Immobilised lactase is used to hydrolyse lactose in dairy waste to glucose and galactose. Enzyme is immobilised in resin particles and packed into a 0.5 m^3 column. The total effectiveness factor for the system is close to unity; Km for the immobilised enzyme is 1.32 kg m^-3; Vmax is 45 kg m^-3 h^-1. The lactose concentration in the feed stream is 9.5 kg m^-3; a substrate conversion of 98% is required. The column is operated with plug flow for a total of 310 d per year. At what flow rate should the reactor be operated?
(a) 1.56 m^3 h^-1
(b) 1.58 m^3 h^-1
(c) 1.50 m^3 h^-1
(d) 1.54 m^3 h^-1
