• 한국식품영양과학회지
• /
• 제26권5호
• /
• pp.844-850
• /
• 1997

$\alpha$-Galactosidase was partially purified from the culture filtrate of pichia guilliermondii by Mannobiose-Sepharose affinity column chromatography. The galactosidase exhibited maximum activity at pH 4.5 and 4$0^{\circ}C$, and was stable in the pH and temperature ranges of 4 to 5.5 and 30 to 6$0^{\circ}C$, respectively. The enzyme was inhibited by $Hg^{2+}$ and $Ag^{2+}$. The enzyme activity was ot affected considerably by treatment with other metal compounds. The enzyme hydrolyzed melibiose to galactose and glucose, raffinose to galactose and sucrose, and $Gal^{3}Man_{3}(6^{3}-$\alpha$-galactosyl-1,4-mannotriose)$ to galactose and mannotriose. On the contrary, it could not hydrolyze $Gal^{3}Man_{4}(6^{3}-galactosyl-1,4-$\alpha$-mannotetraose)$.

• 한국식품영양과학회지
• /
• 제24권2호
• /
• pp.242-246
• /
• 1995

This paper was carried out to investigate changes in cell wall, cell wall polysaccharides, pectic substances extracted from cell wall of persimmon fruits treated with polygalacturonase and $\beta$-galactosidase in vitro. Degrading degree of cell wall treated with cell wall-degrading enzymes were higher in order polygalacturonase, polygalacturonase+$\beta$-galactosidase and $\beta$-galactosidase. Contents of soluble pectic substances in cell wall treated with cell wall-degrading enzymes showed as the same order as degrading degree of cell wall, while contents of insoluble pectin lower. Contents of versene-soluble pectin and total pectic substance were not affected by cell wall-degrading enzymes. Contents of uronic acid and hexose in soluble material isolated from cell wall treated with polygalacturonase and mixed enzyme were higher than those of untreatment and $\beta$-galactosidase treatment.

• 한국미생물·생명공학회지
• /
• 제20권1호
• /
• pp.46-52
• /
• 1992

농축유청으로부터 유청음료 제조를 위한 최적조건을 조사하기 위해 역삼투장치(reverse osmosis system)를 사용하여 치즈유청 속의 유당을 농축한 수 $\beta$-D-glactosidase로 가수분해시켜 그 분해정도를 HPLC(high performance liquid chromatography)로 측정하였다. 유당의 가수분해 정도는 농축적 유청, 2배 농축 유청과 3배 농축 유청 순으로 가수분해되었고 일정량의 효소첨가에 의해 농축된 염이 $\beta$-D-Galactosidase에 대한 약간의 저해작용을 일으켰다.

• 한국미생물·생명공학회지
• /
• 제17권5호
• /
• pp.524-528
• /
• 1989

토양으로부터 분리한 호알카리성 Bucillus sp. YS-309는 $\beta$-galactosidase 생산력이 강력하였으며 중성배지 보다도 알카리배지 중에서 균체생육 및 효소생산량이 많았다. 이 분리균의 최적 배양조건은 lactose 0.5%, yeast extract 0.5%, defatted soybean meal extract 0.6%(v/v)가 함유된 PH9.9의 알카리 배지를 사용하였을 때 얻어졌다. 이 때의 배양온도는 4$0^{\circ}C$, 배양시간은 24-30시간의 바람직한 것으로 나타났다. 또 IPTG와 lactose에 의해 효소생산이 유도적으로 증가하였으며 전자는 후자의 3배 효과가 있었다. Lactose 농도도 균체생육 및 효소생산에 영향을 미쳤으며 그 농도가 1.5% 이상 배지 중에 첨가되면 균체생육 및 효소생산이 모두 감소하였다.

• Journal of Microbiology and Biotechnology
• /
• 제29권11호
• /
• pp.1717-1728
• /
• 2019

The gene encoding β-galactosidase was cloned from Bifidobacterium longum RD47 with combinations of several bifidobacterial promoters, and expressed in B. bifidum BGN4. Among the recombinant bifidobacteria, BGN4+G1 showed the highest β-galactosidase level, for which the hydrolytic activity was continuously 2.5 to 4.2 times higher than that of BGN4 and 4.3 to 9.6 times higher than that of RD47. The β-galactosidase activity of BGN4+G1 was exceedingly superior to that of any of the other 35 lactic acid bacteria. When commercial whole milk and BGN4+G1 were reacted, BGN4+G1 removed nearly 50% of the lactose in the milk by the 63-h time point, and a final 61% at 93 h. These figures are about twice the lactose removal rate of conventional fermented milk. As for the reaction of commercial whole milk and crude enzyme extract from BGN4+G1, the β-galactosidase of BGN4+G1 eliminated 51% of the lactose in milk in 2 h. As shown below, we also compared the strengths and characteristics of the strong bifidobacterial promoters reported by previous studies.

• Asian-Australasian Journal of Animal Sciences
• /
• 제26권4호
• /
• pp.552-557
• /
• 2013

Partially purified ${\alpha}$-galactosidase from Bacillus sp. LX-1 was non-covalently immobilized on a reversibly soluble-insoluble polymer, Eudragit L-100, and an immobilization efficiency of 0.93 was obtained. The optimum pH of the free and immobilized enzyme was 6.5 to 7.0 and 7.0, respectively, while there was no change in optimum temperature between the free and immobilized ${\alpha}$-galactosidase. The immobilized ${\alpha}$-galactosidase was reutilized six times without significant loss in activity. The immobilized enzyme showed good storage stability at $37^{\circ}C$, retaining about 50% of its initial activity even after 18 d at this temperature, while the free enzyme was completely inactivated. The immobilization of ${\alpha}$-galactosidase from Bacillus sp. LX-1 on Eudragit L-100 may be a promising strategy for removal of ${\alpha}$-galacto-oligosaccharides such as raffinose and stachyose from soybean meal and other legume in feed industry.

• 한국미생물·생명공학회지
• /
• 제26권1호
• /
• pp.40-44
• /
• 1998

토양으로부터 갈락토스 전이활성이 우수한 $eta$-galactosidase를 생산하는 미생물을 분리하고 부분동정하여 한국종균협회에 Penicillium sp. KFCC 10888로 등록하였다. 효소는 40% 유당 용액에서 초기 유당의 73%가 전환되었을 때 70%의 높은 전이율을 보였다. 효소의 생합성은 유당에 의하여 유도되지 않았으며 배지성분으로는 콩가루가 효소 생산에 효과적이었다. 효소의 갈락토스 전이반응에 대한 최적 pH는 4.0, 최적온도는 55$^{\circ}C$이었으며, 55$^{\circ}C$에서 열안정성이 우수하였다. 갈락토올리고당의 생성량은 기질의 농도에 비례하였으며, 40%유당용액의 경우 갈락토올리고당의 함량은 고형분중 40%까지 향상되었다.

• Journal of Microbiology and Biotechnology
• /
• 제6권6호
• /
• pp.386-390
• /
• 1996

The ${\beta}$-galactosidase gene from Lactococcus lactis subsp. lactis ATCC 7962 was cloned and its enzymatic properties were characterized, with a view to assessing its potential use as a selection marker in the food-grade cloning vector. Chromosomal DNA from L. lactis subsp. lactis 7962 was cleaved with PstI and ligated into pBR322 for transformation into Escherichia coli TGl. Transformants showing ${\beta}$-galactosidase activity possessed the pBR322 plasmid containing a 10 kilobase (kb) PstI fragment and this plasmid was named pCKL11. The cloned ${\beta}$-galactosidase gene came from the chromosomal DNA of L. lactis subsp. lactis 7962 was confirmed by Southern hybridization. A restriction map of pCKL11 was constructed from the cleavage of both pCKL11 and the purified 10kb insert fraqment. The. optimum pH of the ${\beta}$-galactosidase determined with the E. coli harboring the pCKL11 was 7.0. The optimum temperature was $50^{\circ}C$, while the pI of the enzyme was 7.4. These values were the same as those of the enzyme from the parent strain.

• KSBB Journal
• /
• 제11권4호
• /
• pp.431-437
• /
• 1996

본 연구에서는 질산염(nitrate) 존재하에서 혐기 조건이 되면 최대로 발현되는 변형된 naT 프로모터 를 대장균내에서 단백질을 대량 생산하기 위한 발현 운반체로 쓰일 수 있는지를 조사하였다. 이를 위해 용존산소농도에 따라 naT 프로모터의 유도에 영향을 미치는 염색체 fnT 유전자가 발현되지 못하는 대장 균(ES200l)에 pBR322 플라스미드에 프로모터상 의 10 지역에서 특정부위돌연변이화에 의해 con­s sensus sequence로 바핀 변형된(modified) naT 프 로모터(pMW616)가 도입되어 있는 계(pMW616/ E ES2001 )가 이용되었다. 이 변형된 naT 프로모터의 하류에는 구조유전자(structural gene) 인 질산염 환 원효소대 신에 ${\beta}$-galactosidase를 발현하는 lacZ 유 전자가 클로닝되어 있다. 이 변형된 naT 프로모터의 유도에 대한 최적조건을 찾기 위해 변형된 naT 프로 모터를 유도시키는 방법, 변형된 naT 프로모터가 최 대로 유도되는 질산엽의 농도, 말현된 $\beta$galactosid a ase의 양 빛 변형된 naT 프로모터가 유도되는 특성 들이 조사되었다. 이에 대한 실험으로부터 다음과 같은 결론들이 얻어졌다; 이 변형된 naT 프로모터로 부터 ${\beta}$-galactosidase의 말현은 질산염의 농도에 의 해서는 크게 영향을 받지 않았다. 한편, 변형된 naT 프로모터로부터 ${\beta}$-galactosidase의 말현은 성장단계 에서 대장균을 호기상태에서 OD600이 약 2.27~ 될 때까지 키우다가 유도시 혐기상태로 만드는 것이 가 장 유리하였으며, 이 때 발현된 ${\beta}$-galactosidase의 비활성도는 약 13,000 Miller unit였다. 하지만, 이 변형된 naT 프로모터는 이켓을 유도시키기 전에도 발현된 ${\beta}$-galactosidase의 비활성도가 약 6,000 M Miller unit로 매우 높음으로 인하여 이 변형된 naT 프로모터는 원하는 단백질을 유도성보다는 구성적으 로 발현시키는데 더 적합한 프로모터였다.

• KSBB Journal
• /
• 제26권3호
• /
• pp.199-205
• /
• 2011

Using tetrameric ${\beta}$-galactosidase as a model protein, anchoring motives were screened in Bacillus subtilis spore display system. Eleven spore coat proteins were selected considering their expression levels and the location in the spore coat layer. After chromosomal single-copy homologous integration in the amyE site of Bacillus subtilis chromosome, cotE and cotG were chosen as possible spore surface anchoring motives with their higher whole cell ${\beta}$-galactosidase activity. PAGE and Wester blot of extracted fraction of outer layer of purified spore, which express CotE-LacZ or CotG-LacZ fusion verified the existence of exact size of fusion protein and its location in outer coat layer of purified spore. ${\beta}$-galactosidase activity of spore with CotE-LacZ or CotG-LacZ fusion reached its highest value around 16~20 h of culture time in terms of whole cell and purified spore. After intensive spore purification with lysozyme treatment and renografin treatment, spore of BJH135, which expresses CotE-LacZ, retained only 1~2% of its whole cell ${\beta}$-galactosidase activity. Whereas spore of BJH136, which has cotG-lacZ cassette in the chromosome, retained 10~15% of its whole cell ${\beta}$-galactosidase activity, proving minor perturbation of CotG-LacZ, when incorporated in the spore coat layer of Bacillus subtilis compared to CotE-LacZ. Usage of Bacillus subtilis WB700, of which 7 proteases are knocked-out and thereby resulting in 99.7% decrease in protease activity of the host, did not prevent the proteolytic degradation of spore surface expressed CotG-LacZ fusion protein.