Catabolic processes responsible for producing methane and fart gases?

[pa5tabear]

I apologize for the "coarse" question, but as a budding chemist, I want to know. Obviously some foods make people/animals fart more when those foods are consumed.

What are the catabolic pathways which produce these waste gases? Do we know what the breakdown mechanisms are?

My preliminary guess is that breaking down amino acids is the main source.

 

[mazinse]

and probably glucose

 

[Andy Resnick]

The gas we pass...

Most of the volume is air that is swallowed with food (and not burped back out). The remainder is produced by flora in the large intestine breaking down polysaccharides (especially oligosaccharides), and is mostly CO2 and methane. The odoriferous compounds are generally sulfurous (e.g. hydrogren sulfide), but skatole and indole can be present as well.

 

[pa5tabear]

The gas we pass...

Most of the volume is air that is swallowed with food (and not burped back out). The remainder is produced by flora in the large intestine breaking down polysaccharides (especially oligosaccharides), and is mostly CO2 and methane. The odoriferous compounds are generally sulfurous (e.g. hydrogren sulfide), but skatole and indole can be present as well.

I was looking up polysaccharides and they seem to be complex carbohydrates. This would explain the idea of beans causing farts.

What about the idea of protein farts? When amino acids are broken down for energy, would they be producing more gas than other nutrient sources?

 

[mazinse]

bacteria can make sugar out of the amino acids

 

[pa5tabear]

bacteria can make sugar out of the amino acids

I know that sugar can be made from some of the amino acids (the ones in the glucogenic group), but not all. These can then be fed into the Kreb/Citric Acid cyle, of which CO2 is a byproduct. It is still uncommon for this to happen, though.

As far as protein causing excess gas, I think it probably depends on the conditions of your body. Proteins from food will always be broken down into constituent amino acids. From there, the amino acids can be used to make proteins that the organism requreies, they can be used for energy, or in special circumstances they can be converted into glucose.