Hybrid Methylotrophic Pathway in Serratia marcescens for Sustainable Terpenoid Biosynthesis

Terpenoids are valuable chemicals
used across industries.
Methanol,
a nonsugar-based feedstock, offers an eco-friendly approach to terpenoid
production. In this study, a hybrid methylotrophic pathway was engineered
in Serratia marcescens (S. marcescens) HBQA7, which is tolerant to both methanol
and terpenoid compounds. The pathway utilizes bacterial methanol dehydrogenase
(Mdh) and yeast dihydroxyacetone synthase (Das) to produce monoterpenes
and sesquiterpenes from methanol and xylose. 13C labeling
experiments identified the optimal enzyme pair: Mdh from Acinetobacter gerneri and Das from Pichia angusta, achieving 7.63% 13C enrichment
of the central metabolic intermediate pyruvate. Deletion of pentose
phosphate pathway genes (rpiAB) enhanced methanol
utilization, achieving 22.99% 13C enrichment. Optimization
of the mevalonate (MVA) biosynthetic pathway enabled the production
of 5.12 g/L mevalonate in shake flask culture from methanol and xylose.
Further construction of a haloarchaea-type MVA pathway enabled the
production of geraniol (574.12 mg/L) and (−)-α-bisabolol
(1256.41 mg/L) in shake flask cultures. This study demonstrates the
first methanol conversion into valuable terpenoids in S. marcescens.