Incubation with the strain, brilliant blue R, bromophenol blue, crystal violet, malachite green, methyl green, and methyl orange were decolorized by about 69.3%, 97.7%, 96.3%, 97.9%, 75.1%, and 97.2%, respectively. The triphenlmethane dye, bromophenol blue, was decolorized extensively by growing Clostridium perfringens AB&J cells in liquid cultures under anaerobic condition, although their growth was strongly inhibited in the initial stage of incubation. This group of dyes is toxic, depending on the concentration used. The dye was significantly decolorized at a relatively lower concentration of below 50 $\mu g \;ml^{-1}$, however, the growth of the cells was mostly suppressed at a dye concentration of 100 $\mu g \;ml^{-1}$. The decolorization activity in cell-free extracts was much higher in cytoplasm than in periplasm and cytoplasmic membrane. Therefore, the enzyme related uptake of bromophenol blue seemed to be localized in cytoplasm. The optimal pH and temperature of bromophenol blue uptake fur decolorization activities were 7.0 and 4$0^{\circ}C$, respectively.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.1
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• pp.1-6
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• 1990

The degradation of non-volatile-amines by microorganisms were investigated. The degra-ding activity could be noted in four strains isolated from fermented sardine sauce, and those were Pseudomonas aeruginosa, Pseudomonas fluorescens P-2, Pseudomonas fluorescens P-3 and Enterobacter aerogenes. The strongest degrading activity of non-volatile-amines was showed in Pseudomonas fluorescens P-3 among the four strains isolated. The optimum temperature for degradation by Pseudomonas fluorescens P-3 was $35^{\circ}C$, corresponding to the optimum temperature for growth of this strain, pH between 7.0 and 7.5 could gave effective degradation and the optimum concentration of NaCl was 0 and/or $1\%$.

• Journal of Environmental Science International
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• v.8 no.4
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• pp.451-456
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• 1999

Microorganisms utilizing petroleum as substrate were screened from the seawater in Pusan coastal area. Among them, fifty strains utilized bunker-A oil as a sole carbon and energy source. Five of these fifty strains were selected to experiment this study. According to the taxonomic characteristics of its morphological, cultural and biochemical properties, the selected stains were named Pseudomonas sp. EL-12, Flavobacterium sp. EL-15, Acinetobacter sp. EL-18, Enterobacter sp. EL-27 and Micrococcus sp. EL-43, respectively. The optimal medium compositions and cultural conditions for assimilation of bunker-A oil by the selected strains were 1.5-2% bunker-A oil, 0.1% $NH_4NO_3$, 1-1.5% $MgSO_4$.$7H_2O$, 0.05-0.15% KCl, 0.1-0.15% $CaCl_2$.$2H_2O$, 2.5-3.5% NaCl, initial pH 8-9, temperature 3$0^{\circ}C$ and aeration, respectively. The utilization and degradation characteristics on the various hydrocarbons by the selected stains were showed that bunker oil, n-alkane and branched alkane compounds were highly activity than cyclic alkane and aromatic hydrocarbon compounds.

• Journal of Microbiology and Biotechnology
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• v.12 no.3
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• pp.437-443
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• 2002

A number of soil and wastewater samples were collected from the vicinity of an effluent treatment plant for the chemical industry. Several microorganisms were screened fur their ability to decolorize the triphenylmethane group of dyes. As a result, a novel crystal violet dye-degrading strain LK-24 was isolated. Taxonomic identification including 16S rDNA sequencing and phylogenetic analysis indicated that the isolate had a $99.5\%$ homology in its 16S rDNA base sequence with Stenotrophomonas maltophilia. The triphenylmethane dye, crystal violet, was degraded extensively by growing cells of Stenotrophomonas maltophilia LK-24 in agitated liquid cultures, although their growth was strongly inhibited in the initial stage of incubation. This group of dyes is toxic, depending on the concentration used. The dye was significantly degraded at a relatively lower concentration, below $100{\mu}g\;ml^-1$, yet the growth of the cells was totally suppressed at a dye concentration of $250{\mu}g\;ml^-1$. The degradation products of crystal violet were identified as 4,4'-bis(dimethylamino)-benzophenone and ${\rho}$-dimethylaminophenol by Gas chromatography-Mass spectrometry. The 4,4'-bis(dimethylamino)-benzophenone was easily obtained in a reasonable yield, as it was not metabolized further by S. maltophilia LK-24; however, the ${\rho}$-dimethylaminophenol was not easily identifiable, as it was further metabolized.

• Journal of Microbiology and Biotechnology
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• v.30 no.7
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• pp.1051-1059
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• 2020

Overproduction and accumulation of melanin in the skin will darken the skin and cause skin disorders. So far, components that can inhibit tyrosinase, a melanin synthase of melanocytes, have been developed and used as ingredients of cosmetics or pharmaceutical products. However, most of existing substances can only inhibit the biosynthesis of melanin while melanin that is already synthesized and deposited is not directly decomposed. Thus, their effects in decreasing melanin concentration in the skin are weak. To overcome the limitation of existing therapeutic agents, we started to develop a substance that could directly biodegrade melanin. We screened traditional fermented food microorganisms for their abilities to direct biodegrade melanin. As a result, we found that a kimchi-derived Pediococcus acidilactici PMC48 had a direct melanin-degrading effect. This PMC48 strain is a new strain, different from P. acidilactici strains reported so far. It not only directly degrades melanin, but also has tyrosinase-inhibiting effect. It has a direct melanin-decomposition effect. It exceeds existing melanin synthesis-inhibiting technology. It is expected to be of high value as a raw material for melanin degradation drugs and cosmetics.

• Journal of Microbiology and Biotechnology
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• v.22 no.9
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• pp.1185-1192
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• 2012

This study investigated the hydrocarbonoclastic microbial community present on weathered crude oil and their ability to degrade weathered oil in seawater obtained from the Gulf St. Vincent (SA, Australia). Examination of the native seawater communities capable of utilizing hydrocarbon as the sole carbon source identified a maximum recovery of just $6.6{\times}10^1\;CFU/ml$, with these values dramatically increased in the weathered oil, reaching $4.1{\times}10^4\;CFU/ml$. The weathered oil (dominated by > $C_{30}$ fractions; $750,000{\pm}150,000mg/l$) was subject to an 8 week laboratory-based degradation microcosm study. By day 56, the natural inoculums degraded the soluble hydrocarbons (initial concentrations $3,400{\pm}700mg/l$ and $1,700{\pm}340mg/l$ for the control and seawater, respectively) to below detectable levels, and biodegradation of the residual oil reached 62% ($254,000{\pm}40,000mg/l$) and 66% ($285,000{\pm}45,000mg/l$) in the control and seawater sources, respectively. In addition, the residual oil gas chromatogram profiles changed with the presence of short and intermediate hydrocarbon chains. 16S rDNA DGGE sequence analysis revealed species affiliated with the genera Roseobacter, Alteromonas, Yeosuana aromativorans, and Pseudomonas, renowned oil-degrading organisms previously thought to be associated with the environment where the oil contaminated rather than also being present in the contaminating oil. This study highlights the importance of microbiological techniques for isolation and characterisation, coupled with molecular techniques for identification, in understanding the role and function of native oil communities.