title: Physiology of Candida utilis yeast in zinc-limited chemostat culture.
abstract: Candida utilis NRRLY -900 was grown in aerobic continuous culture in a minimal salts medium with sucrose (1% w/v) as the carbon source. increasing the concentration of zinc in the medium from 2.3 microM results in an increase in the apparent critical dilution rate from 0.3 to 0.47h-1, and in the maximum biomass productivity form 1.5g dry weight per litre per hour (at D=0.33-1) to 2.56g per litre per hour (at D = 0.45-1). The maximum steady-state level of cell-associated zinc (at D = 0.4-1) is 4nmol Zn2+/mg dry weight, during carbon-limited growth, and about 9mumol Zn2+/mg dry weight when FeCI3 is omitted form the medium. At input zinc concentrations <20microM, the cellular zinc concentration decreases linearly in proportion to the input zinc concentration and at <4.5microM Zn2+ the culture becomes zinc-limited. Zinc-limitation results in a decrease iun the growth yield Ysurcosefrom 0.54 to 0.38 cells/g sucrose consumed, and Y0 from 22 to 13g cells/g-atom 02, suggesting an altered efficiency of energy metabolism. The composition of the culture biomass with respect to protein and RNA content is not affected by zinc limitation.
mesh_terms: D000332:Aerobiosis; D002175:Candida / Q000254:growth & development*; D003470:Culture Media; D005656:Fungal Proteins / Q000096:biosynthesis; D010101:Oxygen Consumption; D012331:RNA, Fungal / Q000096:biosynthesis; D013395:Sucrose / Q000378:metabolism; D015032:Zinc / Q000378:metabolism*
chemical_list: D003470:Culture Media; D005656:Fungal Proteins; D012331:RNA, Fungal; D013395:Sucrose; D015032:Zinc