16. A continuous reactor has a dilution rate of 0.5 h^-1. Its residence time would be

A. ln(2)/0.5
B. ln(2) x 0.5
C. 0.5 h
D. 2 h

17. Which of the following is used to calculate mass of substrate in the reactor?

A. Flow rate x substrate concentration in the reactor
B. Volume of reactor x substrate concentration in reactor
C. Flow rate x mass of reactor
D. Volume of reactor x Flow rate

18. If biomass yields are constant, then the biomass productivity of a culture grown in continuous reactor will

A. always decrease with dilution rate
B. increase with dilution rate until washout
C. remain constant irrespective of the dilution rate
D. decrease with dilution rate until washout

19. Low dissolved oxygen concentrations leads to

A. low biomass yields
B. high biomass yields
C. no effect on biomass yields
D. none of the above

20. In a continuous reactor, the medium contains 40 g.l^-1 of maltose and the medium flow rate is 10 liters per hour and the effluent contains 20 g.l^-1 of lactate. What is the productivity of lactate production from this reactor?

A. 50 g maltose.l^-1
B. 50 g lactate.l^-1
C. 200 g maltose.l^-1
D. 200 g lactate.l^-1