Simultaneous Saccharification and Fermentation (SSF)
In simultaneous saccharification and fermentation (SSF) pretreated biomass is subjected to hydrolysis and fermentation in a single unit. This method can be carried out in two different ways:
1. Using a mixture of biomass saccharification microorganisms and fermentation microorganisms.
2. Using genetically engineered microorganisms that can do both saccharification and fermentation.
Simultaneous saccharification and fermentation generally gives higher ethanol yields due to the removal of end product inhibition of the saccharification step, and another advantage is that the SSF method requires only one reactor for both steps. The disadvantage of the SSF method is that a difference in optimum temperature conditions of enzyme for hydrolysis and fermentation conditions can affect the yield when a mixture of biomass saccharification microorganisms and fermentation microorganisms are used. On the other hand, genetically engineered microorganisms that can do both saccharification and fermentation are still a technology in the developing stages.