The effect of the addition of SDS and CTAB lower
than the critical concentration on the accumulation of
GSH is shown in Fig. 3. The extracellular GSH
concentrations were increased by 10 and 15%, respectively,
on increasing the concentration of SDS and
CTAB. In the mean time, the addition of low concentrations
of these ionic surfactants led to the decrease of
intracellular GSH content due to improved membrane
permeability. As the biomass concentration also decreased
along with increasing the concentration of SDS
and CTAB (Fig. 2), and the increased extracellular GSH
concentration only contributed a small part of the total
GSH concentration, the total GSH concentration also
decreased.