• Proceedings of the Korean Society for Applied Microbiology Conference
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• 2005.06a
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• pp.233-244
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• 2005

Guanosine fermentation process can be well predicted and analyzed by the proposed state equations describing the dynamic change of a bioreactor. Pyruvate and alanine were found to be characteristically accumulated along with the decline of the guanosine formation rate during the mid-late phase of the process. The enzymological study of the main pathways in glucose catabolism and the quantitative stoichiometric calculation of metabolic flux distribution revealed that it was entirely attributed to the shift of metabolic flux from hexose monophosphate (HMP) pathway to glycolysis pathway. The process optimization by focusing on the restore of the shift of metabolic flux was conducted and the overcoming the decrease of oxygen uptake rate (OUR) was taken as the relevant factor of the trans-scale operation. As a result, the production of guanosinewas increased from 17 g/L to over 34 g/I.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.5
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• pp.796-801
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• 2000

Kimchi is the Korean traditional food which is fermented properly from salted Korean cabbage of raddish with other various supplements. Kimchi therefore can be the major sources for various kinds of nutrients and other biological substances. The fermentation process accompanies with complicated reaction mechanism which bacteria, fungi and yeast are involved and they produced aroma, taste and bioactive components. To identify nucleoside, this study was conducted with freeze-dried mustard leaf, mustard leaf kimchi and fermented mustard leaf kimchi. Hexane, CH$_2$Cl$_2$, EtOAc and BuOH was used in order to extract their components. The isolated compounds I and II from mustard leaf and mustard leaf kimchi were identified as adenosine and uracil using UV, $^{1}H$-NMR, $^{13}C$-NMR and LC-MS, respectively. Compound I, II and nucleosides are the first report of its occurrence from mustard leaf and their kimchi, the standardized ratios of ingredients for kimchi were 10 of anchovy juice, 8 of red pepper powder, 3 of garlic, 1.5 of ginger, 6 of paste of glutinous rice. The nucleoside of mustard leaf and their kimchi was determined and compared. The order of nucleosides contents of mustard leaf was uridine>cytosine>uracil>adenine>guanosine>guanin, that of fresh mustard leaf kimchi was uridine>uracil>cytosine>guanine>adenosine>adenin>guanosine and that of fermented mustard leaf kimchi (5days at 15$^{\circ}C$) was guanine>adenine>adenosine>guanosine. The differences of nucleoside contents from those were due to various supplements and fermentation process.

• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.2
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• pp.75-88
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• 2001

In this paper, the microbial production of riboflavin is reviewed and includes descriptions of riboflavin overproducers, and the biosynthesis and details of the key-enzyme genes related to riboflavin. There kinds of riboflavin overproducers are known; Bacillus subtilis and Candida famate utilize glucose as a carbon source, but the fungus Ashbya gossypii requires plant oil as its sole carbon source. The starting material in ribofalvin biosynthesis is guanosine triphospate (GTP), which is converted to riboflavin through six enzymatic reactions. Though Bacillus subtilis, Candida famate, and Ashbya gossypii operate via different pathways until GTP, they follow the same pathway from GTP to riboflavin. From the metabolic viewpoint, with respect to improved riboflavin production, the supplementation of GTP, aprocess-limiting precursor must be considered. The GTP fluxes originate from three sources, serine, threonine and glyoxylate cycles. The development of pathways to strengthen GTP supplementation using biotechnological techniques remains an issue fro future research.

• Korean Journal of Food Science and Technology
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• v.22 no.2
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• pp.221-226
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• 1990

Fish flesh of Alaska pollack containing 5% of corn starch were fermented with 8 strains of mold and monitoring of their flavor characteristics, acceptability, nucleotides and their related compounds, amino acid compositions were conducted. All strains were grown vigorously on fish flesh media and formed their characteristic spores with unique flavor by strains. Amino type nitrogen $(NH_2-N)$ content of fermented fish flesh (FFF) were 25-26 times higher than that of raw flesh and 6-15 times higher in extractable nitrogen (Ex-N) content . The strains which produce more ADP (Adenosine 5'-diphosphate) in FFF also showed much higher level of IMP (Inosine 5'-monophosphate) and GMP (Guanosine 5'-monophosphate) content than that of raw flesh. Amino acid composition were differ by strain but lysine was generally highest and arginine, glutamic acid, leucine and alanine in order In review of sensory evaluation , total content of nucleotides, $NH_2-N$, Ex-N and amino acid compositions, suitable strains for fish flesh fermentation were Aspergillus oryzae KFCC 11371, Asp. oryzae KFCC 32343, Penicillium roqueforti KFCC 11269 and Asp. quercinus.