• Biotechnology and Bioprocess Engineering:BBE
• /
• v.10 no.2
• /
• pp.149-154
• /
• 2005

Secretion of the expressed heterologous proteins can reduce the stress to the host cells and is beneficial to their recovery and purification. In this study, fed-batch cultures of Escherichia coli YK537 (pAET-8) were conducted in a 5-L fermentor for the secretory production of human epidermal growth factor (hEGF) whose expression was under the control of alkaline phosphatase promoter. The effects of feeding of glucose and complex nitrogen sources on hEGF production were investigated. When the fed-batch culture was conducted in a chemically de-fined medium, the cell density was 9.68 g/L and the secreted hEGF was 44.7 mg/L in a period of 60 h. When a complex medium was used and glucose was added in pH-stat mode, the secreted hEGF was improved to 345 mg/L. When the culture was fed with glucose at a constant specific rate of $0.25\;gg^{-1}h^{-1}$, hEGF reached 514 mg/L. The effects of adding a solution containing yeast extract and tryptone were further studied. Different rate of the nitrogen source feeding resulted in different levels of phosphate and acetic acid formation, thus affected hEGF expression. At the optimal feeding rate, hEGF production achieved 686 mg/L.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.6 no.4
• /
• pp.306-308
• /
• 2001

A recombinant human growth hormone(hGH) was expressed as a secretory product in the yeast Saccharomyuces cerevisiae. There different leader sequences derived from the mating fac-tor $\alpha$1(MF$\alpha$1) inulinase and invertase were used to direct the secretion of hGH into the extracel-lular medium. Among three leader sequences tested, the inulinase leader sequence was found to be the most efficient in the secretory expression of hGH. In contrast, no hGH was detected in the ex-tracellular medium with the invertase leader sequence. After 48 h shake-flask culture, the yields of hGH secreted into th emedium by the invertase. MF$\alpha$1 inulinase and invertase leader sequences were approximately 0, 0.3 and 0.9 mg/L, respectively. The secretion efficiencies were also found to be 0, 3.8 and 13% for the invertase , MG$\alpha$1 and inulinase leader sequences, respectively.

• Korean Journal of Food Science and Technology
• /
• v.24 no.4
• /
• pp.326-329
• /
• 1992

Mucor sp. KCTC 8405P was cultivated in a jar fermentor for the production of fungal lipid containing ${\gamma}-linolenic$ acid with feeding the glucose solution periodically. The transition of the fungal growth into the mycelial phase from yeast-like growth was achieved by pH shift after the first two day of cultivation in the low pH medium and then lipid accumulation was accelerated until the seven day of cultivation, when the glucose in the culture broth was almost consumed. With the culture conditions applied in this experiment, biomass of 99.3 g/l by the dry cell weight and the total extractable lipid of 38.0 g containing 3.5 g/l ${\gamma}-linolenic$ acid were obtained.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.12
• /
• pp.1781-1786
• /
• 2011

This study was conducted to investigate the cause of microbiological contamination in yogurt and evaluate the effect of physicochemical treatment on the growth inhibition of Hanseniaspora uvarum isolated from yogurt. The yeast strain Hanseniaspora uvarum Y1 was subjected to heat and pH treatments. H. uvarum Y1 was killed at $70^{\circ}C$ and $80^{\circ}C$ after 15 min and survived in a wide pH range from pH 2 to 9. However, it did not survive under pH 1 and over pH 10. In a disk diffusion susceptibility test on H. uvarum Y1, a clear zone (5 mm) of growth inhibition was observed upon treatment with electrolyzed water. The effect of ozone gas on the growth of H. uvarum Y1 was evaluated by viable cell count. Initial cell numbers of $10^2$ and $10^3$ CFU/mL of H. uvarum Y1 were completely killed by treatment for 10 and 30 min, respectively. H. uvarum Y1 was also sterilized by microwave treatment for 1 min. When treated with gamma-irradiation, the rate of killing of H. uvarum Y1 was proportional to the irradiation dose. and complete killing occurred at a dose of 50 kGy.

• The Korean Journal of Mycology
• /
• v.31 no.2
• /
• pp.84-88
• /
• 2003

Basic studies on the cultural characteristics of Pycnoporus coccineus and P. cinnabarinus were performed. They exhibited $30{\sim}40{\circ}C$ optimal temperature ranges and optimal pH ranges of $5{\sim}6$. Among 6 media, they were good at mycelial growths on PDA, LBA and YMA.P. coccineus grew more than P.cinnabarinus on the same medium. Among 10 sawdust media, they were good at mycelial growth on three oak trees and Alnus hirsuta. However, the sawdust of Castanea crenata was bad at mycelial growth. Among 3 coniferous trees, Larix leptolepis showed better growth than the other trees such as Pinus densiflora and P. koraiensis. The fruit body production P. coccineus was about twice better than P. cinnabarinus on Quercus spp. sawdust cultivation.

• Journal of Ginseng Research
• /
• v.14 no.2
• /
• pp.253-264
• /
• 1990

The growth responses of a variety of human intestinal bacteria to extracts of Panax ginseng and five other oriental medicinal Araliaceae were elraluattd in vitro and in vivo. The extracts enhanced the growth of Brifidobnnerilrm breve and B. longlim in media with or without carbon sources, suggesting that bifidus factors) might be involved in the phenomenon. This effect was most pronounced with water extract of P. ginseng, the growth of 27 bifidobacteria strains belonging to B adolescentis, B. longum, B. brim and B. infantis being greatly stimurated, whereas seven B. bifidum strains and other bacteria such as clostridia and Escherichin soli had little or no ability to utilise it for growth. Methanol extracts of p. ginseng were found to selectively inhibit growth of various clostridia including bifidobacteria. Paraputrificum, but this effect was not observed on other bacteria including bifidobacteria. The effect of ginseng extract intake (600 mg/day for two weeks) on the faecal microflora, pH, volatile fatty acids, ammonia, putrefactive products, and -glucuronidase, -glucosidase and nitroreductase activities, and on the blood components (triglyceride, total cholesterol and ammonia) were investigated using seven healthy human volunteers. The total concentration of faecal microflora including Bifidnkaderiifm app. during the period of ginseng extract intake %twas significantly unaffected from the preceding and subsequent control peroids. However, the frequency of occurrence of subjects having C. perfringens was significantly decreased. The faecal pH value was also significantly decreased, suggesting that the intake might increase the activity of Bifidobncterium spry. Other biochemical properties in faeces did not changed significantly. The levels of ammonia and triglycerid in blood were decreased with ginseng extract intake. These results may be an indication of at least one of the Pharmacological actions of p. ginseng as an adaptogen.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.23 no.2
• /
• pp.51-61
• /
• 2021

As a result of examining the germination rate between ginseng varieties, Jagyongjong varieties had the highest germination rate, and Yeonpung. had the lowest germination rate. In the ginseng seed germination rate experiment, the highest germination rate and growth condition were shown in artificial soil conditions of the ratio of Peatmoss 6.5: Pearlite 2: Masato 1.5. Good soil conditions require adequate soil moisture forces during the incubation period. The cultivation of ginseng medicinal crops requires optimal soil breathability, soil pH, and soil stabilization, which are important for root breathing. Microbial activity in the soil has a great influence on the growth of ginseng. The optimum pH of the soil for ginseng cultivation is 5.0-5.5 As a result of the experiment, the soil remained in an appropriate range after a month. In general, when the EC concentration value of the soil for ginseng cultivation is 0.2 mS/cm or more, growth deteriorates, and when the EC concentration value is 0.5 mS/cm or more, concentration obstacles such as root decay occur. As a result of the analysis, the higher the concentration value of EC, the more likely it is to interfere with ginseng growth.

• Journal of Life Science
• /
• v.32 no.2
• /
• pp.119-124
• /
• 2022

To effectively isolate acetic acid bacteria for producing makgeolli vinegar, various products were researched, and Acetobacter pasteurianus CK-1, a strain that is excellent in acetic acid production, was finally isolated. The optimal growth temperature of the isolated strain was confirmed to be 30℃, and it grew well in the pH range of 5.5~6.5, with optimal growth at pH 6. A. pasteurianus CK-1 had the most active proliferation when the initial ethanol concentration in the medium was 4%, and growth was possible even at an ethanol concentration of 7%. When inoculating the isolated strain into makgeolli to induce acetic acid fermentation, the pH at the beginning of fermentation was 3.54, which was gradually lowered to 2.77 after 18 days of fermentation. The acidity was 0.75% at the beginning of fermentation and gradually started to increase from the 4th day of fermentation. The final acidity at the end of fermentation was 5.54%. In the vinegar fermented by inoculating A. pasteurianus CK-1, acetic acid content was detected to be as high as 3,575.7±48.6 mg%, and the malic acid and citric acid contents were 2,150.8±27.6 and 55.8±3.7 mg%, respectively. Further, it was confirmed that the content and ratio of the organic acids produced significantly differed depending on the type of inoculated bacterial strain. During acetic acid fermentation, the populations of yeast and A. pasteurianus CK-1 were inversely changed. In the initial stage of fermentation, yeast dominated, and after 10 days of fermentation, A. pasteurianus CK-1 slowly proliferated and reached stationary phase.

• 대한생식의학회:학술대회논문집
• /
• 2003.12a
• /
• pp.155-155
• /
• 2003

• Journal of Mushroom
• /
• v.21 no.1
• /
• pp.15-21
• /
• 2023

Volvariella bombycinais an edible mushroom commercially cultivated in Korea and other countries. In this study, the culture characteristics and optimal growth conditions of milky mushroom strains were determined. The growth temperature and pH range of V. bombycinawas extensively investigated between 15 and 35℃ and pH 3-11. For efficient cultivation, 20 types of nutrient sources were selected, specifically, 21 carbon sources, 6 organic nitrogen sources, 7 inorganic nitrogen sources, 13 amino acids, 9 organic acids, and 13 inorganic salts. The impact of each of the selected nutrition sources and their concentration on growth was investigated. The optimum temperature and pH were determined to be 30℃ and pH 8.0, respectively. The optimum concentration of medium elements required for mycelial growth of V. bombycinawas determined to be as follows: carbon source, 0.7% Soluble starch; organic nitrogen source, 0.7% Soytone; inorganic nitrogen source, 1.0% (NH₄)₂C₄H₄O₆; amino acid, 0.1% cysteine; organic acid, 0.07% lactic acid; and inorganic salt, 0.07 mM CaCl₂.