Computational Systems Biology Lab

Alpha-tocopherol, an essential dietary supplement, synthesized by photosynthetic organisms is the most biologically active antioxidant component of vitamin E in humans. Attempts to improve the yield of alpha-tocopherol using plant cell cultures has gained significance in recent years. Here, we developed a high alpha-tocopherol yielding cell line of Helianthus annuus using a model based metabolic engineering approach. To this end, we adapted an available genome-scale model of Arabidopsis for simulating H. annuus metabolism using constraint-based analysis to identify and rank suitable enzyme targets for overexpression. Of the various model-predicted enzyme targets, majority belonged to the vitamin E pathway and the MEP pathway while the others included reactions from the nucleotide biosynthesis and amino acid metabolism. Experimental validation of the top strategy (overexpression of p-hydroxyphenylpyruvate dioxygenase,) resulted in a high alpha-tocopherol yielding transformed cell line (up to ˜240 µg g^-1), which was ˜10-fold more than in the untransformed cell line. A cell suspension was developed from the selected transformed cell line for in vitro production of alpha-tocopherol, which resulted in a maximum alpha-tocopherol yield of 412.2 µg g^-1 and titre of 6.4 mg L^-1.We thus demonstrate the utility of model-based metabolic engineering for multi-fold yield enhancement of commercially important plant secondary metabolites.

Original Paper: 

• A. Srinivasan, V. S, K. Raman, and S. Srivastava, “Rational metabolic engineering for enhanced alpha-tocopherol production in Helianthus annuus cell culture,” Biochemical Engineering Journal, vol. 151, p. 107256, 2019.
  [bibtex]

  @article{Srinivasan2019Rational,
    abstract = {Alpha-tocopherol, an essential dietary supplement, synthesized by photosynthetic organisms is the most biologically active antioxidant component of vitamin E in humans. Attempts to improve the yield of alpha-tocopherol using plant cell cultures has gained significance in recent years. Here, we developed a high alpha-tocopherol yielding cell line of Helianthus annuus using a model based metabolic engineering approach. To this end, we adapted an available genome-scale model of Arabidopsis for simulating H. annuus metabolism using constraint-based analysis to identify and rank suitable enzyme targets for overexpression. Of the various model-predicted enzyme targets, majority belonged to the vitamin E pathway and the MEP pathway while the others included reactions from the nucleotide biosynthesis and amino acid metabolism. Experimental validation of the top strategy (overexpression of p-hydroxyphenylpyruvate dioxygenase,) resulted in a high alpha-tocopherol yielding transformed cell line (up to ˜240 µg g-1), which was ˜10-fold more than in the untransformed cell line. A cell suspension was developed from the selected transformed cell line for in vitro production of alpha-tocopherol, which resulted in a maximum alpha-tocopherol yield of 412.2 µg g-1 and titre of 6.4 mg L-1.We thus demonstrate the utility of model-based metabolic engineering for multi-fold yield enhancement of commercially important plant secondary metabolites.},
    added-at = {2019-06-04T18:25:58.000+0200},
    author = {Srinivasan, Aparajitha and S, Vijayakumar and Raman, Karthik and Srivastava, Smita},
    biburl = {https://www.bibsonomy.org/bibtex/2952f0d54abbfa79c5603816ece8ed97e/karthikraman},
    description = {Rational metabolic engineering for enhanced alpha-tocopherol production in Helianthus annuus cell culture - ScienceDirect},
    doi = {https://doi.org/10.1016/j.bej.2019.107256},
    interhash = {4844a665eb5d7dfaccdf0b0dbdbf7c60},
    intrahash = {952f0d54abbfa79c5603816ece8ed97e},
    issn = {1369-703X},
    journal = {Biochemical Engineering Journal},
    keywords = {flux-analysis fseof in-silico metabolic-engineering myown},
    volume = 151,
    pages = 107256,
    timestamp = {2019-09-06T09:18:53.000+0200},
    title = {Rational metabolic engineering for enhanced alpha-tocopherol production in Helianthus annuus cell culture},
    url = {http://www.sciencedirect.com/science/article/pii/S1369703X19301834},
    year = 2019
  }