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BioTechnology QUESTION #10578
Question 1
Pichia pastoris (now Komagataella phaffii) is preferred for recombinant protein production because:
  • It is the fastest-growing yeast under anaerobic conditions
  • It uses the strong methanol-inducible AOX1 promoter for tightly regulated high-level expression✔️
  • It secretes all recombinant proteins into the periplasmic space
  • It does not require a selectable marker for plasmid maintenance
Correct Answer Explanation
Pichia pastoris uses methanol as a sole carbon source, activating the AOX1 (alcohol oxidase 1) promoter — one of the strongest known promoters — to produce recombinant proteins at very high levels (sometimes >30% of total cell protein). Expression is tightly regulated: repressed by glucose/glycerol, induced by methanol. The system also supports secretion, simplifying downstream processing.