Syntrophism:

The growth of one organism is dependent on the product or byproduct of the organism that are near the surroundings. The byproducts can be either nutrients supply, substrates or growth factors. Syntrophism is also referred to as cross feeding. Greek word syn represents togetherness and trophism represents sustenance or nourishment. Most of this syntrophic relationship benefits both the organisms.

Instances of Syntrophic Relationship:

Human produces almost 1 gram of skin flakes per day. It is lived off by dust mites that are found in house hold is day to day example of syntrophism. Unfortunately these dust mites can produce some chemicals that are toxic to human being. Some humans may even be allergic to these chemical compounds. It can be beneficiary or detrimental relationship.

Another instance of syntrpohism is cow consumes abundant grass. It digests the cellulose with the help of microorganisms and converts them into lipids. It is not possible for the cow to ingest all the lipid molecules; hence part of it may come out as dung. The organisms which feed on cow dung or faeces may result in formation of dung beetle.

Syntrophic relationships are prevalently found in sludge digesters, flooded soils and aquatic sediments. Even though there is no direct benefit, it is benefitted by the hydrogen scavenging organism by fermentation or methanogensis. The fermentative bacteria, syntrophobacter receive more energy when hydrogen is produced and methanogenic bacteria, methanospirillum utilize this hydrogen as a substrate for the production of methane gas.  Methane is generated by interspecies hydrogen transfer mechanism. When hydrogen production increases the consumption rate also increases resulting in beneficiation of both the organisms.

Reciprocal Syntrophy:

Group of microorganisms that are present in soil can live off the leaf litter. Right after the autumn season the new leaves occur in the place of old leaves. When the old leaves fall on the ground, microorganisms that are present in soil may mineralize the dried leaves and plant takes up nutrient from the microorganisms. This type of ecological relationship is referred to as reciprocal syntrophism since plant lives off the byproduct of microorganism. Symbiotic relationship is established mostly on the basis of syntrophy.