Advantages of Continuous Fermentation
The advantages of continuous fermentation are:
1. Fermentation conditions do not change with time.
2. The fermentation medium is highly homogenous throughout the entire system due to yeast recirculation and mechanical agitation of the fermentation medium.
3. Higher fermentation efficiency and productivity.
4. Suitable control of contamination in the fermentation medium, due to low fermentation time and high yeast concentration inside the fermenter.
5. Possibility of using conventional yeast as well as other selected strains.
6. Compared to a batch reaction, this mode of operation offers reduced vessel down time for cleaning and filling providing improved volumetric productivity that can translate into smaller reactor volumes and lower capital investments plus ease of control at steady state.
7. Flexibility to run in batch mode when necessary.
Several reactor designs can be used for the cellulosic ethanol fermentation process, and some of these reactor designs are particularly suitable for the biomass gasification-syngas fermentation route. This application of fermentation reactors like trickle-bed reactors (TBR) and continuous stirred-tank reactors (CSTR) are discussed in Chapter 12 of this book.