Definitive screening for accelerated Taxol biosynthetic pathway
optimization and scale up in Saccharomyces cerevisiae cell factories
Abstract
Recent technological advancements in synthetic and systems biology have
enabled the construction of microbial cell factories expressing diverse
heterologous pathways in unprecedentedly short time scales. However, the
translation of such laboratory scale breakthroughs to industrial
bioprocesses remains a major bottleneck. In this study, an accelerated
bioprocess development approach was employed to optimize the
biosynthetic pathway of the blockbuster chemotherapy drug, Taxol.
Statistical design of experiments approaches were coupled with an
industrially relevant high-throughput microbioreactor system to optimize
production of key Taxol intermediates, Taxadien-5α-ol and
Taxadien-5α-yl-acetate, in engineered yeast cell factories. The optimal
factor combination was determined via data driven statistical modelling
and validated in 1L bioreactors leading to a 2.1-fold improvement in
taxane production compared to a typical defined media. Elucidation and
mitigation of a nutrient limitation enhanced product titers a further
two-fold and titers of the critical Taxol precursors, Taxadien-5α-ol and
Taxadien-5α-yl-acetate were improved to 34 and 11 mg/L, representing a
three-fold improvement compared to the highest literature titers in S.
cerevisiae. Comparable titers were obtained when the process was scaled
up a further five-fold using 5 L bioreactors. The results of this study
highlight the benefits of a holistic design of experiments guided
approach to expedite early stage bioprocess development.