Biosynthetic pathways to produce pharmaceuticals over large-scale benchtop chemistry

Question 1:

What is one motivation to use biosynthetic pathways to produce pharmaceuticals over large-scale benchtop chemistry?

Question 2:
Given the process diagram shown in supplemental figure 1, name 2 steps that can be taken to maximize ethanol production over all other products (succinate, formate, etc.). Assume you are working in a highly controlled bioreactor and that you have access to any of the molecules used in the process. Keep in mind that ethanol biosynthesis takes place under anaerobic conditions.

Question 3:

Given a glucose input of 50 kg, what is the maximum theoretical output of ethanol, assuming you have optimally controlled the above reaction and the only product is ethanol. Give your answer in kg of ethanol, and round to two decimal places.