ABSTRACT
Fungi, fungi-like organisms, and bacteria do not “eat” or find nutrition in the ways that many animals do-they lack organized digestive systems in the traditional sense. Instead, they absorb all of the essentials for life directly from the environment. However, many of the simple molecules, such as sugars that are easily transported into the organism, are present only as complex polymers such as cellulose or starch in the environment. Complex carbohydrates and other classes of polymers cannot be used unmodified by the microorganisms. Therefore, these organisms must have a means to degrade the carbohydrate polymers, proteins, etc., into their constituent smaller molecules.
