Role of Saprobionts

AQA A-level BiologyNutrient CyclesLesson 2 of 13

Saprobionts (also called saprotrophs) are microorganisms, mainly bacteria and fungi, that obtain their nutrients from dead organic matter and from waste such as faeces and urine.

They feed by extracellular digestion:

1. They secrete enzymes onto the dead material.
2. The enzymes hydrolyse large, insoluble organic molecules into small, soluble ones. For example, proteases break proteins into amino acids, and carbohydrases break starch and cellulose into sugars.
3. The saprobionts absorb the soluble products and use them in respiration and growth.

More in Nutrient Cycles

• Nutrient Cycles
• The Nitrogen Cycle
• Nitrogen Fixation
• Ammonification
• Nitrification
• Denitrification
• The Phosphorus Cycle
• Mycorrhizae

All 13 lessons in Nutrient Cycles · All AQA A-level Biology topics