Simultaneous solid phase fermentation and saccharification of cassava fibrous residues for production of ethanol.

A total of 16.5% reducing sugars in the saccharified pulp of cassava
fibrous residue are achieved with the use of 30% slurry. The yield of
ethanol was highest and the amount of residual reducing sugars was
lowest with the use of 2.5% acid. The increase in dose of glucoamylase
leads to improved yields of ethanol without any lowering in the
residual reducing sugars. The ethanol yield and productivity were
better and the residual reducing sugars were lower in solid phase
fermentation as compared to the fermentation of liquid hydrolysate
obtained by hydraulic pressing of the saccharified pulp. The slightly
lower yield of ethanol in large batch static fermentation probably due
to poor mass transfer and limited contact of yeast cells as well as
enzyme with their substrates could be effectively overcome by
employing appropriate strategies.