Saprobionts are organisms that digest their food externally and then absorb the products. Fungi are examples of saprobiontic organisms also known as decomposers.
Saprobiontic organisms feed off dead and or decaying matter, to digest this they excrete digestive enzymes which breaks down the cell tissues allowing the organism to extract the nutrients it needs to survive while leaving the indigestible waste. This is called extracellular digestion. This is very important in ecosystems, for the nutrient cycle.
Enzymes are catalysts. Most are proteins.
They are a good source of extra-cellular enzymes for use in industrial processes such as the production of fruit juice. The fungus aspergillus niger is used to produce pectin, which is then used to break down cell walls in the concentrate to make the juice appear less translucent.