Question

Anaerobic digestion proceeds in 4 steps. Which of the following represents the correct order of these four steps?

• A. Hydrolysis $\rightarrow$ Acetogenesis $\rightarrow$ Acidogenesis $\rightarrow$ Methanogenesis
• B. Hydrolysis $\rightarrow$ Acidogenesis $\rightarrow$ Acetogenesis $\rightarrow$ Methanogenesis
• C. Methanogenesis $\rightarrow$ Acidogenesis $\rightarrow$ Acetogenesis $\rightarrow$ Hydrolysis
• D. Acidogenesis $\rightarrow$ Hydrolysis $\rightarrow$ Acetogenesis $\rightarrow$ Methanogenesis

Hint:

• Order: Hydrolysis → Acidogenesis → Acetogenesis → Methanogenesis
• Final product: Biogas (CH$_4$)

Answer 1

The Correct Option is B

Concept: Anaerobic digestion is a biological process that breaks down organic matter in the absence of oxygen in four sequential stages:
• Hydrolysis: Complex polymers $\rightarrow$ simple monomers
• Acidogenesis: Monomers $\rightarrow$ volatile fatty acids
• Acetogenesis: Fatty acids $\rightarrow$ acetate, CO$_2$, H$_2$
• Methanogenesis: Acetate/CO$_2$ $\rightarrow$ methane

Step 1: Understanding the sequence.

• Breakdown starts with hydrolysis
• Followed by fermentation (acidogenesis)
• Then conversion to acetate (acetogenesis)
• Finally methane production (methanogenesis)

Step 2: Matching with options.
Correct order: \[ \text{Hydrolysis} \rightarrow \text{Acidogenesis} \rightarrow \text{Acetogenesis} \rightarrow \text{Methanogenesis} \]

Step 3: Selecting the correct answer.
Thus, option (B) is correct.