I did a lab about the growth filamentous fungi in an airlift bioreactor, and then, based on an HPLC analysis, want to determine the concentration of ethanol produced and the concentration glucose consumed,, biomass amd ethanol yield?

My questions is

a) Why does the glucose level go up and then go down?

b) how to know if the biomass yield is spacious or not?

c) Why does pH go down?