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Industrial alcohol, primarily ethanol, can be produced using batch, fed-batch, or continuous fermentation systems. In this example, a continuous system is shown.

The process begins with corn starch, the main feedstock, which is enzymatically hydrolyzed into fermentable sugars using amylase and glucoamylase.

This sugar-rich mash, supplemented with nitrogen and phosphate, is then continuously fed into the fermenter.

Yeast strains such as Saccharomyces cerevisiae PE2 are cultured in the main fermenter, where they convert sugars into ethanol.

Strict aseptic conditions are maintained to prevent bacterial contamination, which would compete for sugars and significantly lower the final ethanol yield.

Cell-retention systems, typically using centrifuges, recycle yeast biomass into the fermenter.

The clarified fermentation broth, containing ethanol and dissolved components, is then processed for ethanol recovery.

The broth is heated in a distillation column. The ethanol vapor enters a condenser, where it is cooled and converted back to liquid. The purified ethanol is further dehydrated and collected for industrial use.