Nitrate assimilation inCandida nitratophilaand other yeasts

✍ Scribed by A. H. Ali; C. R. Hipkin

• Publisher: Springer
• Year: 1986
• Tongue: English
• Weight: 507 KB
• Volume: 144
• Category: Article
• ISSN: 0302-8933
• DOI: 10.1007/bf00410960

✦ Synopsis

Nitrate assimilation has been studied in four species of yeasts; Candida nitratophila, Candida utilis, Hansenula anomala and Rhodotorula glutinis. Ammonium-grown cultures of these organisms did not assimilate nitrate but acquired the capacity to do so after a 3 h period of nitrogenstarvation. Ammonium inhibited nitrate assimilation completely in nitrate-grown cultures of R. gIutinis. With Candida spp, ammonium and nitrate were assimilated simultaneously but each was assimilated at a lower rate than when either was supplied alone. Nitrogen-starved cultures of C. nitratophila contained enough nitrate reductase activity to sustain high rates of nitrate assimilation, Results indicate that the high levels of nitrate reductase in nitrate-grown cultures of C. nitratophila do not limit nitrate assimilation. Nitrate assimilation appears to be limited by nitrate uptake and/or the supply of reducing equivalents for nitrate reduction in these cultures.