• Korean Journal of Microbiology
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• v.27 no.1
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• pp.43-47
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• 1989

Characteristics and roles of protease released during the germination of Dictyostelium discoideum spores were investigated. When geat activated, the spores germinated, progressively releasing the protease into the extracellular medium. The protease activity exhibited high at pH 2.5. When cyclogeximide was added to culture, complete germination (emergence) and protease release were stopped. Addition of purified nonspecific protease to culture speeded up germination. These results suggest that excreted protease may play a role in removal of the spore wall.

• Microbiology and Biotechnology Letters
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• v.18 no.4
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• pp.344-351
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• 1990

An alkalophilic microoganism producing a detergent-resistant alkaline protease was isolated from soil and identified as Baeiltus sp. The alkaline protease has been partially purified by ammonium sulfate fractionation, DEAE-Cellulose, CM-Cellulose and Sephdex G-100 column chromatography. The purified alkaline protease was highly active at pH 12-13 toward casein and stable at pH values from 6 to ll. The optimum temperature for the enzyme reaction was $55^{\circ}C$. The enzyme was completely inactivated by diisopropyl fluorophosphate (DFP) indicating that the enzyme was serine protease, but considerabiy stable in the presence of surface active agents.

• Journal of Life Science
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• v.31 no.8
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• pp.761-770
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• 2021

In this study, the optimal medium composition for enhancing protease production was established by the Bacillus strain isolated from Makgeolli, a traditional fermented food, using the response surface methodology. B. amyloliquefaciens SRCM115785 was selected as the protease producer by productivity analysis and identified by 16S rRNA gene sequencing. Plackett-Burman design (PBD) was introduced to analyze the effect of each component on protease production among the 11 selected medium components. As a result, glucose, yeast extract, and beef extract were finally selected as factors for enhancing protease production. Central composite design (CCD) analysis was designed as a method to determine the optimal concentration of each component for protease production and the concentration of each medium composition for maximum protease production was predicted to glucose 6.75 g/l, yeast extract 12.42 g/l and beef extract 17.48 g/l. The suitability of the experimental model was proved using ANOVA analysis and as a result of quantitative analysis to prove this, the amount of increase was 230.47% compared to the LB medium used as a control. Through this study, the optimization of medium composition for enhancing protease production was established, and based on this, it is expected that it can be efficient use of protease as an industrial enzyme.

• Microbiology and Biotechnology Letters
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• v.42 no.3
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• pp.293-296
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• 2014

This study was conducted to investigate the effect of culture temperature on the growth rate and protease activity of Antarctic microorganisms. The Antarctic microorganisms PAMC 25641, 25614, 25719 and 25617 were obtained from the Polar and Alpine Microbial Collection (PAMC) at the Korea Polar Research Institute. These microorganisms were confirmed for the excretion of protease on a plate with skim milk. The identification of microorganisms was carried out using the 16S rDNA sequencing method. PAMC 25641 showed the highest protease activity among the subjects tested, and PAMC 25617 exhibited the highest growth rate. The growth rates of the microorganisms were not affected by temperature, except for PAMC 25617. However, protease activities were increased for all strains in a temperature dependent fashion. These results suggest the possible application of Antarctic microorganisms for the efficient production of low temperature proteases.

• Microbiology and Biotechnology Letters
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• v.23 no.2
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• pp.145-149
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• 1995

For the purpose of developing a new biodegradable detergent, we have isolated a gene encoding wide-range temperature applicable alkaline protease from Xanthomonas sp. YL-37 (Lee et al., 1994, Kor. J. Appl. Microbiol. Biotechnol.). An alkaline protease gene was isolated from the gene bank that was prepared from the chromosomal DNA of Xanthomonas sp. YL-37. From the results of agarose gel electrophoresis and a restriction enzyme mapping, a 2.7 kb DNA fragment containing the alkaline protease gene was inserted in the plasmid pUC9. Extracellular activity of a clone having alkaline protease gene was detected on SDS-polyacrylamide gel with activity staining assay. The molecular weight of alkaline protease was determined to be about 64 kDa from 11% SDS-PAGE analysis. Alkaline protease activity, produced from E. coli which harboring the plasmid, showed no difference at reaction temperature 20, 30 and 40$\circ$C, respectively. This result showed that alkaline protease produced from E. coli harboring the plasmid was apparently the same as that of Xanthomonas sp. YL-37.

• 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.

• Korean Journal of Microbiology
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• v.10 no.2
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• pp.69-72
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• 1972

The studies of neutral protease which was obtained by passing through Sephadex A-50 had been reported not long ago. Since that time the author also conducted the research to be investigated the physical properties of acid protease absorbed by Sephadex A-50. The results are summarized as follows : 1) Cultivating Aspergillus oryza SHW-131 on a wheat bran medium, the acid protease including neutral protease is very sensitive for temperature. 3) Activity of acid protease is very sensitive for temeprature. 3) This enzyme was proved, what is called, to be a sort of weak acid protease. It's optimum pH was lied in about 4.5. 4) A range of pH for stability is far more narrow than any other protease. 5) The acid protease is dropped by EDTA solution in its activity.

• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.524-529
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• 2015

This study was conducted to optimize the medium composition for cold-adaptive protease production of Enterobacteriaceae sp. by response surface methodology (RSM). Yeast extract, and TritonX-100 were identified as the significant factors affecting protease from one-factor-at-a-time method. RSM studies for optimizing protease production of Enterobacteriaceae sp. have been carried out for three parameters including yeast extract concentration, TritonX-100 concentration, and culture pH. These significant factors were optimized as 6.690 g/L yeast extract, 0.018 g/L Triton$^{TM}$ X-10, and pH 6.677. The experimentally obtained protease activity was 8.03 U /L, and it became 1.5-fold increase before optimization.

• Korean Journal of Microbiology
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• v.18 no.1
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• pp.15-19
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• 1980

In order to study on the pigment and protease of Serratia marcescens, the correlation between protease activity and pigment formation was investigated. The results are as follows ; (1) The protease activity exhibitied two pH optima 6.0 and 7.5, respectively. (2) The optimal temeprature of proteolytic activity was $45^{\circ}C$. With these-results, it is suggested that the proteolytic enzymes of Serratia masrecescens is stable at neutral pH range and more active at the high temeprature than lthat of otehr proteolytic enzymes.

• Korean Journal of Microbiology
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• v.24 no.1
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• pp.32-37
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• 1986

In fermentation studies it revealed that Streptomyces sp. SMF 3001 started to synthesize extracellular alkaline protease from early exponential phase of cell growth. The biosynthesis of the alkaline protease was greatly induced by skim milk as a sola nitrogen source and further stimulation was observed under inorganic sulphur limited culture. However, it was found that the biosynthesis was apparently repressed by $NH_4^+$ and free amino acids, specially by cysteine. It was considered that the strain SMF 301 of Streptomyces sp. would produce the alkaline protease for the uptake of sulphur compounds from protein contained in the culture broth.