• Microbiology and Biotechnology Letters
• /
• v.16 no.2
• /
• pp.105-110
• /
• 1988

The production of single cell protein using the amylolytic fusant obtained from cell fusion between Hansenula anomala and Saccharomyces cerevisiae was studied. The fusant12 strain was selected for single cell protein production from starchy materials among five fusants. Optimum nitrogen source and its concentration for the growth of fusant12 were ammonium sulfate and 0.1%, respectively. Optimum concentration of soluble starch and optimum pH of the basal medium were lord and pH 5.6, respectively. Autolysis of fusant12 was effectively carried out by addition of 5% (v/v) ethyl acetate to the cell suspension and liquidization for 30 min before incubation for 24 hr at 3$0^{\circ}C$. Coculture of fusant12 and non-amylolytic yeast, Torulopsis candida YA-l5, resulted in the increase of the mass as compared to the monoculture of fusant12. The cell mass on tapioca medium was increased about 2.5 times as on soluble starch medium. The content of crude protein and nucleic acid of the dry cell were 39% and 5.8%, respectively.

• YAKHAK HOEJI
• /
• v.38 no.6
• /
• pp.749-755
• /
• 1994

An interspecific fusant strain, Streptomyces MS1 was obtained by protoplast fusion between S. peucetius subsp. caesius and S. platensis. We studied on the fermentation characteristics of the fusant strain. The fermentation products of the fusant MS1 was identical with S. peucetius, but its production of anthracycline was more stable than S. peucetius under various fermentation conditions in regard to acidogenesis of fermentation broth. The optimal medium composition for anthracycline production by fusant MS1 as follows: sucrose 2.0%, glucose 1.0%, soytone 0.7%, $CaCO_3$ 0.2%, $KH_2PO_4$ 0.013%, casamino acids 0.01%, $K_2SO_4$ 0.025%, $MaCl_2\;6H_2O$ 1.024%, 5M $CaCl_2\;5H_2O$ 0.4%, 1N NaOH 0.7%, 20% L-proline 1.5%. In this condition, the productivity of anthracycline was $80{\sim}100\;{\mu}g/ml$.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.26 no.6
• /
• pp.1077-1085
• /
• 1997

This study was carried out to elucidate the utilization of the fusant for shortening the ripening time by making an observation of the microstructure and the profile of component change. In ripening cheese, moisture content of the sample treated with tested strain is not a remarkable difference among the test samples. With an increase of the ripening time, L. helveticus showed the highest increase in protein content, followed by fusant, and then L. bulgaricus. The fat content of all starters was gradually decreased while it was it was rapidly decreased after 7 days. The pH of all starters was gradually decreased when the ripening time increased. The titratable acidity was greatly increased between a 9th day and a 15th day ripening. In investigating the light microscopic microstructure of ripened cheese samples, the sample treated with fusant indicated little difference from the other starters in decomposition of protein and fat components by microbial enzymes. In SEM observation, the structure of all cheese samples was uniform and the rough texture was converted into smooth texture by the interaction of cheese components and the abscission of single bond in casein matrix when the ripening time is increased. The fusant showed similar results in the examination of component change and its microstructure compared with the other starters. Therefore, it was revealed that the fusant can be partially used as a cheese starter instead of conventional starters by replacing them or combining them together with the other starters for shortening the ripening time.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.24 no.5
• /
• pp.779-784
• /
• 1995

The effective production of 5'-GMP(5'-Guanylic acid) by immobilized 5'-GMP producing fusant RC102(intergeneric protoplast fusion between Brevibacterium ammoniagenes ATCC21263 and Corynebacterium glutamicum ATCC21171) was investigated. The Fusant RC102 was immobilized by entrapping in -carrageenan, agar, polyacrylamide or Ca-alginate. 3% k-carrageenan was selected as the most suitable matrix. In the production of 5'-GMP using the immobilized whole cells of fusant RC102, the optimum conditions were $32^{\circ}C$, pH 8.0, $30\mu\textrm{g}/L\;of\;Mn^{2+},\;1{\times}10^{-6}%\;of\;Zn^{2+}$. In order to use fermentation medium containing CSL(Corn Steep Liquor) plentiful in $Mn^{2+}$, the optimum conditions of penicillin G, D-cycloserine and POESA(polyoxyethylene stearylamine) for production of 5'-GMP were 0.8unit/ml, 0.8unit/ml, 0.8unit/ml and 5mg/ml, respectively. Cationic surfactant, POESA was effective and superior to the antibiotics, penicillin G or D-cyloserine in 5'-GMP productivity. The condinuous fermentation using immobilized fusant RC102 showed that 5'-GMP productivity was stable for more than 15 days.

• Journal of Microbiology and Biotechnology
• /
• v.2 no.2
• /
• pp.108-114
• /
• 1992

The fermentative characteristics in ethanol production from lactose, with increased ethanol tolerance, of a fusant yeast strain constructed by protoplast fusion of Saccharomyces cerevisiae and Kluyveromyces fragilis were studied. The ethanol tolerance of this strain was increased to 8.0%, compared with the parent K. fragilis. During batch ethanol fermentation the optimal cultivation conditions for this fusant yeast were an initial pH of 4.5, a culture temperature $30^\circ{C}$. stirring at 100 rpm without aeration in 10% lactose medium (supplied with 1.0% yeast extract). Using this fusant strain in whey fermentation to ethanol, maximum ethanol production reached 3.41% (w/v) (theoretical yield; 66.7%) after a 48 hour cultivation period.

• YAKHAK HOEJI
• /
• v.38 no.6
• /
• pp.696-702
• /
• 1994

An interspecific fusant strain, MS1, was obtained by protoplast fusion between S. peucetius subsp. caesius and S. platensis. We studied on the microbiological and cultural characteristics of the fusant MS1. In liquid culture, the viscosity of culture broth of S. peucetius increased during incubation However the fusant MS1 formed pellet like S. platensis without viscosity change. On agar medium the colony morphology of MSI resembled S. platensis but the color was similar to S. peucetius. The fermentation products of the fusant MS1 was identical with S. peucetius.

• Microbiology and Biotechnology Letters
• /
• v.21 no.4
• /
• pp.310-315
• /
• 1993

An interspecific fusant was made from the protoplasts of two strains of Lactobacillus genus (L. bulgaricus and L.helveticus). And in order to test the applicability of the fusant in manufacturing the cheddar cheese, functional properties of the strain was examined by determining acid-producing activity, three important enzyme activities and volatile free fatty acid-producing activity. The recombinant strain did not exhibit greatly increased acid-porducing activity. Lipase and volatile free fatty acid-porducing abilities of the fusant, however, were remarkably higher than those of the two parental strains. The fusant actually porduced the cheese porduct of the highest ammount of total volatile free fatty acid after 7 days ripening at 10$^{\circ}C$. Finally, the cheddar cheese ripened with this strain was also evaluated to be high preference and flavor intensity by organoleptic panel tests.

• Microbiology and Biotechnology Letters
• /
• v.14 no.5
• /
• pp.359-363
• /
• 1986

S. diastaticus hydrolysised $\alpha$-1.4 linkage of the starch and was known fermenting yeast strain, but poorly hydrolized $\alpha$-1.6 linkage of the starch. To improve the starch fermentation ability of yeast, we tried that protoplast fusion between S. diastaticus and C. tropicalis and finally two starins of fusant (FPDC42, FPDC43) were obtained. C. tropicalis well hydrolysis both $\alpha$-1.4 and $\alpha$-1.6 linkanges in the starch. The protoplast of parental auxotrophic cells were fused in the presence of 10mM CaCl$_2$ and 35% of polyethylene glycol (M. W. 4,000). The fusion frequency was 10$^{-5}$ to 10$^{-6}$. Properties of the fusants(genetic stability, assimilation of carbon sources, random spore formation, copper resistance, NaCl tolerance, DNA content, cell size and growth rate) were investigated.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.26 no.6
• /
• pp.1068-1076
• /
• 1997

This study was carried out to elucidate the utility of fusant for shortening the ripening time of imitation processed cheese. L. bulgaricus exhibited the highest protease and lactase activity and L. helveticus revealed the highest lipase activity. Fusant was shown to be high in the activity of protease and lactase. The total volatile free fatty acid produced by the cheese treated with L. helveticus was markedly increased after four ripening days and was gently increased after nine ripening days. However, L. bulgaricus significantly increased the total volatile free fatty acid between four and nine ripening days. In the case of fusant, the amount of total volatile free fatty acid was observed to increase at a constant rate relative to the ripening time. In free fatty acid production at different ripening times, L. bulfaricus generated caproic acid and caprilic acid abundantly while it produced a poor quantity of capric acid, lauric acid, and myristic acid. In the cheese sample treated with L. helveticus, the amount of caproic acid and capylic acid was on increase as the ripening time increased. The amount of caproic acid and caprylic acid produced by fusant was less than that produced by the other two starters. In the panel sensory evaluation, the flavor intensity and preference increased as the ripening time increased. The cheese sample treated with fusant showed the highest flavor intensity at 7 days, whereas cheese treated with L. helveticus exhibited the highest flavor intensity at 15 or 30 days. The cheese treated with L. helveticus showed the highest preference at 7 days, but cheese treated with fusant exhibited the highest preference at 30 days.

• Microbiology and Biotechnology Letters
• /
• v.16 no.4
• /
• pp.297-302
• /
• 1988

The protoplasts of Saccharomyces cerevisiae D-71, a thermophilic strain and Zygosaccharomyces rouxii SR-S, an osmotolerant strain were fused, and a fusant (FS-RN 1) was selected, then was characterized for its genetic stability, DNA content, cell capacity, growth rate, tolerance to salts and chemicals, $\beta$-fructofuranosidase level and ethanol fermenting activity. After 6 months of preservation, 5.8% of the fusant clones were segregated to parental types. The DNA content and cell capacity of the fusant were greater than those of the parental strains. Lag period of growth for the fusant was longer than those for the parents. The fusant colonies showed pink-color reaction to triphenyltetrazolium chloride(TTC) test. The fusant appeared to have resistances to NaCl at moderate levels between both parental strains, and resistances to KCI, sodium propionate and cycloheximide similar to either one of the parents. $\beta$-Fructofuranosidase activity of the fusant was 24.2$\times$10$^{-3}$/IU/g(dry wt) for 3 days culture. Ethanol yields ofter 4 days of fermentation by the fusant at 3$0^{\circ}C$ were : 6.0%(v/v) from 40% of glucose and 8.8%(v/v) from 20% of sucrose.