16. Wash out (as defined by D=max) of a continuous stirred tank fermenter is characterized by (X=biomass, S=substrate concentration in bioreactor, So=substrate concentration in feed, P=product concentration in bioreactor): (A) X = 0, S = 0, P = 0 (B) X = 0, S = So, P = 0 (C) X =0, S < 0, P = 0 (D) X <0, S <0, P <0

Answer: (B) X = 0, S = So, P = 0
Explanation: In wash out conditions, biomass (X) will be zero because the system cannot support cell growth. The substrate concentration (S) will be equal to the feed concentration (So), as there is no significant consumption by the washed-out biomass. Product concentration (P) will also be zero due to the absence of biomass to produce the product.