Inoculum percentage in SSF was opti

Inoculum percentage in SSF was optimized as 50% (w/w;
i.e. 50 g of spent yeast pellet added to 100 g of pressmud
with nutrient mix and water added remain the same as
in other trays with varied levels of spent yeast used as
inoculum) with specific enzyme activity of 395.2 U/mg.
When there are still enhanced levels of inoculum, contamination
with fungus was noticed (Table 3). Increasing
the percentage inoculum of washed spent yeast cells on
pressmud gave enhanced levels of invertase till 50% (w/w)
inoculum. Beyond this level, the trend was reversed and
invariably there was fungal growth observed in the plates.
This may be due to the dead yeast being used as substrate
by the fungus present in the unsterilized pressmud and
due to less promising growth rate and activity spectrum of
introduced yeast cells whenin excess, due to contact inhibition
of cells. Humidity enhancement in the microenvironment
also would have favoured fungal contaminations
at higher levels of inoculum added.