• 한국미생물·생명공학회지
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• 제23권5호
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• pp.573-579
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• 1995

A Bacillus strain capable of producing an extracellular malto-oligosaccharides forming $\alpha $-amylase was isolated from soil and designated as Bacillus sp. SUH4-2. The enzyme was purified by ammonium sulfate fractionation, DEAE-Toyopearl and Mono-Q HR 5/5 column chromatographies using a FPLC system. The specific activity of the enzyme was increased by 16.1-fold and the yield was 13.5%. The optimum temperature for the activity of $\alpha $-amylase was 60-65$\circ$C and more than 50% of initial activity was retained after the enzyme was incubated at 60$\circ$C for 40 min. The enzyme was stable over a broad pH range of 5.0-8.0 and the optimum pH was 5.0-6.0. The molecular weight of the enzyme was determined to be about 63.6 kD and isoelectric point was around 5.8. The enzyme activity was strongly inhibited by Mn$^{2+}$, Ni$^{2+}$, and Cu$^{2+}$ ; slightly by Ca$^{2+}$. The purified enzyme produced starch hydrolyzates containing mainly maltose and maltotriose from soluble starch. The starch hydrolyzates were composed of 11% glucose, 59% maltose, 25% maltotriose and 5% maltotetraose.

• 한국식품영양학회지
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• 제7권4호
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• pp.259-266
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• 1994

The hyperthermophilic archaebacterium Thermococcus profundus Isolated from a deep-sea hydrothermal vent system, produced several amylolytic enzymes such as extracellular amylase and pullulanase, intracellular a-1,4-91ucosidase in respone to the presence of complex carbohydrates In the growth medium. This strain showed high activities on 0.5% maltose than on complex carbohydrates One of the amylases was partially purified by ammonium sulfate precipitation, DEAE-Toyopearl chromatography. The amylase exhibited maximal activity at pH 5.5 and 80$^{\circ}C$, and was stable in the range of pH 5.5 to 9.5 and up to 80$^{\circ}C$ for 30 min. The enzyme activity was no dependence on Ca2+ and not inhibited by detergents. The amylase hydrolyzed soluble starch, amylose, amylopectin and glycogen to produce maltose and maltotriose with trace amounts of glucose, but not pullulan and ${\alpha}$-, ${\beta}$-, ${\gamma}$-cyclodextrin. Malto-oligosaccharides ranging from maltotetraose to maltoheptaose were hydrolyzed in an endo fashion.

• 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.

• 한국미생물·생명공학회지
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• 제19권5호
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• pp.514-520
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• 1991

Extrusion시켜 구조변형시킨 전분(질)을 기질로 cyclodextrin glucanotransferse(CGTase)를 활용하여 액화과정을 거치지 않고 직접 cyclodextrin을 합성하는 불용성 extrusion된 전분-수용성 CGTase로 구성된 불균일상 효소반응계에 관하여 연구하였다. Extrusion된 전분을 기질로 이용할 경우 기존의 액화전분을 기질로하는 균일상 효소반응계에서 보다 현저히 증가된 CD 농도, 수율 그리고 합성속도를 얻을 수 있었으며, extrusion된 전분 기질농도가 100g/l일 때 CD생성량과 수율은 각각 54g/l와 0.54였다.

• 한국식품저장유통학회지
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• 제15권3호
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• pp.477-482
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• 2008

고아미 부산물의 $\alpha$-amylase 및 cellulase 혼합처리 조건에 따른 품질특성을 비교하였다. 그 결과, 가용성 고형분 및 환원당은 $\alpha$-amylase 처리구(A)에서 가장 높게 나타났으며, cellulase 함량이 많아질수록 조금씩 감소하였다. 총식이섬유소 및 총당은 두 효소 농도에 따른 큰 차이를 보이지 않았다. 당류 분석 결과, 모든 처리구에서 $G{\sim}G5$가 모두 검출되었으며, 말토올리고당은 $\alpha$-amylase 처리구(A)에서 약 2,200 mg%로 가장 높았다. 최적 가수분해 조건으로 제조된 가수분해 분말의 품질특성을 조사한 결과 색도는 시료간 큰 차이를 보이지 않았다. 식이섬유소 함량 중 불용성 식이섬유소는 고아미 분말(GF)이 6.95%로 가장 낮게 나타났고 고아미 부산물 분말(GBPP)과 고아미 가수분해 분말(GBPHP)은 14% 전후로 비슷한 함량을 나타내었으며, 수용성 식이섬유소는 고아미 가수분해 분말(GBPHP), 고아미 부산물 분말(GBPP), 고아미 분말(GF) 순으로 높게 나타났으나 함량 차이는 크지 않았다. 유리아미노산은 고아미 가수분해 분말(GBPHP), 고아미 부산물 분말(GBPP), 고아미 분말(GF) 순으로 높은 함량을 나타내었다. 당류 분석에서 고아미 가수분해 분말(GBPHP)는 $G{\sim}G5$가 모두 검출되었으며 약 1,800 mg%로 가장 높게 나타났다. 고아미 부산물 분말(GBPP)은 $G{\sim}G2$가 검출되었으며 약 66 mg%가 생성되었고, 고아미 분말(GF)에서는 말토올리고당이 검출되지 않았다. 이상의 결과 고아미 가수분해 분말(GBPHP)이 고아미 분말(GF)및 고아미 부산물 분말(GBPP)에 비하여 기능성이 강화되어 쌀가공식품 소재로의 다양한 활용이 기대되었다.