cut and paste from my link
Fermentation is strictly defined as any way of anaerobically degrade pyruvic acid and recycle NAD+ to keep glycolysis going. You can then categorize this process as lactic acid fermentation (where pyruvate accepts electrons from NADH directly and becomes lactate), alcoholic fermentation (where pyruvate is first decarboxylated to acetaldehyde which then accepts electrons from NADH to become ethanol) and others (which are much more obscure). So technically, human cells are able to carry out lactic acid fermentation. Liver cells also have the enzyme alcohol dehydrogenase (responsible for ethanol formation in yeast and other fungi), but we use it in the reverse direction so to speak to get rid of any alcohol which we consume by converting it to pyruvate.
Plants however, can carry out alcoholic fermatation. They don't normally do it, because plants are usually in contact with oxygen. However, if you flood the root of a plant for about a week the cells are starved of oxygen, and because of this they will start carrying out alcoholic fermentation to survive.
