• Korean Journal of Food Science and Technology
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• v.35 no.6
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• pp.1135-1142
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• 2003

The purification and characteristics of the biosynthesis enzyme of vitamin C from microorganisms related with kimchi fermentation were investigated to define vitamin C biosynthetic pathways in yeast. A yeast strain (Pichia onychis 16-4) which synthesizes vitamin C with galacturonic acid as substrate at high rate was isolated from kimchi. The enzyme $L-galactono-{\gamma}-lactone$ oxidase isolated from the yeast was purified and characterized. The specific activity of the crude enzyme was 7.26 unit/mg protein, which increased to 4,698 unit/mg protein with a chromatography of Sephacryl S-200HR; indicating a 647.1-fold level of purification. The molecular weights of the dissociated enzymes were estimated to be 31,000, 39,000, and 50,000 KD. Among the substrates tested, $L-galactono-{\gamma}-lactone$ was the most effective. The enzyme showed optimum activity ah pH 7.8 and 35c. The purified enzyme uses $O_2$ as the electron acceptor for oxidation of $L-galactono-{\gamma}-lactone$.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.5
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• pp.393-399
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• 2001

Effects of various types of salts (commercial low salt, sea salt, refined salt, and bamboo salt) and concentrations (0, 3.0 and 5.0% ) on the growth of yeasts isolated from Kimchi were investigated. The isolated yeasts used in the study are as follows : Saccharomyces cerevisia, Sporobolomyces albo-rubescens, Issatchenkia orientalis Cryptococcus luteolous, Ustilago maydis, Candida humilis, Pichia onychis, Cadida nitratophila, and Pichia jadinii. The growths of the yeasts were inhibited against each salt concentration. The growths of Candida sp. isolated from the later stage of fermentation was strongly inhibited against 5% concentration of salt. On the other hand the induction phase of Issatchenkia orientalis isolated at the early stage of fermentation was the quickest among all the tested yeasts. Among the salts, bamoo salt was found to be strongest inhibitor of the growth of yeasts.