Journal article
Microbial Synthesis of Human-Hormone Melatonin at Gram Scales
Melatonin is a commercially attractive tryptophan-derived hormone. Here we describe a bioprocess for the production of melatonin using Escherichia coli to high titers. The first engineered strain produced 0.13 g/L of melatonin from tryptophan under fed-batch fermentation conditions. A 4-fold improvement on melatonin titer was further achieved by (1) protein engineering of rate-limiting tryptophan hydroxylase to improve 5-hydroxytryptophan biosynthesis and (2) chromosomal integration of aromatic-amino-acid decarboxylase to limit byproduct formation and to minimize gene toxicity to the host cell.
Fermentation optimization improved melatonin titer by an additional 2-fold. Deletion of yddG, a tryptophan exporter, exhibited an additive beneficial effect. The final engineered strain produced ∼2.0 g/L of melatonin with tryptophan supplemented externally and ∼1.0 g/L with glucose as the sole carbon source for tryptophan supply.
This study lays the foundation for further developing a commercial melatonin-producing E. coli strain.
Language: | English |
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Publisher: | American Chemical Society |
Year: | 2020 |
Pages: | 1240-1245 |
ISSN: | 21615063 |
Types: | Journal article |
DOI: | 10.1021/acssynbio.0c00065 |
ORCIDs: | Luo, Hao , Schneider, Konstantin , Lei, Yang , Herrgard, Markus and Palsson, Bernhard Ø. |
Amino Acid Transport Systems, Neutral Aromatic-L-Amino-Acid Decarboxylases Batch Cell Culture Techniques E. coli Escherichia coli Escherichia coli Proteins Humans Melatonin Protein Engineering Tryptophan Tryptophan Hydroxylase YddG protein, E coli fermentation glucose high titer tryptophan