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Effect of process parameters and surfactant additives on the obtained activity of recombinant tryptophan hydroxylase (TPH1) for enzymatic synthesis of 5-hydroxytryptophan (5-HTP).

Authors :
Vargas MA
Deive FJ
Álvarez MS
Longo MA
Rodríguez A
Bernal C
Martínez R
Source :
Enzyme and microbial technology [Enzyme Microb Technol] 2022 Mar; Vol. 154, pp. 109975. Date of Electronic Publication: 2021 Dec 18.
Publication Year :
2022

Abstract

5-hydroxytryptophan (5-HTP) is an intermediate molecule in the biosynthesis of serotonin, an important neurotransmitter, regulating a series of metabolic and psychological functions in humans. In this work, we studied the heterologous production of Human tryptophan hydroxylase (TPH1) in Escherichia coli, for the synthesis of 5-hydroxytryptophan (5-HTP) from Tryptophan (Trp). To quantify TPH1 activity, a simple fluorescence-based microtiter plate assay was established, based on the changes in fluorescence emission at 340 nm between substrate and product when excited at 310 nm, allowing quick and reliable quantification of released 5-HTP. To increase enzyme production, heterologous TPH1 production was studied in stirred tank bioreactor scale. The effect of rate of aeration (0.25, 0.50 and 0.75 vvm) and agitation (150, 250 and 500 rpm) was evaluated for biomass production, pH, volumetric oxygen transfer coefficient (k <subscript>L</subscript> a) and volumetric TPH1 activity. We determined that high agitation and low aeration allowed reaching the maximum measured enzyme activity. Under such conditions, we observed a 90% substrate conversion, obtaining 90 µM (~0.02 g/L) 5-HTP from a 100 µM Tryptophan substrate solution. Finally, we observed that the addition of Tween 20 (0.1%) in the culture broth under production conditions expanded the pH operation range of TPH1. Our results establish a base for a biocatalytic approach as a potential alternative process for the synthesis of 5-HTP using recombinant TPH1.<br /> (Copyright © 2021 Elsevier Inc. All rights reserved.)

Details

Language :
English
ISSN :
1879-0909
Volume :
154
Database :
MEDLINE
Journal :
Enzyme and microbial technology
Publication Type :
Academic Journal
Accession number :
34952363
Full Text :
https://doi.org/10.1016/j.enzmictec.2021.109975