Zymomonas mobilis is used to convert glucose to ethanol in a batch fermenter under anaerobic conditions. The yield of biomass from substrate is 0.06 g g- 1; YPX is 7.7 g g- 1. The maintenance coefficient is 2.2 g g-1 h-1; the specific rate of product formation due to maintenance is 1.1 h-1. The maximum specific growth rate of Z. mobilis is approximately 0.3 h-1.5 g bacteria are inoculated into 50 litres of medium containing 12 g l-1 glucose. Determine batch culture times required to produce 10 g biomass.

• A. 3.1 h
• B. 3.3 h
• C. 3.5 h
• D. 3.7 h