Explain why a scientist would need to increase the dilution rate in a chemostat from 0.20 hr-1 to 0.50 hr-1.
A. When the dilution rate is low, the availability of an essential nutrient is limited, creating an environment where the organism synthesizes nutrients rapidly to overcome the deficit in the media thus producing toxic waste products. Increasing the dilution rate provides a greater quantity of the nutrient effectively slowing growth and minimizing the level of waste.
B. When the dilution rate is low, the total available energy provided by the media exceeds the maintenance energy required by the culture. Increasing the dilution rate flushes out some of the organisms to strike a balance between available energy and maintenance energy.
C. When the dilution rate is low, the availability of an essential nutrient is limited, creating an environment where the organism can expend energy on survival only, not growth and reproduction. Increasing the dilution rate enables an increase in cell density.
D. When the dilution rate is low, cell reproduction is high, creating a space limitation for the rapidly-dividing organisms. Increasing the dilution rate slows growth to free up available space.
Answer: C
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