Question

Give examples to prove that microbes release gases during metabolism.

Answer 1

There are various examples where we can find that microbial metabolism leads to release of gases. One such example is a very common process called fermentation. Anaerobic bacteria present in large intestines where these act on the undigested carbohydrates and convert them into short chain fatty acids and subsequently convert them into various constituents along with the release of Hydrogen, carbon dioxide and in some cases methane. According to a report 30-50% of werstern people have methanogenic bacteria in their colon thus produce methane by reducing CO₂ and H₂ via the following reaction:

4H₂ + CO₂CH₄ + 2H₂O

In another example sulphur reducing bacteria present in most of non-methanogenic people produce Hydrogen sulphide (HS) by reducing sulphate, utelizing H₂ as shown in the reaction given

4H₂ + SO₄^- + H⁺  HS^-   + 4H₂O

These bacteria include Desulfovibrio, Desulfobacter, Desulfomonas etc.

Another example is the production of biogas by anaerobic digestion of waste organic products. This biogas is used as an alternative for fossil fuel.

There are various other examples where we can find the microbes releasing gases during their metabolism like,

production of N2O from NO in denitrifiers or production of N2 from N2O by denitrifying bacteria. Methane being the dominant gas released during the anaerobic degradation of organic matters gets released into the atmosphere leading to green house effect.