BENG161A_FA18_DiscussionSection_Week7_Problems.pdf - Discussion Questions Week 7*Problems from Midterm 2 2010 from CHE 170 A Biochemical Engineering(UC

BENG161A_FA18_DiscussionSection_Week7_Problems.pdf -...

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Discussion Questions Week 7 *Problems from Midterm 2 2010 from CHE 170 A: Biochemical Engineering (UC Berkeley) 1.Consider the growth of a micro-organism in a batch culture. When the substrate concentration is high, the cell density doubles every 0.75 h-1, the observed substrate yield coefficient is 0.3 g DCW/g, and substrate consumption is allocated towards biosynthesis (60%), maintenance (10%), as well as product formation (30%). The product formation is strictly growth associated. The batch reactor is inoculated with 0.01g DCW/L and 10g/L of substrate. a.Estimate the maximum cell density and the time (after lag phase) required to achieve it. b.Determine the value of the maintenance coefficient (g substrate/ g DCW-h) c.Before inoculation of the batch reactor, you need to sterilize the medium, which contains 10^5 spores/L. The value of kd has been determined to be 1 min-1at 121 C and 61min-1at 140 C. For each temperature, determine the required time in the holding section so as to ensure the medium is 95% sterile. 2.Consider a culture of bacteria that secrete a product in a CSTR operated at steady state. The
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