title: Selective enrichment of aromatic amino acid auxotrophs in Hansenula polymorpha.
abstract: Aromatic amino acid auxotrophs of the methanol-utilizing yeast Hansenula polymorpha were effectively selected by the use of nystatin and a medium that inhibits the growth of tyrosine auxotrophs. The procedure resulted in a frequency of aromatic auxotrophs of 2% of survivors and an enrichment of 20-fold. The new procedure also takes less time than traditional procedures. Of the auxotrophic mutants isolated, two-thirds required tyrosine and the remainder were tyrosine-phenylalanine double auxotrophs.
mesh_terms: D001203:Ascomycota / Q000378:metabolism*; D003470:Culture Media; D008828:Microbiological Techniques; D009154:Mutation; D009761:Nystatin / Q000494:pharmacology; D010843:Pichia / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D003470:Culture Media; D009761:Nystatin; D014443:Tyrosine