• 한국미생물·생명공학회지
• /
• 제20권6호
• /
• pp.707-710
• /
• 1992

Bacillus stearothermophilus No.239 isolated from soil was mutated with N-methyl-N'nitro-N-nitrosoguanidine (MNNG) to yield a series of mutants with increasing levels of cyclomalto-dextrin glucanotransferase (EC 2.4.1.19` CGTase) production. After five consecutive mautation steps, a mutant MNNG 8 with about 14 times of CGTase activity than the parent strain was obtained.

• 한국식품위생안전성학회지
• /
• 제38권5호
• /
• pp.356-360
• /
• 2023

본 연구에서는 강한 내열성을 가지는 비병원성 Bacillus atrophaeus, Bacillus subtilis, Geobacillus stearothermophilus 포자의 열 저항성을 분석하여 레토르트 식품 제조 시 직접적인 멸균 여부 판정에 사용 가능성을 평가하고자 하였다. B. subtilis 포자의 D₁₂₁-value는 2.9±0.1분이었으며, Zvalue는 43.0±1.4℃로 나타났다. G. stearothermophilus 포자의 D₁₂₁-value는 4.3±0.1분이었으며, Z-value는 25.0±1.6℃로 나타났다. B. atrophaeus 포자의 D₁₂₁-value는 3.7±0.1분이었으며, Z-value는 35.8±1.4℃로 나타났다. B. subtilis, G stearothermophilus와 B. atrophaeus 포자의 D₁₂₁-value는 모두 레토르트 식품 멸균 확인에 사용되는 C. botulinum 포자의 D₁₂₁-value 보다 높은 값을 나타내었다. 이러한 결과를 종합하여 볼 때 레토르트 식품 멸균 시 병원성 포자형성균인 C. botulinum 대신 B. subtilis, G. stearothermophilus, B. atrophaeus 포자를 사용할 수 있을 것으로 판단된다. 또한 기존 세균발육 실험에 소요되는 13일보다 단시간인 2-3일에 멸균 여부를 확인할 수 있을 것으로 판단된다.

• 식물병연구
• /
• 제8권4호
• /
• pp.234-238
• /
• 2002

Bacillus stearothermophilus YC4l94는 in vitro 와 in vivo 에서 병원균 Pythium aphanidermatum에 대한 억제 효과를 보였다 in vitro 실험에서 P. aphanidermatum의 유주포자낭 형성과 피낭포자 발아를 억제하였을 뿐 아니라 식물체에 적접 길항균 제제 처리 시 50% 이상의 방제가를 보였다. 그리고 다른 화학 살균제와 비슷한 방제효과를 보여 미생물 제제로서의 개발 가능성을 보여주었다.

• 한국미생물·생명공학회지
• /
• 제22권6호
• /
• pp.599-606
• /
• 1994

Bacillus stearothermomophilus, a strong xylan degrader, was confirmed to express multiple esterase activities in addition to the major xylanolytic enzymes. One of the genes encoding the esterases was isolated from the genomic library of B. stearothermophilus constructed with EcoRl restriction endonuclease and pBR322 plasmid. Three recombinant plasmids showing the tributyrin degrading activity were selected from approximately 7, 000 E. coli HB101 transformants, and were found to have the same insert of a 3.2 kb DNA fragment. Restriction mapping and hybridization studies revealed that the gene(estII) on the hybrid plasmid (pKMG7) had originated from the B. stearothermophilus chromosome, and was distinct from the estl, another esterase gene of B. stearothermophilus isolated in the previous work. The E. coli cells harboring pKMG7 produced an acetylxylan esterase that exibited similar substrate specificity to the esterase encoded by the estI gene.

• 한국미생물·생명공학회지
• /
• 제17권4호
• /
• pp.289-294
• /
• 1989

토양으로부터 세포외 xylanase를 다량 생산하는 균주를 분리하고 분리균의 형태적 내지는 생화학적인 특성을 조사하여 Bacillus stearothermophilus No.236로 동정하였다. 본 분리균은 초기 pH가 pH 6.5 인 0.75% xylan, 0.35% yeast extract, 1.06% $K_2$HPO$_4$, 0.61% NaH$_2$PO$_4$.2$H_2O$, 0.20% (NH$_4$)$_2$SO$_4$, 0.05% MnSO$_4$ 0.07% MgSO$_4$ 0.05% CaCO$_3$의 조성을 지닌 배지에서 5$0^{\circ}C$, 28시간 진탕배양했을 때 배양액 $m\ell$당 약 0.85units로서 가장 높은 효소생산량을 나타내었다. 또 본 xylanase는 xylan에 의해 유도 생산되는 세균 xylanase로서는 그 예가 극히 드문 exo-type의 효소인 것으로 판단되었다.

• 한국미생물·생명공학회지
• /
• 제20권3호
• /
• pp.344-347
• /
• 1992

Bacillus stearothermophilus No.239의 돌연변이주 MNNG 8이 생산하는 CGTase를 사용하여 감자전분을 동시 액화, cyclodextrin(CD) 생산을 하였다. 고농도(30)의 감자전분이 29의 수율로 CD로 전환 되었으며 그 때의 조건은 pH 6.0, $80^{\circ}C$, 4.3mM, $CaCl_2$, $40^{\circ}C$에서 1g의 전분당 3.0 DAU의 CGTase를 첨가하는 것이다.

• 한국미생물·생명공학회지
• /
• 제30권4호
• /
• pp.293-297
• /
• 2002

효모 S. cerevisiae에서 B. stearothermophilus 유래의 CGTase를 발현 생산하였으며, 분비, 생산된 단백질을 정제하여 그 특성을 조사하였다. 재조합 효모 S. cerevisiae 2805/pVT- CGTS가 생산하는 CGTase의 분자량은 효모에서 발현될 때 고당쇄가 부가되어 야생형의 68kDa에 비해 15-160% 증가된 약 78-178 kDa으로 나타났다. 효모 S. cerevisiae에서 발현된 CGTase의 효소반응 최적활성조건은 pH7.0, $65^{\circ}C$였고, 열안정성에 있어서 $75^{\circ}C$에서 약 90%의 잔존활성을 가질 정도로 내열성이 개선되었다. 효모 S. cerevisiae에서 발현된 CGTase는 5% soluble starch를 기질로 약 40.2%의 CD 전환율 및 3 : 6 : 1의 $\alpha$-, $\beta$-, ${\gamma}$-CD의 생산 비율을 나타내어 야생형과 별다른 변화가 없었다.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
• /
• pp.56-59
• /
• 2000

Thermophilic bacterium, Bacillus stearothermophilus NUB3621, was engineered to produce ethanol from glucose by introducing cloned thermostable pyruvate decarboxylase and alcohol dehydrogenase genes. A novel promoter sequence was screened and used for the enhancement of these two enzymes. Successful redirection of metabolic flux into ethanol was obtained. In addition, gene expression profiling using Bacillus subtilis DNA microarray was analyzed to overcome the intrinsic low glucose utilization of B.stearothermophilus. Many known and unknown genes were identified to be up or down regulated under glucose-containing media.

• Journal of Microbiology and Biotechnology
• /
• 제2권2호
• /
• pp.115-121
• /
• 1992

In order to broaden the spectrum of substrate utilization of a Gram negative bacterium Zymomonas mobilis which has a great potential as an industrial ethanol producing microorganism, cloning of $\alpha$-amylase gene into Z. mobilis ZM4 was tried. The $\alpha$-amylase gene was isolated from Bacillus stearothermophilus. By Southern blot analysis, it was proven that the $\alpha$-amylase gene fragment was originated from a naturally occuring plasmid of B. stearothermophilus ATCC 31195. To place $\alpha$-amylase gene under the control of Z. mobilis promoter, two different Z. mobilis expression vectors, pZA26 and pLOI204, were used. The truncated $\alpha$-amylase gene was then introduced into these vectors. Both qualitative and quantitative activities of $\alpha$-amylase were observed in Z. mobilis cells harboring these plasmids with the $\alpha$-amylase gene inserted. Gas chromatographic analysis of ethanol showed that one of the Z. mobilis transconjugants was capable of producing 67 mM ethanol from rich medium(RM) containing 5% soluble starch as a sole carbon source.

• Journal of Microbiology and Biotechnology
• /
• 제8권1호
• /
• pp.21-27
• /
• 1998

The xylA gene of Bacillus stearothermophilus encoding the major ${\beta}$-xylosidase was previously cloned and sequenced. In the present study we examined the regulation of the cloned xylA gene expression in Bauillus subtilis MW15 carrying the xylA::aprA fusion plasmids. The induction of the fused xylA gene expression remained uninfluenced by any of the carbon sources tested but the gene expression was repressed about 2-3 fold in the presence of glucose. Two CRE-like sequences (CRE-1: nucleotides ＋ 124 to ＋136 and CRE-2: ＋247 to ＋259) were recognized within the reading frame region of the xylA gene. The deletion experiments showed that the CRE-2 sequence had a role in catabolite repression (CR) as a true CRE of the xylA gene, but the CRE-1 had no effect on CR of the xylA gene expression. Surprisingly, the deletion of the CRE- 1 sequence reduced about 2~3 fold of the expression of the xylA fused gene. The repression ratios of the xylA gene expression were estimated to be about 0.4 from the assay of subtilisin activity, and about 0.3 at the level of transcription by determining the amounts of xylA transcripts in B. subtilis. While, the level of CR of the xylA gene was assessed to be about l0-fold in previous work when the relative amounts of the xylA transcripts were measured in B. stearothermophilus.