• Applied Biological Chemistry
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• v.39 no.5
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• pp.343-348
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• 1996

Experiments were carried out to find possibility of economic production of SCP in mixed culture by Cellulomonas sp. KL-6 and E. coli LI-10. The best cell growth was obtained at the ratio of 1 : 1(v/v) in mixed culture. When these strains were mixed culture, cell growth was increased to about 63%, compared with those of single culture of strain KL-6. It was found that the majority of the population during growth in mixed culture consisted of strain KL-6. $CaCO_3$ added to the medium as the ratio of 0.1% was enhanced medium pH. Cell growth increased in that circumstances. These strains produced much amounts of cellobiose, but glucose was not detected in filter paper medium. When these organisms were cultured under the optimal medium for 4 days, cell mass was produced $1.0\;g/{\ell}$. The results showed the increase of cell mass up to 53% than those produced in CMC medium.

• Korean Journal of Food Science and Technology
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• v.18 no.3
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• pp.210-214
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• 1986

The culture conditions and cell composition of a hydrogen bacterica, Alcaligenes eutrophus ATCC 17697. were investigated. Optimum pH and temperature for cell growth under autotrophic condition ($H_2$ as energy source, $CO_2$, as crabon source) were around 7.0 and $30^{\circ}C$, respectively. Effect of oxygen partial pressure in the range of 0.059 atm and 0.27 atm on cell growth was also studied. Maximum specific growth rate $({\mu}max=0.31hr^{-1})$ was observed at 0.11 atm of oxygen partial pressure $(H_2:O_2:CO_2=7:1:1)$. The contents of crude protein, nucleic acid and ash in cells were 69.2%, 17.6%, and 3.62%, respectively.

• Korean Journal of Food Science and Technology
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• v.19 no.4
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• pp.324-330
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• 1987

A large number of methanol-assimilating yeasts and bacteria were isolated from samples of soil, sewage, decomposed milk and spoiled sweet-radish pickles. Among the yeasts, one strain was selected and identified as a strain of Candida boidinii. In 1% (v/v) methanol Candida boidinii YF-3 grew well and could grow in as much as 5%. This yeast required boitin for grwoth. Maximum growth was observed at $30^{\circ}C$ and pH 6 in a semisynthetic medium. The productivity was 2.72g dry cells per liter in batch culture with 1%(v/v) methanol and the cell yield for methanol was $0.39\;gg^{-1}$. The specific growth rate was $0.11\;h^{-1}$ and the generation time was 6.4 hours. The protein content of the cell was 45.5% and total nucleic acid content was 5.9%. The amino acid profile was as good as FAO standard for food protein.

• Applied Biological Chemistry
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• v.27
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• pp.29-46
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• 1984

To utilize several species of hard wood as raw materials of feed products, fermentation characteristics of cellulosic substrates to single cell protein was investigated, and results were summarized as follows. Among the microorganisms investigated, Tricoderma viride was selected as one of the most cellulolytic. Mixed culture of fungi did not show a synergistic effect on cellulose degradation. When the fungi were cultured at $28^{\circ}C$ for 7 days in a medium containing wheat bran 25 g, cellulose 0.25 g, proteose peptone 0.025 g and tween 800.025 g, cellulotic activities on carboxy methyl cellulose and filter paper reached maximum at 12 hr. The alkali treatment resulted in increased degradation of substrate from 13 to 18% when treated with enzymes for 12h, and reducing sugar formation increased with decreased size of substrates. Glucose was a very good feedback inhibitor of the enzyme from T.viride than that of xylose. When the substrate was rehydrolyzed, hydrolysis rate was 31% to reducing sugars within 12 hr. Quantative anlysis with HPLC showed the ratio of glucose to xylose in sugar syrups as 1.77 to 1. For the purpose of producing cellulosic-single cell protein from the sawdust of mulberry tree, 15 strains of xylose-assimilating yeast were isolated from 42 samples of rotten woods and compost soils and examined for their ability to utilize xylose. Then three strains were selected by their strong xylose-assimilating activities. The cultivative condition, the growth characteristics, and protein and nucleic acid productivities of three strains were investigated. The results obtained were, 1. Wood hydrolysate of mulberry tree was assimilated by 5 strains of CHS-2, CHS-3, ST-40, CHS-12 and CHS-13. 2. The optimum initial pH and temperature for the growth of strain CHS-13 were 4.4 and $30^{\circ}C$. 3. The specific growth rate of strain CHS-13 was $0.23h^{-1}$ and generation time was 3.01 hrs at the optimum condition. 4. CHS-13 strain assimilated 81 % of sugar in wood hydrolysate. 5. CHS-13 strain was identified as Candida guilliermondii var. guilliermondii 6. When the CHS-13 strain was cultured in the wood hydrolysate containing yeast extract, L-protein content was increased with yeast extract concentration. 7. The L-protein and nucleic acid yields from wood hydrolysate were 0.73 mg/ml and $4.92{\times}10^{-2}\;mg/ml$ respectively. 8. An optimal nucleic acid content of CHS-13 strain was observed in the medium containing 0.2% of yeast extract.

• Applied Chemistry for Engineering
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• v.26 no.3
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• pp.265-269
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• 2015

Chlorella vulgaris (C. vulgaris) is a spherical unicellular green algae and the diameter ranges from 2 to $10{\mu}m$. C. vulgaris possess nutritional excellence because it contains various functional materials including high protein contents, chlorophyll, carotenoid, and chlorella growth factor (CGF). In order to study effects of mutagen, ethyl methane sulphonate (EMS) was used as a chemical mutagen and some mutants could be obtained. We named 2 type mutants as E14 and E24 obtained after treating with EMS. In the cell growth, growth patterns of mutants were similar to those of the wild type. Chlorophyll contents of E14 and E24 increased up to 99 and 52%, respectively compared to those of the wild type. The carotenoid content of E14 increased to 7%, but the value of E24 decreased 5% compared to that of the wild type. For the lipid contents E24 increased to 23%, while E14 decreased 12% when compared to those of the wild type. As a result, there is no difference between the mutants and wild type in the cell growth, but considering that mutants contains more physiological materials than those of the wild type, we can expect the mutants of C. vulgaris could be used as important high added-value materials.

• Applied Biological Chemistry
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• v.37 no.4
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• pp.221-225
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• 1994

For producing single cell protein from the agricultural waste, heat treatment and antibiotics on the growth of Cellulomonas sp. KL-6, isolated in rotting leaf and the adjacent soil mixture, were examined. The organism was able to grow until 5 min. at $65^{\circ}C$, 1 min. at $75^{\circ}C$ and 1/4 min. at $85^{\circ}C$ in gradually rising temperatures. It can be Seen that preheating the suspension at $48^{\circ}C$ results in a marked decrease in heat resistance. On heating at temperature of $55^{\circ}C$ for 30 min., strain KL-6 was more resisted in the 0.1 M phosphate buffer when such substrates as casamino acid (1%), yeast extract (1%) or xylose (5%) were added to it whereas this organism was appeared weaker resistances in 0.1 M phosphate buffer when cysteine (0.03 M), sodium citrate (1%) or casein (1%) were in fused into it. Test strain was susceptible to penicillin-G $(1.563\;{\mu}g/ml)$ and ampicillin $(3.125\;{\mu}g/ml)$, but the organism was resisted to kanamycin $(>200\;{\mu}g/ml)$. The treatment of strain KL-6 with sodium dodecyl sulfate (SDS) resulted in the elimination of R-plasmid from the host strain and the elimination rate with SDS $(10{\sim}30\;{\mu}g/ml)$ was about $9.2{\sim}31.2%$, respectively.

• Korean Journal of Food Science and Technology
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• v.2 no.2
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• pp.61-67
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• 1970

The growth characteristics of Candida tropicalis KIST 359, isolated from soil samples collected at an oil depot in Korea, have been studied by cultivating batches under varying conditions. The conclusions of the study were: 1. The yeast easily assimilates hydrocarbons in a range of $C_{14}-C_{17}$, and the optimum cultivation temperature and pH are $30^{\circ}C$ and 5.5, respectively. 2. Using this strain of micro-organism, gas oil gives a higher cell yield than kerosine and with gas oil except urea all other nitrogen sources $(NH_4NO_3,\;NH_4Cl,\;(NH_4)_2SO_4\;and\;(NH_4)_2HPO_4)$ similarly support a satisfactory growth of the yeast. 3. The highest yield is obtained with a gas oil level of 10%(v/v), and concentrations of nitrogen source and $MgSO_4{\cdot}7H_2O$ of 0.5 and 0.05%(w/v), respectively. 4. The protein content of dried yeast cells is 59.8%. Its amino acid composition can be compared well with that of FAO provisional patterns, but with a low methionine and a high lysine content.

• 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.

• Korean Journal of Microbiology
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• v.47 no.4
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• pp.295-301
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• 2011

Aquaporin is a water channel protein, which is classified as Major Intrinsic Protein (MIP), found in almost all organisms from bacteria to human. To date, more than 200 members of this family were identified. There are two major categories of MIP channels, orthodox aquaporins and aquaglyceroporins, which facilitate the diffusion across biological membranes of water or glycerol and other uncharged compounds, respectively. The full genome sequencing of various fungal species revealed 3 to 5 aquaporins in their genome. Although some functions of aquaporins found in yeast were characterized, however, no functional characteristics were studied so far in filamentous fungi, including Aspergillus sp. In this study, one orthodox aquaporin homolog gene, aqpA, and four aquaglyceroporin homologs, aqpB-E, in a model filamentous fungus Aspergillus nidulans were identified and the function of the aqpA gene was characterized. Knock-out of the aqpA gene didn't show any obvious phenotypic change under the osmotic stress, indicating that the function of the gene does not involved in the osmotic stress response or the function could be redundant. However, the mutant showed antifungal susceptibility resistance phenotype, suggesting that the function of the aqpA gene could be involved in sensing the antifungal substances rather than the osmotic stress response.

• Korean Journal of Food Science and Technology
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• v.6 no.4
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• pp.231-240
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• 1974

The growth of a mixed yeast culture consisting of Canda tropicalis var. KIST 76 and Tricosporon cutaneum KIST 76-H was compared with that of pure cultures under pilot plant conditions. The mixed culture was judged stable based on the nearly constant ratio of the two organisms at the completion of fermentation. We obtained higher cell yields, protein content and productivity in the mixed culture on n-paraffin than the pure culture of C. tropicalis var. KIST 76. T. cutaneum KIST 76-H did not grow on n-paraffin medium. With the batch cultivation of mixed organisms on n-paraffin, the specific growth rates during the exponential growth phase were 0.24-0.33 $hr^{-1};$ cell yields were 96-106% and productivities were 2.9-3.6g/l. hr. The cells obtained contained 55-58% crude protein and 5.5-6.3% lipid. The critical value of dissolved oxygen concentration Ccrit. and saturation constant, km, are approximately 1.5 ppm and 0.228 ppm respectively. Also we established the optimal conditions for the mixed culture in batch fermentation.