Pump 'gas' from biomass: the journey from dream to reality (9)

Fermentation


Typically, fermentation is conducted at ~30 0C for 24-96 hours. The microorganisms include bacteria (such as Zymomonas molis and E. coli) and yeast (i.e. Saccharomyces cerevisiae).

Bactera:
–Embden-Meyerhof pathway and Entner-Doudorpff pathway
–High yield and ethanol tolerance

–Disadvantages
»Inability to convert complex carbohydrate to ethanol
»By-products such as sorbitol, glycerol and acetic acid

Yeast:
–Embden-Meyerhof pathway
–Very robust and well suited to SW lignocelluloses (mannose and later galactose)

But traditional baker's yeast only ferment C6 sugars and need engineer it by genetic modification to ferment both C5 and C6 sugars.