During anaerobic digestion of organic waste, such as in producing biogas, which one of the following is left un-degraded?

Options

(a) Cellulose
(b) Lipids
(c) Lignin
(d) Hemi-cellulose

Correct Answer:

Lignin

Explanation:

Lignin is a complex polymer of phenylpropane units, which are cross-linked to each other with a variety of different chemical bonds.