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GATE 2023 BT – Question 53

Fundamentals of Biological Engineering · Bioreaction Engineering: Batch, fed-batch and continuous processes, microbial and enzyme reactors, optimization and scale up · 2 marks · Numerical answer

The schematic shows a chemostat with cell recycle. $F_0,F_r$ are feed and recycle flow rates, and $X_1,X_0,X$ are reactor, recycle and product cell concentrations. If $X_0/X_1=1.5$, $F_r/F_0=0.7$ and $X_1=7.3\ \mathrm{g/L}$, the value of X (g/L, one decimal place) is ___________.

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Correct answer: 4.68 to 4.72

Explanation

The separator balance gives $X=(1+0.7)X_1-0.7X_0=(1.7-1.05)(7.3)=4.745$, or 4.7 g/L.