Sustainable Hybrid Route to Renewable Methacrylic Acid via Biomass-Derived Citramalate

07 September 2021, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Combined chemical technologies of microbial fermentation and thermal catalysis provides a hybrid process for sustainable manufacturing of biorenewable sugar-derived monomers for plastics. In this work, methacrylic acid (MAA), a target molecule for the polymer industry, was produced from biomass-derived glucose through the intermediate molecule, citramalic acid. The biosynthetic pathway engineered in E. coli produced citramalic acid intermediate with a high yield (91% of theoretical maximum) from glucose by overexpressing citramalate synthase, removing downstream degradation enzyme 3-isopropylmalate dehydratase, and optimizing the fermentation medium. Thermal heterogeneous catalysis converted the citramalate intermediate to methacrylic acid (MAA) via decarboxylation and dehydration. A selectivity of ~71% for the production of MAA and its intermediate α-hydroxybutyric acid was achieved at a temperature of 250 oC and an acidity of 1.0 mol acid/mol citramalate. An alumina catalyst was found to enhance selectivity to MAA in a single reactor pass from 45.6% in the absence of catalyst to 63.2%. This limited selectivity to MAA was attributed to equilibrium between MAA and α-hydroxybutyric acid, but overall process selectivity to MAA was shown to be higher upon separation and recycle of reaction intermediates. A process flow diagram was proposed of the hybrid route for the conversion of glucose to the final end product, methacrylic acid, for poly(methyl methacrylate) (PMMA).


Methacrylic acid
Citramalic Acid

Supplementary materials

Supplementary Information for Sustainable Hybrid Route to Renewable Methacrylic Acid via Biomass-Derived Citramalate
Supplementary information for "Sustainable Hybrid Route to Renewable Methacrylic Acid via Biomass-Derived Citramalate" including product identification and analysis


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.