Table 2.

Fermentative production of ergothioneine in recombinant micro-organisms

Organism	Genetic modification(s)	Titre	Conditions	Reference
Aspergillus oryzae	Expression of egt1 and egt2 genes from Neurospora crassa	231·0 mg/kg of media	Cultivation on solid, rice-based medium	(114)
Escherichi coli	Expression of egtBCDE genes from Mycobacterium smegmatis	24 (sem 4) mg/l (extracellular)	Shake flasks. Medium supplemented with yeast extract, His, Met, 20 mm-thiosulfate as sulfur source for l-cysteine synthesis. IPTG for inducing heterologous gene expression	(115)
Escherichia coli	Expression of the following genes: egtABCDE from M. smegmatis, altered cysE gene encoding serine acetyltransferase feed-back resistant to Cys, native ydeD gene encoding inner membrane Cys exporter, altered serA gene encoding l-serine Feedback inhibition-insensitive mutant of d-3-phosphoglycerate dehydrogenase. Deletion of metJ gene encoding transcriptional repressor	1·3 g/l (extracellular)	Fed-batch in 3-litre bioreactor, 216 h. Complex medium supplemented with IPTG, ammonium ferric citrate, pyridoxine, Met, His, and thiosulfate	(116)
Methylobacterium aquaticum strain 22A	Additional copy of egtBD expressed from a plasmid, deletion of histidine ammonia-lyase (hutH) gene	20 mg/l	Test-tubes. Complex medium with methanol	(113)
Saccharomyces cerevisiae		598 (sd 18) mg/l, of which 59 % was extracellular	Fed-batch fermentation in 1-litre bioreactor, 84 h. Defined medium supplemented with arginine, histidine, methionine and pyridoxine	(570)
Schizosaccahromyces pombe	egt1 overexpression under inducible promoter	368 mg/l	N and glucose starvation. Cultivation method not given	(50)

IPTG, isopropyl β- d-1-thiogalactopyranoside.