Wikipedia Article About Yeast extract on Wikipedia Yeast extract is the common name for yeast autolysates, that is, concentrations of yeast cells that are allowed to die and break up, so that the yeasts' digestive enzymes break their proteins down into simpler compounds. Yeast autolysates are used in Vegemite (Australia), Marmite and Bovril (The United Kingdom), and Cenovis (Switzerland). Autolyzed yeast extract is also the primary source of monosodium glutamate for the food industry.