Loading…

A Novel Two-stage pH Control Strategy for the Production of 5-Aminolevulinic Acid Using Recombinant Streptomyces coelicolor

5-aminolevulinic acid (ALA) has extensive use in photodynamic cancer therapy, tumor diagnosis, and agriculture. In the microbial production of ALA, most efforts have focused on engineering enzymes and the metabolic pathways involved in ALA biosynthesis. The aim of this study was to enhance ALA produ...

Full description

Saved in:
Bibliographic Details
Published in:Biotechnology and bioprocess engineering 2021, 26(4), , pp.669-676
Main Authors: Pham, Diep Ngoc, Kim, Chang-Joon
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:5-aminolevulinic acid (ALA) has extensive use in photodynamic cancer therapy, tumor diagnosis, and agriculture. In the microbial production of ALA, most efforts have focused on engineering enzymes and the metabolic pathways involved in ALA biosynthesis. The aim of this study was to enhance ALA production using recombinant Streptomyces coelicolor expressing the ALA synthase gene (hem A) of Rhodobacter sphaeroides with a novel two-stage pH control strategy. Batch cultures were performed in production medium at different pH values. Although cells grew well at neutral pH (6.8–7.2), the highest amount of ALA was produced with a long culture time (140 h) at a weakly acidic pH (5.5–6.0). In response, a two-stage pH control strategy was developed in which pH was maintained at 6.8–7.2 for cell growth and then shifted to 5.5–6.0 to promote ALA synthesis, resulting in a significant enhancement in ALA production compared to a one-stage pH control strategy. The titer of ALA was further improved up to 482 mg/L in the two-stage pH culture by supplying more glucose in the medium and shifting the pH during the early phase of cultivation.
ISSN:1226-8372
1976-3816
DOI:10.1007/s12257-020-0376-z