SUMMARY: (NCYC 459) was grown in continuous culture at 30° in media containing 3, 6.65, 9 and 12 μmoles phenol/ml. as sole source of carbon. With each medium, wash-out of organisms occurred at dilution rates in the range 0.33-0.36 hr. The yeasts became quickly adapted to the medium with lowest phenol content and grew readily at dilution rates between 0.1 and 0.3 hr. At lower dilution rates, however, the endogenous metabolism of the yeasts tended to outstrip the rate at which phenol was supplied. With 9 μmoles phenol/ml. the best rate of output of yeast was achieved but at 6.65 μmoles phenol/ml., was most fully utilized, utilization being complete up to a dilution rate of 0.3 hr. At the highest contents of phenol in the medium, the yeast adapted less readily and produced considerable amounts of riboflavin. The population became heterogeneous, with some yeasts clumping and other large and fragile. There was some evidence that the latter were unable to metabolize phenol but could utilize catechol, a product of metabolism of the normal organisms.

The appendix provides a comparison between the reported results and those calculated from the growth constants using classical mathematical treatment of continuous culture. Substantial deviations are attributed to high maintenance energy requirements, flocculation of the yeast and toxicity of the medium.


Article metrics loading...

Loading full text...

Full text loading...


Most cited this month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error