Answer: Propionibacterium shermanii.
- A Penicillium roqueforti
- B Propionibacterium shermanii
- C Lactobacillus helveticus
- D Streptococcus thermophilus
Correct answer: B. Propionibacterium shermanii
Explanation: Propionibacterium shermanii produces large amounts of CO2 during cheese ripening, creating the characteristic holes (eyes) in Swiss cheese.
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