Finding more stuff to ferment… Biofuel Finding more stuff to ferment…

Making ethanol

Cellulose Found in the cell walls of plants (wood, fiber, etc.) Long chains of glucose, 15 to 10,000 monosaccharides long Chains are bonded to each other and resistant to hydrolysis Rich source of glucose for food and fermentation, if only we could break it down…

Why can we ferment corn & potatoes, but not corn stalks?

As if that weren’t difficult enough… Cellulose fibers are packed in crystalline bundles, surrounded by lignin and hemicellulose to give the plant strength

Cellulases Enzymes (protein catalysts) that break cellulose into smaller sugars Found in some bacteria, protists and fungi Termites digest cellulose from wood with the help of bacteria and/or protozoans

Cellulases Cellulase-producing bacteria in cow stomachs (rumen) help digest all that grass

Cellulases Saprophytic and parasitic fungi produce cellulases to break down trees on which they are growing

Cellulases Endocellulases – break apart cellulose fibers from each other Exocellulases – break long chains of cellulose into disaccharides Cellobiase – breaks disaccharides into glucose