De Novo High-Titer Production of Delta-Tocotrienol in Recombinant Saccharomyces cerevisiae

Abstract

Delta-tocotrienol as a vitamin E isomer has received much attention because of its diverse biomedical applications. Microbial biosynthesis of delta-tocotrienol is a promising strategy for its economic and environmental advantages. Here, we accomplished complete biosynthesis of delta-tocotrienol in Saccharomyces cerevisiae from glucose. We first constructed and incorporated a heterologous pathway into the genome of S. cerevisiae by incorporating the genes hpd (from Pseudomonas putida KT2440), hpt (from Synechocystis sp. PCC 6803), and vte1 (from Arabidopsis thaliana) for the biosynthesis of delta-tocotrienol. We further enhanced the biosynthesis of the precursor geranylgeranyl diphosphate by overexpressing the thmg1 and ggppssa (from Sulfolobus acidocaldarius) genes, leading to a production titer of delta-tocotrienol of 1.39 ± 0.01 mg/L. Finally, we optimized the fermentation medium using the response surface methodology, enabling a high-titer production of delta-tocotrienol (3.56 ± 0.25 mg/L), ∼2.6-fold of that of the initial culture medium. Fed-batch fermentation in a 2 L fermenter was further used to enhance the production titer of delta-tocotrienol (4.10 ± 0.10 mg/L). To the best of our knowledge, this is the first report on the de novo biosynthesis of delta-tocotrienol in S. cerevisiae, and the highest titer obtained for microbial production of delta-tocotrienol.

Fermentative production of Vitamin E tocotrienols in Saccharomyces cerevisiae under cold-shock-triggered temperature control

“…To sum up, a tocotrienols high-producing yeast strain was successfully constructed by adopting a cold-shock-triggered temperature control system in addition to comprehensive optimization of the heterologous pathway and the endogenous precursor pathways, enabling the fermentative production of tocotrienols with titers of up to 320 mg/L, which was two orders of magnitude higher than the recently reported δ-tocotrienolproducing yeast with titer of 4.1 mg/L 24 . The biosynthesis of γ-and α-tocotrienols is made possible in nonphotosynthetic organisms.…”

“…Considering the GRAS (generally regarded as safe) status of Saccharomyces cerevisiae and its outstanding performance in heterologous production of terpenoids and aromatic compounds 22,23 , construction of efficient yeast cell factory may be a viable approach to sustainable tocotrienols production. De novo biosynthesis of δ-tocotrienol in S. cerevisiae with a titer of 4.1 mg/ L has recently been reported 24 .…”

Secretory Production of Tocotrienols in Saccharomyces cerevisiae

“…3 In 2020, de novo biosynthesis of δ-tocotrienol in Saccharomyces cerevisiae with a titer of 4.1 mg/L was reported. 4 Almost at the same time, we constructed a tocotrienolproducing S. cerevisiae strain YSM5 with a yield of up to 7.6 mg/g DCW. 5 In these studies, tocotrienols were all harvested as intracellular products and the yields were still far from the industrial requirements, calling for further optimization of the cell factories.…”

Revolution of vitamin E production by starting from microbial fermented farnesene to isophytol

“… 22 The de novo production of δ-tocotrienol from glucose with a titer of 4.1 mg/L in fed-batch fermentation was achieved in S. cerevisiae . 23 Furthermore, Shen et al. comprehensively optimized the vitamin E heterologous pathway and the endogenous precursor pathway, designed a cold-shock-triggered temperature control system, and successfully constructed high-tocotrienol-producing S. cerevisiae with the production of 320 mg/L.…”