Analysis of biomass yield
Biomass was quantified gravimetrically in triplicate by centrifuging 2
mL of culture (4000 rcf, 10 min), washing the pellets with 0.9% (w/v)
NaCl and drying them at 105°C for 72h. Dry biomass concentration was
then determined by weighing the dry pellets. Concentrations of residual
glucose and L-arabinose in the cell-free supernatant were analyzed via
HPLC (UltiMate 3000; Thermo Fisher, Waltham, MA) with a Supelcogel
C-610H column (Supelco, Bellefonte, PA). The eluent was 0.1%
H3PO4 and the flow rate constant at 0.5
mL/min.
YX/S was calculated for the time before induction
and after induction, respectively (Equations 1 & 2). For this, only the
net biomass accumulation, corrected for intracellular product, was taken
into account.