Question

Which of the following microorganisms are responsible for converting acetate, hydrogen, and carbon dioxide into methane during the methanogenesis stage?

Options

• Methanobacterium and Methanosarcina

• Fermentative bacteria and Clostridium species

• Hydrolytic bacteria and Bacillus species

• Lactobacillus and Acetobacter species

Answer 1

Methanogenesis is Stage III of anaerobic digestion, performed by methanogens (Archaebacteria), specifically Methanobacterium and Methanosarcina species. These microorganisms convert acetic acid, hydrogen gas, and carbon dioxide produced in earlier stages into methane (CH₄), which is the primary combustible component of biogas. These methanogens are temperature-sensitive organisms, which is why biogas efficiency decreases in colder climates.