Role of Microorganisms in Digestion
By
HASNAT MUEEN
, Role of Microbes in Digestion
Microorganisms have significant role in the digestion process in animals. Various
animals, insects, rodents as well as human are totally or partially dependent on the microbes
for the process of digestion. The symbiotic gut bacteria that can digest complex substances
provide nutritional benefits to the host organisms. Some examples are given below in support
of the fact that microbes do have role in digestion:
1 Microbial role in Digestion in Humans
Nearly 500 to 1000 species of bacteria are inhabited in human gut and are termed as
“Intestinal Microflora”. Bacterial species in human gut belong to few phyla like Firmicutes,
Bacteroidetes, Cyanobacteria, Verrumicrobia, Proteobacteria and Actinobacteria etc.1 Lower
intestinal tract is habitat of vast populations of bacteria. Large bacteria are in colon while few
in stomach and first portion of intestine because of the presence of some corrosive substances
there.
The relationship of many gut microbes and humans is mutualistic. The gut
microorganisms ferment the dietary fibers to produce short chain fatty acids or SCFAs which
are then absorbed by the host and in return host provide shelter and food. They also play role
on metabolism of bile, xenobiotics, and sterols etc.2 The overall composition of gut flora
changes with the diet and highly dependent on the diet.
Without gut flora, humans cannot utilize various substances because they produce the
enzymes for the digestion of these complex substances. Certain starches and fibers etc. only
become digestible because of the gut microorganisms. They are also responsible for
saccharolytic fermentation which is not possible without them. The SCFAs thus produced are
then used as energy source by the host. Gut flora is also responsible for the synthesis of biotin,
1
By
HASNAT MUEEN
, Role of Microbes in Digestion
Microorganisms have significant role in the digestion process in animals. Various
animals, insects, rodents as well as human are totally or partially dependent on the microbes
for the process of digestion. The symbiotic gut bacteria that can digest complex substances
provide nutritional benefits to the host organisms. Some examples are given below in support
of the fact that microbes do have role in digestion:
1 Microbial role in Digestion in Humans
Nearly 500 to 1000 species of bacteria are inhabited in human gut and are termed as
“Intestinal Microflora”. Bacterial species in human gut belong to few phyla like Firmicutes,
Bacteroidetes, Cyanobacteria, Verrumicrobia, Proteobacteria and Actinobacteria etc.1 Lower
intestinal tract is habitat of vast populations of bacteria. Large bacteria are in colon while few
in stomach and first portion of intestine because of the presence of some corrosive substances
there.
The relationship of many gut microbes and humans is mutualistic. The gut
microorganisms ferment the dietary fibers to produce short chain fatty acids or SCFAs which
are then absorbed by the host and in return host provide shelter and food. They also play role
on metabolism of bile, xenobiotics, and sterols etc.2 The overall composition of gut flora
changes with the diet and highly dependent on the diet.
Without gut flora, humans cannot utilize various substances because they produce the
enzymes for the digestion of these complex substances. Certain starches and fibers etc. only
become digestible because of the gut microorganisms. They are also responsible for
saccharolytic fermentation which is not possible without them. The SCFAs thus produced are
then used as energy source by the host. Gut flora is also responsible for the synthesis of biotin,
1
