Understanding Biogas Production

Nidhi Kushwaha from IIT Delhi is concerned with the study of agricultural residue and how it can be used to make biofuel.
What is biofuel?
Its fuel derived from plants so basically its plant based fuel.
They are eco-friendly fuels.

One very common example of biofuel that many of us may have come across is biogas.
Biogas is a mixture of gases like methane, Carbon dioxide and other gases.

Then we discussed about biogas production-
So as Nidhi said for producing biogas plant waste is put in a chamber and anaerobic conditions are provided. Here anaerobic bacteria will breakdown the complex molecules is the plant waste and produce gases.

So we had a confusion whether the microbes doing the process of biogas production are only anaerobic bacteria or aerobic bacteria are involved too?
So through a reference(link below) we found that the process of biogas production involves anaerobic digestion which is done by anaerobic bacteria.


Biogas production involves following process

  1. Hydrolysis- carbohydrates, proteins, lipids are broken down to simple molecules like sugars, amino acids and fatty acids.
  2. Acidogenesis- acids are produced (from the products obtained through hydrolysis)
  3. Acetogenesis- acetate, Hydrogen gas and carbon dioxide are produced (from acids)
  4. Methanogenesis- methane is produced

All the 4 processes involve anaerobic bacteria-
Hydrolysis- Hydrolytic bacteria
Acidogenesis- Acidogeneic bacteria
Acetogenesis- Acetogeneic bacteria
Methanogenesis- acetoclastic methanogens and Hydrogenotrophic methanogens.

So Biogas production occurs due to anaerobic digestion of plant waste to produce biogas
Earthworms living in soil they eat plant waste and digest it.

So how is digestion of plant waste different in earthworm and biogas chamber?
In earthworms gut too anaerobic bacteria are producing enzymes like cellulase which help in digestion of plant waste here the nutrients are used up by the earthworm whereas in biogas production complex molecules breakdown to simpler ones and are converted to acids, then acetate and then methane.

We had a great discussion, Thanks to Nidhi we could discuss about biogas production something I’ve studied in textbook but didn’t really understand before.