• Korean Journal of Medicinal Crop Science
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• v.28 no.1
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• pp.21-28
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• 2020

Background: Owing to its high efficiency in lipid and protein production, peanut (Arachis hypogaea L.) is considered one of most important crops world-wide. The kernels of peanuts are undoubtedly the most important product this plant, whereas the skin is almost completely neglected in nutraceutical terms. However, peanut skin contains potentially health-promoting phenolics and dietary fiber, and there is considerable potential for commercial exploitation. In this study, we evaluated the α-glucosidase inhibitory activity of an extract of peanut skin (PS). Methods and Results: The α-glucosidase inhibitory effects of 80% ethanol extracts of peanut (A. hypogaea L. 'Sinpalkwang') skin were evaluated and found to have a half-maximal inhibitory concentration (IC₅₀) value of 1.2 ㎍/㎖. Progress curves for enzyme reactions were recorded spectrophotometrically, and the inhibition kinetics revealed time-dependent inhibition with enzyme isomerization. Furthermore, using ultra-high performance liquid chromatography combined with quadrupole-orbitrap mass spectrometry, we identified 26 compounds in the peanut skin extract, namely, catechin, epicatechin, and 24 proanthocyanidins. Conclusions: The results suggest that peanut skin can be utilized as an effective source of α-glucosidase inhibition in functional foods and nutraceuticals.

• The Korean Journal of Zoology
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• v.23 no.3
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• pp.137-148
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• 1980

The effects of divalent cations, $Hg^{2+}, Cu^{2+}, Pb^{2+}, Cd^{2+}$, and $Mn^{2+}$ on the total ATPase activity of the fragmented sarcoplasmic reticulum isolated from rabbit skeletal muscle were investigated. The inhibitory effects of the cations on the enzyme activity increased as the concentrations of the ions increased with the order of efficiency of $Hg^{2+}$ > $Cu^{2+}$ > $Pb^{2+}$ > $Cd^{2+}$ > $Mn^{2+}$ in the concentration range between 10 and 500$\mu$M. The 50% inhibition for each ion was almost identical with the inhibition constant (Ki) value for each ion. The Ki's were 10, 30 130, and 350$\mu$M for $Hg^{2+}, Cu^{2+}, Pb^{2+}, and Cd^{2+}$, respectively. $Mn^{2+}$ seemed to be an activator at lower concentrations and an inhibitor at higher concentrations. The presence of the cations did not change the Km values, suggesting that the ions act as a reversible noncompetitive inhibitor on the FSR ATPase. The energy of activation of the enzyme was aproximately 19 Kcal/mole. The presence of the ions decreased the value slightly. A possible mechanism for the reversible noncompetitive inhibitory effect of the cations was discussed.

• KSBB Journal
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• v.4 no.3
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• pp.221-228
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• 1989

Celluose is an insoluble substrate, therefore, a proper mixing of the cellulose suspension is essential for an effective enzymatic hydrolysis. To study the effect of mixing motion of various enzyme reactors on enzymatic hydrolysis of cellulose, three distinct types of biroreator: vertical impeller type bioreator(VITB), horizontal paddle type bioreactor(HPTB), and tumbling drum type bioreactor(TDTB), were assembled and their performance was compared. The optimal agitation speed was 100rpm for VITB and HPTB, 200rpm for TDTB. The saccharification efficiency of each reactor was compared under the optimal agitation intensity. The highest degree of saccharification was achieved in the case of VITB, especially, at high cellulose concentration. The VITB seems to be the most suitable type of bioreactor that can maintain proper mixing pattern for effective enzyme reaction. In the view of energy consumption, the TDTB showed the lowest value: however, the energy consumption was rapidly increased at high concentration of celluose. To dertermine the most suitable type of bioreactor, the entire process, including substrate cost, substrate concentration, and feasibility of scale-up, needs to be evaluated.

• KSBB Journal
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• v.4 no.3
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• pp.215-220
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• 1989

To develop an attrition coupled enzyme reactor with high efficiency-low energy consumption for saccharification of insoluble biomass, a 5L horizontal paddle type bioreactor was constructed and its performance was evaluated. The optimal condition for saccharification of 50g $\alpha$ -cellulose/L was found to be 200rpm with 500g of 3mm glass bead. Especially, the horizontal paddle type bloreactor was very effective for saccharification of high concentration of insoluble cellulose, in which around 72% of $\alpha$ -cellulose was saccharified for 75g $\alpha$ -cellulose/L, and even up to 70% for 100g of $\alpha$ -cellulose/L after 24hours. Under the optimal condition, the power consumption was measured to be around 1.7watth/g. Horizontal paddle type bioreactor seems to have an appropriated structural feature for industrial scale operation and to be an effective and energy saving attrition coupled enzyme reactor.

• KSBB Journal
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• v.5 no.3
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• pp.279-291
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• 1990

Partial hydrolysed and deacetylated chitin, CHITA and CHITB as supports of immobilized enzyme were obtained by treatment of acid and base respectively. Glutaraldehyde, bifunctional reagent, was employed for crosslinking between $\beta$-glucosidase and support. Immobilized enzyme activities of CHITA-Gase and CHITB-Gase were determined with the reaction of p-nitrophenol-$\beta$-D-glucopyranoside(PNG) in batch reactor, CSTR and PFR. Their optimum temperature, pH and enzymatic characteristics including Km and Vmax values were observed with variation of the flow rates. Mass transfer coefficient(h), effectiveness factor(η), deactivation rate(kd ) of two immobilized enzymes were also examined to compare efficiency of reactors.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.1
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• pp.117-120
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• 1999

High yields of protoplasts were obtained following enzymatic digestion of the vagetative thalli of marine green alga Monostroma nitidum. The enzyme mixtures containing $4\%$ Cellulase R-10+$3\%$ Macerozyme R-10+$3\%$ Abalone acetone power produced $4.41\times10^6$ protoplasts per 300 mg of fresh tissue. The highest yield of protoplasts was obtained by 270 minutes treatment of the thalli in enzyme solution. Freshly isolated protoplasts were spherical in shape and ranged between $13\~33\mu$m in diameter. The high efficiency of differentiation were obtained by incubating freshly isolated protoplasts in 0.4 M mannitol f/2 medium for 7 days and then transferring to 0.2 M mannitol f/2 medium. Protoplasts began to form new cell walls three days after initial culture and began to germinate after 10 days, and then form a leafy thallus after further culture in f/2 medium. The addition of antibiotics in media inhibited the differentiation of protoplasts in culture.

• Journal of Microbiology and Biotechnology
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• v.20 no.3
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• pp.467-473
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• 2010

To improve the expression efficiency of recombinant endo-$\beta$-1,4-glucanase in P. pastoris, the endo-$\beta$-1,4-glucanase (egI) gene from Aspergillus niger was synthesized using optimized codons. Fourteen pairs of oligonucleotides with 15 bp overlap were designed and the full-length syn-egI gene was generated by two-step PCR-based DNA synthesis. In the synthesized endo-$\beta$-1,4-glucanase gene syn-egI, 193 nucleotides were changed, and the G+C content was decreased from 54% to 44.2%. The syn-egI gene was inserted into pPIC9K and transformed into P. pastoris GS115 by electroporation. The enzyme activity of recombinant P. pastoris stain 2-7# reached 20.3 U/ml with 1% barley $\beta$-glucan and 3.3 U/ml with 1% carboxymethylcellulose (CMC) as substrates in shake flasks versus 1,270.3 U/ml and 220.7 U/ml for the same substrates in 50-1 fermentors. The molecular mass of the recombinant protein was approximately 40 kDa as determined by SDS-PAGE analysis, the optimal temperature for recombinant enzyme activity was $70^{\circ}C$, and the optimal pH was 5.0 when CMC was used as the substrate.

• Journal of Microbiology and Biotechnology
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• v.16 no.2
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• pp.226-231
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• 2006

Several white-rot fungi are able to produce extracellular lignin-degrading enzymes such as manganese peroxidase (MnP), lignin peroxidase (LiP), and laccase. In order to enhance the production of laccase and MnP using Trametes versicolor KCTC 16781 in suspension culture, the effects of major medium ingredients, such as carbon and nitrogen sources, on the production of the enzymes were investigated. The decolorization mechanism in terms of biodegradation and biosorption was also investigated. Among the carbon sources used, glucose showed the highest potential for the production of laccase and MnP. Ammonium tartrate was a good nitrogen source for the enzyme production. No significant difference in the laccase production was observed, when glucose concentration was varied between 5 g/l and 30 g/l. As the concentration of nitrogen source increased, a lower MnP activity was observed. The optimal C/N ratio was 25 for the production of laccase and MnP. When the concentrations of glucose and ammonium tartrate were simultaneously increased, the laccase and MnP activities increased dramatically. The maximum laccase and MnP activities were 33.7 U/ml at 72 h and 475 U/ml at 96 h, respectively, in the optimal condition. In this condition, over 90% decolorization efficiency was observed.

• Food Science of Animal Resources
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• v.33 no.3
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• pp.341-347
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• 2013

This study was conducted to evaluate the effect of early diet dilution with 40% rice hull on growth performance, carcass characteristic and composition of meat-type ducks, and to reveal the possible mechanism for decreased body fat deposition. 160 1-day-old White Peking ducks with initial body weight of $44.5{\pm}1.0$ g were allotted to two treatments with 8 replicate pens per treatment and 10 ducks per pen (5 male and 5 female). Ducks were fed with the experimental starter diets diluted with 0% (control, RH0), 40% rice hull (RH40) during 8 to 14 d of age, respectively. Thereafter, all ducks were fed with grower diet. Ducks fed with RH40 diet from 8 to 14 d of age increased (p<0.05) feed intake, decreased (p<0.05) body weight, body weight gain and adjusted feed intake (excluded rice hull), abdominal fat, skin with fat, and fat content in carcass, and reduced (p<0.05) activities of hepatic malic dehydrogenase, glucose-6-phosphate dehydrogenase and fatty acid synthetase. When diet dilution was withdrawn in the re-fed period from 15 to 42 d of age, full compensatory growth of body weight, breast meat and leg meat weight were attained. However, ducks were still less (p<0.05) carcass fat content and showed continually lower (p<0.05) hepatic lipogenic enzyme activities at the market age in RH40 ducks than the control. These results indicated that diluting diet with 40% rice hull during 8 to 14 d of age might be a suitable method to improve feed efficiency, and to reduce carcass fat deposition in the production of meat-type ducks.

• Microbiology and Biotechnology Letters
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• v.26 no.4
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• pp.345-351
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• 1998

In an effort to develop a potent system for the production of various dp (degree of polymerization) chitooligosaccharides, 32 enzymes or microbial systems were screened for chitosanolytic acitivity using chitosan as a substrate. The efficiency of each enzyme system was evaluated by the changes of turbidity and viscosity of chitosan solution, the amount of precipitate and the reducing sugar-producing activity in the enzymatic reaction mixture. Based on these assay methods for the chitosanase activity, Bacillus sp. P2l out of 32 screened systems showed highly potent endochitosanase, which was comparable with a commercially available enzyme (E7). Chitooligosaccharides of dp 3-7 were separated by TLC as major enzymatic reaction products, suggesting that the chitosanase from Bacillus sp. P2l be endo-splitting type.