Reconstituting a two-step pathway for <i>N</i>,<i>N</i>-dimethyltryptamine (DMT) biosynthesis in bacteria.
This study demonstrates a novel bacterial pathway for DMT production, with methionine supplementation significantly enhancing yields. However, its clinical relevance is limited without further development.
Where it sits
this study against the rest of the sermorelin corpusSummary and findings
The study reconstructed a two-step bacterial pathway to convert L-tryptophan to DMT using enzymes from Ruminococcus gnavus and Rhinella marina in Escherichia coli. Optimal conditions for DMT production were identified, and methionine supplementation increased DMT levels by 2.8 times. A co-expression strain produced 103 mg/L DMT in complex medium after 48 hours.
Abstract
N,N-dimethyltryptamine (DMT) is a bioactive indole alkaloid that could greatly benefit from scalable, fermentation-based production for research and pharmaceutical applications. In this study, we reconstructed a two-step bacterial pathway converting L-tryptophan to DMT via tryptamine. This involved combining a pyridoxal 5'-phosphate (PLP)-dependent tryptophan decarboxylase from the bacterium <i>Ruminococcus gnavus</i> (RgnTDC) with an <i>S</i>-adenosyl-L-methionine (SAM)-dependent <i>N</i>-methyltransferase from the cane toad <i>Rhinella marina</i> (RmNMT) in <i>Escherichia coli</i>. We optimised conditions for each step, determining 37 °C (pH 8.0) as the optimal condition for tryptamine production and 25 °C (pH 7.5) for DMT. While PLP supplementation did not raise tryptamine levels, methionine supplementation increased DMT levels by 2.8 times, emphasising the importance of methyl-donor supply. Co-culture and co-expression experiments showed that DMT accumulation depends on sufficient methylation capacity. Increased tryptophan availability led to tryptamine accumulation without a proportional increase in DMT formation, indicating a downstream limitation after decarboxylation. Together with the stimulatory effect of methionine supplementation, this result points to <i>N</i>-methylation and methyl-donor supply as key constraints in this system. In shake-flask cultures, a co-expression strain (TN1) produced 103 mg/L DMT after 48 h in complex medium without direct tryptophan supplementation. To enable growth in a defined medium, we used a workflow involving a tryptophan-enriched supernatant from a <i>Corynebacterium glutamicum</i> tryptophan overproducer, which supported de novo DMT formation at 16 mg/L in defined medium. These findings establish a plasmid-based platform for DMT production with <i>E. coli</i> and identify methyltransferase capacity as a key target for further yield improvements.
Background
The study addresses the need for scalable production of N,N-dimethyltryptamine (DMT), a bioactive indole alkaloid with potential research and pharmaceutical applications. Traditional methods of DMT synthesis are limited by scalability and cost, prompting interest in microbial biosynthesis. This research is significant as it explores a novel bacterial pathway for DMT production, potentially offering a more efficient and sustainable method.
Methods
The researchers reconstructed a two-step pathway in Escherichia coli, using a pyridoxal 5'-phosphate (PLP)-dependent tryptophan decarboxylase from Ruminococcus gnavus and an S-adenosyl-L-methionine (SAM)-dependent N-methyltransferase from Rhinella marina. The study optimized conditions for each enzymatic step and evaluated the impact of methionine supplementation on DMT production. Co-culture and co-expression experiments were conducted to assess the methylation capacity and its effect on DMT accumulation.
Results
The primary finding was that methionine supplementation increased DMT levels by 2.8 times. The co-expression strain TN1 produced 103 mg/L DMT in complex medium after 48 hours. In defined medium, using a tryptophan-enriched supernatant, the system produced 16 mg/L DMT. The study identified methyl-donor supply as a key constraint in the pathway, with increased tryptophan availability leading to tryptamine accumulation but not proportional DMT formation.
Interpretation
The study provides a promising approach for microbial DMT production, highlighting the importance of methylation capacity and methyl-donor supply. While the results are significant for optimizing bacterial production, the clinical relevance remains low as the research is preclinical and conducted in bacterial systems. Further research is needed to translate these findings into practical applications for pharmaceutical production.
Key findings
- 37 °C (pH 8.0) optimal for tryptamine production.
- 25 °C (pH 7.5) optimal for DMT production.
- Methionine supplementation increased DMT levels by 2.8 times.
- Co-expression strain TN1 produced 103 mg/L DMT after 48 hours.
- 16 mg/L DMT produced in defined medium with tryptophan-enriched supernatant.
Limitations
- Conducted in bacterial cultures, not human systems.
- Preclinical study, not directly applicable to clinical settings.
- Focus on bacterial optimization may not translate to pharmaceutical production.
- Methyl-donor supply identified as a constraint.