• Journal of Life Science
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• v.20 no.5
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• pp.683-690
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• 2010

The yeast strains of Saccharomyces diastaticus produce one of three isozymes of an extracellular glucoamylase I, II or III, a type of exo-enzyme which can hydrolyse starch to generate glucose molecules from non-reducing ends. These enzymes are encoded by the STA1, STA2 and STA3 genes. Another gene, sporulation-specific glucoamylase (SGA), also exists in the genus Saccharomyces which is very homologous to the STA genes. The SGA has been known to be produced in the cytosol during sporulation. However, we hypothesized that the SGA is capable of being secreted to the extracellular region because of about 20 hydrophobic amino acid residues at the N-terminus which can function as a signal peptide. We expressed the cloned SGA gene in S. diastaticus YIY345. In order to compare the biochemical properties of the extracellular glucoamylase and the SGA, the SGA was purified from the culture supernatant through ammonium sulfate precipitation, DEAE-Sephadex A-50, CM-Sephadex C-50 and Sephadex G-200 chromatography. The molecular weight of the intact SGA was estimated to be about 130 kDa by gel filtration chromatography with high performance liquid chromatography (HPLC) column. Sodium dedecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis showed it was composed of two heterogeneous subunits, 63 kDa and 68 kDa. The deglycosylation of the SGA generated a new 59 kDa band on the SDS-PAGE analysis, indicating that two subunits are glycosylated but the extent of glycosylation is different between them. The optimum pH and temperature of the SGA were 5.5 and $45^{\circ}C$, respectively, whereas those for the extracellular glucoamylase were 5.0 and $50^{\circ}C$. The SGA were more sensitive to heat and SDS than the extracellular glucoamylase.

• KSBB Journal
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• v.20 no.1 s.90
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• pp.60-65
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• 2005

The objective of this work was to evaluate a solid-state fermentation process for the practical production of arachidonic acid(AA) by Mortierella alpina ATCC 32222. In the present investigation, batch culture kinetics for both submerged- and solid-state fermentations was carried out at $25^{\circ}C$ to identify the relationship between growth and arachidonic acid (AA) production. Glucose and yeast extract were used in submerged fermentations by using flasks, while rice bran was used as a sole raw material in the other type of fermentations by using a series of Petri dishes. It was evident that a mixed-growth associated pattern existed between the two variables, irrespective of modes of fermentations. The effect of carbon to nitrogen (CfN) ratio on AA production in solid-state fermentation was studied in the range of 6.5 - 20. As a result, an optimum condition was found to be 6.5. Supplementary carbon source was not necessary to meet the optimum C/N ratio. Unlike the Previous results obtained by other researchers, a supplement of sodium glutamate up to $4\%$ (w/w) to the rice bran medium did not have a positive effect on the AA productivity. However, an increase in AA productivity was obtained with the rice bran medium supplemented with sesame oil.

• Microbiology and Biotechnology Letters
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• v.42 no.2
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• pp.194-201
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• 2014

Clitocybin A is a novel anti-wrinkle cosmetic agent produced by the strain from a Korean native mushroom Clitocybe aurantiaca. In this study, fermentation, extraction, and purification conditions for a large scale production of clitocybin A were optimized, and its cytotoxicity and inhibition activity on the expression of matrix metalloproteinase-1 (MMP-1) were characterized. The mass production of anti-wrinkle agent was achieved according to the 300 L fermentation process with a fed-batch cultivation using the modified yeast-maltose (YM) broth, and a total of 12.5 kg of cell mass was obtained in a 120 L culture broth for 14 days. After extraction and purification, clitocybin A was identified by HPLC. The cytotoxicity of clitocybin A was examined by the MTT assay. When assayed at 100 and 200 ${\mu}g/ml$ concentrations, clitocybin A showed no cytotoxicity, demonstrating safety. The inhibition activity of clitocybin A on the expression of MMP-1 was examined against UV irradiation. Oleanolic acid (control group) showed a relatively low MMP-1 inhibiting activity (ca. 16.7%) at 10 ${\mu}g/ml$ and showed increased cytotoxicity at higher concentrations. In contrast, clitocybin A showed no cytotoxicity at 100 ${\mu}g/ml$, and exhibited a relatively high MMP-1-inhibiting activity (33.1%). These findings indicate that clitocybin A may be a safe and effective anti-wrinkle agent for use in functional cosmetics.

• Applied Biological Chemistry
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• v.51 no.1
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• pp.24-37
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• 2008

Yeast with excellent ferment ability was isolated and selected from wild grape to manufacture wild grape wine. Wild grape wine by SMR-3 isolated from wild grape was better than other strains in quality, such as high alcohol content and low acidity, residual sugar, organic acid and fusel oil content. Fermentation condition was optimized to manufacture wild grape wine with response surface methodology using isolated SMR-3 as an alcohol fermentation strain. As a result of culture conditions, 10.61% of alcohol content was expected under the conditions of $21.91^{\circ}C$ fermenting temperature, $21.48^{\circ}brix$ of initial sugar content, and 14.65 day of fermentation time. Residual sugar content showed the lowest value at $24.48^{\circ}C$ fermentation temperature, $12.78^{\circ}brix$ of initial sugar content, and 9.02 day fermentation time. The highest level of sensory evaluation was found at $20.23^{\circ}C$ fermentation temperature, $25.30^{\circ}brix$ of initial sugar content, and 5.94 day fermentation time. Ethyl alcohol was the main alcohol component in wild grape wine and fusel oil in wild grape wine was hardly detected; thus, the quality of wild grape wine was considered excellent. The optimal fermentation conditions of wild grape wine was superimposed by deriving a regression equation for alcohol content, fusel oil, ethyl alcohol content, and overall palatability for each variable of wild grape wine. Hence, the optimal fermentation conditions are estimated to be: fermentation temperature $24{\sim}28^{\circ}C$, initial sugar content $20{\sim}24^{\circ}brix$, and fermenting time $12{\sim}14$ days.

• The Korean Journal of Mycology
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• v.42 no.4
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• pp.328-332
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• 2014

For mass production of entomopathogenic fungus Beauveria bassiana 149, isolated from moth larva, by two-phase fermentation, we performed selection of carbon and nitrogen sources for liquid culture and examined solid fermentation on carrier, ingredient, temperature, and water content. Spore production with rice powder, corn powder, and starch from sweet potato was higher than that of sucrose and dissolvable starch for liquid fermentation as first-phase fermentation. As a nitrogen source, addition of peptone and yeast powder showed higher spore production than $NaNO_3$, fish powder, and soybean powder. The isolate produced more conidia in sawdust + wheat bran + corn powder, sawdust + wheat bran and rice shell + wheat bran as carrier and ingredient than vermiculite as carrier. Conidia production of B. bassiana 149 in solid-phase fermentation was twice higher at 30 than 20. Conidia yield was higher at 60% and 70% water content ($26.9{\times}10^8$ and $38.6{\times}10^8conidia/g$) than 40% and 50% ($13.9{times}10^8 $and $11.6{\times}10^8conidia/g$), respectively.

• Korean Journal of Plant Tissue Culture
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• v.25 no.4
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• pp.277-282
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• 1998

Whereas cationic extracellular peroxidases (PODs) were observed in the suspension cultures of rose (Rosa sp. L. cv Pual's scarlet) grown under normal conditions, new anionic isozymes were induced within 24 hr by the treatment of low host-specific elicitor (10 mg glucan/L media) prepared from yeast cell wall. Prominent anionic (pI 6.1) and cationic POD (pI 8.4) were purified and characterized to understand the physiological role of the enzymes. Both enzymes were purified (ca.200 fold) by the ammonium sulfate precipitation, ion exchange chromate-graphy and gel filtration chromatography. The Km values of the purified anionic POD for ferulic acid and $\textrm{H}_2\textrm{O}_2$ were 4.64 mM and 0.72 mM, whereas those of the cationic POD were 1.38 mM and 0.48 mM, respetively. The activity of the anionic POD as NADH oxidase was twice higher than that of cationic POD. The NADH oxidation in the anionic POD fraction was inhibited by 60% on the addition of 0.1 mM coniferyl alcohol, while that in the cationic fraction was inhibited by 15%.

• Journal of Microbiology and Biotechnology
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• v.32 no.5
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• pp.630-637
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• 2022

The objective of this study was to optimize industrial-grade media for improving the biomass production of Weissella cibaria JW15 (JW15) using a statistical approach. Eleven variables comprising three carbon sources (glucose, fructose, and sucrose), three nitrogen sources (protease peptone, yeast extract, and soy peptone), and five mineral sources (K₂HPO₄, potassium citrate, ⳑ-cysteine phosphate, MgSO₄, and MnSO₄) were screened by using the Plackett-Burman design. Consequently, glucose, sucrose, and soy peptone were used as significant variables in response surface methodology (RSM). The composition of the optimal medium (OM) was 22.35 g/l glucose, 15.57 g/l sucrose, and 10.05 g/l soy peptone, 2.0 g/l K₂HPO₄, 5.0 g/l sodium acetate, 0.1 g/l MgSO₄·7H₂O, 0.05 g/l MnSO₄·H₂O, and 1.0 g/l Tween 80. The OM significantly improved the biomass production of JW15 over an established commercial medium (MRS). After fermenting OM, the dry cell weight of JW15 was 4.89 g/l, which was comparable to the predicted value (4.77 g/l), and 1.67 times higher than that of the MRS medium (3.02 g/l). Correspondingly, JW15 showed a rapid and increased production of lactic and acetic acid in the OM. To perform a scale-up validation, batch fermentation was executed in a 5-l bioreactor at 37℃ with or without a pH control at 6.0 ± 0.1. The biomass production of JW15 significantly improved (1.98 times higher) under the pH control, and the cost of OM was reduced by two-thirds compared to that in the MRS medium. In conclusion, OM may be utilized for mass producing JW15 for industrial use.

• Journal of Plant Biotechnology
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• v.49 no.4
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• pp.356-361
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• 2022

Bacillus sp. is a useful strain for agriculture because it promotes plant growth and controls plant pathogens through a variety of mechanisms. In this study, we obtained a microbial preparation with a high number of viable cells by culturing newly isolated soil bacteria on an optimized medium. Subsequently, we applied this preparation to lettuce to enhance its growth and yield. First, B. amyloliquefaciens ISP-5 was isolated from soil. Next, optimization of culture medium was carried out using 5 L scale fermenters. When culturing B. amyloliquefaciens ISP-5 on this optimized medium, the number of viable cells was approximately 1000 times higher than that obtained from culturing on the commercial medium. Afterwards, the plant growth promotion properties of the ISP-5 strain were evaluated using lettuce as a test plant. Foliar spray treatment of lettuce was carried out by inoculating half the standard concentration suspension (0.5 × 10⁷ cfu/ml). As a result, leaf width increased by 8.6% and leaf length increased by 12.9% compared to the control group. Live weight also increased by 24.2% and dry weight by 23.9%. Considering the results from field test, B. amyloliquefaciens ISP-5 showed potential as a plant growth-promoting bacteria.

• The Korean Journal of Mycology
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• v.42 no.3
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• pp.191-200
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• 2014

Nuruk samples collected from various regions in Korea were investigated in terms of fungal contents and diversity. In measurement of colony forming unit (CFU) in Nuruk suspensions on DRBC agar, Nuruk samples MS4, MS8, and MS10 were among the highest fungal density, with $1,278.9{\pm}21.6$ (${\times}10^4$), $1,868.0{\pm}27.7$ (${\times}10^4$), and $775.1{\pm}19.2$ (${\times}10^4$) were among the samples showing the highest fungal density. CFU per 20 mg Nuruk, respectively. The majority of fungal components were yeasts, including Pichia anomala, P. kudriavzevii, Kluyveromyces marxianus, and Saccharomycopsis fibuligera, whereas Aspergillus oryzae and Rhizopus oryzae, the representative Nuruk fungi, were predominant only in the low fungal density Nuruks (MS2, MS5, and MS11). Saccharification capability of the fungal isolates was assessed by measurement of amylase activity in the culture broth. The highest amylase activity was found in A. niger and A. luchuensis, followed by S. fibuligera. A. oryzae and R. oryzae showed fair amylase activity but significantly lower than those of the three fungal species. R. oryzae was suggested to play an additional role in degradation of ${\beta}$-glucan in crop component of Nuruk since R. oryzae was the only fungus that showed ${\beta}$-glucanase activity among the fungal isolates. To confirm the safety of Nuruk, aflatoxigenicity of the isolated Aspergillus was estimated using the DNA markers norB-cypA, aflR, and omtA. All of the isolates turned out to be non-aflatoxigenic as evidenced by the deletion of gene markers, norB-cypA and aflR, and the absence of aflatoxin in the culture supernatants shown by TLC analysis.

• KSBB Journal
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• v.10 no.5
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• pp.561-567
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• 1995

Using superoxide dismutase (SOD)-deficient mutants of Saccharomyces cerevisiae, the oxygen toxicity induced by paraquat was studied. In aerobic culture condition, yeasts lacking MnSOD (milochondrial SOD) showed more significant growth retardation than CuZnSOD (cytoplasmic SOD)-deficient yeasts. However, not so big differences in growth pattern of those mutants compared with wild type were observed under anaerobic condition. When exposed to paraquat, the growth of yeasts lacking CuZnSOD was severely affected by higher than 0.01mM of paraquat in culture medium. By the analysis of several cellular components ivolved in free radical generating and scavenging system, it was found that, under aerobic condition, the content of lipid peroxides in cell membrane as well as cellular activity of glutathion peroxidase of CuZnSOD-deficient mutants was increased in the presence of paraquat, although significant decrease of catalase activity was observed in those stratns. In MnSOD-deficient yeast, however, increment in cellular activity of glutathion peroxldase and catalase by paraquat was observed without any deterioration of membrane lipid. It implies that the lack of mitochondrial SOD could be compensated by both of glutathion peroxldase and catalase, but that only glutathion peroxidase might act for CuZnSOD in cytoplasm. In contrast, all of SOD-deficient mutants showed a significant decrease in catalase activity, but slight increase in the activities of glutathion peroxidase, when cultivated anaerobically in the medium containing paraquat. Nevertheless, any significant changes of lipid peroxides in cell membranes were not observed during anaerobic cultivation of SOD-deficient mutants. It suggests that a little amount of free radicals generated by paraquat under anaerobic condition could be sufficiently overcome by glutathion peroxidase but not by catalase.