• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.1
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• pp.72-79
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• 2006

Kojic acid production by Aspergillus flavus strain S44-1 using sucrose as a carbon source was carried out in a 250-mL shake flask and a 2-L stirred tank fermenter. For comparison, production of kojic acid using glucose, fructose and its mixture was also carried out. Kojic acid production in shake flask fermentation was 25.8 g/L using glucose as the sole carbon source, 23.6 g/L with sucrose, and 6.4 g/L from fructose. Reduced kojic acid production (13.5 g/L) was observed when a combination of glucose and fructose was used as a carbon source. The highest production of kojic acid (40.2 g/L) was obtained from 150 g/L sucrose in a 2 L fermenter, while the lowest kojic acid production (10.3 g/L) was seen in fermentation using fructose as the sole carbon source. The experimental data from batch fermentation and resuspended cell system was analysed in order to form the basis for a kinetic model of the process. An unstructured model based on logistic and Luedeking-Piret equations was found suitable to describe the growth, substrate consumption, and efficiency of kojic acid production by A. flavus in batch fermentation using sucrose. From this model, it was found that kojic acid production by A. flavus was not a growth-associated process. Fermentation without pH control (from an initial culture pH of 3.0) showed higher kojic acid production than single-phase pH-controlled fermentation (pH 2.5, 2.75, and 3.0).

• KSBB Journal
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• v.22 no.2
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• pp.114-118
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• 2007

In this study, an amylase-producing fungus, strain 15 was isolated from soil in order to saccharify food wastes with cellulolytic and amylolytic enzymes. The amylase production cultures were performed in Mandel's medium with 1% rice straw and 1% paper wastes as carbon sources. The strain produced various cellulolytic (FPase 0.25, xylanase 20.09, CMCase 3.15 U/mL-supernatant) and amylolytic ($\alpha$-amylase 1.20, gluco-amylase 0.70, $\beta$-amylase 2.40 U/mL-supernatant) enzymes in Mandel's medium. In 10 L jar fermenter, maximum amylase and FPase activities, 3.25 and 0.23 U/mL, were obtained when the culture was grown at 30$^{\circ}C$, 200 rpm and 0.6 vvm for 3 days. In 100 mL flask level and 10 L jar fermenter, amylase produced by the strain 15 showed similar cellulolytic and amylolytic enzyme activities with Trichoderma inhamatum KSJ1 isolated from rotten woods by previous researcher. The ability of saccharification to food wastes also showed similar degree. However, the isolate 15 appeared to be yellowish in YMEA plate comparing to Trichoderma inhamatum KSJ1 in greenish.

• Microbiology and Biotechnology Letters
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• v.30 no.1
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• pp.26-32
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• 2002

For commercial production of Korean fermented anchovy sauce through rapid fermentation, a bacterial strain which showed the high protease activity was isolated from a commercially fermented anchovy sauce. The isolate was Bacillus amyloliquefaciens, and named as B. amyloliquefaciens HTP-8. The incubation temperature, initial pH, and cultivation time for optimal production of protease by B. amyloliquefaciens HTP-8 were $30^{\circ}C$, 7.0, and 3 days, respectively. In jar fermenter, B. amyloliquefaciens HTP-8 showed higher protease activity when grown at pH 7.0. The protease was partially purified by 80% ammonium sulfate precipitation and CM-Sephadex C-50 ion exchange chromatography. The partially purified enzyme had specific activity of 103.3 units/mg, yield of 0.4%, and purification fold of 43.0. The optimal pH and temperature for the protease activity were 10.0 and $50^{\circ}C$, respectively. The protease was relatively stable at the pH range of 7.0~12.0 and at the temperatures below 4$0^{\circ}C$. The activity of the enzyme was inhibited by $Ag^{＋}$ /, $Ba^{2＋}$ and selectively inhibited by PMSF, suggesting that it is a serine protease.

• Journal of Microbiology and Biotechnology
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• v.31 no.4
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• pp.570-583
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• 2021

Pyrococcus furiosus α-amylase can hydrolyze α-1,4 linkages in starch and related carbohydrates under hyperthermophilic condition (~ 100℃), showing great potential in a wide range of industrial applications, while its relatively low productivity from heterologous hosts has limited the industrial applications. Bacillus subtilis, a gram-positive bacterium, has been widely used in industrial production for its non-pathogenic and powerful secretory characteristics. This study was conducted to increase production of P. furiosus α-amylase in B. subtilis through three strategies. Initial experiments showed that co-expression of P. furiosus molecular chaperone peptidyl-prolyl cis-trans isomerase through genomic integration mode, using a CRISPR/Cas9 system, increased soluble amylase production. Therefore, considering that native P. furiosus α-amylase is produced within a hyperthermophilic environment and is highly thermostable, heat treatment of intact culture at 90℃ for 15 min was performed, thereby greatly increasing soluble amylase production. After optimization of the culture conditions (nitrogen source, carbon source, metal ion, temperature and pH), experiments in a 3-L fermenter yielded a soluble activity of 3,806.7 U/ml, which was 3.3- and 28.2-fold those of a control without heat treatment (1,155.1 U/ml) and an empty expression vector control (135.1 U/ml), respectively. This represents the highest P. furiosus α-amylase production reported to date and should promote innovation in the starch liquefaction process and related industrial productions. Meanwhile, heat treatment, which may promote folding of aggregated P. furiosus α-amylase into a soluble, active form through the transfer of kinetic energy, may be of general benefit when producing proteins from thermophilic archaea.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.425-433
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• 1998

The characteristics of the reaction of calcium carbonate $(CaCO_3)$ immobilized with alginate as buffer system for the high concentration cultivation of bifidobacteria in fermenter are described by the mathematical model, and tested for the reusing possibility of the used $CaCO_3$ beads. When$CaCO_3$ beads with the various diameters were reacted in 0.1 M of the mixed organic acids (0.6 M of acetic acid and 0.4 M lactic acid) and in fermenter inoculated Bifidobacterium longum ATCC 15707, the change of bead diameters can be calculated with the amount of the decreased $CaCO_3$ from the surface of bead using the mathematical model. These values was similar to the directly measured bead diameter by a micrometer. Therefore, it was considered that the mathematical model could be used for explaining the reaction charateristics of the $CaCO_3$ bead reacted with the organic acids. When Bifidobacterium longum was incubated at $37^{\circ}C$ for 20 hours in fermenter with $CaCO_3$ beads, the buffering effect of $CaCO_3$, the reduce rate of the bead diameter, and the growth rate of Bifidobacterium longum were higher at the smaller beads than beads with the larger diameters. Also, when Bifidobacterium longum was incubated in fermenter with the mixed beads which were added new beads to the recovered beads in order to equalize with the total surface area of initial beads, the buffering effect of $CaCO_3$ bead and the growth rate of Bifidobacterium longum were very corresponded with the results of the fermentation using the only initial beads. Therfore, it is expected that the used beads can be reused by adding the initial beads.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.3
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• pp.214-222
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• 2012

Several acidogenesis batch tests, and BMP (Biochemical Methane Potential) with food waste leachate was tested at various organic loading rates (OLRs) on the mesophilic ($35^{\circ}C$) and thermophilic ($55^{\circ}C$) conditions. In acidogenesis batch test, VS removal efficiencies were 27.3% and 30.6% at $35^{\circ}C$ and $55^{\circ}C$, respectively. Removal efficiency of VS at $55^{\circ}C$ was higher than that at $35^{\circ}C$. With decrease in VS, SCOD increased as reaction time increased. Solubilization efficiency of VS were 27.4% and 33.4% at each reaction temperature within 4 days acid fermentation. Methane yield were 461 and 413 $mLCH_4/gVS$ at mesophilic and thermophilic BMP test, respectively. SCOD solubilizations in the themophilic acid fermenter showed 8~17% higher than those in the mesophilic fermenter. COD removal efficiency showed higher in the mesophilic acid fermenter at low organic loading rate. While at high organic loading rate, it was higher in the thermophilic acid fermenter. VS removal efficiency was higher at the mesophilic temperature, however, it decreased at OLR higher than 6 kg $COD/m^3{\cdot}day$. On the contrary, VS removal efficiency did not decrease but maintain at thermophilic temperature. The amount of methane gas generated from mesophilic methanogenesis digester was 12.6, 21.6, 27.4 L/day at OLR of 4, 5, 6 $COD/m^3{\cdot}day$, respectively. The amount of methane gas generated from themophilic methanogenesis digester was 14.3, 20.6, 25.2 L/day at each OLR, respectively, which is about 15~20 L/day lower than those generated at mesophilic digester.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.6
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• pp.435-439
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• 2004

Three Bacillus strains were isolated from soil samples. Morphological and physiologi­cal characterization indicated that the isolated strains were B. mycoides, B. licheniformis and B. brevis. White pepper was produced from black pepper by the fermentative method using the isolates in shake flaks as well as in a large-scale fermenter. Volatile oil and piperine contents of the product were $3.2\%$ (v/w) and $4\%$ (v/w) respectively. The moisture content was $15\%$. The mi­crobial contamination was less than 10 per 100 g. The product also exhibited excellent storage stability.

• Journal of Microbiology and Biotechnology
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• v.8 no.5
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• pp.536-539
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• 1998

The anti-complementary activity (immuno-stimulating activity) was tested for the exo-polymers (extra-cellular polymer) produced from submerged mycelial cultures of 21 types of higher fungi. Anti-complementary activity of the exo-polymer from Cordyceps militaris showed the highest (69.0%) followed by Pleurotus ostreatus (63.7%) and Trametes suaveolens (61.4%). The mycelial growth rate and biomass doubling time of C. militaris in a 5 I air-lift fermenter were 0.0255 $h^{-1}$ and 27.2 h, respectively. The yield of the exo-polymer produced from the culture broth of C. militaris was 2.95 mg of dry weight/ml of culture broth. Sugar and amino acid compositions of this exo-polymer were analyzed.

• Journal of Industrial Technology
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• v.20 no.A
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• pp.45-50
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• 2000

A submerged cultivation of Ganoderma lucidum was carried out in an air-lift fermenter system, and the effects of different pH processes on extracellular branched ${\beta}$-1,3-glucan(EPS) production and mycelial growth(MDW) were investigated. The controlled pH process improved the production of branched ${\beta}$-1,3-glucan and biomass in comparison to the uncontrolled pH process. However, the maximum production of branched ${\beta}$-1,3-glucan were obtained by the bi-staged pH process. From these results, we confirmed that the bi-staged pH process was the most effective for improving the production of branched ${\beta}$-1,3-glucan from submerged culture of G. lucidum.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.124-128
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• 2005

This studies were carried out to investigate optimal conditions for Lactic acid bacteria growth, which was grown in a batch fermenter. The optimal temperature was $30^{\circ}C$, optimal pH was 6.5 and agitation speed was 100rpm and didn't supply the air. Used media compositions were yeast extract 5g/L, peptone 10g/L, sugar 20g/L, beef extract 10g/L, tween 80 1ml/L, ammonium citrate 2g/L, sodium acetate 5g/L, magnesium sulfate 0.1g/L, manganese sulfate 0.05g/L, dipotassium phosphate 2g/L. These results would be useful for enhancing lactic acid bacteria concentration.