Australian Centre for Water
and Environmental Biotechnology

AWMC Seminar Program: Alex Prima

Adaptive evolution of pyruvate kinase negative yeast to facilitate coupling of cellular growth with aromatics production through shikimate pathway
Abstract: Redirection of phosphoenol pyruvate (PEP) flux toward shikimate pathway accelerates production of para-aminobenzoic acid (PABA) and para-hydroxybenzoic acid (PHBA) in engineered Saccharomyces cerevisiae. However, most of the flux was directed to pyruvate for growth which render low titer and yield of PHBA and PABA for aromatics production. Here, we investigated the coupling of growth with aromatics production by eliminating synthesis of pyruvate from PEP. The pyruvate synthesis is controlled by two pyruvate kinases encoded by gene CDC19 and PYK2. Knock out pyruvate kinase genes were employed to wire the biosynthesis of aromatics (PHBA and PABA) with growth by channeling the pyruvate from shikimate pathway back to glycolysis. Theoretically these genetic modifications constrain the minimum carbon yield of 28.4%. However, knock out of pyruvate kinases limit the ability to grow when glucose is used as the carbon source such that the theoretical minimum yield cannot be achieved. By applying adaptive evolution, we improved the growth and aromatics production of CDC19 knock out strain. The specific growth rate was improved to 0.065 h-1 from 0.007 h-1 and it accompanied by 22 folds increase of PHBA. This shows the potential improvement for strain improvement strategy. Accumulation of 1.4 mM PHBA and 26 µM PABA were achieved for adapted CDC19 knock out strain.




Event Details
Date & Time: 
Friday, 18 November 2016
9am - 10am
Venue: AIBN Building 75, Level 1 Seminar Room

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