• Journal of Environmental Health Sciences
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• v.4 no.1
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• pp.47-50
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• 1977

This report is intended to describe as brief as possible the result of study on purity of the Korean Bee Honey. Purity of bee honey was measured by scaling the enzyme activities of two different honey groups: such as, the standard group and control group each including the samples of honey originated from the resource of acarcia, chestnut or miscellaneous origin. The samples of honey were collected from different sources: to wit, honey belonging to the standard group were collected from the township of Seoboo, Yangju county, Kyunggido province, Korea, while honey belonging to the control group were collected from the street side shops, market or the companies producing the secondary food from honey. The results of this study were summarized as follow: 1. It was found that honey belonging to the standard group contained less moisture than those belonging to the control group. Republic of Korea Ministry of Health and Social Affairs Food Control Regulation stipulates that honey must contain moisture less than 20%. The samples of' both groups contained moisture more than 20%, although honey belonging to the control group were relatively more so than honey belonging to the standard group. 2. Honey belonging to the standard group were found stronger in sugar reduction activities than those belonging to the control group. It was also noted that honey of acracia origin was strongest in reduction activities of the three different origin in the same group. 3. $\alpha$-Amylase and $\beta$-amylase were discovered to have activated more strongly in honey belonging to the standard group than those belonging to the control group. The enzyme activitie, varied depending on the origin of plant where honey comes from. For instance, honey of miscellaneous origin indicated the strongest activities in $\alpha$-amylase while honey of chestnut origirt indicated strongest in $\beta$-amylase.

• Journal of Microbiology and Biotechnology
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• v.27 no.5
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• pp.896-908
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• 2017

In this study, a total of 58 different kinds of nuruk (a traditional Korean fermentation starter) were prepared, including 46 kinds of restored nuruk from ancient documents. Each nuruk was evaluated by analysis of its saccharification power, and the enzyme activities of glucoamylase, ${\alpha}$-amylase, ${\beta}$-amylase, protease, and ${\beta}$-glucanase. The range of saccharification power (sp) of the restored nuruk ranged between 85 and 565 sp. The diastatic enzymes, ${\alpha}$-amylase, ${\beta}$-amylase, and glucoamylase, were significantly correlated to the saccharification power value; conversely, ${\beta}$-glucanase and protease did not have a correlative relationship with saccarification power. In addition, their brewing properties on chemical and organoleptic aspects of traditional alcoholic beverage production were compared. Each raw and supplementary material contained in nuruk showed its own unique characteristics on Korean alcoholic beverage brewing. For the first time, in this study, the traditional Korean nuruk types mentioned in ancient documents were restored using modernized production methods, and also characterized based on their brewing properties. Our results could be utilized as a basis for further study of traditional alcoholic beverages and their valuable microorganisms.

• Journal of Plant Biology
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• v.17 no.4
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• pp.143-156
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• 1974

The purpose of this experiment was to study one side of germination physiology based on that protein profiles and protease relating to protein metabolism, that peroxidase, catalase, $\alpha$-amylase, $\beta$-amylase, and malate dehydrogenase involved in the carbohydrate metabolism of seed germination. All these experiments were divided into the two groups with and without acetone treatment, and were carried out. The protein bands of each germinating stage between the groups treated with and without acetone showed certain basic pattern in polyacrylamide gel disc electrophoresis. However, there was a little difference in the number of protein band, optical density, and migration velocity between two groups. The isozyme bands of peroxidase, and catalase between two groups in polyacrylamide gel disc electrophoresis did not show the numeral difference, but the optical density of certain germinating stage treated with acetone was higher than the group untreated with it and it showed their enzyme activity. The $\alpha$-amylase and $\beta$-amylase activities which involved in starch metabolism of seed germination were higher in the treated group than the other. On one hand, the protease activity of hydrolase occurred in the seeds for germination was also higher, more or less in the treated group than in the other. The isozyme band pattern of malate dehydrogenase in TCA cycle of energy metabolism pathway was very different between two groups growing for 72 hours with and without acetone treatment in cellulose acetate electrophoresis. It indicated that two isozyme bands of malate dehydrogenase was high. Consequently these experimental results mentioned above indicated that acetone treatment before sowing had an effect on dissolving certain complexed lipid substance involved in the seed coats, the activity of carbohydrate hydrolase increased with water absorption which was most comfortable in its germination, dissolved glycerin and fatty acid became certain energy source, and they stimulated the acceleration of respiration metabolism.

• Applied Biological Chemistry
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• v.35 no.4
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• pp.232-236
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• 1992

In order to manufacture of soy paste, Changes of chemical composition and enzyme activity of soybean by different processing method were investigated. The results are summarized as follows: Changes of chemical compositions were; Raw(A) and soaked(B) soybeans contain about 2% of more crude fat than roasted(C) and steamed(D) soybeans, roasted and steamed soybeans contain $1.16{\sim}1.74%$ of more protein than those of raw and soaked soybeans, and Raw and roasted soybeans contain $0.11{\sim}0.41%$ of more crude fiber than those of soaked and steamed soybeans. ${\alpha}-amylase$, ${\beta}-amylase$, protease, lipase activity of raw and soaked soybeans were $2{\sim}5$ folds higher than those of roasted and steamed soybeans. Trypsin inhibitor activity of raw, soaked, roasted and steamed soybeans was indicated 56.7%, 42.9%, 32.9% and 20.8% in the order, respectively.

• Microbiology and Biotechnology Letters
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• v.7 no.4
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• pp.217-223
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• 1979

Six strains of mold which had high saccharifying and acid-productive ability were isolated from wild sources. The strain M-80 among them and Aspergillus kawachii, which was generally used as rice makkulli koji were used for this studies. The results obtained were summarized as follows. 1) $\alpha$-amylase activities of the strain M-80 and Asp, kawachii showed similarly as about 140W. V., while $\beta$-amylase activity of M-80 was 54 A. U. and Asp. kawachii was 40 A. U. 2) Acid protease activity of M-80 was higher then Asp. kawachii but alkaline protease activity was lower Asp. kawachii respectively. 3) The contents of total acid, ethanol and fusel oil in makkulli brewing with M-80 were higher those of Asp. kawachii and methanol contents of the tested two strains were about 33mg/％. 4) Fifteen kinds of free amino acid were detected from makkulli brewing of two strains, and free amino acid contents of M-80 were 10％ higher than those of Asp. kawachii.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.1052-1056
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• 2004

A secretion signal sequence-selection vector (pGS40) was constructed based on an $\alpha$-amylase gene lacking a secretion signal and employed for selecting secretion signals from Lactococcus lactis ssp. cremoris LM0230 chromosomal DNA. Six fragments were identified based on their ability to restore $\alpha$-amylase secretion in E. coli, and among these, a fragment, S405, conferred the highest secretion activity (84%) in E. coli. Meanwhile, S407, which conferred poor secretion activity in E. coli, was quite active in L. lactis. The results suggested that the efficiency of a secretion signal depended on the host. All six fragments had an open reading frame (ORF) fused to the reporter gene, and the potential Shine-Dalgamo (SD) sequence and putative promoter sequences were located upstream of the ORF. Deduced amino acid sequences from the six fragments did not show any homology with known secretion signals. However, they contained three distinguished structural features and cleavage sites, commonly found among typical secretion signals. The characterized secretion signals could be useful for the construction of food-grade secretion vectors and gene expression in LAB.

• Journal of Microbiology and Biotechnology
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• v.22 no.8
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• pp.1077-1083
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• 2012

Previously, an extracellular ${\alpha}$-amylase (BKA) had been purified from the culture of Bacillus sp. KR8104. Subsequently, the crystal structure of the active enzyme revealed a 422 amino acids polypeptide. In this study, the bka was cloned into E. coli, which encoded a polypeptide of 659 amino acids including two additional fragments: one 44 residues N-terminal fragment and another 193 residues C-terminal fragment. In order to investigate the role of the C-terminal fragment, two constructs with and without this region [$BKA{\Delta}$(N44) and $BKA{\Delta}$(N44C193)] were designed and expressed in E. coli BL21. The optimum pH, thermal stability, and the end-products of starch hydrolysis were found to be similar in both constructs. The $K_m$ and $V_{max}$ values for $BKA{\Delta}$(N44) were lower than $BKA{\Delta}$(N44C193), using either starch or ethylidene-blocked 4-nitrophenylmaltoheptaoside as a substrate.

• Mycobiology
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• v.44 no.3
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• pp.155-161
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• 2016

The most economically important species used in a wide range of fermentation industries throughout Asia belong to Aspergillus section Flavi, which are morphologically and phylogenetically indistinguishable, with a few being toxigenic and therefore a major concern. They are frequently isolated from Korean fermentation starters, such as nuruk and meju. The growing popularity of traditional Korean alcoholic beverages has led to a demand for their quality enhancement, therefore requiring selection of efficient non-toxigenic strains to assist effective fermentation. This study was performed to classify the most efficient strains of Aspergillus section Flavi isolated from various types of traditional wheat nuruk, based on a polyphasic approach involving molecular and biochemical evaluation. A total of 69 strains were isolated based on colony morphology and identified as Aspergillus oryzae/flavus based on internal transcribed spacer and calmodulin gene sequencing. Interestingly, none were toxigenic based on PCR amplification of intergenic regions of the aflatoxin cluster genes norB-cypA and the absence of aflatoxin in the culture supernatants by thin-layer chromatography analysis. Saccharification capability of the isolates, assessed through ${\alpha}-amylase$ and glucoamylase activities, revealed that two isolates, TNA24 and TNA15, showed the highest levels of activity. Although the degrees of variation in ${\alpha}-amylase$ and glucoamylase activities among the isolates were higher, there were only slight differences in acid protease activity among the isolates with two, TNA28 and TNA36, showing the highest activities. Furthermore, statistical analyses showed that ${\alpha}-amylase$ activity was positively correlated with glucoamylase activity (p < 0.001), and therefore screening for either was sufficient to predict the saccharifying capacity of the Aspergillus strain.

• Journal of Microbiology and Biotechnology
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• v.27 no.11
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• pp.1999-2009
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• 2017

The secretion efficiency of a protein in a Sec-type secretion system is mainly determined by an N-terminal signal peptide and its combination with its cognate protein. Five signal peptides, namely, two synthetic Sec-type and three Bacillus licheniformis alpha-amylase-derived signal peptides, were compared for periplasmic expression of the human growth hormone (hGH) in E. coli. Based on in silico predictions on the signal peptides' cleavage efficiencies and their corresponding mRNA secondary structures, a number of amino acid substitutions and silent mutations were considered in the modified signal sequences. The two synthetic signal peptides, specifically designed for hGH secretion in E. coli, differ in their N-terminal positively charged residues and hydrophobic region lengths. According to the mRNA secondary structure predictions, combinations of the protein and each of the five signal sequences could lead to different outcomes, especially when accessibility of the initiator ATG and ribosome binding sites were considered. In the experimental stage, the two synthetic signal peptides displayed complete processing and resulted in efficient secretion of the mature hGH in periplasmic regions, as was demonstrated by protein analysis. The three alpha-amylase-derived signal peptides, however, were processed partially from their precursors. Therefore, to achieve efficient secretion of a protein in a heterologous system, designing a specific signal peptide by using a combined approach of optimizations of the mRNA secondary structure and the signal peptide H-domain and cleavage site is recommended.

• Korean Journal of Food Science and Technology
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• v.30 no.5
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• pp.1092-1096
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• 1998

This work was to study the possibility of using germinated colored rice as a raw material for sikhe. Colored rice was soaked in water at $15^{\circ}C$ for 2 days and then germinated at 15, 20, 25 and $30^{\circ}C$ for upto 10 days. The higher the germination temperature, the higher the germination speed, the rate of increase in ${\alpha}-amylase$ activity, and the rate of increase in extract and its sugar content. The viscosity of extract rapidly decreased first and then slightly increased during germination. The germination speed of colored rice was lower than that of brown rice at $25^{\circ}C$. The germinated colored rice can be used for sikhe not as a saccharifying agent but as a substitute for white rice for the nutritional purpose.