Thermo Fisher, C18000, X-33, <i>Pichia pastoris </i> Yeast Strain

X-33 Pichia pastoris Yeast Strain is used as a wild-type host for recombinant protein expression in the Pichia system. X-33 has a wild-type genotype and a Mut+ His+ phenotype, so it can efficiently utilize methanol and does not require histidine supplementation because of a his4 auxotrophy. This makes the strain particularly convenient with Zeocin-resistant expression vectors such as pPICZ and related Pichia vectors. Integrated expression constructs can be selected with the appropriate antibiotic and induced through the AOX1 promoter when a methanol-inducible vector is used. The strain is supplied as one stab culture for research use. X-33 is useful when a straightforward wild-type Pichia background is preferred for expression screening, secretion studies or scale-up of recombinant protein production.