Engineered microbial production of grape flavoring

Image 1:  Engineered bacteria that produce grape flavoring. Credit: The Korea Advanced Institute of Science and Technology (KAIST)

Researchers report a microbial method for producing an artificial grape flavor. Methyl anthranilate (MANT) is a common grape flavoring and odorant compound currently produced through a petroleum-based process that uses large volumes of toxic acid catalysts.

Professor Sang-Yup Lee's team at the Department of Chemical and Biomolecular Engineeringdemonstrated production of MANT, a naturally occurring compound, via engineered bacteria. The authors engineered strains of Escherichia coli and Corynebacetrium glutamicum to produce MANT through a plant-based engineered metabolic pathway.

The authors tuned the bacterial by optimizing the levels of AAMT1, the key enzyme in the process. To maximize production of MANT, the authors tested six strategies, including increasing the supply of a precursor compound and enhancing the availability of a co-substrate. The most productive strategy proved to be a two-phase extractive culture, in which MANT was extracted into a solvent. This strategy produced MANT on the scale of 4.47 to 5.74 grams per liter, a significant amount, considering that engineered microbes produce most at a scale of milligrams or micrograms per liter.

According to the authors, the results suggest that MANT and other related molecules produced through can be produced at scale by engineered microbes in a manner that would allow them to be marketed as natural one, instead of artificial one.

Image 2. Overview of the strategies applied for the microbial production of grape flavoring. Credit: The Korea Advanced Institute of Science and Technology (KAIST)

More information: Zi Wei Luo et al. Microbial production of methyl anthranilate, a grape flavor compound, Proceedings of the National Academy of Sciences (2019). DOI: 10.1073/pnas.1903875116

Journal information: Proceedings of the National Academy of Sciences

Provided by The Korea Advanced Institute of Science and Technology (KAIST)