• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1998년도 공동 심포지엄 및 추계학술발표회
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• pp.174-177
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• 1998

The effects of surfactants affecting polycyclic Aromatic Hydrocarbon(PAHs) solubility and biodegradation in soil slurry were investigated. The critical micelle concentration(CMC) values of surfactants used in this study were 12.7mg/L(Brij 30), 13.4mg/L(Tween 80), 13.6mg/t(Triton X-100). The solubility of PAH increased as the Hydrophile-Lipophile Balance(HLB) value of surfactant decrease. At surfactant biodegradation and toxicity experiement using respirometer, Brij 30 did not show any toxic effect and substrate inhibition upon the level of 1.5g/L. Also, biodegradation of Brij 30 gave no reduction on the phenanthrene biodegradation rate. When the desorption rate of phenanthrene between sand and clay is compared, lower percentage of phenanthrene was desorbed at clay because of the larger surface aera and higher organic content of clay. At the biodegradation experiments of phenanthrene in soil slurry phase, more than 90% of initial phenanthrene adsorbed onto both sand and clay were biodegraded by phenanthrene- acclimated cultures.

• Fisheries and Aquatic Sciences
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• 제21권10호
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• pp.33.1-33.11
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• 2018

As a process for commercial application, production of reducing sugar, antioxidant, and DNA protective compounds from shrimp-shell powder was investigated in a fed-batch biodegradation using Bacillus cereus EW5. The fed-batch biodegradation was operated in a 5-L bioreactor for 96 h according to three times pulse-feeding strategy. On the basis of the equal working volume (3 L), the fed-batch biodegradation showed a better production of the target compounds than the batch biodegradation, with higher cell density and shortened biodegradation period. The maximum values of the target compounds were 0.297 mg/mL of reducing sugar, 92.35% DPPH radical scavenging activity, 98.16% ABTS radical scavenging activity, and 1.55 reducing power at $A_{700}$, which were approximately 12.1, 3.4, 5.2, and 8.4% enhanced, respectively, compared with those obtained from the batch biodegradation. The fed-batch culture supernatant also showed the enhanced DNA damage inhibition activity than the batch culture supernatant. As a result, the fed-batch biodegradation accompanied by high cell density could produce more useful compounds, enabling an increase in the reutilization value of shrimp-shell waste.

• 한국의류산업학회지
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• 제5권3호
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• pp.289-294
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• 2003

The purpose of the study was to get the valuable data for developing the new natural fat soaps which have an excellent biodegradation performance. Thus, natural fat soaps mixed with the two types of detergents (AOS and LAS) on the various concentrations were made and the biodegradation of the samples were analysed by Dissolved Oxygen method using active sludge. Also, the results were compared with the commercial synthetic detergents and market soaps. The results from the study were the followings: 1. The plant fat soap and the wasted oil soap with the concentration of 5 mg/l and 15 mg/l had an excellent biodegradation rather than animal fat soap. 2. There was little difference among samples with the concentration of 5 mg/l, but there was much difference among them with the concentration of 15 mg/l. 3. The periods for consuming oxygen of wasted oil soap mixed AOS and LAS was the fastest.

• 한국환경과학회지
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• 제2권2호
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• pp.95-102
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• 1993

In order to find the most fitted biodegradation model, biodegradation models to the initial 4-chlorophenol concentrations were investigated and had been fitted by the linear regression. The degrading bacterium, EL-091S, was selected among phenol-degraders. The strain was identified with Pseudomows sp. from the result of taxonomical studies. The optimal condition for the biodegradation was as fellows: secondary carbon source, concentration of ammonium nitrate, temperature and pH were 200mg/l fructose, 600 mg/l, $30^{\circ}C$ and 7.0 respectively. The highest degradation rate of the 4-chlorophenol was about 58% for 24 hours incubation on the optimal condition. Biodegradation kinetics model of 5 mg/l 4-Chlorophenol, 10 mg/l 4-chlorophenol and 50 mg/l 4-chlorophenol were fitted the zero order kinetics model, respectively. Key Words : 4-chlorophenol, Pseudomonas sp., zero order kinetics model.

• 한국응용과학기술학회지
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• 제9권2호
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• pp.165-174
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• 1992

The standardized activated sludge for the biodegradation test of anion surfactants has been produced from the collected microorganisms in the soil and the wastewaters treatment plant. The activated sludge was kept under control of the pH, dissolved oxygen, microorganisms and inoculated the basal medium flasks with LAS and LAS mixed with heavy metals [Cd(II), Cu(II), Zn(II)]. Based of results, the inhibition effect(%) of heavy metals in LAS biodegradation were 1. All 1% when LAS 30mg/l-Cd(II), Cu(II) and Zn(II) 0.1mg/l, respectively 2. All 1${\sim}$10% when LAS 30mg/l-Cd(II), Cu(II) and Zn(II) 1mg/l, respectively 3. All 10${\sim}$40% when LAS 30mg/l-Cd(II), Cu(II) and Zn(II) 10mg/l, respectively 4. All 30${\sim}$65% when LAS 30mg/l-Cd(II), Cu(II) and Zn(II) 100mg/l, respectively And toxicity order of heavy metals to the microorganisms in LAS biodegradation were Cd>Cu>Zn in low concentration(0.1${\sim}$1mg/l)and Cd>Zn>Cu in high concentration(10${\sim}$100mg/l).

• 한국미생물·생명공학회지
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• 제22권4호
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• pp.415-422
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• 1994

The biodegradation of aromatic compounds by a mixed culture GE1 was investigated in an artificial wastewater containing 250 mg/l of benzene, toluene, and phenol in semicontinuous culture. In the control group (no strains) with an aeration rate of 75 ml/l/min, 37% of phenol and 83% of benzene were volatilized during early 24 hrs and toluene was disappeared from the medium within 12 hrs. The biodegradation of benzene and toluene was effective in SB (strains + biofilm) treatment, while phenol was degraded more quickly in SG (strains + glucose) treatment including glucose as an additional carbon source. aromatic compounds added at a concentration of 250 mg/l were completely removed by SG treatment after 16 hrs or 32 hrs, respectively. The removal rate of COD was high as much as 80 mg/l/h in SG treatment during early period, but COD revealed a stable value of 116~140 mg/l after 12 hrs caused by increased biomass. Therefore, it is concluded that the mixed GE1 could be used for the wastewater treatment including aromatic compounds such as benzene, toluene, and phenol.

• Journal of Microbiology and Biotechnology
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• 제17권7호
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• pp.1147-1151
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• 2007

Biodegradation of endocrine-disrupting bisphenol A was investigated with several white rot fungi (Irpex lacteus, Trametes versicolor, Ganoderma lucidum, Polyporellus brumalis, Pleurotus eryngii, Schizophyllum commune) isolated in Korea and two transformants of T. versicolor (strains MrP 1 and MrP 13). I. lacteus degraded 99.4% of 50 mg/l bisphenol A in 3 h incubation and 100% in 12 h incubation. which was the highest degradation rate among the fungal strains tested. T. versicolor degraded 98.2% of 50 mg/l bisphenol A in 12 h incubation. Unexpectedly, the transformant of the Mn-repressed peroxidase gene of T. versicolor, strain MrP 1, degraded 76.5% of 50 mg/l bisphenol A in 12 h incubation, which was a lower degradation rate than wild-type T. versicolor. The removal of bisphenol A by I. lacteus occurred mainly by biodegradation rather than adsorption. Optimum carbon sources for biodegradation of bisphenol A by I. lacteus were glucose and starch, and optimum nitrogen sources were yeast extract and tryptone in a minimal salts medium; however, bisphenol A degradation was higher in nutrient-rich YMG medium than that in a minimal salts medium. The initial degradation of endocrine disruptors was accompanied by the activities of manganese peroxidase and laccase in the culture of I. lacteus.

• 한국미생물·생명공학회지
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• 제31권2호
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• pp.197-200
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• 2003

In oil-contaminated environments, anaerobic biodegradation of toluene depended on the concentration and distribution of terminal electron acceptor as well as the physicochemical properties such as DO concentration, redox potential and pH. This study showed the anaerobic biodegradation of toluene in two different soils by using nitrate reduction, ferric iron reduction, sulfate reduction and methanogensis. Toluene degradation rates in the soil samples taken from rice filed and tidal mud flat by nitrate reduction were higher than those by other processes. Tho soil samples from the two fields were enriched for 130 days by providing toluene as a sole carbon source and nitrate or sulfate as a terminal electron acceptor. The toluene degradation rates in the enriched denitrifying consortia obtained from the rice field and tidal mud flat soil were 310.7 and 200.6 $\mu$mol$ L^{-1}$ / $d^{-1}$, respectively. The toluene (legradation rates in the enriched sulfate-reducing consortia from the fields ranged fi-om 149.1 to 86.1$\mu$mol $L^{-1}$ / $d^{-1}$ .

• 한국환경보건학회지
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• 제23권3호
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• pp.85-90
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• 1997

The objective of this study was to investigate biodegradation of TPA(terephthalic acid) and EG (ethylene glycol), treatment efficiency of polyester weight loss wastewater and microbial characteristics by aerated submerged biolfilm(ASB) p.rocess. In a batch reactor, pH increased from 7.0 to 8. 5 in the biodegradation of TPA. Whereas, in case of EG, decreased from 7.0 to 5.2. COD concentration rapidly decreased within 24hr in the biodegradation of TPA and EG. COD removal velocity constant(k) were 0.065-0.088 hr$^{-1}$. The biodegradation velocity of TPA was 1.4 times faster than that of EG. The ratio of suspended biomass to the total biomass in the reactor was 18.3-33.3%, increased as a high ratio of EG content. Biofilm thickness, biofilm dry density and attached biomass were 346-432 $\mu$m, 41.8-61.9 mg/cm$^3$, 1.45-2.67 mg/cm$^2$, respectively. There values increased as a high ratio of TPA content. In the hydraulic retention time of 36 hr, organic loading rate of 4 kgCOD/m$^3\cdot$ day and packing ratio of 70%, the effluent concentrations of TCOD, SCOD in a continuous flow reator were 1,388 mg/l, 147 mg/l and removal efficiencies were 77%, 97.6%, respectively.

• Environmental Engineering Research
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• 제24권2호
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• pp.309-317
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• 2019

This study evaluated the kinetics of acrylamide (AM) biodegradation by mixed culture bacteria and Enterobacter aerogenes (E. aerogenes) in sequencing batch reactor (SBR) systems with AQUASIM and linear regression. The zero-order, first-order, and Monod kinetic models were used to evaluate the kinetic parameters of both autotrophic and heterotrophic nitrifications and both AM and chemical oxygen demand (COD) removals at different AM concentrations of 100, 200, 300, and 400 mg AM/L. The results revealed that both autotrophic and heterotrophic nitrifications and both AM and COD removals followed the Monod kinetics. High AM loadings resulted in the transformation of Monod kinetics to the first-order reaction for AM and COD removals as the results of the compositions of mixed substrates and the inhibition of the free ammonia nitrogen (FAN). The kinetic parameters indicated that E. aerogenes degraded AM and COD at higher rates than mixed culture bacteria. The FAN from the AM biodegradation increased both heterotrophic and autotrophic nitrification rates at the AM concentrations of 100-300 mg AM/L. At higher AM concentrations, the FAN accumulated in the SBR system inhibited the autotrophic nitrification of mixed culture bacteria. The accumulation of intracellular polyphosphate caused the heterotrophic nitrification of E. aerogenes to follow the first-order approximation.