• 한국미생물·생명공학회지
• /
• 제22권1호
• /
• pp.73-79
• /
• 1994

The optimum cultural temperature and time for the pullulanase production by Bacillus cereus subsp. mycoides were 35$\circ $C and 48 hrs, respectively. The addition of egg albumin and casein to the basal medium increased the enzyme production. The enzyme was purified by ammonium sulfate fractionation and DEAE-cellulose column chromatography. specific activity of the purified enzyme was 82.37 U/mg protein and yield of theenzyume activity was 62.1%. The purified enzuyme showed a single band on ployacrylamide disc gel electrophoresis and its molecular weight was estimated to be 66.,000 by SDS-polyacrylamide disc gel electrophoresis. The isoelcular point for the purified enzyme was pH 5.0. The optimum temperature and pH were 50$\circ $C and pH 6.5, respectively. The purified enzyme was stable below 40$\circ $C and in the pH range of 6.5~10.0 The pullulanase activity was greatly inhited by Ag$^{+}$, Hg$^{2+}$ and EDTA, and its heat stability was increased by the addition of Ca$^{2+}$. The tydrolysis product with the enzyme on pullulan was maltotriose.

• 한국생명과학회:학술대회논문집
• /
• 한국생명과학회 2001년도 10주년 기념 국제학술 심포지움 및 추계학술대회
• /
• pp.53-53
• /
• 2001

• 한국식품과학회지
• /
• 제22권5호
• /
• pp.533-538
• /
• 1990

풀루란 발효에서 500rpm에서 통기속도를 0.5vvm, 1.0vvm, 2.0vvm으로 증가시켰을 때 최대 비성장속도는 $0.168(hr^{-1})$에서 $0.192({hr^{-1})$로 증가되었으며 풀루란의 최대 비생산속도는 $0.046({hr^{-1})$에서 $0.093({hr^{-1})$으로 증가되었다. 풀루란 발효액의 물성은 power-law를 따르는 Pseudoplasticity를 나타냈으며 Power-law 변수들과 풀루란 농도 사이에는 $lnK(t)=ln({\tau})_o-n(t)\;ln({\gamma})_o$와 $K(t)=AP(t)^B$의 상관관계를 보였다.

• KSBB Journal
• /
• 제9권2호
• /
• pp.133-139
• /
• 1994

Aureobasidium pullulans를 설탕 및 맥아당을 주 탄소원으로 하는 배지에서 각각 배양하면서 여러 종류의 올리고당류의 합성, 기질 이용성, 그리고 과당 전이효소 및 포도당전이효소의 생산특성에 대해 고찰하였다. 맥아당 배지에 비하여 설탕배지에서 초기 기질의 소비속도가 더 빨랐고 합성된 올리고당류는 두 경우 모두 최대 중합도 6까지의 올리고당류를 생산하였고, 이때 합성된 올라고당류의 최대 농도는 초기 설탕농도 100g/ㅣ 의 경우에서 58g/ㅣ 이었다 이들은 대부분 배양 중에 탄소원으로 다시 이용되었으나 중합도 6의 이소말토올리고당은 기질로 이용되지 않고 배양 말기까지 계속 잔존하였다. 설탕을 주 탄소원으로 하는 배지에서 맥아당은 과당전이효소 및 포도당전이효소의 생산을 촉진시켰으나, 맥아당을 주 탄소원으로 하는 배지에서 설탕은 포도당전이 효소의 생산에 전혀 영향을 미치지 않았다.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
• /
• pp.342-345
• /
• 2000

Effect of volcanic ash on cell growth of Aspergillus sp. and production of exopolymers by Agrobacterium sp. and Aureobasidium pullualns was investigated. The volcanic ash contained various mineral salts such as $SiO_2$, $Al_2O_3$, CaO, $K_2O$. Maximal cell growth of Aspergillus sp. was obtained when 0.3% volcanic ash was added to medium. Cell growth of Aspergillus sp. increased with higher concentration of volcanic ash in medium. Amount of cell growth with 0.3 % volcanic ash was 6.7 times higher than that without volcanic ash. Volcanic ash also stimulated production of exopolymer as well as cell growth. Production of curdlan with 0.1% volcanic ash was 12.40 g/l whereas that without volcanic ash was 9.15 g/l. Production of pullulan with volcanic ash was also higher than that without volcanic ash.

• Journal of Microbiology and Biotechnology
• /
• 제2권1호
• /
• pp.7-13
• /
• 1992

A moderately thermophilic, alkalophlic and powerful crystalline cellulose-digesting bacterium, Bacillus K-12, was isolated from filter paper wastes and found to be similar to Bacillus circulans or Bacillus pumilis, except for its ability to grow at a moderately high pH and temperature. The isolate grew at a pH ranging from 6 to 10 and at a temperature ranging from 35 to $65^{\circ}C$ and produced a large amount of cellulase components containing avicelase, xylanase, CMCase, and FPase when grown in avicel medium for 5 to 7 days at $50^{\circ}C$. The crude enzyme preparation from the culture broth hydrolyzed xylan, raw starch, pullulan and ${\beta}-1,3$ glucan such as laminarin. Furthermore, the enzyme hydrolyzed crystalline cellulose to cellobiose and glucose and had a broad pH activity curve (pH 6~9). The enzyme was stable up to $70^{\circ}C$.

• KSBB Journal
• /
• 제4권2호
• /
• pp.134-142
• /
• 1989

Aureobasidium pullulans에 의한 세포외 다속류 생성연구를 통한 결론은 다음과 같다. (1) sucrose 농도가 50 g/l 이상일 때는 기질에 의한 저해 작용이 나타나고 있음을 알았으며 실소원의 증가에 따라서 균체량은 증가하지만 세포외 다속류 생성은 최적농도 (1 g/l )까지 증가하고 그 이상에서는 감소했으며 멜라닌 색소 출현시간은 길어졌다. (2) 최대 균체 성장은 초기 pH 3.0에서 보인 반면에 세포외 다속류 생성은 초기 pH 7.5에서 최대 값은 나타내었고 최대 PH가 증가함에 따라서 효모형 비율이 증가했으며 멜라닌 색소 출현시간은 pH 4.5~8까지는 거의 일정하게 나타났지만 pH 3 이하에서는 전혀 멜라닌 색소가 나타나지 않았다. (3) 탄소원과 실소원을 증가시켰을 때 pH 5 이하에서는 멜라닌 색소는 나타나지 않았으나 pH 6에서 pH 8.5 로 pH가 높아짐에 따라 멜라닌 색소는 빨리 나타나는 경향을 보였다. (4) 용존산소 농도가 높을수록 균체량과 세포외 다속류 생성이 증가했고 멜라닌 색소 출현시간이 빨라졌으며 potassium phosphate가 전혀 들어있지 않는 배지에서는 멜라닌 색소 출현은 관찰할수가 없었다.

• KSBB Journal
• /
• 제17권6호
• /
• pp.555-559
• /
• 2002

프럭토올리고당 합성효소의 생산능력이 우수한 균주를 선발하기 위하여 Aureobasidium pullulan 3종을 배양하여 비교해본 결과 ATCC 9348이 비효소활성 측면에서 가장 우수했으며, 세 균주 모두 균체성장과 효소생산패턴과는 대체적으로 선형적인 관계가 있었다. 균의 형태학적 측면에서 볼 때 배양초기에는 대부분 mycelia cells 형태이었으나 배양이 점차 진행되면서 yeast-like cells 및 chlamydospores 형태로 바뀌었고, 이러한 형태변화와 더불어 균체외효소에 대한 균체내효소의 활성비율도 변화됨을 알 수 있었다. 2.5-L 발효조를 사용하여 pH 영향을 조사해본 결과 pH 7.0 범위에서 효소생산이 최대로 나타났고 pH 4.0 또는 pH 8.0 조건에서는 균체외효소에 대한 균체내효소 활성이 높게 나타나는 것으로 보아 배양조건에 따라 효소의 배출효율이 달라지는 것을 알 수 있었다. 또한 값싼 원료인 당밀로부터 A. pullulans 효소를 사용하여 사료첨가제로서의 프럭토올리고당 생산이 가능함을 확인하였다.

• Journal of Microbiology and Biotechnology
• /
• 제18권3호
• /
• pp.457-464
• /
• 2008

An extracellular enzyme (RMEBE) possessing ${\alpha}-(1{\rightarrow}4)-(1{\rightarrow}6)$-transferring activity was purified to homogeneity from Rhodothermus marin us by combination of ammonium sulfate precipitation, Q-Sepharose ion-exchange, and Superdex-200 gel filtration chromatographies, and preparative native polyacrylamide gel electrophoresis. The purified enzyme had an optimum pH of 6.0 and was highly thermostable with a maximal activity at $80^{\circ}C$. Its half-life was determined to be 73.7 and 16.7 min at 80 and $85^{\circ}C$, respectively. The enzyme was also halophilic and highly halotolerant up to about 2M NaCl, with a maximal activity at 0.5M. The substrate specificity of RMEBE suggested that it possesses partial characteristics of both glucan branching enzyme and neopullulanase. RMEBE clearly produced branched glucans from amylose, with partial ${\alpha}-(1{\rightarrow}4)$-hydrolysis of amylose and starch. At the same time, it hydrolyzed pullulan partly to panose, and exhibited ${\alpha}-(1{\rightarrow}4)-(1{\rightarrow}6)$-transferase activity for small maltooligosaccharides, producing disproportionated ${\alpha}-(1{\rightarrow}6)$-branched maltooligosaccharides. The enzyme preferred maltopentaose and maltohexaose to smaller maltooligosaccharides for production of longer branched products. Thus, the results suggest that RMEBE might be applied for production of branched oligosaccharides from small maltodextrins at high temperature or even at high salinity.

• Journal of Microbiology and Biotechnology
• /
• 제17권9호
• /
• pp.1521-1526
• /
• 2007

A maltogenic amylase gene from Lactobacillus gasseri ATCC33323 (LGMA) was expressed in Lactococcus lactis MG1363 using the P170 expression system. The successful production of recombinant LGMA (rLGMA) was confirmed by the catalytic activity of the enzyme in liquid and solid media. The N-terminal amino acid sequencing analysis of the rLGMA showed that it was Met-Gln-Leu-Ala-Ala-Leu-, which was the same as that of genuine protein, meaning the signal peptide was efficiently cleaved during secretion to the extracellular milieu. The optimal reaction temperature and pH of rLGMA ($55^{\circ}C$ and pH 5, respectively) and enzymatic hydrolysis patterns on various substrates (${\beta}$-cyclodextrin, starch, and pullulan) supported that rLGMA was not only efficiently secreted from the Lactococcus lactis MG1363 but was also functionally active. Finally, the branched maltooligosaccharides were effectively produced from liquefied com starch, by using rLGMA secreted from Lactococcus lactis, with a yield of 53.1%.