saprotrofos

Saprotrophs (saprotrofos) are organisms that obtain energy and nutrients by decomposing dead organic matter. They do not photosynthesize and rely on extracellular enzymatic breakdown of complex polymers such as cellulose, lignin, proteins, and lipids to access nutrients. Saprotrophy is widespread across biological groups, especially fungi and bacteria.

Mechanism: They secrete enzymes such as cellulases, lignin-modifying enzymes, proteases, and chitinases into their substrate, breaking down polymers into absorbable molecules that can be taken up by the organism. This enables the decomposition of leaf litter, fallen wood, dung, and other detritus.

Ecological role: Saprotrophs are central to nutrient cycling and the carbon cycle. By converting dead biomass into simpler compounds, they release minerals and organic carbon back into ecosystems, enhancing soil fertility and enabling plant growth. They also play a key role in composting and wood decay processes.

Diversity and examples: In fungi, many saprotrophs include white-rot and brown-rot fungi and numerous molds and yeasts. Bacteria and actinomycetes are important saprotrophs in soils and aquatic environments. Some protists and oomycetes also behave as saprotrophs. Some species are facultative, capable of parasitism or mutualism as well as saprotrophy.

Terminology: The terms saprotroph and saprobe are often used interchangeably in ecology to describe organisms that feed on dead organic matter. The concept emphasizes the role of decomposition in nutrient availability and ecosystem functioning.