• KSBB Journal
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• 제13권5호
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• pp.621-625
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• 1998

The raw starch hydrolysis by amylase prepared from alkaline-tolerant Bacillus sp. were investigated. Degree of hydrolysis(%) of 5%(w/v) raw rice, corn and potato starch by this enzyme were about 40, 25 and 20%, respectively. The hydrolysis action on raw starch by change of blue value was similar to the action pattern of exo ${\beta}$-amylase. The hydrolysis products of rice starch were mainly glucose and maltose. Oligosaccarides were also detected. From the above results, this enzyme was considered as exo type ${\alpha}$-amylase. This enzyme activity on the raw starch and the gelatinized starch were 28.40 and 86.60 IU/mg protein, respectively, and the ratio of raw starch-digesting activity to gelatinized starch-digesting activity (raw starch digestivity) was about 32%. The Km values for the raw and the gelatinized starch were 4.22 and 3.0mg/mL, respectively, and the VmaX values were 0.20 and 0.31mg/mL/min, respectively.

• 한국미생물·생명공학회지
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• 제19권2호
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• pp.163-170
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• 1991

Production of cyclodextrin (CD) directly from raw corn starch without liquefaction using cyclodextrin glucanotransferase (CGTase) was carried out in an agitated bead reaction system. Similar CD yield and production rate comparable with those of conventional method using liquefied starch were obtained. Especially high purity-CD in the reaction mixture without accumulation of malto-oligosaccharides was obtained. The maximum 54g/l of CD was obtained at raw starch concentration of 200g/l. CD yield was inversely proportional to raw starch concentration, and conversion yield was 0.48 at substrate concentration of 100g/l. The optimal amount of enzyme (CGTase unit/g raw starch) was found to be around 6.0. Granular structure of raw starch degraded by CGTase was observed by SEM in order to investigate the enhancing mechanism, along with those of acid or alkali pretreated raw starch, amylose, and amylopectin. Kinetic constants of CGTase on raw starch in an agitated bead reaction system were evaluated, and CGTase was competitively inhibited by CD.

• Journal of Microbiology and Biotechnology
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• 제3권2호
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• pp.99-107
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• 1993

Two strains (No. 26 and 143) of bacteria which secrete both pectinase and raw-starch-digesting amylase simultaneously, were isolated from various domestic soil samples. The two bacteria were identified as Pasteurella ureae judging by their morphological and physiological characteristics. The optimal culture conditions for the production of raw-starch-digesting enzyme by the Pasteurella ureae 26 were using $NH_4NO_3$ as the nitrogen source at $37^{\circ}C$ with the pH of 7.5, and 15 of C/N ratio. Since the enzyme was produced only when raw or soluble starch was used as a carbon source, but not when glucose or other sugars was used, the enzyme was considered to be an inducible enzyme by starch. Thin layer chromatography of the hydrolyzed product of starch by the raw-starch-digesting enzyme of the strain No. 26 showed that glucose, maltose and other oligosaccharides were present in the hydrolyzates, and therefore the enzyme seemed to be ${\alpha}-amylase$. The enzyme had adsorbability onto raw com starch in the pH range of 3 to 9.

• 한국미생물·생명공학회지
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• 제11권3호
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• pp.181-185
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• 1983

증자하지 않은 Cassava의 생전분의 ethanol 발효생산을 위하여 Aspergilius shirousami 가생산하는 당화효소를 이용하여 단순당화 및 동시당화 발효를 하였다. Cassava 생전분의 당화률은 증자한 것에 비해 30% 정도였으며 10배의 효소를 가하여도 60%밖에 안되었으나. 동시당화-발효에서는 당화율이 크게 증가하여 ethanol 생성량이 증자한 전분에 비해 90% 이상이 되었다.

• 한국식품과학회지
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• 제27권5호
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• pp.773-775
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• 1995

The effect of alum$(Al{\cdot}K(SO_4)_2{\cdot}12H_{2}O)$ on the activity of raw starch-digesting enzyme produced by alkali-tolerant Bacillus sp. was investigated. In adding alum of 0.5%(w/w), activities of raw starch-digesting enzyme on the gelatinized and raw rice starches have not been inhibited. In case of adding alum of 5%(w/w), competitive and uncompetitive inhibition were observed for the gelatinized and raw rice starches, respectively. The inhibitory effect on the raw starch was much higher than that on the gelatinized starch.

• 한국식품과학회지
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• 제16권4호
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• pp.398-402
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• 1984

Rhizopus oryzae 가 생산(生産)하는 glucoamylase 의 각종기질(各種基質)에 대(對)한 분해반응(分解反應)을 검토(檢討)하였다. Glucoamylase I 과 II 는 amylose, amylopectin, glycogen, 가용성 전분, pullulan, maltose, maltotriose, maltotetriose, maltopentaose, maltohexaose, maltoheptaose, maltooctaose를 가수분해(加水分解)하였으나, ${\alpha}-cyclodextrin$, ${\beta}-cyclodextrin$, sucrose, raffinose, 젖당은 가수분해(加水分解)하지 못하였다. $37^{\circ}C$, 32시간(時間)의 반응(反應)에서 glucoamylase I 은 amylopectin, 가용성 전분, amylose를 거의 100% 분해하였고 glycogen 만을 88%정도 분해 하였으나, glucoamylase II 는 공시기질(供試基質) 4 종(種)을 거의 100% 분해하였다. Glucoamylase I 과 II 의 반응생성물질(反應生成物質)은 glucose 만이었고 ${\alpha}-glucosyltransferase$ activity는 없었다. Glucoamylase I 과 II 는 생찹쌀 전분을 가장 잘 분해(分解)시키나 생감자 전분, 생미숙 바나나 전분, 생칡 전분, 생참마 전분, raw high amylose corn starch의 분해능(分解能)은 glucoamyase I 에 비(比)하여 생전분(生澱粉)의 분해력(分解力)이 강(强)하였다.

• 한국미생물·생명공학회지
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• 제25권2호
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• pp.166-172
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• 1997

Aspergillus niger was selected as a strain producing the potent raw starch hydorlyzing enzyme. These experiments were conducted to investigate the conditions of the glucoa- mylase production, the purification of the enzyme, some characteristics of the purified enzyme and hydrolysis rate on various raw starches such as com, rice, potato, glutinous rice, sweet potato, wheat and barley. The optimum cultural temperature and time for the enzyme production on wheat bran medium were $30^{\circ}C$ and 96hrs, respectively. The respective addition of yeast extract and nutrient broth on wheat bran medium increased slightly the enzyme production. The enzyme was purified by ammonium sulfate fractionation and DEAE-cellulose column chromatography. The specific activity of the purified enzyme was 30.7u/mg-protein and the yield of enzyme activity was 25.8%. The purified enzyme showed a single band on polyacrylamide disc gel electrophoresis and its molecular weight was estimated to be 56,000 by SDS-polyacrylamide disc gel electrophoresis. The isoelectric point for the purified enzyme was pH3.7. The optimum temperature and pH were $65^{\circ}C$ and pH 4.0, respectively. The purified enzyme was stable in the pH range of pH 3.0-9.5 and below $45^{\circ}C$, and its thermal stability was slightly increased by the addition of $Ca^{2+}$. The purified enzyme was activated by $Co^{2+},\;Sr^{2+},\;Mn^{2+},\;Fe^{2+},\;Cu^{2+}$. Raw rice starch, raw corn starch, raw glutinous rice starch, raw sweet potato starch, raw wheat starch and raw barley starch showed more than 90% hydrolysis rate in 48hrs incubation. Even raw potato starch, most difficult to be hydrolyzed, showed 80% hydrolysis rate. The purified enzyme was identified as glucoamylase.

• Food Science and Biotechnology
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• 제18권1호
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• pp.118-123
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• 2009

In order to find out the effect of low level of starch acetylation on physicochemical properties of potato starch, amylose content, digestibility of raw and gelatinized starch, thermal properties, pasting properties, and the swelling power of native and acetylated potato starches were measured. The amylose content was significantly lower in acetylated starch than in their counterpart native starches. Though a tendency in the decrease in digestibility of raw starch was observed with starch acetylation, acetylation did not alter the proportion of readily digestible starch (RDS), slowly digestible starch (SDS), and resistant starch (RS) of both raw and gelatinized potato starches. No clear increase in the swelling power was observed, however, the peak and onset gelatinization temperatures and the enthalpy required for starch gelatinization decreased with starch acetylation. Peak and breakdown viscosities were reduced due to acetylation of potato starch while final viscosity and set back were increased.

• 한국미생물·생명공학회지
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• 제18권4호
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• pp.352-359
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• 1990

분쇄마찰매체효소반응계에서 glucoamylase와 Alpha-amylase의 보완작용에 의한 옥수수 생전분의 효소당화 mechanism을 규명코자, 분리.정제된 상기 효소의 혼합 비율에 따른 당화양상 및 생성당 조성, 전분입자 구조, 생전분입자의 particle size 분포, X-ray 회절양샹의 변화 등을 관찰하였다. 분쇄마찰매체 효소반응계에서도 효소를 분리하여 사용하였을 때보다 glucoamylase와 $\alpha$-amylase를 혼합사용할 경우 당화율이 크게 향상되었으며, 고순도의 glucose 생산에 적합한 두 효소의 혼합비율은 약 1:1-1:2(unit) 로 판명되었다.

• 한국미생물·생명공학회지
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• 제19권3호
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• pp.290-295
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• 1991

Maltose 생산효소인 Fungamyl과 생전분의 알칼리성 현탁액에 고형분쇄마찰매체를 첨가교반하면서 증자액화과정을 거치지 않고 생전분으로부터 maltose를 직접 생성시키는 연구를 수행하였다. 불용성 생전분을 기질로 하는 분쇄마찰 효소반응계에서 효소반응은 증자액화된 전분을 기질로 하는 기종의 maltose 제조법과 비슷한 효소반응속도를 보였다. 그러나 24시간후 maltose 농도는 증자법을 초과하여, 생전분의 농도가 150g/l일 때 95g/l의 maltose를 얻을 수 있었고, 첨가생전분에 대한 수율은 0.60이었다. 또한 생산된 포도당, maltose, maltoriose의 농도는 각각 20, 95 그리고 13g/l였으며, maltose의 함량은 72%로서 증자법의 6%0에 비하여 매우 높았다.