• Microbiology and Biotechnology Letters
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• v.25 no.2
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• pp.109-114
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• 1997

The Oomycete Saprolegnia ferax produces an extracellular $\beta$-amylase, Maximum enzyme yield was attained after 7 days of growth in YNB starch medium (pH 6.5) at 25$\circ$C. The amylase was pu- rified 24-fold by ultrafitration, HPLC DEAE column and HPLC gel filtration. The purfied enzyme was a monomeric glycoprotein with a molecular weight of about 44,000 dalton. The pH and temperature optima were 6.5 and 50$\circ$C, respectively. The enzyme was fairly stable up to 50$\circ$C and at acidic pH region (pH 4.0-7.0). The apparent Km and Vmax values of the enzyme against soluble starch were 0.77 mg/ml and 2,174 $\mu$moles/mg protein, respectively. Amino acid analysis indicated that the enzyme was enriched in alanine, glycine, leucine and acidic amino acid. Starch hydrolysis with the enzyme released maltose but not glucose, whereas maltotriose, Schardinger dextrin ($\alpha$-cyclodextrin) and pullulan were not hydrolysed by the enzyme. The enzyme was inhibited by Schardinger dextrin, p-chloromercuribenzoate(PCMB), CU$^{2+}$' and Hg$^{2+}$. Inhibition of the enzyme by PCMB could be reversed by the addition of cysteine and mercaptoethanol.

• Elastomers and Composites
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• v.43 no.4
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• pp.221-229
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• 2008

Starch as matrix polymer was used to do graft copolymerization with 2-ethylhexylacrylate, methyl methacrylate and acrylic acid. The polymerization was carried out by radical emulsion polymerization with increasing contents of starch. When 0.174% of $\alpha$-amylase as enzyme for starch was added, it was found that it made the best stable emulsion. The glass transion temperature of the polymerized material was increased with starch contents. The particle size and viscosity of the emulsion increased with starch contents due to the increased hydroxy group. Peel strength also increased with contents of starch because the enhanced hydroxy group caused to increase affinity between substrate surface and polymer materials. However, the initial tackiness decreased with starch contents owing to film hardness by higher glass transion temperature.

• Journal of The Korean Society of Grassland and Forage Science
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• v.25 no.3
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• pp.169-176
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• 2005

To evaluate the possibility of predicting a specific nutrient component, which nay be difficult in analysis, from a component of nutrient relatively easy to analyze, six grass roughage sources (bermuda grass hay, klein grass hay, oat hay, orchard grass straw, tall fescue straw and timothy hay) mainly used in Korea were analyzed for the heat-stable $\alpha-amylase$ treated neutral detergent fiber (aNDF), acid detergent fiber (ADF), acid detergent lignin (ADL), neutral detergent insoluble crude protein (NDICP) and acid detergent insoluble crude protein (ADICP) as well as proximate analytical components, and correlation coefficients between nutrient components were calculated. Some chemical components appeared to have significant correlation (p<0.05) through Pearson's correlation coefficients (i.e. between crude protein (CP) and NDICP in oat hay, orchard grass straw and tall fescue, between CP and ADICP in oat hay and timothy hay, between crude fiber (CF) and aNDF in klein grass hay, tall fescue straw and timothy hay, between CF and ADF in oat hay, tall fescue straw and timothy hay, and between CF and ADL in orchard pass straw and timothy hay). It is therefore suggested that it would be worthy to predict a specific nutrient component, which may be difficult in analysis such as aNDF, ADF, ADL, NDICP and ADICP, from a component of nutrient relatively easy to analyze such as CP and CF. However, it would be needed to improve the correlation coefficients, more samples should be measured.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.180-184
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• 2003

Several bacteria and yeasts were isolated from soil and characterized for the development of functional probiotics which can be used as a livestock feed additive. From the soil, the microbial strains which have acid/bovine resistance, antibiotics resistance and high stability, were isolated. Most strains selected were very tolerable against acids and very stable in a broad range of pH. Some strains could survive 100% at pH 2.5. The growth of the strains was not affected in the presence of bile acid, pathogenic E. coli and several antibiotics such as tetracycline, nisin, kanamycin, streptomycin, ampicillin. Acidogenic capability test showed that all the strains can produce acids. The hydrolytic activities were analysed for amylase, protease, lipase and cellulase to decompose various organic compounds. All the strains were found to be gram negative, round type, non-kinetic and the color is yellow or white.

• The Korean Journal of Mycology
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• v.11 no.1
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• pp.15-21
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• 1983

Exodextranase from Aspergillus ustus was purified by chromatography and characterized by various conditions. The optimal pH of the purified dextranase was 6.5 and this enzyme was maximally activated at $40^{\circ}C$. The enzyme was stable at the temperature below $50^{\circ}C$. The enzyme was markedly inactivated by $Hg^{2+},\;Cu^{2+},\;KCN\;and\;Co^{2+},\;but\;Ba^{2+},\;Fe^{2+},$ cysteine, EDTA, and ascorbic acid enhanced the activity of the enzyme. The main products from the hydrolysis of dextran incubated with the dextranase were glucose, isomaltotriose and oligosaccharide. When dextran was incubated with the mixture of pullulanase and ${\alpha}-amylase$, it was hydrolyzed into glucose, isomaltose and oligosaccharide. Polysaccharides in the decade teeth powder were hydrolyzed by the dextranase into glucose, isomaltotriose and oligosaccharides. In the hydrolysis of the teeth powder with the mixture of dextranase, pullulanase and ${\alpha}-amylase$, were proved to be similar to the dextran hydrolysates.

• Food Science and Preservation
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• v.22 no.5
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• pp.699-707
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• 2015

To improve the utilization of the domestic plant Salvia miltiorrhiza Bunge (Danshen), this study investigated changes in the physicochemical qualities of Danshen extracts obtained from low-temperature extraction using the enzymes amylase, cellulase, pectinase, and protease. Changes in the yield, pH, sugar content, and chromaticity were investigated. The changes were found to be highest in the amylase-treated extract with the following values: yield, 58.3%; pH, 6.04; sugar content, $5.97^{\circ}Brix$. With regard to antioxidant properties, Danshen extracts treated with amylase showed the highest DPPH and ABTS scavenging activities of 84.25% and 74.11% at 55 ppm. The total phenolic compound content was highest in the group subjected to enzyme treatment at $60^{\circ}C$. The salvianolic acid B level of the Danshen extract was the highest in the amylase-treated group, with a value of 3,002.6 mg/100 g. Cryptotanshinone level was the highest in the amylase- and protease-treated group with a value of 3.8 mg/100 g. Tanshinone I was the highest in the protease-treated group, with a value of 14.2 mg/100 g. The results showed that the indicator components of Danshen were detected as stable in the extracts after using amylase for low-temperature extraction; therefore, it would be possible to use Danshen industrially as a functional ingredient through mass production. Furthermore, the enzyme-treatment extraction could be utilized for a variety of natural products.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.119-127
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• 2013

Twenty-three strains of Leuconostoc species and 45 strains of Weissella species inhibiting the growth of Lactobacillus sakei, one of the most populous lactic acid bacteria in over-ripened kimchi, were isolated from kimchi in our previous study. Among these hetero-fermentative 68 strains, Leuconostoc mesenteroides CK0128, Weissella cibaria CK0633, and W. cibaria KK0797 exhibited a relatively high survival rate in MRS medium, which was adjusted to pH 4.3 using an acid mixture consisting of acetic and lactic acids, and produced a large amount of exopolysaccharides. The culture supernatants of 3 strains were fractionated by a molecular weight cutter and lyophilized. The fractions with a molecular weight smaller than 3,000 Da showed antagonistic activity against Staphylococcus aureus and Lb. sakei. The anti-bacterial substances were very stable to heat treatments ($121^{\circ}C$, 15 min) and active at acidic conditions below pH 5. ${\alpha}$-Amylase, lipase, and proteolytic enzymes (proteinase K and pepsin) did not affect their activities. These non-proteinaceous anti-bacterial substances inhibited the growth of several food pathogens.

• Journal of Microbiology and Biotechnology
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• v.12 no.1
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• pp.96-105
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• 2002

A bacteriocin-producing strain identified as Pediococcus acidilactici was isolated from kimchi. The bacteriocin was identified to belong to the pediocin family and exhibited bactericidal activity against most Gram-positive bacteria as well as some Gram-negative bacteria. The bacteriocin was stable up to $80^{\circ}C with wide pH ranges (5.0-10.0). The bactericidal activity remained unchanged after treatment with nonproteolytic enzymes such as nuclease and ${\alpha}$-amylase, however, it was destroyed after treatment with protease. The bacteriocin was effectively extracted by the pH-mediated adsorption-desorption method and purified effectively by semi-preparative RP-HPLC. The molecular weight of the bacteriocin was 4,622, as determined by electrospray mass spectrometry. The amino acid sequence consisted of 44 amino acid residues with four cysteines. The high solubility and pH stability of the isolated pediocin provide definite advantages over nisin and other bacteriocins in regards to its potential applications.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.3
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• pp.221-228
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• 2001

This study was carried out to investigate the effect of germination condition and drying temperature on growth and physicochemical properties of brown rice. Three brown rice seeds of Ilpumbyeo, Dasanbyeo and Heugjinjubyeo were stored at room temperature for six weeks to test the time-sequence germination viability. Relatively stable germination ratio was maintained until 2 weeks after storage. However, 3 weeks after storage, germination ratio of brown rice seeds started to decrease rapidly and their germination ratio was lower than 80%. For this reason, brown rice was recommended for seeding within 2 weeks after hulling. During the initial 5 days, germination ratio of 24 hours pre-soaking brown rice was higher about 2-3% than that of non-soaking brown rice. The $25^{\circ}C$ was considered as the most favorable temperature for brown rice germination, because of the high germination ratio and desirable coleoptile growth of the brown rice, and little seed rotting symptoms. The scanning electron micrographs showed the structural differences between hot-air dried and freeze dried germinated-brown rice kernel. In the freeze dried germinated-brown rice, seed coat (pericarp, tegmen and aleurone layer) was mechanically disrupted from the endosperm, and many cleavages were observed among starch storing cells and starch granules. The endosperm of freeze-dried brown rice kernels formed the sponge-like structures and showed the fragile traits. For this reason, hot-air drying is considered as more suitable method than freeze drying for germinated-brown rice. The crude protein and amylose contents were slightly changed, but there were no significant differences during the germination period. Crude fiber content was decreased, but crude Int and total amino acid contents were increased as seeding days increased. A rapid increase in $\alpha$-amylase activities of germinating brown rice was observed at S days after seeding, and $\alpha$-amylase activities were decreased from 8 days after seeding. Total free sugar contents were decreased during the germination period. There was continuous decline in the contents of sucrose and glucose until 8 days after seeding, but fructose and maltose content were gradually increased from the 5 days after seeding.

• Food Science and Biotechnology
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• v.17 no.3
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• pp.679-682
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• 2008

A lactic acid bacterium producing an antimicrobial substance against Escherichia coli O157:H7 was isolated from raw milk and identified as Lactobacillus amylovorus ME-1. In addition to E. coli O157 :H7, the antimicrobial substance also inhibited the growth of Bacillus cereus, Listeria monocytogenes, Pseudomonas aeruginosa, Salmonella typhimurium, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pyrogenes, and Yersinia enterocolitica. The antimicrobial substance was stable at pH 2-12 and $121^{\circ}C$ for 15 min and insensitive to proteinase K, protease, amylase, and catalase. Purification of the antimicrobial substance was conducted through methanol and acetonitrile/ethylacetate extraction, ultrafiltration with a 500 Da cutoff, thin layer chromatography (TLC) with silicagel 60, and high performance liquid chromatography (HPLC) with a $C_{18}$ reverse phase column. The ${\lambda}_{max}$ of the purified antimicrobial substance was determined as 192 nm by ultra violet (UV) scanning, while the molecular weight was estimated as 453 Da based on the mass spectrum. Accordingly, the current results suggest that the antimicrobial substance from the L. amylovorus ME-1 was not a bacteriocin, but rather a new non-proteinaceous substance distinct from acidophilin, acidolin, diacetyl, and reuterin.