Mock MB, Summers RM. Mixed culture biocatalytic production of the high-value biochemical 7-methylxanthine.
J Biol Eng 2023;
17:2. [PMID:
36627657 PMCID:
PMC9830774 DOI:
10.1186/s13036-022-00316-6]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 12/07/2022] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND
7-Methylxanthine, a derivative of caffeine noted for its lack of toxicity and ability to treat and even prevent myopia progression, is a high-value biochemical with limited natural availability. Attempts to produce 7-methylxanthine through purely chemical methods of synthesis are faced with complicated chemical processes and/or the requirement of a variety of hazardous chemicals, resulting in low yields and racemic mixtures of products. In recent years, we have developed engineered microbial cells to produce several methylxanthines, including 3-methylxanthine, theobromine, and paraxanthine. The purpose of this study is to establish a more efficient biosynthetic process for the production of 7-methylxanthine from caffeine.
RESULTS
Here, we describe the use of a mixed-culture system composed of Escherichia coli strains engineered as caffeine and theobromine "specialist" cells. Optimal reaction conditions for the maximal conversion of caffeine to 7-methylxanthine were determined to be equal concentrations of caffeine and theobromine specialist cells at an optical density (600 nm) of 50 reacted with 2.5 mM caffeine for 5 h. When scaled-up to 560 mL, the simple biocatalytic reaction produced 183.81 mg 7-methylxanthine from 238.38 mg caffeine under ambient conditions, an 85.6% molar conversion. Following HPLC purification and solvent evaporation, 153.3 mg of dried 7-methylxanthine powder was collected, resulting in an 83.4% product recovery.
CONCLUSION
We present the first report of a biocatalytic process designed specifically for the production and purification of the high-value biochemical 7-methylxanthine from caffeine using a mixed culture of E. coli strains. This process constitutes the most efficient method for the production of 7-methylxanthine from caffeine to date.
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