• Microbiology and Biotechnology Letters
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• v.8 no.2
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• pp.77-85
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• 1980

This experiment was conducted to investigate the conditions for production and the characteristics of pretenses. Aspergillus oryzae KC-15, which is selected as a superior strain for the production of the protease, was used in this study. The results obtained were as follows: 1. The optimum culture time for the production of acid, neutral and alkaline protease on wheat bran medium were about 48, 48 and 72hr, respectively. The protease-produced by the strain were mainly alkaline and neutral one, but the production of acid protease was feeble extremely. 2. The addition of NaH$_2$PO$_4$, Na$_2$HPO$_4$, glucose, rice powder and Na-glutamate respectively to wheat bran media were effective for the production of alkaline and neutral protease, and the addition of (NH$_4$)$_2$HPO$_4$, glucose and rice powder respectively were effective for the production of acid protease. 3. Characteristics of professes(equation omitted) 4. As a heat resistance agent, NaH$_2$PO$_4$was the most effective one. The optimum amount of NaH$_2$PO$_4$was 10mg for alkaline and neutral protease, and 5mg for acid protease. 5. The heat resistance of the Protease by NaH$_2$PO$_4$was not recognized mostly above 6$0^{\circ}C$. 6. After the treatment of enzyme solution with 10mg of NaH$_2$PO$_4$for 30 minutes at 55$^{\circ}C$, the residual activities measured for alkaline, neutral and acid protease were 58, 57 and 55％ respectively.

• Korean Journal of Microbiology
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• v.18 no.2
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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.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.346-351
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• 2002

A bacterium producing the neutral pretense was isolated from soil, and was identified as Bacillus sp. DS-1 by 16S rRNA sequence comparison and biochemical determinations. The production of protease from Bacillus sp. DS-1 was increased 20% and 30% by the additions of 1% glucose and 1% yeast extract, respectively. The optimum pH and temperature for the protease activity were pH 7.0 and 55$^{\circ}C$. Bacillus sp. DS-1 produced a metalloprotease as a major protease in culture medium, since the pretense activity in culture supernatant was inhibited by the presence of 1 mM EDTA significantly.

• Journal of Microbiology and Biotechnology
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• v.10 no.1
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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.

• Korean Journal of Microbiology
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• v.14 no.2
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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.

• Korean Journal of Microbiology
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• v.14 no.2
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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.

• Korean Journal of Microbiology
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• v.26 no.4
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• pp.355-361
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• 1988

The aims of the present studies were to understand the physiolosical and genetic characters of Streptomyces sp. isolated from soil. It revealed that Streptomyces sp. SMF301 had very fast growth rate and produced extracellular protease and heavily sporulated on rich media. It also showed $\beta$-lactamase activity and pigment production. Nonsporulating mutants were isolated after NTG or acriflavin treatment and their characters were compared with the parent strain. It was found that the mutants obtained by acriflavin treatment and ghier characters were compared with the parent strain. It was found that the mutants obtained by acriflavin treatment lost the pigment formation and $\beta$-lactamase production. Protease actibity of the mutant was lowered and the pH optimum was changed toward neutral. It was found that the changes were resulted from the reduction of alkaline protease biosynthesis in the bald mutant. Therefore it is considered that sporulation, pigment formation, $\beta$-lactamase production, and alkaline protease production in Streptomyces sp. might be controlled with a closely related relationship.

• The Korean Journal of Food And Nutrition
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• v.6 no.2
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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.

• Microbiology and Biotechnology Letters
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• v.22 no.1
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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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• v.14 no.12
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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.