Conventional process of starch fermentation

Traditionally, production of ethanol from starch comprises of three general separate processes namely; liquefaction using я-amylase enzyme, which reduces the viscosity of the starch and fragments the starch into regularly sized chains, followed by saccharification whereby the starch is converted into sugar using glucoamylase enzyme. Each of the process operated at different temperature and pH optima with respect to the maximum enzyme reaction rate. The final process involved the fermentation of sugar into ethanol using yeast. The simplified flow of the process can be summarized as in Figure 1.

Starch

a-amylase

Lower saccharides

glucoamylase

_ 1 | mf

Glucose

yeast

Ethanol

1/

. ..

—————- j

—————— >

Fig. 1. Conventional Starch Fermentation.