• 생명과학회지
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• 제14권3호
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• pp.391-395
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• 2004

B. stearothermophilus NO2의 CGTase 유전자 (cgtS)를 구성적 $P_{JH}$ promoter 하류에 subcloning 하여 재조합 plasmid pIH-CGT1 (8.14 kb)을 구축하고 B. subtilis DB431에 형질 전환하였다. B. subtilis DB431/pJH-CGT1를 5가지 배지(LB, 2${\times}$LB, 5% molasses+2% CSL, CS, LBG)로 flask 배양하여 균체증식과 CGTase발현량 및 분비국재성을 조사하여 최적 배지를 결정하였다. 그 중 〔5% molasses+2% CSL〕 배지에서 9시간에 1.8 unit/$m\ell$의 CGTase가 발현$.$생산되었다. 이 결과를 토대로 3. subtilis DB431/pJH-CGT1를 〔10% molasses + 5% corn steep liquor〕 배지에서 발효조 회분 배양한 결과, 30시간 배양시 CGTase의 최대 발현량은 4.2 unit/$m\ell$, 90%의 분비 효율, 90% 이상의 plasmid 안정성을 나타내었다. 저렴한 산업용 molasses 배지로 발효조 회분배양시 플라스크 배양보다 균체증식과 CGTase 발현량이 2배 이상의 증가된 값을 얻었다.

• Journal of Microbiology and Biotechnology
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• 제10권4호
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• pp.551-553
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• 2000

A strong constitutive $P_{JH}$ promoter from Bacillus was applied to overexpress the endoxylanase gene in B. subtilis. The expression plasmid, pHJKJ4, was designed to contain the $P_{JH}$ promoter and endoxylanase promoter ($P_B$), and introduced into B. subtilis DB104. Through batch fermentation of the trasformant cell on a maltose medium, endoxylanase was produced in a growth-associated manner as the predominant protein. The total activity reached about 600 unit/ml at the end of the cultivation, which corresponded to 698 mg endoxylanase protein/l with a specific activity of 860 unit/mg protein. It was also found that the segregational plasmid instability was less than 30% and most of the endoxylanase activity was detected in the culture medium. This result suggests that the secretory production of endoxylanase can be significantly enhanced with the use of the $P_{JH}$ promoter and high-cell density culture techniques, quantitatively as well as qualitatively.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.707-710
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• 2003

A strong constitutive $P_{JH}$ promoter from Bacillus was applied to overexpress the end oxylanase gene in Bacillus subtilis. The expression plasmid, pJHKJ4, was designed to contain the $P_{JH}$ promoter and endoxylanase promoter $(P_B)$, and introduced into Bacillus subtilis DB431 The total activities of the enzymes reached about 140 unit/ml by cultivation of B. subtilis DB431 harboring pJHKJ4 in LB glucose medium. Ultrafilteration is effective its yield is 70%.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.536-539
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• 2003

A strong constitutive $P_{JH}$ promoter from Bacillus sp. was applied to overexpress the endoxylanase gene in Bacillus subtilis. The expression plasmid, pJHKJ4, was designed to contain the $P_{JH}$ promoter and open reading frame of endoxylanase including its own promoter. The plasmid was introduced into B. subtilis DB431 and the resulting transformant was grown on LB glucose medium. The endoxylanase activity in the culture supernatant reached about 140 unit/ml. The enzyme in the supernatant was efficiently concentrated to 70% by two-step treatments of ammonium sulfate saturation and ultrafiltration. The stabilization of concentrated enzyme solution at different storage temperatures was examined with various stabilizers such as NaCl, $CaCl_2$, sucrose, sorbitol, polyethylene glycol, and Tween-80.

• 한국미생물·생명공학회지
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• 제32권4호
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• pp.322-327
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• 2004

구성적 promoter인 $P_{JH}$ promoter 하류에 연결된 Bacillus sp. 유래의 endoxylanase를 B. subtilis에서 과발현 하였다. 발현된 plasmid, pJHKJ4는 자체 promoter($P_{B}$)와 Bacillus의 강력한 promoter($P_{JH}$)가 tandem으로 위치하여 transcription되었다. B.subtilis DB431에 형질전환된 균주를 glucose가 함유된 LB 배지에서 배양 후 총활성 및 분비효율은 140 U/ml 으로 나타났다. 배양상등액은 ultrafiltration(MW cut off 10 kDa and 30 kDa)과 염석법으로 농축하였다. 효소의 농축에서 ultrafiltration이 70% ammonium sulfate precipitation 보다 효과적이었다. $50^{\circ}C$ 에서 농축된 효소액의 안정화는 NaCl, glycerol, sorbitol, and $CaCl_{2}$ 등의 다양한 안정제를 농도별로 첨가하여 안정제의 효과를 검토한 결과 가장 효과적인 안정제는 NaCl과 $CaCl_{2}$ 이었다.