Answer: Clarification of fruit juices.
- A Production of antibiotics
- B Clarification of fruit juices
- C Sewage treatment
- D Nitrogen fixation
Correct answer: B. Clarification of fruit juices
Explanation: Pectinases break down pectin in fruit cell walls, and along with proteases, they are used commercially to clarify fruit juices and improve their quality.
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