• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.27 no.3
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• pp.159-167
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• 2021

The need for biodegradable plastic continues to increase, improvement of physical properties is necessary for actual use in the market. In this study, composite film was produced by adding peroxide additives to bioplastic according to concentration to investigate changes in the melt index, elongation, morphology, and TGA of the composite film. The addition of peroxide compatibilizer showed superior elongation of film and TGA compared to those of control. The added amount of compatibilizer affected the extrusion process, and it was revealed that adding an appropriate amount of peroxidizer is important. Analysis of the composite film's morphology revealed a heterogeneous dispersion sequence due to different rates of crystallization depending on the resin, and surface physical properties were best in the group added with 4% peroxide. The results above showed that the test group added with 4% peroxide compatibilizer was superior in the production of composite biodegradable film.

• Membrane Journal
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• v.18 no.2
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• pp.124-131
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• 2008

The biodegradable hyaluronic acid membranes cross-linked with lactide using the crosslinking agent, 1,3-butadiene diepoxide (BD), were prepared as a potential biocompatible material for tissue engineering. The degree of lactide and BD reaction of the crosslinked membrane was determined by the analysis of nuclear magnetic resonance spectroscopy 6% of growth inhibition was observed in case of high BD concentration but the value is low enough not to affect cell growth. As the crosslinking reaction temperature increased, elongation increased and swelling ratio decreased. The rate of degradation was found to increase with the crosslinking temperature. The drug release experiment showed that the transport of drug through the membrane decreased with the crosslinking temperature.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.395-401
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• 2002

Methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK) have been widely used as solvents in various industries. Biodegradation of MEK and MIBK by Pseudomonas putida KT-3, which could utilize MEK or MIBK as a sole carbon source, was characterized, and the cosubstrate interaction in MEK/MIBK mixture was also studied. Within the range of initial MEK concentration (from 0.5 to 5.5 mM), an increased substrate concentration increased the specific degradation rate of MEK by P putida KT-3 (from 3.15 to 10.58 mmol/g DCW$\cdot$h), but the rate sightly increased at 11.0 mM of initial MEK concentation (11.28 mmol/g DCW$\cdot$h). The similar degradation rates of MIBK (4.69-4.92 mmol/g DCW$\cdot$h) were obtained at more than 3.0 mM of initial MIBK concentation. Kinetic analysis on the degradation of MEK/MIBK mixture by P. putida KT-3 showed that MEK or MIBK acted as a competitive inhibitor. Maximum degradation rate ($V_{max}$), saturation constant ($K_{m}$) and inhibition constant ($K_{1}$) were as follows: $V_{max,MEK}$=12.94 mmol/g DCW$\cdot$h; $K_{m,MEK}$=1.72 mmol/L; $K_{l,MEK}$=1.30 mmol/L; $V_{max,MIBK}$=5.00 mmol/g-DCW$\cdot$h; $K_{m,MIBK}$=0.42 mmol/L; $K_{l,MEK}$=0.77 mmol/L.

• Journal of the Korean Chemical Society
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• v.51 no.2
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• pp.154-159
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• 2007

Biodegradation of Quinoline by free and immobilized Bacillus brevis has been investigated. The rate of quinoline degradation by immobilized Bacillus brevis on coconut shell carbon is faster than the rate by the microorganism immobilized on foam pieces and free cells. A complete removal of 100 ppm of Quinoline in the sample was achieved at a hydraulic retention time of 20 hours with the biocatalyst prepared by immobilizing Bacillus brevis onto coconut shell carbon. The biocatalyst had a reasonable shelf life and desirable recycle capacity.

• Journal of the Korean GEO-environmental Society
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• v.11 no.8
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• pp.65-71
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• 2010

In this study, we have evaluated biodegradability of diesel-oxygenates including DBM and gasoline-oxygenates having similar physio-chemical properties using indigenous aerobic microorganisms from a diesel-contaminated soil. Toluene and Ethanol have shown higher biological activity and the first-order degradation rate constants ranged around $0.11{\sim}0.3day^{-1}$. However, MTBE, gasoline-oxygenate has shown as a limited substrate. Moreover, As increased initial concentrations of DBM and TGME, degradation rates of those were decreased relatively. As a strategy to evaluate biodegradability of DBM and TGME, reduction of diesel-oxygenates, $CO_2$ production and toxicity by algae were monitored. This results indicated possible mineralization of diesel-oxygenates, But we could predict that residual byproduct produced even though complete consumption of diesel-oxygenates were observed if algal toxicity variation considered. In conclusion, it is the first report that diesel-oxygenates including DBM could be biodegraded effectively by indigenous soil microorganisms and this result increased the possibility of bioremediation technology to apply into oil-contaminated sites.

• Applied Chemistry for Engineering
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• v.35 no.4
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• pp.273-283
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• 2024

As the adverse environmental impacts due to plastic waste become more severe, there is an increasing demand for developing a sustainable ecosystem using biodegradable polymers. Biodegradable polymers are those that can be biochemically decomposed through the enzymatic activity of microorganisms. Currently, a variety of biodegradable polymers with varying properties is being investigated. In particular, polymer blends with an aim to control the biodegradation rate and mechanical properties are under active research. The biodegradable polymer industry, which has not yet reached economies of scale, does not have a cost advantage compared to petroleum-derived polymers. To overcome this challenge, there is an urgent need to expand its application fields to various high-value industries (separators, electronic materials, and medical fields). This review summarizes the current state-of-the-art biodegradable polymers, polymer blends, and recent research trends in new niche applications.

• Polymer(Korea)
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• v.30 no.1
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• pp.28-34
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• 2006

A series of methoxypoly(ethylene glycol) $(MPEG)-poly(\varepsilon-co-L-lactide)$ (PCLA) diblock copolymers were synthesized by ring-opening polymerization of a mixture of $\varepsilon-caprolactone$ and L-lactide with different ratios in the presence of $Sn(Oct)_2$. The characterization of MPEG-PCLA diblock copolymers were examined by $^1H-NMR$, GPC, DSC, and XRD. Kinetic study on ring-opening polymerization of monomer mixtures was carried out in various conditions such as a variation with polymerization time, amount of catalyst, and temperature. The highest conversion obtained in 1.2 ratic of initiator venn catalyst at $110\;^{\circ}C$. The biodegradable characterization of MPEG-PCLA diblock copolymers in aqueous solution was carried out by using GPC for $1\~14$ weeks. The biodegradability of MPEG-PCLA diblock copolymers increased as the L-lactide content of diblock copolymers increased. In conclusion, we confirmed the dependence of polymerization rate according to various conditions. In addition, we can control the biodegradability of MPEC-PCLA diblock copolymers by changing the ratio of PCL and PLA block segment.

• Journal of Environmental Science International
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• v.5 no.1
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• pp.83-91
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• 1996

A recycling soap was prepared from non-cooking oils. The effects of physlcal and chemical properties of the recycling soap on biodegradation are expected to be different due to the thermal histories of the non-cooking oils. Therefore, the biodegradation rate of the recycling soap was studied by using Klebssella Pneumoniae(K. pneumoniae), and the growth rate of K. pnewoniae in soap solution was observed. The biodegradation rate of the recycling soap appeared to be slower as the thermal histories of the non-cooking oils became larger. This might be resulted from hydrolysis, in which the ester bonds in the oils are broken to produce hydroxyl group. It was also observed that the growth rate of the microorganism decreased with the increase in the thermal histories of the oils. As a result, it is desired that recycling soap should be produced from the non-cooking oils with the prober ranges of thermal histories to reduce water contamination. The non-cooking oils with larger thermal histories are considered to be recycling through the cracking process before used. Key Words : non-cooking oils, recycling soap, thermal history, biodegradation, microorganism growth.

• Journal of Soil and Groundwater Environment
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• v.8 no.2
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• pp.44-54
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• 2003

A kinetic model for evaluating effects of surfactant on the biodegradation of HOC(hazardous organic chemicals) in soil-slurry systems was developed. The model includes the partition of HOC and surfactant, the dissolved-, micellar-, and sorbed-phase biodegradation, the enhanced solubilization of HOC by surfactant addition, and the mass transfer of HOC. Phenanthrene as HOC and Trition X-100, Tergitol NP-10, Igepal CA-720, and Brij 30 were used in the model simulations. The biodegradation rate was increased even with a small micellera-phase bioavailability. The biodegradation was not greatly enhanced due to decreased aqueous HOC concentration by increasing surfactant dose in both cases with and without micellar-phase bioavailability. The effect of sorbed-phase biodegradation on total biodegradation rate was not highly important compared to aqueous- and micellar-phase biodegradation. The model can be applied for surfactant screening and optimal design of surfactant-based soil bioremediation process.

• Polymer(Korea)
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• v.34 no.2
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• pp.172-177
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• 2010

Although many researchers have studied the efficacy of paclitaxel (PTX) on many cells during the last two decades, little work has been reported on the importance of release kinetics inhibiting cell proliferation. The aim of this study is to examine the release behavior of the PTX on various biodegradable polymers such as poly(lactic-co-glycolic acid)(PLGA), poly-L-lactide (PLLA), and polycaprolactone (PCL) for drug-eluting stents (DES). The PTX from the fabricated films was released for 8 weeks and the degree of degradation of the films was observed by FE-SEM. Although the degradation time of PCL was the slowest, the PTX release rate was the fastest among them and followed by PLGA and PLLA with the equivalent PTX concentration. It suggests that hydrophobic drug such as PTX from polymer with low $T_g$ like PCL could be moved easily and released rapidly in body temperature.