• 한국미생물·생명공학회지
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• 제8권2호
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• pp.77-85
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• 1980

Protease의 생산능이 우수한 Asp. oryzae KC-15를 선정하고 다음과 같은 결과를 얻었다. 1. Wheat bran medium에서의 최적배양시간은 acid protease와 neutral protease는 약 48시간, alkaline protease는 약 72시간이었고 본 균주가 생산하는 protease는 alkaline protease와 neutral pro-tease가 주체이며 acid protease는 극히 미약하였다. 2. Wheat bran medium 에 $Na_2$HPO$_4$, NaH$_2$PO$_4$, Glucose, rice powder 및 Na-glutamate의 첨가는 alkaline protease와 neutral psotease의 생산에, (NH$_4$)$_2$HPO$_4$, glucose 및 rice powder의 첨가는 acid protease의 생산에 효과적이었다. 3. 조효소의 특징(equation omitted) 4. 내열제로서 NaH$_2$PO$_4$가장 효과적이었으며 최적첨가량은 alkaline protease와 neutral protease 에 대하여는 10mg, acid protease에 대하여는 5mg 이었다. 5. 6$0^{\circ}C$ 이상에서는 NaH$_2$PO$_4$의 내열효과는 거의 인정할 수 없었다. 6. NaH$_2$PO$_4$10mg을 첨가하고 55$^{\circ}C$에서 30분간 처리하였을 때의 잔존활성은 alkaline protease는 약 58%, neutral protease는 약 57%, acid protease는 약 55 %이었다.

• 미생물학회지
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• 제18권2호
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• pp.51-58
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• 1980

Mutational experiments were performed to improved to improve the protease productivity of Aspergillus flavus KU 153, which is selected among the wild strains. A UV-induced mutant strain having high protease productivity was obtained by the use of the clear zone method as a simple criterion for a primary screening test. Neutral and alkaline protease activities of hte mutant strain were higher than 1.8 times, comopared with those of the parental strain, respectively, while in the case of acid protease, it was 2.7 times. The mutant strain selected was more powerful in the production of cellulase and amylase, as well s protease in wheat bran, compared with those of the parental strain. protease production of the parental strain has reached maximum level at 3 days culture, while alkaline nad neutral protease production of the mutantstrain has reached at 2 days culture. On the other hand, the mutant strain formed the spore slowly, compared with the parental strain. Column chromatography of the neutral protease on DEAE-Sephadex A-50 showed that the mutant strain was not induced the formation of another neutral protease isozyme, but induced the variation in the function of regulatory gene.

• 한국미생물·생명공학회지
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• 제30권4호
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• pp.346-351
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• 2002

토양으로부터 pretease활성이 우수한 균주를 선별하여 형태학적, 생화학적 동정과정 및 16 rRNA염기서열 분석 등의 방법을 이용하여 Bacillus sp. DS-1으로 동정하였다. Bacillus sp. DS-1은 초기 배지의 pH가 7.0인 조건에서 정지기에서 가장 높은 활성을 나타내었다. Bacillus sp. DS-1으로부터 protease를 생산하기 위해 탄소원으로는 1% glucose, 질소원으로는 1% yeast extract를 첨가할 때 대조구와 비교하여 각각 20%와 30% 더 효과적인 것으로 나타났다. Bacillus sp. DS-1이 생산하는 protease의 최적활성은 55$^{\circ}C$와 pH 7.0이었다. 1 mM의 EDTA첨가에 의해 protease활성이 84%실활 되었고 이 결과로부터 Bacillus sp. DS-1의 상등액에 존재하는 주된 protease 활성은 metalloprotease임을 알 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제10권1호
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• pp.103-106
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• 2000

Bacillus cereus KCTC 3674 excretes at least two kinds of extracellular proteases into the growth medium. Two major bands of the protease activity with molecular weights of approximately 100 and 38 kDa were obtained after gelatin-SDS-PAGE. The protease with a molecular weight of 38kDa was identified as an extracellular neutral (metallo-) protease. The neutral protease was quite thermostabile but labile to alkaline pH. On the contrary, the 100-kDa protease was thermolabile but stable to alkaline pH. The production of 38-kDa neutral protease was strongly affected by temperature, oxygen, carbonylcyanied m-chlorophenylhydrazone(CCCP) that was defined as a protonophofre, and cerulenin which inhibited lipid synthesis and caused changes in the membrane composition. On the other hand, the production of the 100-kDa protease was strongly affected by only temperature and cerulenin. Quinacrine (0.2 mM), which inhibits the penicillinase-releasing proteases of Bacillus licheniformis, had no effect, whatsoever, on the production of extracellular proteases in B.cereus KCTC 3674.

• 미생물학회지
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• 제14권2호
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• pp.49-49
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• 1976

Enzyme activities, such as glucoamylase dextrinogenic amylase, cellulase, acid protase and neutral protease, of Rhizopus isolated from various substrates collected throughout South Korea are measured, and their enzyme activities are surveyed from taxonomical, ecological and physiological viewpoint. Effect of carbon sources and phytohormones on the amylalse production of Rhizopus are also measured. Among the 735 strains of Phizopus isolated, strain number 587 exhibiting most prominent dextrinogenic amylase and netral protease activity is selected as the best strain, and the strain number 673, 108, 329, 165 and 728 are seleted for their predominant cellulase, acid protease, glucoamylase, dextrinogenic amylase and neutral protease activities, respectively. R.acidus and R.nigricans which exhibited relatively higher callulalse activity, showed lower activities for both amylase. R.tritici exhibited higher protease activity. The relations between activities and various substrates of wild strains are not outstnading difference, although the strains isolated from inland region exhibited more or less higher amylase and cellulase activities, than those of coast region, generally. Lactose and dextrin are most effective carbon sources for glucoamylase and dextrinogenic amylase production of the Rhizopus niveus, respectively. Although all phytohormones tested are effective for production of amylase by the Rhizopus strains, except nicotinamide for glucoamylase production, biotin and ascorbate are most effective for dextrinogenic amylase and glucoamylase production, respectively.

• 미생물학회지
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• 제14권2호
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• pp.47-56
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• 1976

Enzyme activities, such as glucoamylase dextrinogenic amylase, cellulase, acid protase and neutral protease, of Rhizopus isolated from various substrates collected throughout South Korea are measured, and their enzyme activities are surveyed from taxonomical, ecological and physiological viewpoint. Effect of carbon sources and phytohormones on the amylalse production of Rhizopus are also measured. Among the 735 strains of Phizopus isolated, strain number 587 exhibiting most prominent dextrinogenic amylase and netral protease activity is selected as the best strain, and the strain number 673, 108, 329, 165 and 728 are seleted for their predominant cellulase, acid protease, glucoamylase, dextrinogenic amylase and neutral protease activities, respectively. R.acidus and R.nigricans which exhibited relatively higher callulalse activity, showed lower activities for both amylase. R.tritici exhibited higher protease activity. The relations between activities and various substrates of wild strains are not outstnading difference, although the strains isolated from inland region exhibited more or less higher amylase and cellulase activities, than those of coast region, generally. Lactose and dextrin are most effective carbon sources for glucoamylase and dextrinogenic amylase production of the Rhizopus niveus, respectively. Although all phytohormones tested are effective for production of amylase by the Rhizopus strains, except nicotinamide for glucoamylase production, biotin and ascorbate are most effective for dextrinogenic amylase and glucoamylase production, respectively.

• 미생물학회지
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• 제26권4호
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• pp.355-361
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• 1988

성장속도가 빠르고포지형성이 우수한 방사균 일주를 토양에서 분리한 뒤 분리균의 특성을 조사한 결과 세포외 단백질 분해 효소가 중성과 알카리성의 두 종류가 생성되었으며 $\beta$-lactamase도 생성함을 알았다. 이 균주를 acriflarin 또는 NTG로서 처리하여 얻은 변이주는 포자의 형성, $\beta$-lactamase의 생성 및 protease의 생합성 능력이 소실 또는 크게 저하되었다. 일단계의 변이주 취득에서 동시에 형질의 변화가 다양하게 나타난 원인을 규명한 결과 호알카리성 protease의 생합성이 크게 저하되었음을 알았다. 따라서 방선균에서 포자형성과 호알카리성 protease의 활성이 일정한 연관성이 있을 것으로 판단되었다.

• 한국식품영양학회지
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• 제6권2호
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• pp.96-102
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• 1993

A Nuluk, a Korean traditional koji for brewing, was made with wheat flour and Rhizopus japonicus T2 which had a good aroma and strong abilities in producing saccharogenic and proteolytic enzymes, and cultural conditions for the production of those two enzymes were tested. The productivity of saccharogenic enzyme was markedly improved when Nuluk was made with unsteamed wheat flour as compared with that with steamed one, but that of acid protease was reduced. The addition of water containing 0.5% hydrochloric acid was unfavorable for the production of saccharogenic enzyme and neutral protease. The optimum ratio of water added to wheat flour for the production of saccharogenic enzyme and proteolytic enzyme was 28% on the basis of wheat flour. The productivity of saccharogenic enzyme was enhanced "when the Nuluk was molded after 10~20 hours precultivation but that of proteolytic enzyme was reduced as compared with no molding. The optimum temperature for the production of saccharogenic enzyme was 28f and that of proteolyic enzyme was also 28$^{\circ}C$. The optimum cultural time for the production of saccharogenic enzyme was 36 ~72 hours at 3$0^{\circ}C$ and that of proteolytic enzyme was 36 hours.ours.

• 한국미생물·생명공학회지
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• 제22권1호
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• pp.59-64
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• 1994

The production and the characteristics of protease produced by Bacillus sp. SH-8 and Bacillus sp. SH-8M were investigated under the different pH conditions. Bacillus sp. SH-8 and Bacillus sp. SH-8M showed the maximum activity of protease at 60 hours(70 units/ml) AND 96 houre(50 units/ml) cultivation, respectively, under the alkaline condition(pH 10.2). However, Bacillus sp. SH-8M exhibited the maximum activities in 8 days cultivation at pH 6.9 and in 6 days cultivation at pH 7.7 Bacillus sp. SH-8M showed the protease activity at the pH change from alkaline to neutral condition, whereas Bacillus sp. SH-8 did not. In addition. all the enzymatic characteristics of protease produced by Bacillus sp. SH-8 and Bacillus sp. SH-8M were similar with the regardless of different pH conditions.

• Asian-Australasian Journal of Animal Sciences
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• 제14권12호
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• pp.1769-1774
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• 2001

Bacillus licheniformis strains L-25 and PWD-1 are two thermophilic feather-degrading bacteria. Despite isolated from different environmental conditions, they were both capable of breaking down chicken feathers and growing in a medium in which feather was the only source of carbon and nitrogen. A 1.46-kb keratinase gene (ker B) was isolated from strain L-25 by a polymerase chain reaction (PCR) using L-25 genomic DNA as templates. Sequencing results reveal that ker B shares great sequence identity with a previously published keratinase gene of B. licheniformis PWD-1 (ker A). Only two amino acids differences were found in the deduced amino acid sequence between the keratinases from L-25 and PWD-1. However several nucleotide changes were found upstream of the putative promoter region. Protease inhibition studies indicated that neutral protease activity accounted for approximate 25 to 30% of total extracellular proteolytic activity produced by strain L-25 in the feather medium. In contrast, no measurable neutral protease activity was produced by strain PWD-1 in the feather medium. When glucose (1%), a common catabolic repressor, was added into the feather medium, L-25 was still able to grow and produce keratinase. Strain PWD-1 produced no neutral protease activity and its growth was severely inhibited in the feather medium containing glucose. L-25 produced an enhanced level of keratinase in the feather medium in comparison with PWD-1.