6. At acidic pH, penicillin remains in

A. aqueous phase
B. solvent phase
C. both (a) and (b)
D. precipitates

7. Chlortetracycline is soluble in

A. organic solvents
B. water
C. ether
D. all of these

8. Penicillin is produced by

A. aerobic fermentation
B. anaerobic fermentation
C. aerobic fermentation followed by anaerobic fermentation
D. anaerobic fermentation followed by aerobic fermentation

9. Penicillin is recovered after fermentation as

A. potassium penicillin
B. calcium penicillin
C. sodium penicillin
D. penicillin only

10. Media composition for the production of streptomycin is

A. soybean meal, glucose, peptone, malt extract, sodium chloride
B. soybean meal, glucose, peptone, malt extract, ammonium chloride
C. soybean meal, glucose, peptone, malt extract, calcium carbonate
D. soybean meal, glucose, peptone, malt extract, ammonium sulfate