• KSBB Journal
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• v.5 no.3
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• pp.255-261
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• 1990

Cell fusion between complementary mutants isolated from astaxanthin-producing yeast, Phaffia rhodozyma, was carried out to obtain astaxanthin-overproducing strains by protoplast fusion technique. The frequency of protoplast fusion was ranged from 2.3$\times$10-5 to 6.0$\times$10-5, and nuclear fusion in the cells of hybrids was demonstrated by several techniques such as isolation of recombinants after mitotic segregation of parental genetic markers, estimation of DNA content, direct observation of nuclei with nuclear staining, and comparison of survival rate to UV exposure. One of several hybrids, Fl, showed approximately 3-fold increase in astaxanthin content when compared with wild parent.

• KSBB Journal
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• v.17 no.2
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• pp.176-181
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• 2002

Astaxanthin (3,3＇-dihydroxy-${\beta}$, ${\beta}$-carotene-4-4＇-dione), a natural pigment of pink to red color, is widely distributed in nature particularly in the skin layer of salmonoids and the crust of shrimp, lobster, etc. Recently, it was produced from the yeast culture of Phaffia rhodozyma. Because of its high thermal stability and antioxidant functionality, its applications can be extended into food, cosmetics, and pharmaceutical ingredient beyond the traditional feed additive. Because of its very high lipophilicity, astaxanthin has been extracted traditionally by strong organic solvents such as chloroform, petroleum ether, acetone, etc. In this study, we developed a surfactant-based solubillization system for astaxanthin, and used it to extract astaxanthin from disrupted yeast cells. Among Tween 20, Triton X-100 and SDS, Tween 20 was identified as the most suitable surfactant in terms of extraction capacity and safety. The ethylene oxide group of Tween 20 was identified as the most significant factor to increase the HLB value that determined the extraction capacity. The effects of micelle formation condition, such as the molar ratio of astaxanthin and Tween 20, pH, and ionic strength were also investigated. pH and ionic strength showed no significant effects. The optimal molar ratio between astaxanthin and Tween 20 was 1 : 12. Antioxidant activity of astaxanthin was higher than ${\beta}$-carotene and ${\alpha}$-tocopherol. Astaxanthin in the crude extract from the yeast cell was more resistant to air and/or light degradation than pure astaxanthin, probably because of the presence of other carotenoids and lipids.

• Toxicological Research
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• v.22 no.4
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• pp.381-390
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• 2006

Astaxanthine is a pigment that belongs to the family of the xanthophylls, the oxygenated derivatives of carotenoids whose synthesis in plants derives from lycopene. Astaxanthine is also a carotenoid widely used in salmonid and crustacean aquaculture to provide the pink color characteristic of that. Recent study reported that astaxanthine has the role as a detoxicant against the free radicals. On our study, we estimated the genotoxicity in ICR mice and possibility as antioxidant reagents of mutant Phaffia rhodozyma strain over expressing the astaxanthine by gamma-lay and carophyll pink including astaxanthine in apoE knock out mice, respectively. In our study, we administered Phaffia rhodozyma (2 mg and 3 mg) and carophyll pink for 4 and 8 week. The clinical sign and mortality were not detected compared with control groups. In the mutant frequency of hprt gene and chromosome aberration in splenic cells, there was not detected abnormality. There was not critical change in hematological and serum biochemical test compared to control. In expression level of repair enzyme, increase of catalase were detected and increase of expression level of Nrf-2 was detected in Phaffia rhodozyma (3 mg) and carophyll pink in 8 week treated group. In GSH level, the group of treated with Phaffia rhodozyma (3 mg) showed the increase of the GSH. In conclusion, mutant Phaffia rhodozyma and caphyll pink may be applied to the effective food additives to reduce the free radical.

• Journal of Aquaculture
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• v.9 no.4
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• pp.363-375
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• 1996

The effects of the yeast, Phaffia rhodozyme in the diet on growth, body composition, muscle elasticity and pigmentation of Israeli strain of common carp, colored carp and Nile tilapia were investigated. Ten percent of the yeast was added to semi purified diet as an experimental feed 1. Ten percent of brewers yeast in the semi purified diet (experimental feed 2) was tested for comparing the growth performance between two semi purified diets. A commercial diet was also used for the check of growth rate of the semi purified diets. All experimental fish were fed for 10 weeks. The weight gains among the experimental fish were not significantly different (P>0.05). There were not significantly different in body composition, muscle elasticity among the the fishes fed three experimental diets. There were significant differences (P<0.05) of pigment deposition in the muscle of Israeli strain of common can and on the skin of colored carp between treated and non treated group. But there were no differences of pigment deposition in flesh and skin of tilapia among the three diets.

• Proceedings of the Zoological Society Korea Conference
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• 1994.10a
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• pp.259-259
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• 1994

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.720-726
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• 1999

High voltage pulsed electric fields (PEF) technology is a non-thermal technique which is applicable to extract useful components froms biological materials. This research suggested the possibility for extracting carotenoid pigments from Phaffia rhodozyma by PEF treatments. The yeast cell suspensions were treated with high voltage pulses in a recycled PEF treatment chamber which consists a pair of thin plates of stainless steel adhering to a small chamber with approximately $1{\sim}4\;mm$ gap. A 2.5 log reduction in survivability and more than 98% of electropermeabilization of the yeast cells could be achieved by PEF treatment for $300\;{\mu}s$ with an electric field of 30 kV/cm and pulse duration of $1\;{\mu}s$. When the yeast cell suspended in 0.01% NaCl solution were treated with PEF under various conditions, carotenoid pigments were not extracted. However, the PEF treatment of the yeast cell suspensions in 0.01% $CaCl_2$ solution, have positive effects on the extraction of carotenoid pigments ($27.3\;{\mu}g/g$ of dried yeast).

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.271-274
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• 2000

A study was carried out to select a nitrogen source and the optimize the C/N ratio for the maximum cell growth of Phaffia rhodozyma in fed-batch culture. The yeast extract was the best organic nitrogen source. In the batch culture experiments, the highest cell yield was obtained 0.575 g-cell/g-glucose from 10 g/L and 10 g/L yeast extract. In the fed-batch experiments, the maximum cell concentration was obtained 33.1 g/L from the C/N ratio of 2:1 while the astaxanthin concentration of cell was Increased by increasing the C/N ratio, of feed medium.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.301-304
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• 2000

Fed-batch culture was designed to increase cell concentration and astaxanthin content by mutant AJ-6 of Phaffia rhodozyma. Fed-batch culture was performed in the continuous feeding with manual adjustment of flow rate to control glucose concentration. When the final glucose concentration was 100 g/L, the cell and astaxanthin were 38.3 g/L, 34.8 mg/L, respectively. Addition of ethanol(10 g/L), when glucose was depleted, the cell and astaxanthin concentration were 37.2 g/L and 45.6, respectively, 5 g/L of acetic acid supplied, 40.6 g/L, 43.9 mg/L were obtained. Ethanol and acetic acid enhanced the astaxanthin content act as precursor of carotenoid synthesis.

• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.314.1-314
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• 1995

• Journal of Microbiology and Biotechnology
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• v.8 no.6
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• pp.650-655
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• 1998

The chromosomal DNA fragment from Phaffia rhodozyma CBS 6938 which is able to autonomously replicate in the yeast Saccharomyces cerevisiae was cloned on an integrative URA3 plasmid. Its minimal fragment exhibiting autonomously replicating activiy in the S. cerevisiae gave a higher frequency transformation efficiency than that found for centromere-based plasmid, and enabled extrachromosoma1ly stable transmission of the plasmids in one copy per yeast cell under non-selective culture condition. The 836-bp DNA element lacked an ORF and did not contain any acceptable match to an ARS core consensus. Sequence analysis, however, displayed a cluster of three hairpin-Ioop-sequences with individual $\triangle {G_{25}}^{\circ}C$ free energy value of -10.0, -17.5, and -17.0 kcal. $mor^{-l}$as well as a 9-bp sequence with two base pair mismatches to the S. cerevisiae/E. coli gyrase-binding site. This 836-bp sequence also included one 7-bp sequence analogous to the core consensus of centromeric DNA element III (CDEIII) of S. cerevisiae, but CDEIII-like 7 bp sequence alone did not give a replicative function in this yeast.