In a glucose-yeast extract medium, Lactococcus lactis has a maximum specific growth rate (um) of 1.23 h-1. What would be the specific growth rate of this organism at steady state in a 4 litre reactor being fed at 2 litres per hour?

• 0.5 h-1
• 1.2 h-1
• 2.4 h-1
• 4 h-1