Fig. 2From: Directed evolution and secretory expression of a pyrethroid-hydrolyzing esterase with enhanced catalytic activity and thermostabilityScreening of mutants with better thermostability (→). After being treated at 60 °C for 55 min, the clones were overlayed with 0.3 mg/mL α-naphthyl acetate and 1.3 mg/mL Fast Blue B. Clones with enhanced thermostability (M1) rapidly turned deep brown around the colonyBack to article page