Symbiotic bacteria are bacteria living in symbiosis

Symbiosis

Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...

 with another organism or each other. For example, Zoamastogopera, found in the stomach of termites, enable them to digest cellulose

Cellulose

Cellulose is an organic compound with the formula , a polysaccharide consisting of a linear chain of several hundred to over ten thousand β linked D-glucose units....

.

Some types of cyanobacteria are endosymbiont to types of lichens and sponges.

Symbiotic bacteria are able to live in or on plant

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

 or animal

Animal

Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...

 tissue

Tissue (biology)

Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...

. In digestive systems, symbiotic bacteria help break down foods that contain fibre. They also help produce vitamins.
Symbiotic bacteria can live near hydrothermal vents. They usually have a mutual relationship with other bacteria. Some live in tube worm

Giant tube worm

Giant tube worms, Riftia pachyptila, are marine invertebrates in the phylum Annelida related to tube worms commonly found in the intertidal and pelagic zones...

s.

A use for symbiotic bacteria has recently been in paratransgenesis

Paratransgenesis

Paratransgenesis is a technique that attempts to eliminate a pathogen from vector populations through transgenesis of a symbiont of the vector. The goal of this technique is to control vector-borne diseases. The first step is to identify proteins that prevent the vector species from transmitting...

 for controlling important vectors for disease, such as the transmission of Chagas disease

Chagas disease

Chagas disease is a tropical parasitic disease caused by the flagellate protozoan Trypanosoma cruzi. T. cruzi is commonly transmitted to humans and other mammals by an insect vector, the blood-sucking insects of the subfamily Triatominae most commonly species belonging to the Triatoma, Rhodnius,...

 by Triatome

Triatoma

Triatoma is a genus of assassin bug in the subfamily Triatominae The members of Triatoma are blood-sucking insects that can transmit serious diseases, such as Chagas disease....

 kissing bugs.
Symbiotic bacteria in legume roots provide the plants with ammonia in exchange for the plants carbon and a protected home.