Answer: Streptococcus.
- A Streptococcus
- B Aspergillus
- C Penicillium
- D Lactobacillus
Correct answer: A. Streptococcus
Explanation: Streptokinase is produced by the bacterium Streptococcus and is used as a clot-dissolving enzyme in heart attack patients.
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