Simultaneous saccharification, filtration and fermentation
(SSFF) seems to be an advantageous alternative to both SHF and
SSF, since the problem of enzyme inhibition can be avoided. In
addition, both the enzyme cocktail and the fermenting organism
in SSFF can be used at their different optimal conditions. Furthermore,
it would be possible to reuse the fermenting organism several
times.
The aim of this work was to assess and present a new concept
‘‘simultaneous saccharification, filtration and fermentation
(SSFF)’’, which thus circumvents the disadvantages of both SSF
and SHF. With SSFF, pretreated lignocellulosic slurry is exposed
to the enzymes and a sugar-rich filtrate is transferred to the fermentation
by cross-flow filtration. Fermented liquid is pumped
back to the hydrolysis vessel, while a culture of a flocculating
strain of Saccharomyces cerevisiae is retained by settling (Fig. 1).
In addition, this work includes a comparison of SSFF and SSF
and also an assessment of a couple of potential weak spots of
SSFF; the lifetime of a cross-flow membrane in cellulose-rich
slurry, and the risk for infection in a yeast culture which is used
for several batches.