• Microbiology and Biotechnology Letters
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• v.19 no.3
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• pp.281-289
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• 1991

Neurospora crassa (KCTC 6079) produces tyrosinase (EC 1.14.18.1) during sexual differentiation under derepressed conditions in the presence of inducers such as amino acid analogues, antimetabolites or protein synthesis inhibitors. The selection of inducer concentration and induction time as well as inducer type are critical for the optimization of the enzyme production. The best inducer was found to be cycloheximide. Since cycloheximide was toxic to the cells, an optimal inducer concentration and an optimal induction time were determined to maximize the enzyme production from batch cultures. Mathematical models for the cell growth and the enzyme production were proposed and used for process optimization. By optimizing the induction conditions, maximum tyrosinase productivity was increased significantly.

• Journal of Microbiology and Biotechnology
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• v.18 no.3
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• pp.434-442
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• 2008

We observed that an inclusion body (IB) of recombinant ${\beta}$-galactosidase that was produced by the araBAD promoter system in Escherichia coli (E. coil) showed enzyme activity. In order to improve its activity, the lowering of the transcription rate of the ${\beta}$-galactosidase structural gene was attempted through competition between an inducer (L-arabinose) and an inducer analog (D-fucose). In the deep-well microtiter plate culture and lab-scale fermentor culture, it was demonstrated that the addition of D-fucose caused an improvement in specific ${\beta}$-galactosidase production, although ${\beta}$-galactosidase was produced as an IB. In particular, the addition of D-fucose after induction led to an increase in the specific activity of ${\beta}$-galactosidase IB. Finally, we confirmed that the addition of D-fucose after induction caused changes in the structure of ${\beta}$-galactosidase IB, with higher enzyme activity. Based on these results, we expect that an improved enzyme IB will be used as a biocatalyst of the enzyme bioprocess, because an enzyme IB can be purified easily and has physical durability.

• KSBB Journal
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• v.21 no.2
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• pp.85-89
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• 2006

Typical property of the white-rot fungi is their ability to degrade lignin and other aromatic compounds with non-specific extracellular enzyme. In this work, the modification of the strain(Funalia trogii ATCC 200800) and the culture condition was performed to enhance enzyme productivity. Single cell was separated by the protoplasts formation and several putative laccase and manganese peroxidase inducers were tested. By adopting the modified strain, enzyme productivity increased comparing with that of the original strain. Extracellular enzyme formation was highly stimulated by the addition of copper and various aromatic compounds in the glucose-based culture medium.

• Journal of the Korean Wood Science and Technology
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• v.26 no.3
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• pp.41-47
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• 1998

Some white-rot fungi, screened at the Laboratory of Forest Products Microbiological Chemistry, Chungbuk National University were cultured and added the inducer of laccase enzyme, 2,5-xylidine. The fungi named by CB-13, CB-20, CB-99, CB-100 and CB-123 strains showed positive results in the decolorization of aromatic compounds, carminic acid and Rhemazol brilliant blue R. Concerned to the inducing effect of 2,5-xylidine on laccase activity, CB-20, CB-100 and CB-123 strains showed very high activity by addition of 2,5-xylidine, whilst CB-13, CB-99 and CB-124 strains produced relatively high laccase enzymes, regardless of inducer addition. There were no any laccase activities on CB-25, CB-64 and CB-139, even in addition of inducer. It is confirmed that some screened fungi have decolorizing ability on aromatic compounds, carminic acid and Rhemazol brilliant blue R. Also, the addition of inducer, 2,5-xylidine, has increased the activity of laccase enzyme which is secreted from some white-rot fungi.

• Korean Journal of Microbiology
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• v.14 no.1
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• pp.17-24
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• 1976

Celluloytic microorgnasims were isolated form the various sources and four of them were identified as Trichoderma roningi, Aspergillus niger, Penicillium chrysogenum, and Streptomyces sp. The induction of extracellular5 cellulase of these species in the liquid culture media containing carboxymethylcellulose (CMC) or Avicel as inducer showed that CMC was a better effective inducer for the production of CMCase(Cx cellulase component) as well as Avicelase(C$_{1}$ cellulase component) than Avicel. It is believed that certain hydrolysis products of cellulose(CMC) could serve as an inducer for an enzyme synthesis. In T. roningi, Asp. niger, and Strptomyces sp., the optimum temperature of CNCase on CMC-culture medium was 50.deg. but temperature around 40.deg.C was found to be optimum for the activities of CMCase prepared from P.ehrysogenum. The optimum temperature for Avicelase activitiles on Avicel-culture media of T. roningi and P. chrysogenum was $40{\circ}C$ whereas temperature $50{\circ}C$ was found to be optimum for Avicelase from A.niger and Streptomyces sp. The optimal activities of these CNCase and Avicelase prepared from. T. ronigi, Pen.chrysogenum and Streptomyces sp. were found similarly to be at pH's around 5.4 and 6.0 while pH 4.8 was optimum for the activities of CMCase and Avicelase from A.niger, indicating that A.niger in acidic media would yield an enzyme of high activity.

• Korean Journal of Microbiology
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• v.22 no.2
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• pp.77-84
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• 1984

This examined some conditions for the induction of ${\beta}$-D-galactosidase synthesis in Candida kefyr CBS 834. The optimal pH, temperature, and inoculum size either for growth or${\beta}$-D-galactosidase synthesis were 5.5, $30^{\circ}C$ and above 0.2 at A610nm, respectively. Enzyme activity began to increase at 2h after the addition of inducer, and continued to increase linearly up to $2{\sim}3h$ before reaching stationary phase, and thereafter its activity was decreased. ${\beta}$-D-galactosidase was induced either by lactose or galactose but not either by glucose or ethanol. The greater activity of ${\beta}$-D-galactosidase on galactose than on lactose indicated that the former might be natural inducer for ${\beta}$-D-galactosidase synthesis. The rate of its induction as a function of lactose concentration showed that enzyme activity increased linearly above 4mM, while it was very low below that. Glucose represed the induction of ${\beta}$-D-galactosidase, and the period of adaptation to inducer from other carbon sources was relatively short.

• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.75-81
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• 1997

Streptomyces chibaensis J-59 did not grow in the culture medium containing only xylose or xylan as a carbon source, because it was defective in xylulokinase production; xylB mutant. S. chibaensis J-59 was able to produce xylanase and $\beta $-xylosidase as well as glucose isomerase. The glucose isomerase in S. chilbaensis J-59 was induced in the medium containing xylan or xylose which could be utilized as an inducer but not sa carbon and energy sources. So we tried to produce glucose isomerase whthout consumption of xylose or xylan as an inducer by using xylB mutant S. chilbaensis J-59. The optimum condition for the production of the glucose isomerase was attained in a culture medium composed of 1% xylan, 0.15% glucose, 1.5% corn steep liquor, 0.1% MaSO$_{4}$ $\CDOT $7H$_{2}$O, and 0.012% CoCL$_{2}$ $\CDOT $ 6H$_{2}$O(pH 7.0). The production of the enzyme reached to a maximum level when the bacteria were cultured for 42 h at 30$\circ $C. The enzyme production in a jar fermentor was increased twice as much as that in a flask culture.

• Microbiology and Biotechnology Letters
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• v.18 no.6
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• pp.566-570
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• 1990

Regulation of $\beta$ -galactosidase formation was studied with Lactobacillus sporogenes. Synthesis of the enzyme was effectively induced by isopropyl- $\beta$-D-thiogalactopyranoside (IPTG) or galactose, and to a much lower level by lactose. When 15 mM glucose was added at the different intervals to the cultures that had been in contact with IPTG, the same levels of inhibition of the enzyme synthesis were observed (approximately one-third the differential rate of a control culture without glucose). This suggests that glucose did not interfere with the entry of the inducer into the cells, but interfere with the formation of $\beta$ -galactosidase through catabolite repression. The glucose inhibitory effect was not overcome by adding CAMP or cGMP to the culture media.

• The Korean Journal of Mycology
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• v.14 no.1
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• pp.43-47
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• 1986

Among the representative phenolic compounds in relation to lignin derivatives and protein synthesis inhibitors, the most effective inducer for the extracellular polyphenol oxidase (PO) of Lentinus edodes JA01 was gallic acid and ferulic acid for Pleurotus ostreatus. Optimum concentration of these inducers was 2.0 mM and 1.0 mM, respectively. Addition of gallic acid after two days culture had the best effect on production of PO enzyme of L. edodes JA01 and for P. ostreatus, and addition of ferulic acid after three days culture had the best effect. Also, in case of L. edodes JA01, polyphenol oxidase activity was parallel to growth curve, whereas the maximum enzyme activity of P. ostreatus was shown at exponential growth phase and declined thereafter.

• Korean Journal of Microbiology
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• v.18 no.2
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• pp.59-66
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• 1980

Two strains S-P and S-P-2, both Streptomyces sp., have been isolated and were found to have relatively high specific enzyme activity compared to other organisms reported. The specific activity of the enzyme produced from these two strains were 0.25 and 0.2 international units respectively. The productivity of the enzyme achieved was about 50 IU/l/hr. Glucose isomerase form these strains was found to be stable under the temperature of heat treatment (at $65^{\circ}C$) for fixation of enzyme inside the dell. This organism has an advantage in that it did not require toxic metalic ion for enzyme activity and could utilize xylan in leu of xylose as an inducer. The optimal temperature and pH of enzymatic reaction purpose of using these data for the optimal operation and designing of enzyme reactor system. The reaction mechanism was found to follow the single substrate reversible reaction kinetics. The kinetic constants determined experimentally are : $K_{mf}=0.33M,\;K_{mb}=1.0M,\;V_{mf}=0.88{\mu}mole\;per\;min.,\;V_{mb}= 2.96{\mu}mole\;per\;min.\;and\;K_{eq}=0.74.