Bioreactor cultivations of improved carboxylesterase-AFT1 P. pastoris strains. (A) Carboxylesterase activity levels (U L-1) of strain CE#12 (red squares) and strain CE#12-AFT1-A (purple circles). Closed symbols: hypoxic conditions; open symbols: aerobic conditions. (C) Carboxylesterase activity levels (U L-1) of strain CE#18 (green triangles) and strain CE#18-AFT1-A (blue rhomboids). Dashed lines: biomass values (DCW, g L-1). (B) and (D) Reducing SDS-PAGE of supernatant samples from different cultivation time points (hypoxic conditions). BSA: bovine serum albumin standard (66.5kDa).