• Journal of the Korean Chemical Society
• /
• v.61 no.5
• /
• pp.244-250
• /
• 2017

Reduction of (${\pm}$)-3-ketoproline ethyl ester (1) by $NaBH_4$ in the presence of $CaCl_2$ and $MgCl_2$ as the chelating agents gave selective products cis-3(R/S)-alcohols, while reduction by $NaBH_4$ alone or chelated with $NiCl_2$ and $AlBr_3$ gave mixtures of cis- and trans-alcohols. The reduction of (${\pm}$)-1 by various vegetables however, gave exclusively the cis-alcohol as the major and trans-alcohol as the minor. On the contrary, reduction of (${\pm}$)-1 by carrot afforded a mixture of cis- and trans-alcohols, in which the trans-alcohol exists as the major product. In addition, we found that this biocatalyst selectively converted S-enantiomer of (${\pm}$)-1 to the cis-alcohol, and R-enantiomer to a mixture of cis- and trans-alcohols with cis-alcohol as the major product. This fact prompted us to use various fresh plant tissues for stereoselective reduction of diverse types of pyrrolidinones, as its stereoselectivity towards racemic mixtures is higher compared to that using chemical reducing agents.

• Food Science of Animal Resources
• /
• v.37 no.6
• /
• pp.813-822
• /
• 2017

The aim of this study was to prepare diacylglycerol (DAG) by enzymatic glycerolysis of lard. The effects of reaction parameters such as lipase type, reaction temperature, enzyme amount, substrate molar ratio (lard/glycerol), reaction time, and magnetic stirring speed were investigated. Lipozyme RMIM was found to be a more active biocatalyst than Novozym 435, and the optimal reaction conditions were 14:100 (W/W) of enzyme to lard substrate ratio, 1:1 of lard to glycerol molar ratio, and 500 rpm magnetic stirring speed. The reaction mixture was first incubated at $65^{\circ}C$ for 2 h and then transferred to $45^{\circ}C$ for 8 h. At the optimum reaction conditions, the conversion rate of triacylglycerol (TAG) and the content of DAG in the reaction mixture reached 76.26% and 61.76%, respectively, and the DAG content in purified glycerolized lard was 82.03% by molecular distillation. The distribution of fatty acids and Fourier transform infrared spectra in glycerolized lard samples were similar to those in lard samples. The results revealed that enzymatic glycerolysis and molecular distillation can be used to prepare more highly purified DAG from lard.

• Transactions of the Korean hydrogen and new energy society
• /
• v.27 no.4
• /
• pp.378-385
• /
• 2016

In this study, we synthesized a biocatalyst consisting of glucose oxidase (GOx), polyethyleneimine (PEI) and carbon nanotube (CNT) with addition of glutaraldehyde (GA)(GA/[GOx/PEI/CNT])for fabrication of glucose sensor. Main bonding of the GA/[GOx/PEI/CNT] catalyst was formed by crosslinking of functional end groups between GOx/PEI and GA. Catalytic activity of GA/[GOx/PEI/CNT] was quantified by UV-Vis and electrochemical measurements. As a result of that, high immobilization ratio of 199% than other catalyst (with only physical adsorption) and large sensitivity value of $13.4{\mu}A/cm^2/mM$ was gained. With estimation of the biosensor stability, it was found that the GA/[GOx/PEI/CNT] kept about 88% of its initial activity even after three weeks. It shows GA minimized the loss of GOx and improved sensing ability and stability compared with that using other biocatalysts.

• Preventive Nutrition and Food Science
• /
• v.11 no.4
• /
• pp.318-322
• /
• 2006

The objective of this experiment was to investigate the effect of extrusion of ginseng roots in twin screw extruder on susceptibility of ginseng starch toward hydrolysis by ${\alpha}-amylase$ BAN 480L (Novozyme, Denmark) and cellulase Celluclast 150L and saccharification by amyloglucosidase AMG-E (Novozyme, Denmark). The extrusion was conducted at 22% and 30% moisture contents of feed at screw speed 300 rpm. Barrel temperature at zone 1 was adjusted at $100^{\circ}C$ and $120^{\circ}C$. The results showed that extrusion process improved the ginseng ${\alpha}-amylase$ susceptibility as compared to traditionally dried ginseng (white and red ginseng). Reducing sugar of hydrolyzed extruded samples was 2,500% of its initial concentration, whereas the reducing sugar of hydrolyzed non-extruded sample was only 200% of its initial concentration. However, addition of cellulase during liquefaction lowered the saccharification yield of both non-extruded and extruded samples as well.

• KSBB Journal
• /
• v.29 no.4
• /
• pp.225-231
• /
• 2014

A microbial fuel cell (MFC) and bioelectrochemical systems are novel bioprocesses which employ exoelectrogenic biofilm on electrode as a biocatalyst for electricity generation and various useful chemical production. Previous reports show that electrogenic biofilms of MFCs are time varying systems and dynamically interactive with the electrically conductive media (carbon paper as terminal electron acceptor). It has been reported that maximum power point tracking (MPPT) method can automatically control load by algorithm so that increase power generation and columbic efficiency. In this study, we developed logic based control strategy for external load resistance by using $LabVIEW^{TM}$ which increases the power production with using flat-plate MFCs and MPPT circuit board. The flat-plate MFCs inoculated with anaerobic digester sludge were stabilized with fixed external resistance from $1000{\Omega}$ to $100{\Omega}$. Automatic load control with MPPT started load from $52{\Omega}$ during 120 hours of operation. MPPT control strategy increased approximately 2.7 times of power production and power density (1.95 mW and $13.02mW/m^3$) compared to the initial values before application of MPPT (0.72 mW and $4.79mW/m^3$).

• Journal of Soil and Groundwater Environment
• /
• v.20 no.3
• /
• pp.83-91
• /
• 2015

Mine soil contamination by high levels of metal ions that prevents the successful vegetation poses a serious problem. In the study presented here, we used the microbial biocatalyst of urease producing bacterium Sporosarcina pasteurii or plant extract based BioNeutro-GEM (BNG) agent. The ability of the biocatalysts to bioremediate contaminated soil from abandoned mine was examined by solid-state composting vegetation under field conditions. Treatment of mine soil with the 2 biocatalysts for 5 months resulted in pH increase and electric conductivity reduction compared to untreated control. Further analyses revealed that the microbial catalysts also promoted the root and shoot growth to the untreated control during the vegetation treatments. After the Sporosarcina pasteurii or plant extract based BNG treatment, the microbial community change was monitored by culture-independent pyrosequencing. These results demonstrate that the microbial biocatalysts could potentially be used in the soil bioremediation from mine-impacted area.

• Journal of Life Science
• /
• v.15 no.3 s.70
• /
• pp.332-336
• /
• 2005

Epoxide hydrolase activities of various microbial cells were analyzed by colorimetric assay based on alkylation of epoxides with 4-(p-nitrobenzyl)pyridine (NBP). The epoxide hydrolase activity was determined by measuring the decrease of color intensity at 560 nm due to the decrease of styrene oxide substrate by epoxide hydrolase-catalyzed hydrolysis reaction. The experimental conditions of NBP colorimetric assay were optimized for the efficient measurement of epoxide hydrolase activities from various microbial cells.

• Korean Journal of Environmental Agriculture
• /
• v.30 no.2
• /
• pp.202-208
• /
• 2011

BACKGROUD: ${\alpha}$- and ${\beta}$- Endosulfan isomers of endosulfan, an endocrine disrupting chemical, are widely used cyclodiene organochlorine pesticide in worldwide, and it has widespread application in agriculture and can contaminate river-system as runoff from soil or aerial deposition METHOD AND RESULTS: In this study, an attempt was made to isolate an endosulfan degrading fungus from endosulfan-polluted agricultural soil. Through repetitive enrichment and successive subculture in media containing endosulfan and its metabolites as the sole carbon source, a fungus designated KEF-1 was isolated. Based on phylogenetic analysis, strain KEF-1 was assigned to the genus Eutypella. Also, the ITS (internal transcribed spacer) sequences of KEF-1 were submitted to GenBank under accession number EF581006. In potato dextrose broth containing 8 ${\mu}g$/mL endosulfan, strain KEF-1 completely degraded the endosulfanin 12 days. CONCLUSION: These results suggested that Eutypella sp. KEF-1 has potential as a biocatalyst for endosulfan bioremediation

• Food Science and Biotechnology
• /
• v.18 no.1
• /
• pp.79-83
• /
• 2009

Acidolysis of olive oil with omega-3 (n-3) polyunsaturated fatty acids (PUFAs) was carried out to produce a structured lipid. Novozym $435^{(R)}$ from Candida antarctica was used as the biocatalyst. Response surface methodology (RSM) was used to determine optimum conditions for lipase-catalyzed enrichment of olive oil. Three factors, 5 levels, central composite design was used. The effects of incubation time, temperature, and substrate mole ratio on incorporation ratio (n-3 fatty acids/total fatty acids, %) were investigated. From the evaluation of response surface graphs, the optimal conditions for incorporation of long chain n-3 PUFAs into olive oil were $40-60^{\circ}C$ for temperature, 30-45 hr for reaction time, and 3:1-5:1 (n-3 fatty acids/olive oil) for substrate mole ratio. Experiments conducted under optimized conditions predicted by the model equation obtained from RSM yielded structured lipids with 50.8% n-3 PUFAs. This value agreed well with that predicted by the model. Oxidative stability tests showed that the product was more susceptible to oxidation than unmodified olive oil. Antioxidant addition improved the oxidative stability of the product.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.2
• /
• pp.281-285
• /
• 2006

Microbial fuel cells (MFC) stacked with bipolar plates have been constructed and their performance was tested. In this design, single fuel cell unit was connected in series by bipolar plates where an anode and a cathode were made in one graphite block. Two types of bipolar plate stacked MFCs were constructed. Both utilized the same glucose oxidation reaction catalyzed by Gram negative bacteria, Proteus vulgaris as a biocatalyst in an anodic compartment, but two different cathodic reactions were employed: One with ferricyanide reduction and the other with oxygen reduction reactions. In both cases, the total voltage was the mathematical sum of individual fuel cells and no degradation in performance was found. Electricity from these MFCs was stored in a supercapacitor to drive external loads such as a motor and electric bulb.