• Journal of the Korean Wood Science and Technology
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• v.26 no.3
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• pp.53-62
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• 1998

In this research, 7 species of white rot fungi were used for determining the resistance against pentachlorophenol (PCP). Three fungi with good PCP resistance were selected for evaluating the biodegradability, and biodegradation mechanism by HPLC and GC/MS spectrometry. Among 7 fungi, there were significant differences on PCP resistance on 4 different PCP concentrations. In the concentrations of 50 and 100ppm ($\mu$g of PCP per g of 2% malt extract agar), most fungi were easily able to grow, and well suited to newly PCP-added condition, but in that of more than 250ppm, the mycelia growths of Ganoderma lucidum 20435, G. lucidum 20432, Pleurotus ostreatus, and Daldinia concentrica were significantly inhibited or even stopped by the addition of PCP to the culture. However, Trametes versicolor, Phanerochaete chrysosporium, and Inonotus cuticularis still kept growing at 250ppm, indicating the potential utilization of wood rot fungi to high concentrated PCP biodegradation. Particularly, P. chrysosporium even showed very rapid growth rate at more than 500ppm of PCP concentration. Three selected fungi based on the above results showed an excellent biodegradability against PCP. P. chrysosporium degraded PCP up to 84% on the first day of incubation, and during 7 days, most of added PCP were degraded. T. versicolor also showed more than 90% of biodegradability at 7th day, and even though the initial stage of degradation was very slow, I. cuticularis has been approached to 90% at 21 st day after incubation with dense growing pattern of mycelia. Therefore, the PCP biodegradability was definitely dependent on the rapid suitability of fungi to newly PCP-added condition. In addition, the PCP biodegradation by filtrates of P. chrysosporium, T. versicolor, and I. cuticularis was very minimal or limited, suggesting that the extracellular enzyme system may be not so significantly related to the PCP biodegradation. Among the biodegradation metabolites of PCP, the most abundant one was pentachloroanisole which resulted in a little weaker toxicity than PCP, and others were tetrachlorophenol, tetrachloro-hydroquinone, benzoic acid, and salicylic acid, suggesting that PCP may be biodegraded by several sequential reactions such as methylation, radical-induced oxidation, dechlorination, and hydroxylation.

• Macromolecular Research
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• v.16 no.5
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• pp.473-480
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• 2008

In this study we investigated bacterial and cell adhesion to poly(propylene carbonate) (PPC) films, that had been synthesized by the copolymerization of carbon dioxide (a global warming chemical) with propylene oxide. We also assessed the biocompatibility and biodegradability of the films in vivo, and their oxidative degradation in vitro. The bacteria adhered to the smooth, hydrophobic PPC surface after 4 h incubation. Pseudomonas aeruginosa and Enterococcus faecalis had the highest levels of adhesion, Escherichia coli and Staphylococcus aureus had the lowest levels, and Staphylococcus epidermidis was intermediate. In contrast, there was no adhesion of human cells (cell line HEp-2) to the PPC films, due to the hydrophobicity and dimensional instability of the surface. On the other hand, the PPC films exhibited good biocompatibility in the mouse subcutaneous environment. Moreover, contrary to expectation the PPC films degraded in the mouse subcutaneous environment. This is the first experimental confirmation that PPC can undergo surface erosion biodegradation in vivo. The observed biodegradability of PPC may have resulted from enzymatic hydrolysis and oxidative degradation processes. In contrast, the PPC films showed resistance to oxidative degradation in vitro. Overall, PPC revealed high affinity to bioorganisms and also good bio-degradability.

• Food Engineering Progress
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• v.15 no.3
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• pp.257-261
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• 2011

Biodegradable plastics were developed using biodegradable pellets made of corn stalk and rice husk and their safety as food packages and their biodegradability against light (ultraviolet (UV)), heat, and fungi were evaluated. Four kinds of 50-${\mu}m$ biodegradable plastics were produced by extruding the mixtures of the biodegradable pellets, low-density polyethylene (LDPE), high-density polyethylene (HDPE), and linear low-density polyethylene (LLDPE) with different compositions. Developed biodegradable plastics were safe to be used as food packages. The initial tensile strength and percentage elongation of the plastics were similar to those of LDPE, but the values decreased with increased their exposure time to UV and heat. The fungal biodegradability of the biodegradable plastics was higher than that of LDPE. The biodegradability of the biodegradable plastics shows the potential for them to be used as sustainable food packages.

• Composites Research
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• v.22 no.3
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• pp.18-28
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• 2009

Blends of poly(lactic acid) (PLA) and poly(butylene terephthalate) (PBT) were prepared by reaction extrusion with para-phenylene diisocyanate (PPDI). The crystallization behavior and biodegradability were investigated by using a differential scanning calorimeter (DSC), a wide angle X-ray diffractometer (WAXD), a contact angle goniometer, and a buffer solution containing esterase. The addition of PBT into PLA polymer matrix induced the cold crystallization of PLA phase, and the crystallization rate of PLA phase was significantly accelerated when both PBT and PPDI participated in the reaction with PLA simultaneously. But the chain extension caused by PPDI decreased the crystallinity and hydrophilicity of PLA and PBT phases. The crystallinity and hydrophilicity did not affect the biodegradability of PLA/PBT blends. However, phase separation between PLA and PBT in PLA/PBT blends increased the interfacial area exposed to the hydrolysis of enzyme, resulting in the improved degradability rate of PLA phase. In contrast, the improved interfacial adhesion between PLA and PBT matrices by the reaction with PPDI reduced the area exposed to the enzyme to decrease the degradation rate of PLA phase.

• Textile Coloration and Finishing
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• v.20 no.2
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• pp.29-37
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• 2008

Polar amino groups of the waste SS(silk-sericin) were modified by two isocyanate compounds of MOI[2-(methacryloyloxy)ethyl isocyanate] and AOI [2-(acryloyloxy)ethyl isocyanate]. When the MOISS (MOI-modified silk sericin) or AOISS(AOI-modified silk sericin) was pressed hot, vinyl groups in the MOI or AOI were polymerized and then the flexible and transparent films were obtained. Tensile moduli and strengths of the MOISS films were significantly improved as the MOI contents increased. By the addition of the isocyanate compounds, silk sericin films exhibited lower solubility to the distilled water($80^{\circ}C$) and also lower swell ratio to the distilled water(room temperature). In the effect of tensile properties and restraining the water swelling, MOI was better than AOI. BOD(biochemical oxygen demand)/TOD(theoretical oxygen demand) of the pure sericin film was almost 100% perfect level after 10 days immersion into the activated sludge. With increasing isocyanate content reacted with polar amino groups, BOD/TOD decreased. When more than 50 mol% of polar amino groups remained unreacted, sericin films could retain more biodegradability. Comparing with MOI from the viewpoint of biodegradability, AOI was more effective.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.3
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• pp.315-322
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• 2007

The purpose of this study was to investigate the biodegradability and performance of organic removal and methane production rate when treating piggery wastewater using a granule of two-phase anaerobic process applied UASB. BMP test was conducted as simple means to monitor relative biodegradability of substrate and to determine methane production of an organic material. The two-phase anaerobic process is consisted of a continuous flow stirred-tank reactor (CFSTR) for the acidification phase and an Upflow Anaerobic Sludge Blanket reactor (UASB) for the methanogenesis. The acidogenic reactor played key roles in reducing the periodically applied shock-loading and in the acidification of the influent organics. A stable maximum biogas production rate was 400mL. The methane contents ranged from 73 to 80% during the experimental period. It is known that most of the removed organic matter was converted to methane gas, and the produced biogas might be high quality for its subsequent use.

• 수도
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• v.24 no.4 s.85
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• pp.79-87
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• 1997

In an effort to prevent the formation of DBPs from disinfection and the microbial regrowth in distribution systems, the ozonation followed by biological filtration process in drinking water treatment train has been recently developed as an alternative process to reduce effectively water-born organic matter as precursor. There are, however, insufficient for the consistent information and data about the relation between ozone dosage based on organic surrogate parameter, TOC or DOC and effect of ozonation on BDOC formation. This study is to review critically for the effect of ozonation on biodegradability on the basis of published technical papers including the output from author's research laboratory. It truned out that : 1. ozonation in the presence of organic matter has a tendancy to increase in BDOC content, 2. the rate of BDOC formation was maximum below 1mg $O_3/mg$ DOC of ozone dose, but about maximum content of BDOC was obtainable at the range from 1.5mg $O_3/mg$ DOC to 2mg $O_3/mg$ DOC, 3. from above 1mg $O_3/mg$ DOC, the rate of BDOC formation became slow down, 4. from above 2mg $O_3/mg$ DOC, BDOC formation was quantitatively negligible, In conclusion, it needs further systematic study and research concerned to biodegradability and treatability by ozonation in terms of organic characteristics and experimental conditions because it was hard to find out the consistent experimental data comparable each other that were performed by numbers of research authors.

• Korean Journal of Environmental Biology
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• v.17 no.3
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• pp.249-255
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• 1999

The effect of surface roughness on biodegradability of poly (3-hydroxybutyrate) was investigated. The PHB film prepared by cooling the molten polymer slowly ($-0.5^{\circ}C$/min) had higher crystallinity and melting temperature than that prepared by quenching into liquid nitrogen followed by annealing at $90^{\circ}C$ for 2 hours. However, the former sample was found to degrade faster than the latter due to presence of microscopic crack. Roughening the surface of a PHB film by hot pressing under a coarse surfaced plate accelerated the bioerosion considerably of the sample in comparison with the sample having the same thermal history but smooth surface.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.591-594
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• 1998

Biodegradable microsphere containing bovine serum albumine (BSA) as a model drug were prepared with the microgel based on poly(caprolactone diol) by a modified solvent evaporation method. The influence of the stirring speed, the concentration of microgel and the mixing rate but increased with increasing the concentration of microgel in methylene chloride. The biodegradability of microsphere in 100 unit/mL of lipase solution was investigated. A lot of small pores appeared on the surface of microsphere after 3 hours of incubation time and the pores and cracks were developed with increasing the incubation time and microsphere lost their own shape after 36 hours of incubation time.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.680-684
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• 2011

Seed oil of Balanites aegyptica was transesterified to produce biodiesel and its quality and biodegradability assessed. The specific gravity (SG), density and flash point of the methyl esters were found to be 0.897, 0.89 g/$cm^3$ and $163^{\circ}C$ respectively. Biodegradability of the biodiesel assessed by the standard $CO_2$ evolution method using two different inoculums revealed that the Balanites aegyptica biodiesel was readily biodegradable in both inoculums (82.58% and 86.98%), compared with the $D_2$ diesel which was partially biodegradable (27.02% and 27.33%). These suggest that Balanites aegyptiaca seed oil is a potential source of environmentally friendly biodiesel.