The pH-controlled SSF experiments were carried out in DasGip
Parallel Bioreactor System (Juelich, Germany). The bioreactors are
autoclavable glass vessels (350 mL each) with stainless steel head
plates with standardized ports for pH-controls, substrate feeding,
gassing and sampling and equipped with cooling condensers.
They have direct drive head plate mounted stirring with two 6
blade Ruston impellers which allows proper mixing. The fermentation
was performed with a working volume of 200 mL at controlled
pH 6.5 and 35 C. The stirring speed was set at 400 rpm initially,
then lowered and maintained at 100 rpm after 2 h.