An Engineered Yeast Efficiently Secreting Penicillin
Figure 7
Quantification of produced β-lactam compounds in HpPen3 and HpPen4 cultures.
Strains HpPen3 and HpPen4 were grown in glucose/methanol-limited chemostat cultures in the presence of 1 mM AAA and 1 mM PAA. β-lactam compounds were quantified by IP-LC–ESI-ID-MS/MS in spent medium and cell extracts. PenG could not be detected in HpPen3 cultures, but was clearly detectable in HpPen4 cultures, where it was efficiently excreted into the medium. The PenG precursor IPN was present in both HpPen3 and HpPen4 cells; however, the amount was significantly lower in the PenG producing HpPen4 cells. Concentrations are expressed as µmol/l culture. Samples were taken in triplicate. The bars represent the standard error (SE).