• Journal of Life Science
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• v.13 no.5
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• pp.705-711
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• 2003

The gellan was produced by Pseudomonas elodea under aerobic condition. In this study, the effects of inoculum size, carbon sources and concentration, nitrogen source, and C/N ratio on the cell growth and the production of gellan were evaluated. The maximum growth of P. elodea and gellan production was obtained at 5% (v/v) of inoculum size and glucose showed best results among 9 carbon sources tested. The maximum specific yield of 2.22 and productivity of $0.03 g/\ell$h were obtained at 1.0% (w/v) of glucose. The maximum gellan production was obtained at medium without ammonium nitrate. This indicates that nitrogen limitation is essential for the production of gellan. The highest cell and gellan production were obtained at 20 of C/N ratio.

• 한국생물공학회:학술대회논문집
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• 2002.04a
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• pp.457-460
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• 2002

In an effort to isolate novel strains expressing a thermostable esterase that hydrolyzed the rac-ketoprofen ethyl ester to ketoprofen in the stereospecific manner, we screened various soils and composts from broad ecological niches in which the activity was expected to be found. Three hundreds of microbial strains were tested to determine their ester-hydrolyzing activity by using an agar plate containing insoluble tributyrin as an indicative substrate, and then further screened by activity on the (R,S)-ketoprofen ethyl ester. Twenty-six strains were screened primarily at high growth and incubation temperature and further compared the ability to ethyl ester-hydrolyzing activity in terms of conversion yield and chiral specificity. Consequently, a strain JYl44 was isolated as a novel strain that produced a (R)-stereospecific esterase with high stability and systematically identified as a Bacillus stearothermophilus JY144. The enzyme indeed stables at a broad range of temperature, upto 65 $^{\circ}C$, and pH ranging from 6.0 to 10.0. The optimal temperature and pH for enzymatic conversion were 50 $^{\circ}C$ and 9.0, respectively. Based on the observations that resulted a poor cell growth, and enzyme expression in wild type strain, we further attempted the gene cloning into a general host Escherichia coli and determined its primary structure, concomitantly resulting a high level expression of the enzyme. The cloned gene had an open reading frame (250 amino acids) with a calculated molecular mass of 27.4 kDa, and its primary structure showed a relative high homology (45-52 %) to the esterases from Streptomyces and Bacillus strains. The recombinant whole cell enzyme could efficiently convert the rac-ketoprofen ethyl ester to (R)-ketoprofen, with optical purity of 99 % and yield of 49 %.

• Microbiology and Biotechnology Letters
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• v.10 no.2
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• pp.155-162
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• 1982

A cell-recycled continuous fermentation process was studied to produce ethanol from molasses using Sacchoromyces uvarum ATCC26602 at 35 $^{\circ}C$. The fermentation system was divided into two stages in order to reduce the inhibitions of ethanol and substrate for cell growth and fermentation rate. The first reactor was aerated at the rate of 0.12 vvm whilst the second was kept anaerobic. In medium composition studies, it was revealed that inorganic nutrient supplement to the diluted molasses with 14% fermentable sugar was not needed for the fermentation, however, phosphate limitation was observed when cell propagation was contemplated. By using the cell-recycled continuous fermentation system, 14.5 hour was required to produce 8.4-9.0% (v/v) of ethanol from diluted molasses containing 14% of fermentable sugar. The ethanol productivity was 6.2g/$\ell$hr with the yield of 88.1-94.4% to the theoretical value.

• Journal of Ginseng Research
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• v.24 no.4
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• pp.157-161
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• 2000

Cell growth and production of phenolic compounds by callus cultures of Panax ginseng C. A. Meyer were investigated under various phytohormones concentrations and inoculum size. The results indicated that the cell growt was improved by a MS medium supplemented with 2 mg/L of CPA. The maximum cell yield was obtained at inoculum size of 1 g/flasd. The production of phenolic compounds in the callus cultures was higher than those in the ginseng root. Especially, one cell line (20601) showed the highest content of phenolic compounds and antioxidant activity.

• Journal of Hydrogen and New Energy
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• v.22 no.4
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• pp.451-457
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• 2011

Purple non-sulfur (PNS) bacterium $Rhodobacter$ $sphaeroides$ KD131 was studied with the aim of achieving maximum hydrogen production using various carbon and nitrogen sources at different pH conditions. Cells grew well and produced hydrogen using $(NH_4){_2}SO_4$ or glutamate as a nitrogen source in combination with a carbon substrate, succinate or malate. During 48h of photo-heterotrophic fermentation under 110$W/m^2$ illumination using a halogen lamp at $30^{\circ}C$, 67% of 30mM succinate added was degraded and the hydrogen yield was estimated as 3.29mol $H^2$/mol-succinate. However, less than 30% of formate was consumed and hydrogen was not produced due to a lack of genes coding for the formate-hydrogen lyase complex of strain KD131. Initial cell concentrations of more than 0.6g dry cell weight/L-culture broth were not favorable for hydrogen evolution by cell aggregation, thus leading to substrate and light unavailability. In a modified Sistrom's medium containing 30mM succinate with a carbon to nitrogen ratio of 12.85 (w/w), glutamate produced 1.40-fold more hydrogen compared to ammonium sulfate during the first 48h. However, ammonium sulfate was 1.78-fold more effective for extended cultivation of 96h. An initial pH range from 6.0 to 9.0 influenced cell growth and hydrogen production, and maintenance of pH 7.5 during photofermentation led to the increased hydrogen yield.

• Food Science and Preservation
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• v.20 no.6
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• pp.834-839
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• 2013

The extraction yield, total phenolics content, antioxidant activity, cancer cell growth inhibition (A549 and MCF 7), and lung cancer cell (A549) viability of red rice and black rice were investigated, to evaluate the functional properties of colored rice. The extraction yields and the total phenolics contents of the rice cultivars were Heugseol > Heugkwang > Hongjinju > Jeogjinju > Ilpum. Also, the DPPH radical scavenging activity of the black rice did not differ from that of the red rice, whereas its activity among its cultivars was Jeogjinju > Heugseol > Heugkwang > Hongjinju > Ilpum. The ABTS antioxidant activity of the black rice (Heugkwang, Heugseol) was greater than that of the red rice. The total phenolics was partly attributed to its high antioxidant. On the other hand, the effect of the red rice on the lung cancer cell (A549) viability was higher than that of the black rice. The breast cancer cell (MCF 7) growth inhibition activity of the black rice did not differ from that of the red rice. Our results indicate that the ABTS antioxidant activity of black rice is better than that of red rice, and the lung cancer cell (A549) viability of red rice is better than that of black rice.

• Journal of Microbiology and Biotechnology
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• v.19 no.1
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• pp.17-22
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• 2009

The mixotrophic growth with methanol plus thiosulfate was examined in nutrient-limited mixotrophic condition for Methylobacterium goesingense CBMB5 and Methylobacterium fujisawaense CBMB37. Thiosulfate oxidation increased the growth and protein yield in mixotrophic medium that contained 150mM methanol and 20mM sodium thiosulfate, at 144 h. Respirometric study revealed that thiosulfate was the most preferable reduced inorganic sulfur source, followed by sulfite and sulfur. M. goesingense CBMB5 and M. fujisawaense CBMB37 oxidized thiosulfate directly to sulfate, and intermediate products of thiosulfate oxidation such as polythionates, sulfite, and sulfur were not detected in spent medium and they did not yield positive amplification for tested soxB primers. Enzymes of thiosulfate oxidation such as rhodanese and sulfite oxidase activities were detected in cell-free extracts of M. goesingense CBMB5, and M. fujisawaense CBMB37, and thiosulfate oxidase (tetrathionate synthase) activity was not observed. It indicated that both the organisms use the "non-S4 intermediate" sulfur oxidation pathway for thiosulfate oxidation. It is concluded from this study that M. goesingense CBMB5, and M. fujisawaense CBMB37 exhibited mixotrophic metabolism in medium containing methanol plus thiosulfate and that thiosulfate oxidation and the presence of a "Paracoccus sulfur oxidation" (PSO) pathway in methylotrophic bacteria are species dependant.

• Microbiology and Biotechnology Letters
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• v.6 no.4
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• pp.173-179
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• 1978

1) To study the productivity of single cell protein from the n-paraffin utilizing yeast, 235 yeast strains were isolatea from 90 samples 2) Optimum cell growth temperature of three strains selected was 40~45$^{\circ}C$ and these were identified as Candida tropicalis, Candida krusei and Torulopsis molischiana. 3) A-28 strain easily assimilated tetradecane, hexadecane and octadecane, but B-8 strain and C-15 strain assimilated more hexadecane than other n-paraffins. 4) Out of the selected three strains, the mass doubling time, specific growth rate and cell yield were 3.4~4.0 hours, 0.170~0.215, 86~98%, respectively. 5) Crude protein, fat, fiber, ash and nitrogen free extract of the selected three strains were found to be 48.2~61.2% 3.7~8.0%, 3.5~4.2%, 5.6~6.7%, 23.5~31.8%, respectively, and thiamine and riboflavin contents of dried yeast cell were 0.78~0.93 mg% and 6.03~7.3 mg%, respectively. 6) Yeast protein contained evenly most of amino acid, but the sulfur-containing amino acids were particularly low.

• Korean Journal of Agricultural Science
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• v.3 no.2
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• pp.244-250
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• 1976

Candida brumptii was one of the best isolates which could grow on alcohol distillation slops (reported in the previous paper). Attempts were made to investigate the cultural conditions for cell mass production by this strain, and the results obtained were as follow. The supernatant of the alcohol distillation slops without dilution support ed better growth of the strain than diluted ones. The addition of ammonium sulfate (0.2%), ammonium phosphate (0.1-0.2%), potassium phosphate (0.2%) to the supernatant resulted in positive effects for the growth, among the various inorganic nitrogen and other salts supplements. BOD and COD of the supernatant were reduced approximately 30% and 20%, respectively in 3 days culture. Cell production was maximized when grown at $35^{\circ}C$ and pH 5.0. The yield of cell mass was 1.03% by dry weight and its crude protein content was about 52.65%

• Journal of Plant Biology
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• v.37 no.2
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• pp.237-244
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• 1994

Callus tissues derived from protoplast of Alnus hirsuta were shown to produce red pigments under the continuous light. The R4 cell line with high yield of the pigments was selected. One of the red pigments was identified as anthocyanin; glucose and galactose as sugar moiety and cyandin as aglycone, by spectroscopic analysis, cellulose TLC and GLC. Both callus growth and anthocyanin accumulation were remarkably stimulated by 2,4-D. The highest anthocyanin yield was observed when $1\;\mu\textrm{M}$ 2,4-D in combination with $0.1\;\mu\textrm{M}$ BAP was supplemented to the culture medium. In case of inorganic salts, anthocyanin yield was enhenced by reducing concentration of phosphate from 5.0 mM to 2.5 mM and by increasing the ratio of ${NO_3}^{-}$ type to 80% for total nitrogen source.source.