Document Detail

Dependence of apparent viscosity on mycelial morphology of Streptomyces fradiae culture in various nitrogen sources.
MedLine Citation:
PMID:  10933823     Owner:  NLM     Status:  MEDLINE    
To examine what causes increased viscosity in culture broth in Streptomyces fradiae culture, various natural nitrogen sources were investigated. Extracellular protease activity increased with culture time and decomposed the natural nitrogen source into amino acids. In the case of gluten meal, after a culture time of 5 d, concentrations of glutamic acid and aspartic acid had increased to 600 and 200 mg/L, respectively, which were about 3- and 2-fold as high as levels in cultures under similar conditions using Pharmamedia. For various amino acids tested, the addition of glutamic acid or aspartic acid mixture to the culture medium raised the apparent viscosity to its highest demonstrated value, 260 mPa.s after 5 d of culture, which was 3-fold higher than without amino acids. Consumption of the decomposed glutamic acid and aspartic acid was dependent on the activities of glutamate dehydrogenase and aspartate aminotransferase, respectively. When ammonium ion was used as the nitrogen source, cell concentration reached 1.75 g/L measured as an intracellular nucleic acid concentration, which was about 2.3-fold higher than that with any other natural nitrogen source. However, apparent viscosity was only 75 mPa.s, a value one-third that of the amino acid mixture, and 70% of the pellets were bigger than 1.2 x 10(4) microm(2). In the case of gluten meal or the amino acid mixture, pellets bigger than 1.2 x 10(4) microm(2) comprised only 8%. This demonstrates that consumption of some amino acids affected the formation of filamentous morphology, which caused an increase in the apparent viscosity of the culture broth, and the apparent viscosity was not caused by the mycelial concentration but the mycelial morphology.
D B Choi; E Y Park; M Okabe
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Biotechnology progress     Volume:  16     ISSN:  8756-7938     ISO Abbreviation:  Biotechnol. Prog.     Publication Date:    2000 Jul-Aug
Date Detail:
Created Date:  2000-09-05     Completed Date:  2000-11-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8506292     Medline TA:  Biotechnol Prog     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  525-32     Citation Subset:  IM    
Institute of Life Science, Chosun University, 375, Seo-Suk Dong, Dong-ku, Kwang-Ju, Korea.
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MeSH Terms
Amino Acid Oxidoreductases / metabolism
Amino Acids / metabolism
Aspartic Acid / pharmacology
Culture Media
Endopeptidases / metabolism
Glutamate Dehydrogenase / metabolism
Glutamic Acid / pharmacology
Nitrogen / metabolism*
Streptomyces / cytology*
Reg. No./Substance:
0/Amino Acids; 0/Culture Media; 56-84-8/Aspartic Acid; 56-86-0/Glutamic Acid; 7727-37-9/Nitrogen; EC 1.4.-/Amino Acid Oxidoreductases; EC 1.4.1.-/aspartate dehydrogenase; EC Dehydrogenase; EC 3.4.-/Endopeptidases

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