Table 4 The system metabolic engineering strategies on tryptophan pathway for the microbial production of aromatic compounds
From: Metabolic engineering of microorganisms for production of aromatic compounds
Product | Precursor | Carbon source | Host | Titer (g/L) | Time (h) | Bioprocess strategy | Systems metabolic engineering strategies | References |
|---|---|---|---|---|---|---|---|---|
Anthranilic acid | CHA | Glucose | E. coli | 14 | 34 | Fed-batch (fermentor, 1Â L) | Random mutagenesis in gene trpD encoding anthranilate phosphoribosyl transferase; Overexpressing following genes encoding feedback resistant DAHP and transketolase | [180] |
Serotonin | l-TRP | Glucose | E. coli | 0.1543 | 24 | Two-step fermentation (fermentor, 1.5Â L) | Introducing gene encoding aromatic amino hydroxylase in one host; Introducing gene encoding tryptophan decarboxylase in tryptophanase knock-out strain | [184] |
Indigo | l-TRP | Glucose | E. coli | 18 | ~ 72 | Fed-batch (fermentor, 14 L) | Introducing gene encoding naphthalene dioxygenase; Common metabolic pathway engineering strategies: knocking-out genes encoding pyruvate kinase I and II, and overexpressing genes feedback resistant DAHP and transketolase | [186] |
Indirubin | l-TRP | Tryptophan | E. coli | 0.2236 | 48Â h | Batch (fermentor, 10Â L) | Integrating novel gene encoding flavin-containing monooxygenase (FMO) from Methylophaga aminisulfidivorans; Investigating the effect of cysteine and oxygen on indirubin synthesis | [188] |
Violacein | l-TRP | Glucose | C. glutamicum | 5.436 | ~ 120 | Fed-batch (fermentor, 3 L) | Introducing vio operon vioABCDE from Chromobacterium violaceum; Replacing RBS in vio genes; Overexpressing them under inducible promoter; Optimizing induction time | [195] |
Deoxy-violacein | l-TRP | Glycerol | E. coli | 1.6 | 200 | Fed-batch (fermentor, 0.7Â L) | Integrating and overexpressing vio operon vioABCE under the control of araBAD promoter; Deleting araBAD gene; Inducing by l-arabinose | [192] |