Answer: Anaerobic microbes including bacteria and archaea hydrolyze, ferment, and ultimately convert organic waste to methane through a multi-stage process.
- A Microbes mainly provide passive structural support within the digester tank, with little biochemical contribution in most cases under typical conditions
- B Anaerobic microbes including bacteria and archaea hydrolyze, ferment, and ultimately convert organic waste to methane through a multi-stage process
- C Microbes present in the digester produce mainly carbon dioxide gas, with little methane generated at any stage according to standard textbooks
- D Mainly generally aerobic microbes are utilized throughout the entire biogas production process inside the digester in general practice as frequently described
Correct answer: B. Anaerobic microbes including bacteria and archaea hydrolyze, ferment, and ultimately convert organic waste to methane through a multi-stage process
Explanation: Biogas production is a multi-stage anaerobic process: hydrolytic bacteria break down complex organic molecules, acidogenic bacteria produce organic acids, acetogenic bacteria produce acetate, and finally methanogenic archaea produce methane - all microbial groups are essential.
Sewage passes through physical removal (primary), then aerobic biological treatment where microbes form flocs that consume organic matter (secondary); the settled activated sludge is then digested anaerobically to produce biogas - a deliberate switch from aerobic to anaerobic conditions between stages.
Concept context
Microorganisms in food, medicine, sewage treatment, biocontrol, and biofertilizers