• Journal of Biomedical Engineering Research
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• v.16 no.1
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• pp.9-16
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• 1995

Biodegradable poly (I ,4-butanediol succinate) (PBS) was synthesized from 1,4-butanediol and succinic anhydride. The glass transition temperature of poly (I, 4-butanediol succinate) was revealed at $73^{\circ}C$. The crystallization and cold crystallization of the polymers were investigated as a function of holding time in melt state, cooling rate. reheating, and molecular weight. Chain scission and/or cmsslinking did not occur in the melt state at var.ious holding times. Slower scanning rate can allow more times for nucleation, rearrangement, and packing of the polymer chain, so the onset temperature of crystallization from the melt was increased. PBS crystallized from the melt was found to have spherulitic structure. The degradation behavior of PBS was studied under basic conditions and with microorganisms using the modified ASTM method. In the basic solution. PBS lost up to 85% of its mass within two days. Based upon visual observation, the crystalline structure of films composed of larger molecular weight polymers retained their crystallinity longer than similar structures in low molecular weight samples.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.1028-1033
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• 2009

In this study, the dynamics of living cells (LC) and dead cells (DC) in a laboratory-scale biofilm membrane bioreactor for waste gas treatment was examined. Toluene was used as a model pollutant. The bacterial cells were enumerated as fluoromicroscopic counts during a 140 operating day period using BacLight nucleic acid staining in combination with epifluorescence and confocal laser scanning microscopy (CSLM). Overall, five different phases could be distinguished during the biofilm development: (A) cell attachment, (B) pollutant limitation, (C) biofilm establishment and colonization, (D) colonized biofilm, and (E) biofilm erosion. The bioreactor was operated under different conditions by applying different pollutant concentrations. An optimum toluene removal of 89% was observed at a loading rate of 14.4 kg $m^{-3}d^{-1}$. A direct correlation between the biodegradation rate of the reactor and the dynamics of biofilm development could be demonstrated. This study shows the first description of biofilm development during gaseous toluene degradation in MBR.

• Environmental Engineering Research
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• v.13 no.1
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• pp.8-13
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• 2008

The extent of solubility enhancement by biosurfactant was examined at various pHs prior to the biodegradation experiments. The molar solubilization ratio (MSR) was calculated from the batch solubilization experiments and the highest MSR was detected at pH 5. The effect of the biosurfactant, rhamnolipids, on the phenanthrene mineralization in soil-water system was investigated. The strain 3Y was selected for the mineralization assay and large amounts of phenanthrene were degraded at neutral pH in soil-water system without the biosurfactant. The addition of 150 mg/L rhamnolipids showed no effect on mineralization of phenanthrene in soil-water system, and total mineralization rates after 6 weeks incubation at each pH showed no differences in presence and absence of rhamnolipids. Our result indicated that the toxic effect of rhamnolipids can disappear when soil particles exist, and also the enhanced solubility of phenanthrene does not work for mineralization enhancement in this soil-water system.

• Journal of the Korean Applied Science and Technology
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• v.15 no.4
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• pp.27-34
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• 1998

The natural body foam product which palm oil is added to this product, differs from products for clothes and Kitchen detergent, industrial and domestic detergent, and It has a various characteristics as a soft detergent for bath and hair product. Up to now, vidal sassoon product which imports form overseas and sells in our country, increases every year in consumption quantity. The development of this product tested to consider the quality of product in the effect of import transfer. First of all, the experiment of this product tested the fundamental items of pH, foam formation force, the moisture effect of product, the biodegradation degree of product. In case of palm oil, when it was added to this product in 0.25wt%, we could get experiment results that pH appeared in 6.2, foam formation force in product 1wt% solution appeared in 104ml per 30sec, the skin moisture effect of product appeared in incleasing from 82 a.u to 90 a.u within one hour since we have used the product, the biodegradation degree of surfactant appeared in 96.7%. According to the experiment result of product, we could know the fact that it has a high quality in comparison with other products.

• Journal of Korean Society of Water and Wastewater
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• v.11 no.2
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• pp.76-93
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• 1997

Activated carbon is widely used for the treatment of water, wastewater and other liquid wastes. Biological activated carbon (BAC) process is water and wastewater treatment process developed in the 1970's. In addition to activated carbon adsorption, biodegradation organic pollutants occurs in the BAC bed where a large amount of aerobic biomass grows. This results in a long operation time of the carbon before having to be regenerated and thus a low treatment cost. Although the BAC process has been widely used, its mechanisms have not been well understood, especially the relationship between biodegradation and carbon adsorption, whether these two reactions can promote each other or whether they just simultaneously exist in the BAC bed. Also, the phenomenon of bioregeneration has been confused that previously occupied adsorption sites appear to be made available through the actions of microorganisms. And that, because biological process is influenced by low temperature, the mechanism of the BAC process is also effected by temperature variation in our country of winter temperature near the freezing point. Therefore, the objective of this study examines closely the mechanism of the BAC process by temperature variation using phenol as substrate. From this study, biological activated carbon is good substrate removal better than non adsorbing materials (charcoal, sand) as temperature variation, especially low temperature(near $5^{\circ}C$).

• Journal of Microbiology
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• v.35 no.2
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• pp.117-122
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• 1997

Several dominant 4-CPA-degrading bacteria were isoalted from agricultural soils. Most of the isolates were identified as Burkholderia species by fatty acid methyl ester (FAME) analysis, but they were idstinct in chromosomal patterns obtained by PCR amplification of repetitive extragenic palindromic (REP) sequences. These strains were generally restricted in their substrate utilization capabilities. The 4-CPA degradative enzymes were idnducible by 4-CPA and some isolates appeared to mineralize 4-CPA via formation of 4-chlorophenol and 4-chlorocatechol as intermediates during its biodegradation pathway. Plasmid DNAs were not detected from most of the isoaltes and their 4-CPA genes wer on the chromosomal DAN. The 4-CPA degradation patterns in axenic cultures and natural soils varied depending on the strains and soils. The inoculation of 4-CPA degraders much improved the removal of 4-CPA from the 4-CPA treated soils.

• YAKHAK HOEJI
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• v.21 no.4
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• pp.193-199
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• 1977

ABS, Alkyl benzene sulfonate, persists for long periods in stream because of its resistance to biologic degradation. Its bio-degradation is very varied in the environments. This investigation was therefore undertaken in order to know the biodegradation of synthetic detergents which are comprising soft and hard forms from February 1976 to September 1976. The biodegradations by spontaneuos settling and aeration were determined. The reduction rates of ABS, DBS, and LAS were 9.8%, 13.7% and 10.4% by the settlings for 5 days at $25^{\circ}$ and 63.3%, 27.2%, and 43.9% by aeration respectively. It was not contributed effectively to biodegradate the synthetic detergents by the simulaneous incubation with micro-organisms isolated from sewage such as Enterobacter sp., E. coli, Bacillus sp., Flavobacterium sp., Pseudomonas sp., Staphylococcus sp., and etc. Tricking filter could also eliminate some amount of detergent. By the application of this investigation, it could be designed that detergents would be regulated in abuse in context with water pollution and be treated at a proper process in the sewage treatment plant to be installed.

• Korean Journal of Environmental Biology
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• v.26 no.3
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• pp.247-251
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• 2008

Degradation behavior in the seawater of Tongyeong, Incheon, Kunsan and Hongsung was explored for Mater-Bi$^{(R)}$, poly(3-hydroxybutyrate-co-3-hydroxy valerate) (PHBV), poly(butylene succinate-co-butylene adipate) (PBSA) and polycaprolactone (PCL) which can eventually be used for various fishery tools. Acinetobacter lwoffu/junii and Shewanella algae/putrefaciens inhabited all the seawater samples. Eikenella corrodens was also detected in all the seawater samples, although identified with poor confidence by VITEK system. Mater-Bi$^{(R)}$ was degraded faster than PHBV, PBSA and PCL in the seawater in contradiction to the degradation behavior in soil environment. The seawater retrieved from Incheon exhibited the most elevated activity for the plastic degradation, which may be partly ascribed to the largest number of total viable counts.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.152-157
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• 2003

Diesel-contaminated soils were ozonated for different times (0 - 900 min) and incubated for 9 wk to monitor petroleum hydrocarbons (PH)-degradative potential of indigenous microorganisms in the soils. Increased ozonation time decreased not only concentration of PH but also number of microorganisms in the soils. Microorganisms in the ozonated soils increased during 9-wk incubation as monitored by culture- and nonculture-based methods. Higher (1-2 orders of magnitude) cell number was observed by quantitative analysis of soil DNA using probes detecting genes encoding 165 rRNA(rrn), naphthalene dioxygenase (nahA), toluene dioxygenase (todC), and alkane hydroxylase (alkB) than microbial abundance estimated by culture-based methods. Such PH-degraders were relatively a few or under detection limit in 900-min ozonated soil. Further PH-removal observed during the incubation period supported the presence of PH-degraders in ozonated soils. Highest reduction (25.4%) of total PH (TPH) was observed in 180-min ozonated soil white negligible reduction was shown in 900-min ozonated soil during the period, resulting in lowest TPH-concentration in 180-min ozonated soil among the ozonated soils. Microbial community composition in 9-wk incubated soils revealed slight difference between 900-min ozonated and unozonated soils as analyzed by whole cell hybridization using group-specific rRNA-targeted oligonucleotides. Results of this study suggest that appropriate ozonation and subsequent biodegradation by indigenous microorganisms may be a cost-effective and successful remediation strategy for PH-contaminated soils.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.368-371
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• 2003

Accidental release of petroleum products from underground storage tank(USTs) is one of the most common causes of groundwater contamination. BTEX is the major components of fuel oils, which are hazardous substances regulated by many nations. In addition to BTEX, other gasoline consituents such as MTBE(methyl-t-buthyl ether), anphthalene are also toxic to humans. Natual attenuation processes include physic, chemical, and biological trasformation. Aerobic and anaerobic biodegradation are believed to be the major processes that account for both containment of the petroleum-hydrocarbon plum and reduction of the contaminant concentrations. Aerobic bioremediation has been highly effective in the remediation of many fuel releases. However, Bioremediation of aromatic hydrocarbons in groundwater and sediments is ofen limited by the inability to provide sufficient oxygen to the contaminated zones due to the low water solubility of oxygen. Anaerobic processes refer to a variety of biodegradation mechanisms that use nitrate, ferric iron, sulfate, and carbon dioxide as terminal electron accepters. The objectives of this study was to conduct laboratory-scale microcosm studies in assessing enhanced bioremediation potential of BTEX and MTBE under various electron accepters(aerobic, nitrate, ferric iron, sulfate) in contaminated Soil. these results suggest that, presents evidence and a variety pattern of the biological removal of aromatic compounds under enhanced nitrate-, Fe(III)-, sulfate-reducing conditions.