• Korean Journal of Food Science and Technology
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• v.4 no.4
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• pp.252-258
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• 1972

Methods of separating yeast cells from oil-water-cell emulsion and subsequent purification of the recovered yeast have been studied. In addition, the results of preliminary feeding experiments in which a yeast grown on gas oil was incorporated into chick rations are reported. According to the present study, it appears that the recovery of the yeasts would be easier at pH 9, since the emulsion is relatively more unstable. A class of surface active agent at a concentration of 0.3% was found to facilitate the separation of the yeast from the emulsion. The use of electrolytes such as NaCl and KCl were found to be most effective in breaking the emulsion. Solvent treatment using iso-propyl alcohol and its azeotropic mixture with hexane at $58^{\circ}C$ are particularly suitable for purification of the yeast. In the feeding experiment it was found that 5 percent of the fishmeal in the control ration could be replaced by the yeast with no adverse effect on performance. However, when 8 percent of the fish meal in the control ration was replaced by the yeast, some effect on live-weight gain of the chicks was observed.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.380-383
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• 2000

The effect of on the cell growth, the elaboration of pullulan, the morphology and were the effect of on the molecular weight of pullulan were investigated. A. pullulans showed maximum pullulan production when initial pH 6.5 was 11.98 g/l in shake-flask culture. In batch culture, the maximum pullulan production of 15.16 g/l was obtained at an aeration rate of 0.5 vvm. The mixture of yeast-like form and mycelial form of cells was found at the constant pH 4.5, at which condition, the elaboration of pullulan was high, about 13.31 g/l. However, pullulan with its higher molecular weight (>1,000,000) was produced at the constant pH 6.5.

• Journal of Energy Engineering
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• v.15 no.2 s.46
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• pp.118-126
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• 2006

This publication provides an overview of the state-of-the-art and perspective of biological $H_2$ production from water and/or organic substances. The biological $H_2$ production processes, being explored in fundamental and applied researches, are direct and indirect biophotolysis from water, photo-fermentation, dark anaerobic fermentation and in vitro $H_2$ production. The development of biological $H_2$ production technology, as an energy carrier, started at the late 1940's in the lab-scale. Now it has a high priority in the world, especially USA, Japan, EU and Korea.

• KSBB Journal
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• v.9 no.4
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• pp.406-411
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• 1994

An extractive fermentation process was developed to produce citric acid from g1ucose. Citric acid is a strong inhibitor to this fermentation. A mixture of tertiary amine and oleyl alcohol was used to selectively extract citric acid from the fermentation broth, hence enhancing the productivity by over 200%. Although the toxicity of the solvent was significant in the range of higher than 30% of amine, immobilization in polyurethane foam was useful to protect the cells from the toxicity of the solvent.

• Korean Journal of Microbiology
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• v.42 no.3
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• pp.172-176
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• 2006

In order to increase the productivity of lipstatin by Steptomyces toxytricini, the effect of medium components on the lipstatin production was investigated. Using TSB medium as a basal medium, a variety of carbon sources, nitrogen sources, lipid and fatty acids was supplemented into a fermentation medium. The seed culture of S. toxytricini grown in 25 ml TSB medium at $28^{\circ}C$ for 3 days with agitation at 200 rpm was inoculated in the size of 2% in fermentation media containing different components and fermented at $28^{\circ}C$ for 60 more hrs. In the examination of the effect of carbon sources, the best cell growth was observed in fermentation media supplemented with glucose or glycerol, but the lipstatin productivity was the highest in media containing lactose or sucrose. Among complex nitrogen sources, yeast extract was the best one for cell growth, but the highest lipstatin production was found in TSB media composed of 1.7% casitone and 0.3% soytone. The increased concentration of triolein as a lipid caused the promotion of cell growth but the significant suppression of lipstatin production. When 0.5% fatty acids were supplemented to fermentation medium, unsaturated fatty acids like linoleic or oleic acid suppressed cell growth as well as lipstatin production, but 2 times higher lipstatin production was achieved by stearic acid, a saturated fatty acid, differently from expectation.

• KSBB Journal
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• v.22 no.1
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• pp.1-6
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• 2007

The optimum liquid culture conditions were investigated for cell growth and polysaccharide production from liquid culture of Lentinus edodes. In flask culture, the optimal medium compositions for the polysaccharide production contained glucose 60 g/L, yeast extract 10 g/L, $KH_2PO_4$ 2.0 g/L, and $MgSO_4{\cdot}7H_2O$ 1.0 g/L. The maximum mycelial growth and polysaccharide production were 11.01 g/L and 1.64 g/L, respectively. In bioreactor, through the variation of aeration in order to increase mycelial growth and polysaccharide production, the maximum mycelial growth and polysaccharide production were 55.9 g/L at 8th day and 7.34 g/L at 7th day of cultivation with 1.5 vvm, respectively.

• Korean Journal of Environmental Biology
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• v.29 no.4
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• pp.305-311
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• 2011

The distribution of flocculating activity of culture broth was examined and the major constituent with flocculating activity was identified. Most of flocculating activity was found in culture broth without cells. As the activity was maintained by the digestion with pronase, it suggests that the activity is due to the polysaccharide. The bioflocculant obtained from $Lactobacillus$ $jensenii$ YW-33 was precipitated by 60~80% EtOH fractionation (LJ-80). LJ-80 was separated by ion-exchange chromatography using DEAE-Toyopearl 650C and LJ-80-II showed more potent flocculating activity than those of other fractions. The major activity fraction LJ-80-II was further purified on the gel permeation using Sepharose CL-6B to LJ-80-II-1. GPC (Sepharose CL-6B) and HPLC were used to determine whether LJ-80-II-1 has a homogenecity. The molecular weight of purified LJ-80-II-1 was estimated over 800,000 dalton by gel permeation chromatography. Purified LJ-80-II-1 contained 98.4% total sugar, 0.6% protein. Main sugar of purified LJ-80-II-1 was composed of mannose : galactose : glucose with a molar ratio of 1.61 : 0.25 : 1.00.

• Microbiology and Biotechnology Letters
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• v.10 no.2
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• pp.87-93
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• 1982

The cultural conditions of Mucor plumbeus FRI 0007 were investigated for the maximum production of felt and lipid. It was found that the lower the pH and the higher the incubation temperature, the higher accumulation of the felt and lipid. Shake culture rendered higher lipid accumulation and lower felt accumulation than static culture. Maximum production of felt and lipid content were 47.8 g/$\ell$ and 50.73%, respectively, when the organisms were static-cultured at a temperature of 37$^{\circ}C$ and pH of 3.5 for 25 days latroscan thinchrographic analysis showed that the higher amount of triglyceride was obtained when static-cultured at a low pH. Fatty acid composition of the microbial lipid was affected by the incubation temperature, types of nitrogen source and speed of agitation: lower degree of saturation was observed as the incubation temperature decreased and the speed of agitation increased. Fatty acids of monoglyceride and diglyceride were mainly palmitic and oleic acids and those of triglycerides were mainly palmitic, oleic acids.

• Journal of Life Science
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• v.14 no.4
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• pp.560-566
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• 2004

Agrocybe aegerita is Hymenomycetes fungus belonging to the order Agaricales and family of Bolbitiaceae. Much less is known about liquid culture of Agrocybe aegerita. Thus, the present study was to investigate the liquid cultural characteristics of Agrocybe aegerita my-celium. The optimal medium for the mycelial growth and density was ME medium, optimal tem-perature and initial pH were 25$\pm$1$^{\circ}C$ and 5.5, respectively. And optimal culture time for mycelial growth was 12 days. The modified optimal medium compositions were dextrin 3% (w/v), yeast extract 2% (w/w), MgSO$_4$0.05% (w/v), and KH$_2$PO$_4$0.15% (w/v). Under optimal culture conditions, the mycelial growth of modified optimal medium was higher than that of ME medium.

• Microbiology and Biotechnology Letters
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• v.13 no.4
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• pp.321-327
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• 1985

Cultivation conditions for the production of extracellular alkaline protease by a nonpiamentation Serratia sp. and purification of the enzyme were studied. The maximum enzyme level was obtained at the beginning of stationary phase when the organism was cultured on brain heart infusion medium at $25^{\circ}C$ under aeration (gyratory shaking, 180 cycles/min). The enzyme was purified about 100 fold with 16.5％ yield by ammonium sulfate precipitation, ammonium sulfate fractionation followed by DEAE-cellulose chromatography (1st and 2nd). The purified enzyme moved as a single symmetrical peak in the analytical ultracentrifuge. The enzyme demonstrated its maximum activity at pH 8.5-9.0 and 4$0^{\circ}C$ when vitamin-free casein was used as a substrate.