Type of decomposers

Four types of decomposers are involved in decomposition which are fungi, bacteria, insects, and earthworms.

Fungi

• Fungi are spore-forming, heterotrophs organisms that decompose or break down dead or decaying organic materials.
• Fungi are the principal decomposer in the ecosystem due to they do not involve in photosynthesis, but algae are not decomposers.
• The decomposer fungi release enzyme in the environment for the breakdown of liters (i.e., pre-digesting process). That enzyme breaks down the dead material during the process of digestion which is ultimately taken up or absorbed by the fungi itself.
• Fungi, including Trichoderma reesei, Aspergillus phoenicis, and Penicillium echinulatum are decomposer fungi. These fungi produce enzyme-like glucosidase, cellobiohydrolase, and cellobiose dehydrogenase that break down cellulose, hemicellulose, pectin, xylene, etc.

Bacteria

• An abundant amount of bacteria are present in the soil environment, in both the dormant and vegetative forms. They are involved in the early stages of decomposition.
• Bacteria can break down different organic compounds by releasing different types of enzymes. For example, Streptomyces and Acidothermus produce the enzyme endonuclease (endo-1-4-B glucanase), which breaks down cellulose by breaking the internal bond.
• Bacterial decomposer includes Proteobacteria, Actinobacteria, Bacteroidetes, Alphaproteobacteria, Gammaproteobacteria, etc.

Insects 

• Insects are considered to be detritivores (secondary decomposers) that feed dead material by mouth and digestion of the litter in their intestine.
• The significance of these organisms is that they are capable of feeding on a wide variety of organic matter, including animal parts, plants, and also other insects. 
• Flies, dung beetles, maggots, and ants are insects decomposer.
• Properly developed digestive systems are absent in maggots. Due to this reason, they produce different enzymes (e.g., serine, protease, leucine, aminopeptidase, carboxypeptidase). These enzymes are involved in the breaking down of various organic materials and require nutrients obtained for the growth and development of decomposers.

Earthworms

• The earthworm is the most common example of an animal decomposer. They feed on dead animals and plants as well as fecal waste, and in their intestine, litter reacts with enzymes resulting breakdown of litter. The end product is expelled into the soil, and its mix with soil helps in soil fertility.
• Many farms and farmers use worms for the decomposition of various organic matter to produce compost, which improves soil fertility.